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Question 1
Incorrect
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The T-tubular system in cardiac muscle is:
Your Answer: Located at the junction of the a and i zones
Correct Answer: Transmits action potential from sarcolemma to the SR to allow for Ca2+ release into the cytoplasm
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors, which are voltage gated calcium channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 2
Incorrect
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Why does arterial blood pressure drop during pregnancy?
Your Answer: The enlarged uterus leads to inferior vena cava compression
Correct Answer: Progesterone relaxes vascular smooth muscle
Explanation:Progesterone relaxes vascular smooth muscle thus resulting In a decrease in total peripheral resistance. This accounts for the increase in the cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Correct
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Question 4
Incorrect
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The following are examples of the functions of the vascular endothelium except:
Your Answer: Vasomotor control
Correct Answer: Tumour suppression
Explanation:Vascular endothelium has many important functions including regulation of vascular tone, molecular exchange between blood and tissue compartments, hemostasis and signaling for the immune regulation and inflammation. Depending on specific tissue needs and local stresses, endothelial cells are capable of evoking either antithrombotic or prothrombotic events. Tumor suppression is related to genes, or anti-oncogenes, that regulate a cell during cell division and replication.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 5
Incorrect
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Which of the following would be a contraindication to thrombolysis?
Your Answer:
Correct Answer: Intracranial neoplasm
Explanation:Absolute contraindications to thrombolysis include:
- Previous intracranial bleeding at any time
- Stroke in less than 6 months
- Closed head or facial trauma within 3 months
- Suspected aortic dissection
- Ischemic stroke within 3 months (except in ischemic stroke within 3 hours time)
- Active bleeding diathesis
- Uncontrolled high blood pressure (>180 systolic or >100 diastolic)
- Known structural cerebral vascular lesion
- Arterio-venous malformations
- Thrombocytopenia
- Known coagulation disorders
- Aneurysm
- Brain tumours
- Pericardial effusion
- Septic embolus
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Incorrect
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Which one of the following ECG findings is least associated with digoxin use?
Your Answer:
Correct Answer: Prolonged QT interval
Explanation:Digoxin ECG features:•   ST depression (‘reverse tick’)•   flattened/inverted T waves• Prolonged PR interval•   short QT interval•   arrhythmias e.g. AV block, bradycardia, ventricular tachycardia or fibrillation (for example paroxysmal atrial tachycardia with A-V block – so-called PAT with block) is said to be pathognomonic (i.e. diagnostic) of digoxin toxicity.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 7
Incorrect
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The positive inotropic effect of digoxin is due to?
Your Answer:
Correct Answer: Inhibition of the sodium potassium ATPase in the myocardium
Explanation:Digitalis compounds are potent inhibitors of cellular Na+/K+-ATPase. This ion transport system moves sodium ions out of the cell and brings potassium ions into the cell. By inhibiting the Na+/K+-ATPase, cardiac glycosides cause the intracellular sodium concentration to increase. This then leads to an accumulation of intracellular calcium via the Na+/Ca++ exchange system. In the heart, increased intracellular calcium causes more calcium to be released by the sarcoplasmic reticulum, thereby making more calcium available to bind to troponin-C, which increases contractility (inotropy).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 8
Incorrect
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Which of the following are responsible for the 4th heart sound?
Your Answer:
Correct Answer: Ventricular hypertrophy
Explanation:The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Incorrect
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Depolarization spreads rapidly through cardiac muscle fibers because of the presence of:
Your Answer:
Correct Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in between the cells. They allow for the formation of low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 10
Incorrect
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Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme?
Your Answer:
Correct Answer: Guanylyl cyclase
Explanation:Impaired production or excess catabolism of NO impairs this endothelium-dependent vasodilator function and may contribute to excessive vasoconstriction under various pathological situations.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 11
Incorrect
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With regard to the endothelial structure, the epithelium constitute:
Your Answer:
Correct Answer: Simple squamous
Explanation:The single layer of squamous epithelium lining the heart and blood vessels is known as the endothelium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 12
Incorrect
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In the blood supply of the heart, ‘dominance’ refers to the coronary artery which supplies the?
Your Answer:
Correct Answer: Posterior interventricular artery
Explanation:Dominance of the coronary artery system is defined by the artery that gives rise to the posterior interventricular artery. Dominance of the right coronary artery is more common (68%). It gives rise to the large posterior interventricular branch which goes down to the apex of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Incorrect
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Which of the following occurs during a Valsalva manoeuvre?
Your Answer:
Correct Answer: An initial rise in blood pressure
Explanation:The Valsalva maneuver involves forced expiration against a closed glottis. It has several phases, each affecting the cardiovascular system differently:
- Phase I: During the initial forced expiration against the closed glottis, there is a transient rise in intrathoracic pressure, which compresses the thoracic aorta and causes a brief increase in blood pressure.
- Phase II: Continued straining leads to decreased venous return to the heart, reducing cardiac output and causing a drop in blood pressure. This phase is characterized by a compensatory increase in heart rate.
- Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
- Phase IV: Blood pressure then rises rapidly as venous return to the heart is restored, leading to increased cardiac output. This is often followed by a reflex bradycardia (slow heart rate).
Given these phases, the most accurate statement about what occurs during the Valsalva maneuver is the initial rise in blood pressure (Phase I).
Other options explained:
- Forced inspiration against a closed glottis: Incorrect. The Valsalva maneuver involves forced expiration, not inspiration, against a closed glottis.
- Low intrathoracic pressures throughout: Incorrect. The Valsalva maneuver involves high intrathoracic pressures due to forced expiration.
- Disruption of autonomic function: Incorrect. The Valsalva maneuver affects autonomic function but does not disrupt it. Instead, it triggers autonomic responses to changes in blood pressure and heart rate.
- No change: Incorrect. The Valsalva maneuver causes significant changes in blood pressure and heart rate.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 14
Incorrect
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Question 15
Incorrect
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Regarding cardiac muscle contractility, the afterload refers to:
Your Answer:
Correct Answer: The resistance against which blood is expected
Explanation:The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 16
Incorrect
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Which of the following causes an increase in venous return?
Your Answer:
Correct Answer: An increase in the negative intra-thoracic pressure
Explanation:During inspiration, intrathoracic pressure becomes more negative and intra-abdominal pressure more positive. This increases the venous pressure gradient from abdomen to thorax and promotes filling of the central veins.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Incorrect
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Question 18
Incorrect
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What is a characteristic findings on ECG in hyperkalaemia?
Your Answer:
Correct Answer: Tall, tented T waves
Explanation:Hyperkalaemia leads to:
– Prolonged PR interval
– Small P waves
– Tall, tented T waves
– Widened QRS complexes and eventually asystole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Incorrect
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Regarding the length of systole and diastole which of the following is true?
Your Answer:
Correct Answer: The duration of systole is more fixed than diastole
Explanation:The duration of systole is more fixed than the duration of diastole. When the heart rate increases the timing of systole remains more or less the same however, diastole decreases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 20
Incorrect
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Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?
Your Answer:
Correct Answer: Potassium channels
Explanation:Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 21
Incorrect
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If both the noradrenergic and the cholinergic systems are blocked in the heart, the rate will be approximately:
Your Answer:
Correct Answer: 100/min
Explanation:The normal heart beat is about 70/min. This is due to a predominant parasympathetic activity. If sympathetic activity was unopposed the heart rate would have been 150/min. When both the noradrenergic and cholinergic systems are blocked the heart rate is 100/min. This is the normal firing rate of the SA node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 22
Incorrect
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Myocardium requires more oxygen to expel blood in:
Your Answer:
Correct Answer: A stenotic aortic valve
Explanation:In aortic valve stenosis, increased ventricular pressure Is needed to expel the blood into the aorta. Increased pressure means increased contractility hence increase O2 consumption by the heart muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 23
Incorrect
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Water hammer pulse is found in:
Your Answer:
Correct Answer: Aortic insufficiency
Explanation:Watson’s water hammer pulse is the medical sign which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were the sound of a water hammer that was causing the pulse. A water hammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow. This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 24
Incorrect
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In the cardiac cycle, all of the following are true except:
Your Answer:
Correct Answer: Mitral valve is closed by contraction of papillary muscles
Explanation:Mitral valve is closed by contraction of papillary muscles: This statement is incorrect. The mitral valve closes due to the pressure difference between the left ventricle and the left atrium at the onset of ventricular systole. The papillary muscles contract to prevent prolapse of the valve into the atrium but do not cause the valve to close.
The left ventricular volume is maximal at the end of atrial systole: This statement is true. At the end of atrial systole, the atria have pushed the remaining blood into the ventricles, making the ventricular volume maximal (end-diastolic volume).
The left ventricular pressure is maximal just before the aortic valve opens: This statement is true. Left ventricular pressure peaks just before the aortic valve opens, as the ventricle contracts to overcome the pressure in the aorta.
The ejection fraction is about 55%: This statement is true. The ejection fraction, which is the percentage of blood ejected from the ventricles with each contraction, is typically around 55%.
The ‘a’ wave is due to atrial systole: This statement is true. The ‘a’ wave on the venous pressure curve corresponds to atrial systole, reflecting the increased pressure from atrial contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 25
Incorrect
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What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?
Your Answer:
Correct Answer: Gap junctions
Explanation:The cardiac muscles have gap junctions in-between the cells. They form low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 26
Incorrect
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The initial rapid depolarization in the action potential of cardiac muscle cells is due to:
Your Answer:
Correct Answer: Opening of voltage-gated Na+ channels
Explanation:The initial depolarization of the action potential in a cardiac muscle cell is due to the sodium current generated by opening of the voltage gated sodium channels leading to an influx of sodium ions into the cell and raising the membrane potential towards threshold.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 27
Incorrect
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The rate of depolarisation of the sinus node membrane potential is modulated by all the following except:
Your Answer:
Correct Answer: Cardiac output
Explanation:Cardiac output has no effect on the depolarization of the pacemaker potential of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 28
Incorrect
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Which of the following phases in depolarization and repolarization of cardiac muscle cells are caused by the inactivation of Na+ channels?
Your Answer:
Correct Answer: Phase 1 : rapid repolarization
Explanation:Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 29
Incorrect
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Which of the following causes the closure of the ductus arteriosus during birth?
Your Answer:
Correct Answer: Reduced levels of prostaglandins
Explanation:Ductus arteriosus is kept open by the prostaglandin E2 which is a vasodilator. At birth the high levels of cyclooxygenase blocks the production of prostaglandins which results in the closure of the ductus arteriosus.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Incorrect
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Angina pectoris develops when blood through the coronary artery becomes:
Your Answer:
Correct Answer: Restricted, limiting blood blow
Explanation:Angina pectoris develops when stenosis ( >70%) of the artery occurs as a result of formation of an atherosclerotic plaque. This leads to a decrease in the O2 carried to the thickened heart muscle by the blood, leading to the characteristic chest pain associated with angina pectoris.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 31
Incorrect
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The principle by which the energy of contraction is proportional to the initial length of cardiac muscle fiber is known as:
Your Answer:
Correct Answer: Starling’s law
Explanation:The Frank starling relationship describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increase venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and increased development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relation is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 32
Incorrect
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Which factors increase the end-diastolic volume?
Your Answer:
Correct Answer: Constriction of veins
Explanation:End diastolic volume is also known as preload. It is the amount of blood the heart contracts against. Constriction of veins will decrease venous pooling and increase venous return, hence increasing the end diastolic volume. Standing will increase venous pooling hence decreasing venous return and end diastolic volume. Raised intrapericardial pressure will also decrease venous return and hence end diastolic volume.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 33
Incorrect
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Concerning surface anatomy, where is the aortic valve found?
Your Answer:
Correct Answer: Situated in the left third intercostal space underneath the sternum
Explanation:The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 34
Incorrect
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Hyperkalaemia [K+ =7meq/l] can lead to the following ECG changes [Ca++ normal]
Your Answer:
Correct Answer: Peaked T waves
Explanation:Hyperkalaemia causes the formation of tall tented T waves due to altered repolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 35
Incorrect
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In cardiac muscle, which of the following is directly responsible for the release of Ca2+ stored in the sarcoplasmic reticulum (calcium-induced calcium release)?
Your Answer:
Correct Answer: Ryanodine receptor (RyR)
Explanation:Ryanodine receptor (RyR) is a ligand-gated Ca2+ channel with Ca2+ as its natural ligand. In skeletal muscle, Ca2+ entry from ECF by this route is not required for Ca2+ release. Instead, the DHPR that serves as the voltage sensor unlocks release of Ca2+ from the nearby SR via physical interaction with the RyR. The release is amplified through ca-induced ca release. However, in cardiac muscle, it is the influx of extracellular Ca2+ through the voltage-sensitive DHPR in the T system that triggers ca-induced ca release trough the RyR at the SR.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 36
Incorrect
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Which of the following isoforms of Nitric oxide synthase (NOS) is found in endothelial cells?
Your Answer:
Correct Answer: Nos 3
Explanation:There are only 3 isoforms:NOS 1: found in nervous systemNOS 2: in macrophages and other immune cellsNOS 3: In endothelial cells
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 37
Incorrect
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The coronary sinus drains into the:
Your Answer:
Correct Answer: Right atrium
Explanation:The coronary sinus drains into the right atrium. Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 38
Incorrect
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The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?
Your Answer:
Correct Answer: Ca
Explanation:Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 39
Incorrect
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Which heart sounds are matched correctly?
Your Answer:
Correct Answer: All of the above
Explanation:In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds, and gallop rhythms S3 and S4. S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. S4 when audible in an adult is called a presystolic gallop or atrial gallop. This gallop is produced by the sound of blood being forced into a stiff or hypertrophic ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 40
Incorrect
-
What is troponin?
Your Answer:
Correct Answer: A component of thin filaments
Explanation:Skeletal muscle cytoplasmic proteins include myosin and actin (also known as thick and thin filaments, respectively) which are arranged in a repeating unit called a sarcomere. Troponin is a component of thin filaments (along with tropomyosin), and is the protein to which calcium binds.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 41
Incorrect
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Arterioles stemming from the coronary artery can also empty into the heart directly via the:
Your Answer:
Correct Answer: Arteriosinusoidal vessels
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers. They include arteriosinusoidal vessels, which connect the arterioles to the heart chambers. The thebesian veins drain the capillaries into the chambers and the arterioluminal vessels drain small arteries directly into the chambers.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 42
Incorrect
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Question 43
Incorrect
-
Select the correct statement regarding the 4th heart sound, it?
Your Answer:
Correct Answer: Can be heard in atrial systole.
Explanation:The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle by atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 44
Incorrect
-
Concerning surface anatomy, where is the apex beat found?
Your Answer:
Correct Answer: 5th intercostal space mid clavicular line
Explanation:The location of the apex beat may vary but it is mostly found in the left 5th intercostal space 6 cm from the anterior median line or in the mid clavicular line.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 45
Incorrect
-
Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by binding of which molecule to the exposed site on the myosin.
Your Answer:
Correct Answer: ATP
Explanation:A crossbridge is a myosin projection, consisting of two myosin heads, that extends from the thick filaments. Each myosin head has two binding sites: one for ATP and another for actin. The binding of ATP to a myosin head detaches myosin from actin, thereby allowing myosin to bind to another actin molecule. Once attached, the ATP is hydrolysed by myosin, which uses the released energy to move into the cocked position whereby it binds weakly to a part of the actin binding site.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 46
Incorrect
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Which of the following concerning PR interval is INCORRECT?
Your Answer:
Correct Answer: Always measured from the beginning of p wave to the beginning of r wave
Explanation:The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization. The PR interval is only measured from the beginning of P wave to beginning of R wave if the Q wave is absent.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 47
Incorrect
-
The interventricular septum is supplied anteriorly by the?
Your Answer:
Correct Answer: Left anterior descending artery
Explanation:The anterior interventricular artery or left anterior descending artery supplies the anterior 2/3rds of the interventricular septum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 48
Incorrect
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Which one of the following is a risk factor for torsade de pointes?
Your Answer:
Correct Answer: Hypothermia
Explanation:The following is a list of factors associated with an increased tendency toward torsades de pointes:- Hypokalaemia (low blood potassium)- Hypomagnesemia (low blood magnesium)- Hypocalcaemia (low blood calcium)- Bradycardia (slow heartbeat)- Heart failure- Left ventricular hypertrophy- Hypothermia- Subarachnoid haemorrhage- Hypothyroidism
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 49
Incorrect
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The postextrasystolic potentiation of myocardial contractility is due to:
Your Answer:
Correct Answer: Increase in intracellular Ca2+
Explanation:The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 50
Incorrect
-
Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s syndrome?
Your Answer:
Correct Answer: Aortic aneurysm
Explanation:Marfan syndrome (MFS) is a genetic disorder of connective tissue. The degree to which people are affected varies. People with Marfan’s tend to be tall, and thin, with long arms, legs, fingers and toes. They also typically have flexible joints and scoliosis. The most serious complications involve the heart and aorta with an increased risk of mitral valve prolapse and aortic aneurysm.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 51
Incorrect
-
The Wiebel-Palade body found in the endothelial cells is responsible for the production and release of which factor?
Your Answer:
Correct Answer: Von Willebrand factor
Explanation:Weibel-Palade bodies are the storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and heart. They store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in haemostasis and inflammation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 52
Incorrect
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Question 53
Incorrect
-
The amount of a substance taken up by an organ (or whole body) per unit time is = (the arterial level - the venous level) * the blood flow. This statement describes?
Your Answer:
Correct Answer: The Fick principle
Explanation:The essence of the Fick principle is that blood flow to an organ can be calculated using a marker substance if the following information is known:- Amount of marker substance taken up by the organ per unit time- Concentration of marker substance in arterial blood supplying the organ- Concentration of marker substance in venous blood leaving the organ
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 54
Incorrect
-
Which statement about the 2nd heart sound is true?
Your Answer:
Correct Answer: It is caused by closure of the aortic and pulmonary valves.
Explanation:The second heart sound is produced due to closure of the aortic and pulmonary valves. It is a high pitched dub sound.
Normally the aortic closure sound (A2) occurs prior to the pulmonic closure sound (P2), and the interval between the two (splitting) widens on inspiration and narrows on expiration. With quiet respiration, A2 will normally precede P2 by 0.02 to 0.08 second (mean, 0.03 to 0.04 sec) with inspiration. In younger subjects inspiratory splitting averages 0.04 to 0.05 second during quiet respiration. With expiration, A2 and P2 may be superimposed and are rarely split as much as 0.04 second. If the second sound is split by greater than 0.04 second on expiration, it is usually abnormal. Therefore, the presence of audible splitting during expiration (i.e., the ability to hear two distinct sounds during expiration) is of greater significance at the bedside in identifying underlying cardiac pathology than is the absolute inspiratory increase in the A2–P2 interval.
The respiratory variation of the second heart sound can be categorized as follows: (1) normal (physiologic) splitting; (2) persistent (audible expiratory) splitting, with normal respiratory variation; (3) persistent splitting without respiratory variation (fixed splitting); and (4) reversed (paradoxical) splitting.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 55
Incorrect
-
Impulse conduction through the AV node is slow and depends on the action potential produced by which of the following.
Your Answer:
Correct Answer: Calcium flux
Explanation:The action potentials in the SA and AV nodes are largely due to Ca2+, with no contribution by Na+ influx.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 56
Incorrect
-
What are the diagnostic criteria for an ST segment elevation type of acute myocardial infarction?
Your Answer:
Correct Answer: 1 mm ST elevation in 2 limb leads
Explanation:The current guidelines for the ECG diagnosis of the ST segment elevation type of acute myocardial infarction require at least 1 mm (0.1 mV) of ST segment elevation in the limb leads, and at least 2 mm elevation in the precordial leads. These elevations must be present in anatomically contiguous leads. (I, aVL, V5, V6 correspond to the lateral wall; V3-V4 correspond to the anterior wall ; V1-V2 correspond to the septal wall; II, III, aVF correspond to the inferior wall.)
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 57
Incorrect
-
Calcium needed for cardiac muscle contraction is made available during which phase of the action potential?
Your Answer:
Correct Answer: 2
Explanation:It is made available during the plateau phase of the action potential i.e. phase 2. During the plateau phase of the action potential, Calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 58
Incorrect
-
Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?
Your Answer:
Correct Answer: Troponin c
Explanation:Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 59
Incorrect
-
Regarding blood supply to the heart;
Your Answer:
Correct Answer: Coronary arteries fill as the heart relaxes
Explanation:The heart muscles acts like the skeletal muscle in the fact that it also compress the vessels during contraction. As the pressure in the ventricle is slightly greater than in the aorta the coronary vessels collapse during systole. Blood flows through them during the diastole phase of contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 60
Incorrect
-
According to Starling's law of the heart:
Your Answer:
Correct Answer: The extent of the preload is proportional to the end-diastolic volume
Explanation:Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 61
Incorrect
-
AV valves open during?
Your Answer:
Correct Answer: Early diastole
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 62
Incorrect
-
Most of the venous blood returns to the heart through the:
Your Answer:
Correct Answer: Coronary sinus and anterior cardiac veins
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins which drain into the right atrium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 63
Incorrect
-
With regards to the cardiac cycle which of the following is true
Your Answer:
Correct Answer: Right atrial systole occurs before left atrial systole: as below
Explanation:Cardiac cycle: The first event in the cycle is atrial depolarization (a P wave on the surface ECG) follows by RIGHT ATRIAL and then LEFT ATRIAL contraction. Ventricular activation (QRS) follows after a short interval (the PR interval). LEFT VENTRICULAR contraction starts shortly thereafter RIGHT VENTRICULAR contraction begins. At the end, the aortic valve closure is followed by pulmonary valve closure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 64
Incorrect
-
The effects of β1 stimulation include the following
Your Answer:
Correct Answer: Increased strength of contraction
Explanation:β1 stimulation include the phosphorylation of L type Ca++ channels and phospholamban and increased Ca++ influx from myocytes.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 65
Incorrect
-
Question 66
Incorrect
-
The following products of the vascular endothelium produce vasodilation except:
Your Answer:
Correct Answer: Endothelin
Explanation:Endothelin: This is incorrect in the context of vasodilation. Endothelin is actually a potent vasoconstrictor produced by the endothelium, leading to the narrowing of blood vessels and increased blood pressure.
Nitrous oxide (Nitric oxide): This is correct for vasodilation. Nitric oxide is a powerful vasodilator produced by the endothelium, which helps relax and widen blood vessels.
Prostacyclin: This is correct for vasodilation. Prostacyclin (PGI2) is a vasodilator and inhibits platelet aggregation, helping to maintain blood flow and reduce clot formation.
Endothelial-derived hyperpolarizing factor (EDHF): This is correct for vasodilation. EDHF causes vasodilation by hyperpolarizing the smooth muscle cells of blood vessels.
Vascular endothelial growth factor (VEGF): This is correct for vasodilation. VEGF primarily promotes the growth of new blood vessels but also has vasodilatory effects through nitric oxide production.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 67
Incorrect
-
Absolute refractory period in a cardiac action potential graph occurs during.
Your Answer:
Correct Answer: All of the above
Explanation:Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 68
Incorrect
-
During which phase of the cardiac cycle does most of the ventricular filling occur?
Your Answer:
Correct Answer: Ventricular diastole
Explanation:During the phase of ventricular diastole when the heart muscle relaxes and all the valves are open, blood flows easily into the heart. This is the phase of rapid ventricular filling. During isovolumetric contraction and relaxation the volume of blood in the heart does not change. During ventricular ejection blood enters into the aorta and pulmonary vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 69
Incorrect
-
Which of the following regulates the calcium release channels?
Your Answer:
Correct Answer: Calstabin 2
Explanation:Ca2+ is released from the SR through a Ca2+ release channel, a cardiac isoform of the ryanodine receptor (RyR2), which controls intracytoplasmic [Ca2+] and, as in vascular smooth-muscle cells, leads to the local changes in intracellular [Ca2+] called calcium sparks. A number of regulatory proteins, including calstabin 2, inhibit RyR2 and, thereby, the release of Ca2+ from the SR.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 70
Incorrect
-
Question 71
Incorrect
-
Which of the following statements is true regarding pulsus alternans?
Your Answer:
Correct Answer: It is found in association with a third heart sound
Explanation:Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis. A pathological third heart sound is usually associated.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 72
Incorrect
-
A 27-year-old man presents with a regular tachycardia of 190 bpm. He is healthy and has no past medical history. Blood pressure and blood tests are all within normal parameters however the ECG confirms a narrow complex tachycardia. The tachycardia persists after giving IV adenosine 6mg. What should be the next step in management of this patient?
Your Answer:
Correct Answer: IV 12mg adenosine
Explanation:For narrow complex tachycardias with no compromise then vagal manoeuvres should be trialled first. The Valsalva manoeuvre should be the first vagal manoeuvre tried and works by increasing intra-thoracic pressure and affecting baroreceptors (pressure sensors) within the arch of the aorta. It is carried out by asking the patient to hold his/her breath while trying to exhale forcibly as if straining during a bowel movement. Adenosine, an ultra-short-acting AV nodal blocking agent, is indicated if vagal manoeuvres are not effective. Adenosine may be safely used during pregnancy. In adults the recommended first dose of intravenous adenosine is 6 mg. The dose is administered rapidly and then followed by a saline flush. Adenosine is only present in the circulation for about 5 seconds, so it is an excellent drug for diagnosis and treatment. If there was a response to adenosine but it was not long lasting, an additional dose of 12 mg of adenosine intravenously can be attempted. Doses greater than 12 mg are not recommended. If adenosine fails then Verapamil or a beta blocker can be used as alternatives. If the patient is hemodynamically unstable or other treatments have not been effective, synchronized electrical cardioversion may be used.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 73
Incorrect
-
Question 74
Incorrect
-
How does pregnancy affect the cardiac output of a patient?
Your Answer:
Correct Answer: Increased cardiac output due to increase in heart rate and stroke volume
Explanation:Cardiac Output increases to a similar degree as the blood volume. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state. Steady rises are shown on Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 75
Incorrect
-
The following is true in relation to coronary venous drainage?
Your Answer:
Correct Answer: Most venous return ultimately drains into right atrium via the coronary sinus
Explanation:Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 76
Incorrect
-
The major factor in controlling coronary artery blood flow is considered to be?
Your Answer:
Correct Answer: Metabolites of oxygen consumption
Explanation:There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 77
Incorrect
-
In a 30 year old male with hypertrophic obstructive cardiomyopathy (HOCM), which of the following is not associated with increased risk of sudden death?
Your Answer:
Correct Answer: Age
Explanation:Hypertrophic cardiomyopathy (HCM) is a disease in which a portion of the myocardium (heart muscle) is enlarged without any obvious cause, creating functional impairment of the heart. It is the leading cause of sudden death in young athletes. The major risk factors for sudden death (SD) are recent unexplained syncope unlikely to be neurocardiogenic; HCM-related SD in first-degree or other close relatives; repetitive and/or prolonged nonsustained ventricular tachycardia (NSVT) episodes on Holter or extended ambulatory monitoring; massive left ventricular hypertrophy (LVH) (wall thickness ≥30 mm); extensive/diffuse late gadolinium enhancement (LGE); end-stage heart failure usually with systolic dysfunction; and thin-walled akinetic LV apical aneurysm with regional scarring.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 78
Incorrect
-
Tunica intima is made up of?
Your Answer:
Correct Answer: Endothelial cells
Explanation:Tunica intima is a single cell thick lining of endothelial cells that lines the inside of the blood vessels. It is the inner most layer of the blood vessel.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 79
Incorrect
-
Troponin I is inhibited by calcium binding to:
Your Answer:
Correct Answer: Troponin c
Explanation:At rest troponin I is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin I which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 80
Incorrect
-
The Sinoatrial node in the majority of people is supplied by the?
Your Answer:
Correct Answer: Right coronary artery
Explanation:In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 81
Incorrect
-
Factors influencing cardiac output include which of the following?
Your Answer:
Correct Answer: All of the above
Explanation:There is a correlation between resting CO and body surface area. The output per min per square meter of body surface (the cardiac index) averages 3.2l.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 82
Incorrect
-
Which of the following best describes the cardiac muscle?
Your Answer:
Correct Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 83
Incorrect
-
Where would one normally find venous valves?
Your Answer:
Correct Answer: Saphenous vein
Explanation:The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 84
Incorrect
-
In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should be made at:
Your Answer:
Correct Answer: 200 J
Explanation:Defibrillation is a common treatment for life-threatening cardiac dysrhythmias and ventricular fibrillation. If the patient is in Ventricular tachycardia (VT) or ventricular fibrillation (VF) on the monitor, immediately apply the pads and shock the patient with 120-200 Joules on a biphasic defibrillator or 360 Joules on a monophasic defibrillator.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 85
Incorrect
-
Afferent fibers from the baroreceptors of the great arteries form branches of which cranial nerves?
Your Answer:
Correct Answer: Glossopharyngeal and vagus nerves
Explanation:The receptors of the carotid sinus are innervated by the carotid sinus nerve, a branch of the glossopharyngeal nerve. The aortic arch receptors located in the arch of the aorta are innervated by the aortic depressor nerve, a branch of the vagus nerve.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 86
Incorrect
-
Question 87
Incorrect
-
Coronary flow is reduced during
Your Answer:
Correct Answer: Tachycardia
Explanation:Maximum amount of blood flow in the coronary arteries occur during diastole. When the heart rate increases which is also called tachycardia the duration of diastole decreases. Hence the amount of blood flow to the cardiac muscle also decreases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 88
Incorrect
-
The branche(s) of the left coronary artery include:
Your Answer:
Correct Answer: Left circumflex artery & anterior interventricular artery
Explanation:The left main coronary divides into branches:
1. The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart.
2. The circumflex artery branches off the left coronary artery and encircles the heart muscle.
The anterior interventricular artery is otherwise known as the anterior descending branch. The posterior descending artery comes from Right coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 89
Incorrect
-
Which of the following is NOT true of the parasympathetic control of the heart?
Your Answer:
Correct Answer: It can be blocked by beta blockers
Explanation:Parasympathetic fibers do not innervate the Beta receptors on the heart. They are innervated by the sympathetic nerve fibers. Then a beta blocker such as propranolol will block the sympathetic outflow and increase the parasympathetic tone of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 90
Incorrect
-
Which of the following conditions has no effect on cardiac output?
Your Answer:
Correct Answer: Sleep
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 91
Incorrect
-
Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your Answer:
Correct Answer: Inhibiting the breakdown cAMP
Explanation:Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contraction.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 92
Incorrect
-
In the Fick‘s method of measuring cardiac output, the arterial oxygen content can be measured in a sample obtained from
Your Answer:
Correct Answer: The pulmonary vein
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Note that (Ca – Cv) is also known as the arteriovenous oxygen difference.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 93
Incorrect
-
The a-wave is created by:
Your Answer:
Correct Answer: Regurgitation of some blood to the great veins when the atria contracts in atrial systole
Explanation:The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 94
Incorrect
-
Which factor produced by the endothelium is responsible for the regulation of vascular cell growth?
Your Answer:
Correct Answer: Vascular endothelial growth factor (VEGF)
Explanation:VEGF is produced by the endothelial cells and is the major growth factor responsible for causing vasculogenesis. Some isoforms of this growth factor also have a prominent role in formation of lymphatic vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 95
Incorrect
-
Which is the most common site for primary cardiac tumours to occur in adults?
Your Answer:
Correct Answer: Left atrium
Explanation:Myxomas are the most common type of primary heart tumour. The tumour is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction. About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 96
Incorrect
-
According to Poiseuille’s formula, which 1 of the following will lead to increased flow?
Your Answer:
Correct Answer: Shorter tube
Explanation:V = π p r4 / 8 η lwhere V = discharge volume flow (m3/s)p = pressure difference between the ends of the pipe (N/m2, Pa)r = internal radius of pipe (m)l = length of pipe (m)η = viscosity of fluid
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 97
Incorrect
-
The approximate incidence of deep venous thrombosis (DVT) in the general population each year is:
Your Answer:
Correct Answer: 1 per 1000
Explanation:About 1 in 1000 adults per year has DVT, but as of 2011, available data is dominated by North American and European populations. DVT is rare in children, with an incidence of about 1 in 100,000 a year. From childhood to old age, incidence increases by a factor of about 1000, with almost 1% of the elderly experiencing DVTs yearly.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 98
Incorrect
-
Which of the following is true of the Natriuretic hormones?
Your Answer:
Correct Answer: They are released in response to hypervolemia
Explanation:Natriuretic hormones are vasodilators released in response to hypervolemia.
Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.
Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Â Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.
Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.
C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 99
Incorrect
-
Coronary arteries fill up during
Your Answer:
Correct Answer: Diastole
Explanation:During contraction of the ventricular myocardium (systole), the subendocardial coronary vessels (the vessels that enter the myocardium) are compressed due to the high ventricular pressures. This compression results in momentary retrograde blood flow (i.e., blood flows backward toward the aorta) which further inhibits perfusion of myocardium during systole. However, the epicardial coronary vessels (the vessels that run along the outer surface of the heart) remain open. Because of this, blood flow in the sub endocardium stops during ventricular contraction. As a result, most myocardial perfusion occurs during heart relaxation (diastole) when the subendocardial coronary vessels are open and under lower pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 100
Incorrect
-
What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?
Your Answer:
Correct Answer: To detect hypokalaemia
Explanation:All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 101
Incorrect
-
Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors
Your Answer:
Correct Answer: Ryanodine receptors
Explanation:Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 102
Incorrect
-
When looking at the JVP what does the c wave signify:
Your Answer:
Correct Answer: Isovolumetric ventricular contraction
Explanation:The C wave signifies a rise in the atrial pressure during isovolumetric contraction due to the tricuspid valve bulging into the atria.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 103
Incorrect
-
Regarding the surface anatomy of the orifices of the heart, where is the aortic valve located?
Your Answer:
Correct Answer: Opposite the left 3rd intercostal space to the left of the sternum
Explanation:The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 104
Incorrect
-
Which of the following is NOT an effect of a positive inotropic agent on the heart?
Your Answer:
Correct Answer: It decreases the rate of rise in ventricular blood pressure during systole
Explanation:Inotropic agents increase the contractility of the heart as well as the rate of rise in ventricular blood pressure during systole, generating a greater pressure and increasing the stroke volume e.g. like catecholamines do.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 105
Incorrect
-
Which of the following results in the resting membrane potential of a myocyte?
Your Answer:
Correct Answer: Activation of outward K+ channels
Explanation:Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 106
Incorrect
-
The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:
Your Answer:
Correct Answer: Pace maker potential
Explanation:Rhythmically discharging cells have a membrane potential that, after each impulse, declines to the firing level. Thus this prepotential or Pacemaker potential triggers the next impulse. The inherent leakiness of the sinus nodal fibers to Na+ and Ca2+ causes their self excitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 107
Incorrect
-
Regarding cardiac contractility, catecholamines exert their inotropic effect via:
Your Answer:
Correct Answer: Î’1-adrenergic receptors and gs
Explanation:Catecholamines exert their inotropic effect on the heart via the B1 adrenergic receptors and Gs, stimulating adenyl cyclase and increasing the production of cAMP.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 108
Incorrect
-
Regarding cardiac output, an increased ejection fraction results from increases in which of the following?
Your Answer:
Correct Answer: Strength of contraction without increase in muscle fiber length
Explanation:When the strength of contraction increases without an increase in fiber length, the EF increases.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 109
Incorrect
-
Which of the following is the most common causative organism in infective endocarditis?
Your Answer:
Correct Answer: Streptococcus viridans
Explanation:Viridans Alpha-haemolytic streptococci, that are present in the mouth are the most frequently isolated microorganisms when the infection is acquired in a community setting. In contrast, Staphylococcus blood stream infections are frequently acquired in a health care setting where they can enter the blood stream through procedures that cause break in the integrity of skin like surgery, catheterisation or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs.Prosthetic valve endocarditis is commonly caused by Staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 110
Incorrect
-
Question 111
Incorrect
-
Which of the following has the shortest duration:
Your Answer:
Correct Answer: Atrial systole
Explanation:Atrial systole: 0.1s
Atrial diastole: around 0.4s
Ventricular diastole: 0.4-0.53s
Ventricular systole: 0.27s
PR interval: 0.12-0.2 s
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 112
Incorrect
-
Initial depolarization of cardiac muscle is due to influx of:
Your Answer:
Correct Answer: Na+
Explanation:Initial depolarization of the cardiac muscle results from opening of the sodium voltage gated channels. This results in the influx of sodium and an increase in the membrane potential towards threshold. Potassium efflux results in repolarization.
The cardiac action potential has 5 phases:
- Phase 0—depolarization because of the opening of fast sodium channels. Potassium flux also decreases.
- Phase 1—partial repolarization because of a rapid decrease in sodium ion passage as fast sodium channels close.
- Phase 2—plateau phase in which the movement of calcium ions out of the cell, maintains depolarization.
- Phase 3—repolarization, sodium, and calcium channels all close and membrane potential returns to baseline.
- Phase 4—resting membrane potential (−90 mV), resulting from the activity of the Na+/K+ ATPase pump which creates a negative intracellular potential because of the exchange of three sodium ions for only two potassium ions.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 113
Incorrect
-
The following contributes to the rate of depolarization?
Your Answer:
Correct Answer: All of the options given
Explanation:Depolarization occurs due to impulses generated by the SA node. As the heart beats to the rhythm of the SA node, certain factors will effect the rate of depolarization. All the mentioned options effect the rate of depolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 114
Incorrect
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Question 115
Incorrect
-
Which one of the following have not been shown to improve mortality in patients with chronic heart failure?
Your Answer:
Correct Answer: Furosemide
Explanation:A number of drugs have been shown to improve mortality in patients with chronic heart failure:
- ACE inhibitors (SAVE, SOLVD, CONSENSUS)
- spironolactone (RALES)
- beta-blockers (CIBIS)
- hydralazine with nitrates (VHEFT-1)
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 116
Incorrect
-
Activation of nitric oxide synthesis by endothelial cells is triggered by:
Your Answer:
Correct Answer: All of the above
Explanation:Acetylcholine, histamine, bradykinin, vasoactive intestinal peptide (VIP) and shear stress on the endothelial cells causing the release of NO. NO is formed from arginine and causes vasodilatation of the blood vessels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 117
Incorrect
-
Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?
Your Answer:
Correct Answer: Displaced apex beat
Explanation:Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 118
Incorrect
-
The ‘c’ wave in JVP corresponds more closely with:
Your Answer:
Correct Answer: Isovolumetric contraction
Explanation:The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections (peaks) and two downward deflections (troughs) have been described:The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 119
Incorrect
-
The posterior aspect of the interventricular septum is supplied by:
Your Answer:
Correct Answer: A branch of the right coronary artery
Explanation:The posterior aspect of the heart is supplied by the posterior interventricular artery which is a branch of the right coronary artery.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 120
Incorrect
-
Coronary blood flow occurs in?
Your Answer:
Correct Answer: Diastole
Explanation:Coronary arteries are unique in that they fill during diastole, when not occluded by valve cusps nor compressed by myocardial contraction).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 121
Incorrect
-
The hyperpolarization phase of pacemaker cells is dominated by ____ current.
Your Answer:
Correct Answer: K+
Explanation:The hyperpolarization phase is a continuation of the repolarization phase but the membrane potential dips below the resting membrane potential. This results due to the fact that the K+ channels take a longer time to close than the Na+ channels. Hence efflux of the K+ will result in hyperpolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 122
Incorrect
-
The coronary arteries fill during?
Your Answer:
Correct Answer: Diastole
Explanation:During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 123
Incorrect
-
Which one of the following is a cause of a soft second heart sound?
Your Answer:
Correct Answer: Aortic stenosis
Explanation:Second heart sound (S2) forms the dub of lub-dub and is composed of components A2 and P2. •   loud: hypertension•   soft: AS•   fixed split: physiological split (normally occurs during inhalation), right bundle branch block, pulmonary stenosis, and atrial septal defect.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 124
Incorrect
-
The triangle with the heart at its centre, using limb leads is called:
Your Answer:
Correct Answer: Einthoven
Explanation:The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 125
Incorrect
-
Which of the following does not contribute to increased stroke volume during exercise?
Your Answer:
Correct Answer: Increased length of filling time during diastole
Explanation:Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 126
Incorrect
-
Which of the following does not lower ventricular rate in atrial fibrillation?
Your Answer:
Correct Answer: Adrenaline
Explanation:Adrenaline is a sympathetic neurotransmitter which increases the heart rate. During atrial fibrillation the atria is contracting at more than 200 beats/min. Acetylcholine is a parasympathetic neurotransmitter decreasing the heart rate. Digital also depresses the conduction at the AV conduction. Vagal discharge and occulocardiac reflux decrease the heart rate and convert the tachycardia into normal sinus rhythm.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 127
Incorrect
-
When is the blood pressure at its lowest during pregnancy?
Your Answer:
Correct Answer: Second trimester
Explanation:It is lowest during the second trimester.
Previous studies have reported changes in blood pressure (BP) throughout pregnancy, and it was generally accepted that in clinically healthy pregnant women, BP falls gradually at first trimester, reaching the lowest around 22–24 weeks, rising again from 28 weeks, and reaching preconception levels by 36 weeks of gestation
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 128
Incorrect
-
Question 129
Incorrect
-
When observing a JVP, which of the following would lead to prominent v waves?
Your Answer:
Correct Answer: Tricuspid regurgitation
Explanation:The v wave corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return. In Tricuspid regurgitation there is additional blood from the regurgitant flow and thus this leads to a more prominent V wave.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 130
Incorrect
-
Which of the following is NOT associated with the development of aortic regurgitation?
Your Answer:
Correct Answer: Dilated cardiomyopathy
Explanation:Aortic insufficiency, is often due to the aortic root dilation, which is idiopathic in over 80% of cases, but otherwise may result from aging, syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Bechet’s disease, reactive arthritis and systemic hypertension. Additionally, aortic insufficiency has been linked to the use of some medications and other potential causes that affect the valve directly including Marfan’s syndrome, Ehlers–Danlos syndrome, ankylosing spondylitis, and systemic lupus erythematosus. In acute cases of aortic insufficiency, the main causes are infective endocarditis, aortic dissection or trauma. Dilated cardiomyopathy is associated with the development of mitral regurgitation, not aortic regurgitation
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 131
Incorrect
-
A sarcomere is the area between:
Your Answer:
Correct Answer: Two adjacent z lines
Explanation:The area that lies between the two adjacent Z lines is known as a sarcomere and is the contractile unit of the muscle. The line passing in the middle of the myosin filaments is the M line. It also passes through the middle of the sarcomere.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 132
Incorrect
-
All valves are closed in which phase of the cardiac cycle?
Your Answer:
Correct Answer: Isovolumetric relaxation
Explanation:The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 133
Incorrect
-
Endothelial cells are attached to adjacent cells by adherent junctions via:
Your Answer:
Correct Answer: Cadherins
Explanation:Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 134
Incorrect
-
The bradycardia that occurs in patients with raised intracranial pressure is a result of the?
Your Answer:
Correct Answer: Cushing reflex
Explanation:When intracranial pressure is increased, the blood supply to RVLM neurons is compromised. This results in an increase in their discharge as a result of hypoxia and hypercapnia. The resultant rise in systemic arterial pressure (Cushing reflex) tends to restore the blood flow to the medulla.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 135
Incorrect
-
Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:
Your Answer:
Correct Answer: Weakening of the troponin i interaction with actin
Explanation:At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 136
Incorrect
-
Question 137
Incorrect
-
Digoxin causes:
Your Answer:
Correct Answer: Increase in cytosolic calcium concentration
Explanation:Digoxin is a positive inotrope which inhibits NA/K ATPase, increases cardiac contractility and can cause hypokalaemia.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 138
Incorrect
-
Stimulation of the carotid sinus results in:
Your Answer:
Correct Answer: Drop in blood pressure
Explanation:Stimulation of the carotid sinus will result in an increase in the baroreceptor discharge. This will travel via the afferent nerves to the medulla. Signals will pass through the vagus nerve to decrease the sympathetic outflow to the heart and the blood vessels. This inhibition will result in vasodilation of the blood vessels, venodilation and bradycardia hence decreasing the total peripheral resistance and lowering the blood pressure.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 139
Incorrect
-
B1 adrenergic stimulation produces:
Your Answer:
Correct Answer: Increase in calcium cytosolic concentration
Explanation:Norepinephrine secreted by the sympathetic endings binds to B1 receptors, and the resulting increase in intracellular cAMP facilitates the opening of L channels, increasing Ica and the rapidity of the depolarization phase of the impulse and activates PKA which leads to phosphorylation of the voltage-gated Ca2+ channels, causing them to spend more time in the open state.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 140
Incorrect
-
Where does the SA node develop?
Your Answer:
Correct Answer: From structures on the right side of the embryo.
Explanation:The SA node develops from the right side of the embryo and the AV node from the left. This is the reason why in adults the right vagus supplies the SA node and the left vagus supplies the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 141
Incorrect
-
Question 142
Incorrect
-
Which of the following components regulate cardiac output?
Your Answer:
Correct Answer: All of the above
Explanation:Cardiac output is regulated by the autonomic nervous system with sympathetic nerves having a positive chronotropic and inotropic effect and parasympathetic nerves having the opposite effect. An increase in preload will increase cardiac output likewise an afterload increase will also increase cardiac output.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 143
Incorrect
-
Question 144
Incorrect
-
Which coronary artery supplies the right atria?
Your Answer:
Correct Answer: Right coronary
Explanation:The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 145
Incorrect
-
Which of the following is a method for measurement of cardiac output?
Your Answer:
Correct Answer: Indicator dilution method
Explanation:There are two methods of calculating the cardiac output in humans other than doppler with echocardiography: The direct Fick’s method and the indicator dilution method. In the indicator dilution technique, a known amount of a substance such as a dye or, more commonly, a radioactive isotope is injected into an arm vein and the concentration of the indicator in serial samples of arterial blood is determined. The output of the heart is equal to the amount of indicator injected divided by its average concentration in arterial blood after a single circulation through the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 146
Incorrect
-
Direct conduction from the atrium to the ventricles is prevented by:
Your Answer:
Correct Answer: Annulus fibrosus
Explanation:The annulus fibrosus disconnects the syncytium complex. The atria are rapidly activated however the activation peters out when the insulating layer-the annulus fibrosus-is reached.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 147
Incorrect
-
The direct determinants of cardiac output are
Your Answer:
Correct Answer: Stroke volume and heart rate
Explanation:Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:Cardiac Output [L/min] = Stroke Volume [L/beat] x Heart Rate [beats/min]
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 148
Incorrect
-
What is the function of the BK channel on the vascular smooth muscle membrane?
Your Answer:
Correct Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel
Explanation:BK channels, also known as large-conductance calcium-activated potassium channels, play a critical role in regulating vascular smooth muscle tone. When BK channels open, they allow a large efflux of potassium ions (K+) out of the cell. This efflux of K+ causes the membrane potential to become more negative (hyperpolarization), which in turn leads to the closure of voltage-gated calcium channels. The closure of these calcium channels reduces the influx of calcium ions (Ca2+) into the smooth muscle cells, resulting in decreased intracellular calcium levels and subsequent relaxation of the smooth muscle.
Thus, BK channels promote smooth muscle relaxation by hyperpolarizing the membrane and reducing the activity of voltage-gated Ca2+ channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 149
Incorrect
-
Concerning surface anatomy, where is the mitral valve found?
Your Answer:
Correct Answer: Situated in the 4th intercostal space to the left of the sternum
Explanation:The mitral valve is situated in the left 4th intercostal space just beneath the sternum.
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This question is part of the following fields:
- Cardiovascular
- Medicine
-
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Question 150
Incorrect
-
Which of the following is true with AV nodal delay?
Your Answer:
Correct Answer: Shortened by sympathetic stimulation
Explanation:AV nodal delay Is about 0.1s before the action potential spreads to the ventricles. It is shortened by stimulation of the sympathetic nervous system and lengthened by stimulation of the parasympathetic system.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
