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  • Question 1 - How does pregnancy affect the cardiac output of a patient? ...

    Incorrect

    • How does pregnancy affect the cardiac output of a patient?

      Your Answer: Increased cardiac output due to increase in stroke volume, whilst the heart rate remains unchanged

      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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.3
      Seconds

  • Question 2 - Endothelial cells produce the following substance(s): ...

    Incorrect

    • Endothelial cells produce the following substance(s):

      Your Answer: Nitric oxide

      Correct Answer: All of the above

      Explanation:

      Endothelial cells produce thromboxane, prostacyclins, nitric oxides, endothelins, IL-1 and TNF.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.3
      Seconds

  • Question 3 - Which of the following factors serve to decrease cardiac output? ...

    Correct

    • Which of the following factors serve to decrease cardiac output?

      Your Answer: Standing from a lying position

      Explanation:

      Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13
      Seconds

  • Question 4 - Where would one normally find venous valves? ...

    Correct

    • Where would one normally find venous valves?

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.3
      Seconds

  • Question 5 - Closure of the tricuspid valve is marked by which of the following features...

    Incorrect

    • Closure of the tricuspid valve is marked by which of the following features of the jugular venous waveform?

      Your Answer: a wave

      Correct Answer: c wave

      Explanation:

      The jugular venous pressure (JVP) classically has three upward deflections and two downward deflections. 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).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.7
      Seconds

  • Question 6 - Coronary flow is reduced during ...

    Correct

    • Coronary flow is reduced during

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11.8
      Seconds

  • Question 7 - Which vagus nerve mainly supplies the AV node? ...

    Incorrect

    • Which vagus nerve mainly supplies the AV node?

      Your Answer: Right vagus

      Correct Answer: Left vagus

      Explanation:

      As the AV node develops from the left side of the embryo It is supplied by the left vagus nerve.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      12
      Seconds

  • Question 8 - The positive inotropic effect of digoxin is due to? ...

    Correct

    • The positive inotropic effect of digoxin is due to?

      Your 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).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14
      Seconds

  • Question 9 - Cholinergic vagal supply to the SA and AV nodes results in slowing of...

    Correct

    • Cholinergic vagal supply to the SA and AV nodes results in slowing of the heart rate via:

      Your Answer: M2 muscarinic receptors

      Explanation:

      M2 muscarinic receptors are the receptors for the parasympathetic system to the SA and the AV node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      24
      Seconds

  • Question 10 - Which of the following statements is true regarding pulsus alternans? ...

    Incorrect

    • Which of the following statements is true regarding pulsus alternans?

      Your Answer: It is found in patients with a small pericardial effusion

      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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      18.5
      Seconds

  • Question 11 - Which of the following phases in depolarization and repolarization of cardiac muscle cells...

    Incorrect

    • Which of the following phases in depolarization and repolarization of cardiac muscle cells are caused by the inactivation of Na+ channels?

      Your Answer: Phase 0 : rapid depolarization

      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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      1
      Seconds

  • Question 12 - Regarding cardiac contractility, catecholamines exert their inotropic effect via: ...

    Correct

    • Regarding cardiac contractility, catecholamines exert their inotropic effect via:

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.6
      Seconds

  • Question 13 - The coronary arteries fill during? ...

    Correct

    • The coronary arteries fill during?

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.6
      Seconds

  • Question 14 - In the blood supply of the heart, ‘dominance’ refers to the coronary artery...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 15 - Which of the following is a method for measurement of cardiac output? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 16 - What is the effect of catecholamines (i.e. increased heart rate) on the pressure...

    Incorrect

    • What is the effect of catecholamines (i.e. increased heart rate) on the pressure volume loop?

      Your Answer:

      Correct Answer: Shifts the diastolic pressure curve upward and leftward

      Explanation:

      Catecholamines have a positive ionotropic and chronotropic effect on the heart. The ventricles develop greater tension during systole resulting in an increase in the stroke volume. The increase in stroke volume results in a decrease in the end diastolic volume. This pushes the loop towards the left and upwards.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 17 - Which of the following best describes the cardiac muscle? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 18 - Regarding the cardiac muscle striations as viewed under the microscope, which areas are...

    Incorrect

    • Regarding the cardiac muscle striations as viewed under the microscope, which areas are dark?

      Your Answer:

      Correct Answer: A band and z line

      Explanation:

      Dark bands: a, h. Dark line: z. Clear band: i, m

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 19 - If both the noradrenergic and the cholinergic systems are blocked in the heart,...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 20 - Which of the following occurs during a Valsalva manoeuvre? ...

    Incorrect

    • 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:

      1. 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.
      2. 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.
      3. Phase III: Upon releasing the strain, there is a sudden drop in intrathoracic pressure, which momentarily decreases blood pressure.
      4. 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 21 - Where is the carotid sinus located? ...

    Incorrect

    • Where is the carotid sinus located?

      Your Answer:

      Correct Answer: After the bifurcation of the carotid artery, on the internal carotid

      Explanation:

      The carotid sinus is a small dilation in the internal carotid artery just above its bifurcation into the external and internal carotid branch. Baroreceptors are present at this dilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 22 - Where does the SA node develop? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 23 - In the jugular venous pressure wave… ...

    Incorrect

    • In the jugular venous pressure wave…

      Your Answer:

      Correct Answer: Consists of 3 peaks and 2 troughs

      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).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 24 - Stimulation of the carotid sinus results in: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 25 - The hyperpolarization phase of pacemaker cells is dominated by ____ current. ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 26 - Coronary arteries arise from? ...

    Incorrect

    • Coronary arteries arise from?

      Your Answer:

      Correct Answer: None of the above

      Explanation:

      Coronary arteries arise from the sinuses behind 2 of the cusps of the aortic valve at the root of aorta.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 27 - Which of the following corresponds to an oblique line drawn from the sternal...

    Incorrect

    • Which of the following corresponds to an oblique line drawn from the sternal end of the left 3rd costal cartilage to the sternal end of the right 6th costal cartilage?

      Your Answer:

      Correct Answer: Atrio-ventricular (coronary) groove

      Explanation:

      The AV groove corresponds to the right border of the heart. The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 28 - Which ion channel does not contribute to the myocardial action potential? ...

    Incorrect

    • Which ion channel does not contribute to the myocardial action potential?

      Your Answer:

      Correct Answer: Chloride channel

      Explanation:

      The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 29 - In the Fick‘s method of measuring cardiac output, the arterial oxygen content can...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 30 - The average end diastolic volume in a healthy individual’s ventricle is? ...

    Incorrect

    • The average end diastolic volume in a healthy individual’s ventricle is?

      Your Answer:

      Correct Answer: 130 ml

      Explanation:

      The end diastolic volume in a healthy individual is about 130 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 31 - Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 32 - Which of the following supplies the AV node? ...

    Incorrect

    • Which of the following supplies the AV node?

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      The AV node is supplied by the right coronary artery near the origin of the posterior IV artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 33 - The Wiebel-Palade body found in the endothelial cells is responsible for the production...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 34 - Concerning surface anatomy, where is the mitral valve found? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 35 - Which of the following is NOT associated with the development of aortic regurgitation?...

    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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 36 - A 27-year-old man presents with a regular tachycardia of 190 bpm. He is...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 37 - Activation of baroreceptor reflex involves: ...

    Incorrect

    • Activation of baroreceptor reflex involves:

      Your Answer:

      Correct Answer: Short term regulation of systemic blood pressure

      Explanation:

      Baroreceptors are found in the heart and the blood vessels. They are the carotid sinus and the aortic arch receptors and respond to the minute to minute change in the blood pressure i.e. a change in the pulsatile pressure and not to a change in the mean arterial pressure. If the pulse pressure decreases, the rate of firing of the receptors decreases, stimulating an increase in the heart rate and blood pressure. Mechanisms that regulate the long term blood pressure control include the renin-angiotensin-aldosterone mechanism.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 38 - The right border of the heart corresponds to which line on the surface...

    Incorrect

    • The right border of the heart corresponds to which line on the surface of the chest?

      Your Answer:

      Correct Answer: Line drawn from the 3rd right costal cartilage to the 6th right costal cartilage

      Explanation:

      The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 39 - Which of the following components regulate cardiac output? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 40 - In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 41 - The postextrasystolic potentiation of myocardial contractility is due to: ...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 42 - All of the following are consistent with the indicator dilution method except--- ...

    Incorrect

    • All of the following are consistent with the indicator dilution method except---

      Your Answer:

      Correct Answer: In thermodilution, the indicator used is warm saline

      Explanation:

      In thermodilution, the indicator used is cold saline.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 43 - The steps of cardiac cycle in sequence are: ...

    Incorrect

    • The steps of cardiac cycle in sequence are:

      Your Answer:

      Correct Answer: Isovolumic contraction, ejection, isovolumic relaxation, passive ventricular filling, active ventricular filling.

      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.1st stage: diastole, or passive filling 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. 2nd stage: atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle (active filling).3rd stage: isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. 4th stage: ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. 5th 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 44 - Afferent fibers from the baroreceptors of the great arteries form branches of which...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 45 - The areas of extensive series of sarcoplasmic folds known as intercalated discs always...

    Incorrect

    • The areas of extensive series of sarcoplasmic folds known as intercalated discs always occur at what portion of the muscle fiber?

      Your Answer:

      Correct Answer: Z lines

      Explanation:

      The muscle fibers of the heart branch and interdigitate, but one complete unit is surrounded by a cell membrane. The place where one muscle fiber abuts the other, the cell membrane of both the fibers run parallel to each other through a series of extensive folds. These areas always occur on the Z lines and are known as intercalated discs.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 46 - AV valves open during? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 47 - Which of the following intercellular connections is important in endothelial barrier function? ...

    Incorrect

    • Which of the following intercellular connections is important in endothelial barrier function?

      Your Answer:

      Correct Answer: Tight junctions

      Explanation:

      Tight junctions surround the apical margins of the epithelial cells such as in the intestinal mucosa and the choroid plexus. They are also important to the endothelial barrier function. They are made up of ridges that adhere to each other strongly at the cell junction, obliterating the space completely between the cells.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 48 - Which of the atrial pressure changes represents the a-wave of the JVP ...

    Incorrect

    • Which of the atrial pressure changes represents the a-wave of the JVP

      Your Answer:

      Correct Answer: 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 49 - The function of ATP in cardiac muscle contraction includes: ...

    Incorrect

    • The function of ATP in cardiac muscle contraction includes:

      Your Answer:

      Correct Answer: Binding to myosin after the power stroke to allow uncoupling of actin and myosin

      Explanation:

      After calcium binds to the troponin C, there is a conformational change in the structure of troponin I and tropomyosin, which moves out of the way and frees the site where myosin can bind to actin. This results in the formation of the cross linkage of the actin and myosin giving rise to the power stroke in the contraction phase. This occurs with the release of ADP. When ATP combines to this complex it breaks and the cycle repeats itself.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 50 - Tunica intima is made up of? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 51 - What are the diagnostic criteria for an ST segment elevation type of acute...

    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.)

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 52 - Which vaso metabolite decreases coronary blood flow? ...

    Incorrect

    • Which vaso metabolite decreases coronary blood flow?

      Your Answer:

      Correct Answer: Endothelin

      Explanation:

      Decreased O2, increased CO2, lactate, prostaglandins, adenine nucleotides, adenosine, H+, K+ and cyanide produce vasodilation and thus an increase in coronary blood flow.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 53 - When looking at the JVP what does the c wave signify: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 54 - Preload: ...

    Incorrect

    • Preload:

      Your Answer:

      Correct Answer: Is the degree to which the myocardium is stretched before is contracts

      Explanation:

      Preload is end diastolic volume. It is the degree to which the heart muscle fiber is stretched when it fills up completely just before the heart contracts.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 55 - Initial depolarization of cardiac muscle is due to influx of: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 56 - Calcium needed for cardiac muscle contraction is made available during which phase of...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 57 - With regard to the endothelial structure, the epithelium constitute: ...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 58 - Normal stroke volume is about: ...

    Incorrect

    • Normal stroke volume is about:

      Your Answer:

      Correct Answer: 70 ml

      Explanation:

      Stroke volume is the amount of blood that is pumped from the heart into the aorta. It is typically 70 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 59 - In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?...

    Incorrect

    • In which organ will you find extremely porous sinusoidal capillaries, with discontinuous endothelium?

      Your Answer:

      Correct Answer: Liver

      Explanation:

      The liver is the organ which contains sinusoidal capillaries with discontinuous endothelium. The brain, lungs and the intestine all contain continuous capillaries, however the kidney contains fenestrated capillaries to aid in filtration.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 60 - Describe the location of the SA node: ...

    Incorrect

    • Describe the location of the SA node:

      Your Answer:

      Correct Answer: Junction of the SVC and right atrium

      Explanation:

      Anatomically the SA node is located at the junction of the superior vena cava and the right atrium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 61 - Coronary arteries fill up during ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 62 - Concerning surface anatomy, where is the aortic valve found? ...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 63 - Select the correct statement regarding the 4th heart sound, it? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 64 - Which of the following suggests the presence of mitral regurgitation as well as...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 65 - Which of the following antiarrhythmic drugs may be used in the treatment of...

    Incorrect

    • Which of the following antiarrhythmic drugs may be used in the treatment of long QT syndrome?

      Your Answer:

      Correct Answer: Atenolol

      Explanation:

      Beta-blockers are the mainstay of treatment in long QT syndrome. Implantable cardioverter-defibrillators are the most effective treatment in genotypes with a high risk of recurrence.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 66 - Pacemaker cells in the SA node and the AV node are connected by?...

    Incorrect

    • Pacemaker cells in the SA node and the AV node are connected by?

      Your Answer:

      Correct Answer: Gap junctions

      Explanation:

      Gap junctions allows for rapid propagation of the action potential from one cell to the other. The cells of the heart are connected by gap junctions.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 67 - Which of the following has the shortest duration: ...

    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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 68 - The following determines the strength of contraction ...

    Incorrect

    • The following determines the strength of contraction

      Your Answer:

      Correct Answer: Plateau phase

      Explanation:

      The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (or refractory) phase in myocyte action potential prevents early reactivation of the myocytes and directly determines the strength of contraction

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 69 - Concerning S3, which of the following statements is INCORRECT? ...

    Incorrect

    • Concerning S3, which of the following statements is INCORRECT?

      Your Answer:

      Correct Answer: Coincide with atrial contraction

      Explanation:

      A third heart sound also called a ventricular gallop occurs at the beginning of diastole after S2 and is lower in pitch than S1 or S2 as it is not of valvular origin. The third heart sound is benign in youth, some trained athletes, and sometimes in pregnancy but if it re-emerges later in life it may signal cardiac problems, such as a failing left ventricle as in dilated congestive heart failure (CHF). 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. It may also be a result of tensing of the chordae tendineae during rapid filling and expansion of the ventricle. In other words, an S3 heart sound indicates increased volume of blood within the ventricle. An S3 heart sound is best heard with the bell-side of the stethoscope (used for lower frequency sounds). A left-sided S3 is best heard in the left lateral decubitus position and at the apex of the heart, which is normally located in the 5th left intercostal space at the midclavicular line. A right-sided S3 is best heard at the lower-left sternal border. The way to distinguish between a left and right-sided S3 is to observe whether it increases in intensity with inhalation or exhalation. A right-sided S3 will increase on inhalation, while a left-sided S3 will increase on exhalation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 70 - What type of intercellular connection found between cardiac muscle fibers allow for the...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 71 - The AV Node: ...

    Incorrect

    • The AV Node:

      Your Answer:

      Correct Answer: It decelerates impulses passing to the ventricles

      Explanation:

      The action potentials in the sinoatrial (SA) and atrioventricular (AV) nodes are largely due to Ca2+, with no contribution by Na+ influx. The depolarization continues to conduct slowly through the atrioventricular (AV) node. The AV node is located in the right posterior portion of the interatrial septum. This is small and bean-shaped. The atrial conductive system is organized so that the cardiac impulse does not travel from the atria into the ventricles too rapidly; this delay allows the atria to empty before ventricular contraction begins. It is the AV node and its adjacent conductive fibers that delay this transmission into the ventricles. Conduction through the AV Node is represented on the ECG by the PR interval.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 72 - The coronary sinus drains into the: ...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 73 - Excitation-contraction coupling in cardiac muscle involves all of the following except: ...

    Incorrect

    • Excitation-contraction coupling in cardiac muscle involves all of the following except:

      Your Answer:

      Correct Answer: Binding of Ca2+ to calmodulin

      Explanation:

      In the excitation contraction coupling model, an action potential is 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. These are voltage gates calcium channels. Calcium binds to calmodulin during contraction of the smooth muscle and not the cardiac muscles.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 74 - Which of the following is NOT an effect of a positive inotropic agent...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 75 - Calcium is mobilized from the sarcoplasmic reticulum through: ...

    Incorrect

    • Calcium is mobilized from the sarcoplasmic reticulum through:

      Your Answer:

      Correct Answer: Ryanodine receptor (RyR2) calcium release channels

      Explanation:

      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. As a result intracellular calcium increases binding to troponin C resulting in contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 76 - Catecholamines… ...

    Incorrect

    • Catecholamines…

      Your Answer:

      Correct Answer: Activate adenylyl cyclase

      Explanation:

      Norepinephrine and epinephrine activate or deactivate adenylyl cyclase resulting in a decrease or an increase in the production of cAMP.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 77 - Factors influencing cardiac output include which of the following? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 78 - Coronary vasoconstriction can be caused by: ...

    Incorrect

    • Coronary vasoconstriction can be caused by:

      Your Answer:

      Correct Answer: Beta blockage

      Explanation:

      Coronary arteries contain alpha and beta receptors. The alpha receptor stimulates vasoconstriction and beta receptors stimulate vasodilation. When the chronotropic and inotropic effects of noradrenergic receptors are blocked by a B blocking drug, stimulation of the noradrenergic nerves will cause coronary vasoconstriction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 79 - Concerning coronary arteries, what is the net effect of B2 stimulation on the...

    Incorrect

    • Concerning coronary arteries, what is the net effect of B2 stimulation on the heart (e.g. Running athlete)?

      Your Answer:

      Correct Answer: Vasodilation via production of metabolites

      Explanation:

      The coronary arterioles contain α-adrenergic receptors, which cause vasoconstriction, and β-adrenergic receptors, which cause vasodilation. Activity in the noradrenergic nerves to the heart and injections of norepinephrine cause coronary vasodilation. However, norepinephrine also increases the heart rate and the force of cardiac contraction, and the vasodilation is due to production of vasodilator metabolites in the myocardium secondary to the increase in its activity. As exercise has the same effect as sympathetic stimulation, it will result in vasodilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 80 - Arterioles stemming from the coronary artery can also empty into the heart directly...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 81 - Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly...

    Incorrect

    • Blood flow to the subendocardial portions of the left ventricular muscle occurs mainly during:

      Your Answer:

      Correct Answer: Diastole

      Explanation:

      The sub endocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure from 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 sub endocardium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 82 - Although variable, branches of which artery most often supply the SA and AV...

    Incorrect

    • Although variable, branches of which artery most often supply the SA and AV nodes?

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      The RCA (right coronary artery) supplies the SA and the AV nodes along with the postero-basal wall of the left ventricle, posterior one third of the inferior vena cava, right ventricle and the posteromedial papillary muscle in the left ventricle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 83 - Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?...

    Incorrect

    • Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?

      Your Answer:

      Correct Answer: Dihydropyridine receptors

      Explanation:

      Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.

      Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.

      Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 84 - Troponin I is inhibited by calcium binding to: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 85 - Endothelial cells are attached to adjacent cells by adherent junctions via: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 86 - Xanthines (for example Caffeine), exhibit their positive inotropic effect by: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 87 - The rate of depolarisation of the sinus node membrane potential is modulated by...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 88 - Activation of nitric oxide synthesis by endothelial cells is triggered by: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 89 - The isoforms of nitric oxide synthase which are found in the nervous system...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 90 - Concerning surface anatomy, where is the base of the heart ...

    Incorrect

    • Concerning surface anatomy, where is the base of the heart

      Your Answer:

      Correct Answer: 2nd left costal to 3rd right costal cartilage

      Explanation:

      The base of the heart, also known as the superior border of the heart corresponds to a line connecting the inferior border of the 2nd left costal cartilage to the superior border of the 3rd right costal cartilage.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 91 - All valves are closed in which phase of the cardiac cycle? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
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  • Question 92 - The principle by which the energy of contraction is proportional to the initial...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 93 - The following products of the vascular endothelium produce vasodilation except: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 94 - The following contributes to the rate of depolarization? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 95 - A sarcomere is the area between: ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 96 - What is troponin? ...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 97 - What is the isolated effect of B2 stimulation on the coronaries? ...

    Incorrect

    • What is the isolated effect of B2 stimulation on the coronaries?

      Your Answer:

      Correct Answer: Vasodilatation

      Explanation:

      Norepinephrine and epinephrine are agonists for all adrenergic receptor subtypes, although with varying affinities. Based on their physiology and pharmacology, adrenergic receptors have been divided into two principal types: alpha and beta. These types have been further differentiated into alpha-1, alpha-2, b1, and b2 receptors.

      Alpha-1 Receptors are located on postsynaptic cells in smooth muscle and elicit vasoconstriction.

      Alpha-2 receptors are localized on presynaptic membranes of postganglionic nerve terminals that synthesize norepinephrine. When activated by catecholamines, alpha-2 receptors act as negative feedback controllers, inhibiting further norepinephrine release.

      Activation of myocardial b1 receptors stimulates the rate and strength of cardiac contraction, and consequently increases cardiac output. b1 Receptor activation also stimulates renin release from the kidney. Another class of antihypertensive agents acts by inhibiting b1 receptors.

      Activation of b2 receptors by epinephrine relaxes vascular smooth muscle and results in vasodilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 98 - Myocardial contractility is improved by: ...

    Incorrect

    • Myocardial contractility is improved by:

      Your Answer:

      Correct Answer: Caffeine

      Explanation:

      Caffeine and other theophyllines breakdown cAMP and have a positive ionotropic effect on the heart. Drugs like quinidine, procainamide and conditions like hypoxia and hypercapnia decreases the contractility of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 99 - Which factor produced by the endothelium is responsible for the regulation of vascular...

    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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 100 - The initial rapid depolarization in the action potential of cardiac muscle cells is...

    Incorrect

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (7/13) 54%
Medicine (7/13) 54%
Passmed
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