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Question 1
Correct
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Question 2
Correct
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Question 3
Correct
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Calcium needed for cardiac muscle contraction is made available during which phase of the action potential?
Your 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 4
Incorrect
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Regarding the surface anatomy of the orifices of the heart, where is the aortic valve located?
Your Answer: Opposite the left upper sternal border in the 2nd intercostal space
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
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Question 5
Incorrect
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Vasodilatation in skeletal muscle can be caused by:
Your Answer: Thromboxane a2
Correct Answer: Sympathetic cholinergic nerves
Explanation:In skeletal muscles some fibers that cause vasodilation run with the nerves of the sympathetic system but are cholinergic in nature. These nerves are not active during rest but become active during exercise and stress.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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What is troponin?
Your 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 7
Correct
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Question 8
Incorrect
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Which of the following are responsible for the 4th heart sound?
Your Answer: Rapid ventricular filling
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
Correct
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Which one of the following ECG findings is least associated with digoxin use?
Your 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 10
Correct
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Which of the following regulates the calcium release channels?
Your 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
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Question 11
Correct
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Regarding the length of systole and diastole which of the following is true?
Your 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 12
Correct
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Question 13
Correct
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The branche(s) of the left coronary artery include:
Your 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
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Question 14
Incorrect
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The following is true of the sinus node:
Your Answer: It discharges at a rate of 80-100 bpm
Correct Answer: It generates impulses automatically & at a quicker rate than other cardiac cells
Explanation:The SA node exhibits automaticity. It generates the impulses to which the heart beats. It fires at a faster speed than the rest of the nervous components of the heart i.e. the AV nodes, purkinje fibers. This is the reason when the SA node fails the heart beats to the rhythm of the AV node.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Incorrect
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Factors influencing cardiac output include which of the following?
Your Answer: Stroke volume
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 16
Correct
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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: 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.
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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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Which of the following results in the resting membrane potential of a myocyte?
Your Answer: Activation of fast Na channels
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 18
Correct
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Question 19
Incorrect
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The positive inotropic effect of digoxin is due to?
Your Answer: Inhibition of breakdown of cAMP
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 20
Incorrect
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Activation of nitric oxide synthesis by endothelial cells is triggered by:
Your Answer: Shear stress
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 21
Correct
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Which of the following would be a contraindication to thrombolysis?
Your 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 22
Incorrect
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Impulse conduction through the AV node is slow and depends on the action potential produced by which of the following.
Your Answer: Non of the above
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 23
Correct
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Question 24
Incorrect
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Which structure forms the major part of the sternocostal surface of the heart?
Your Answer: Left ventricle
Correct Answer: Right ventricle
Explanation:The anterior (sternocostal) surface is formed mainly by the right ventricle.
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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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Regarding cardiac output, an increased ejection fraction results from increases in which of the following?
Your Answer: Strength of contraction with increase in muscle fiber length
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
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Question 26
Incorrect
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Direct conduction from the atrium to the ventricles is prevented by:
Your Answer: Bundle of his
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 27
Correct
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Xanthines (for example Caffeine), exhibit their positive inotropic effect by:
Your 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
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Question 28
Correct
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In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should be made at:
Your 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
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Question 29
Incorrect
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In the jugular venous pressure wave…
Your Answer: Giant v wave occurs in tricuspid stenosis
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).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 30
Correct
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The interventricular septum is supplied anteriorly by the?
Your 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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SESSION STATS - PERFORMANCE PER SPECIALTY
