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  • Question 1 - The average end diastolic volume in a healthy individualā€™s ventricle is? ...

    Incorrect

    • The average end diastolic volume in a healthy individualā€™s ventricle is?

      Your Answer: 80 ml

      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
      86.5
      Seconds

  • Question 2 - Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms ...

    Incorrect

    • Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms

      Your Answer: Down regulation of phospholambin

      Correct Answer: Increased phosphorylation of phosholamban

      Explanation:

      Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      124.4
      Seconds

  • Question 3 - Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme? ...

    Incorrect

    • Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme?

      Your Answer: Phospholipase c

      Correct Answer: Guanylyl cyclase

      Explanation:

      Impaired production or excess catabolism of NO impairs this endothelium-dependent vasodilator function and may contribute to excessive vasoconstriction under various pathological situations.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      79.9
      Seconds

  • Question 4 - The approximate incidence of deep venous thrombosis (DVT) in the general population each...

    Correct

    • The approximate incidence of deep venous thrombosis (DVT) in the general population each year is:

      Your Answer: 1 per 1000

      Explanation:

      About 1 in 1000 adults per year has DVT, but as of 2011, available data is dominated by North American and European populations. DVT is rare in children, with an incidence of about 1 in 100,000 a year. From childhood to old age, incidence increases by a factor of about 1000, with almost 1% of the elderly experiencing DVTs yearly.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      52.3
      Seconds

  • Question 5 - Which of the following isoforms of Nitric oxide synthase (NOS) is found in...

    Incorrect

    • Which of the following isoforms of Nitric oxide synthase (NOS) is found in endothelial cells?

      Your Answer: Nos 5

      Correct Answer: Nos 3

      Explanation:

      There are only 3 isoforms:NOS 1: found in nervous systemNOS 2: in macrophages and other immune cellsNOS 3: In endothelial cells

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      88
      Seconds

  • Question 6 - 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: Starling method

      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
      936.7
      Seconds

  • Question 7 - The Wiebel-Palade body found in the endothelial cells is responsible for the production...

    Correct

    • The Wiebel-Palade body found in the endothelial cells is responsible for the production and release of which factor?

      Your 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
      8.7
      Seconds

  • Question 8 - Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:...

    Correct

    • Transport of Ca2+ into the reticulum to initiate cardiac muscle relaxation in via:

      Your Answer: Serca (sarcoplasmic or endoplasmic reticulum Ca2+ ATPase)

      Explanation:

      Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11.6
      Seconds

  • Question 9 - Which of the following would be a contraindication to thrombolysis? ...

    Incorrect

    • Which of the following would be a contraindication to thrombolysis?

      Your Answer: Pre-proliferative diabetic retinopathy

      Correct Answer: Intracranial neoplasm

      Explanation:

      Absolute contraindications to thrombolysis include:

      • Previous intracranial bleeding at any time
      • Stroke in less than 6 months
      • Closed head or facial trauma within 3 months
      • Suspected aortic dissection
      • Ischemic stroke within 3 months (except in ischemic stroke within 3 hours time)
      • Active bleeding diathesis
      • Uncontrolled high blood pressure (>180 systolic or >100 diastolic)
      • Known structural cerebral vascular lesion
      • Arterio-venous malformations
      • Thrombocytopenia
      • Known coagulation disorders
      • Aneurysm
      • Brain tumours
      • Pericardial effusion
      • Septic embolus

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.7
      Seconds

  • Question 10 - In a 30 year old male with hypertrophic obstructive cardiomyopathy (HOCM), which of...

    Incorrect

    • In a 30 year old male with hypertrophic obstructive cardiomyopathy (HOCM), which of the following is not associated with increased risk of sudden death?

      Your Answer: Family history of sudden death

      Correct Answer: Age

      Explanation:

      Hypertrophic cardiomyopathy (HCM) is a disease in which a portion of the myocardium (heart muscle) is enlarged without any obvious cause, creating functional impairment of the heart. It is the leading cause of sudden death in young athletes. The major risk factors for sudden death (SD)Ā are recent unexplained syncope unlikely to be neurocardiogenic; HCM-related SD in first-degree or other close relatives; repetitive and/or prolonged nonsustained ventricular tachycardia (NSVT) episodes on Holter or extended ambulatory monitoring; massive left ventricular hypertrophy (LVH) (wall thickness ā‰„30 mm); extensive/diffuse late gadolinium enhancement (LGE); end-stage heart failure usually with systolic dysfunction; and thin-walled akinetic LV apical aneurysm with regional scarring.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      81.6
      Seconds

  • Question 11 - The internodal tract of Bachman: ...

    Incorrect

    • The internodal tract of Bachman:

      Your Answer: Does not contain purkinje fibers

      Correct Answer: Connects the SA node to the AV node

      Explanation:

      Internodal tract of Bachman connects the SA node to the AV node conducting the electrical impulses generated from the SA node to the AV node and from the AV node to the rest of the electrical complex of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.4
      Seconds

  • Question 12 - What is the main reason for checking the urea and electrolytes prior to...

    Incorrect

    • What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?

      Your Answer: To detect a metabolic acidosis

      Correct Answer: To detect hypokalaemia

      Explanation:

      All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.2
      Seconds

  • Question 13 - 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 14 - Endothelial cells produce the following substance(s): ...

    Incorrect

    • Endothelial cells produce the following substance(s):

      Your Answer:

      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
      0
      Seconds

  • Question 15 - 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 16 - Which coronary artery supplies the right atria? ...

    Incorrect

    • Which coronary artery supplies the right atria?

      Your Answer:

      Correct Answer: Right coronary

      Explanation:

      The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 17 - 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 18 - The function of Troponin T in cardiac muscle is? ...

    Incorrect

    • The function of Troponin T in cardiac muscle is?

      Your Answer:

      Correct Answer: Allows attachment of troponin components to tropomyosin

      Explanation:

      Troponin T binds the troponin components to tropomyosin. Troponin I inhibits the interaction of myosin with actin, and troponin C contains the binding sites for the Ca2+ that helps initiate contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 19 - 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 20 - Which of the following does not contribute to increased stroke volume during exercise?...

    Incorrect

    • Which of the following does not contribute to increased stroke volume during exercise?

      Your Answer:

      Correct Answer: Increased length of filling time during diastole

      Explanation:

      Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 21 - 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 22 - 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 23 - Which of the following is NOT true of the parasympathetic control of the...

    Incorrect

    • Which of the following is NOT true of the parasympathetic control of the heart?

      Your Answer:

      Correct Answer: It can be blocked by beta blockers

      Explanation:

      Parasympathetic fibers do not innervate the Beta receptors on the heart. They are innervated by the sympathetic nerve fibers. Then a beta blocker such as propranolol will block the sympathetic outflow and increase the parasympathetic tone of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 24 - 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 25 - Which of the following normally has a slow depolarizing ā€œprepotentialā€? ...

    Incorrect

    • Which of the following normally has a slow depolarizing ā€œprepotentialā€?

      Your Answer:

      Correct Answer: Sinoatrial node

      Explanation:

      There are 2 main types of action potentials (AP) in the heart, the slow response and the fast response:The slow response is initiated by the slow calcium-sodium channels, found in the SA node (which is the natural pacemaker of the heart) and the conduction fibers of the AV node.The fast response occurs in the atrial and ventricles muscle cells and the purkinje fibers.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 26 - Which is the most common site for primary cardiac tumours to occur in...

    Incorrect

    • Which is the most common site for primary cardiac tumours to occur in adults?

      Your Answer:

      Correct Answer: Left atrium

      Explanation:

      Myxomas are the most common type of primary heart tumour. The tumour is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction. About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 27 - Depolarization spreads rapidly through cardiac muscle fibers because of the presence of: ...

    Incorrect

    • Depolarization spreads rapidly through cardiac muscle fibers because of the presence of:

      Your Answer:

      Correct Answer: Gap junctions

      Explanation:

      The cardiac muscles have gap junctions in between the cells. They allow for the formation of low resistance passages, which allow ions to diffuse through every muscle fiber rapidly and result in the cardiac muscles functioning as a syncytium, without any protoplasmic bridges involved.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 28 - 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 29 - 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 30 - 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 31 - 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 32 - How many molecules of myosin attach to actin at any given time? ...

    Incorrect

    • How many molecules of myosin attach to actin at any given time?

      Your Answer:

      Correct Answer: 1

      Explanation:

      1 molecule of myosin binds to actin at any give time.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 33 - Which of the following pairs are correct concerning arteriolar tone? ...

    Incorrect

    • Which of the following pairs are correct concerning arteriolar tone?

      Your Answer:

      Correct Answer: Hormonal control: catecholamines affect the adrenergic receptors of the vascular smooth muscle

      Explanation:

      Catecholamines released from the adrenal medulla act on the noradrenergic receptors of the vascular smooth muscles. In the skeletal muscles and liver it causes vasodilation whilst it causes vasoconstriction in the rest of the blood vessels of the body.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 34 - Which of the following conditions has no effect on cardiac output? ...

    Incorrect

    • Which of the following conditions has no effect on cardiac output?

      Your Answer:

      Correct Answer: Sleep

      Explanation:

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

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 35 - Xanthines such as caffeine and theophylline are positively inotropic due to: ...

    Incorrect

    • Xanthines such as caffeine and theophylline are positively inotropic due to:

      Your Answer:

      Correct Answer: Inhibition of cAMP breakdown

      Explanation:

      Xanthines exert their positive inotropic effect by inhibiting the breakdown of the cAMP resulting in stronger and sustained contractions.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 36 - Stroke volume in a average sized man lying in supine position is about?...

    Incorrect

    • Stroke volume in a average sized man lying in supine position is about?

      Your Answer:

      Correct Answer: 70 ml

      Explanation:

      The stroke volume of an average sized man who is lying is the supine position is about 70 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 37 - Which of the following conditions does not influence the cardiac output? ...

    Incorrect

    • Which of the following conditions does not influence the cardiac output?

      Your Answer:

      Correct Answer: Sleep

      Explanation:

      Sleep has no effect on the cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 38 - B1 adrenergic stimulation produces: ...

    Incorrect

    • B1 adrenergic stimulation produces:

      Your Answer:

      Correct Answer: Increase in calcium cytosolic concentration

      Explanation:

      Norepinephrine secreted by the sympathetic endings binds to B1 receptors, and the resulting increase in intracellular cAMP facilitates the opening of L channels, increasing Ica and the rapidity of the depolarization phase of the impulse and activates PKA which leads to phosphorylation of the voltage-gated Ca2+ channels, causing them to spend more time in the open state.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 39 - The direct determinants of cardiac output are ...

    Incorrect

    • The direct determinants of cardiac output are

      Your Answer:

      Correct Answer: Stroke volume and heart rate

      Explanation:

      Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:Cardiac Output [L/min] = Stroke Volume [L/beat] x Heart Rate [beats/min]

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 40 - According to Poiseuilleā€™s formula, which 1 of the following will lead to increased...

    Incorrect

    • According to Poiseuilleā€™s formula, which 1 of the following will lead to increased flow?

      Your Answer:

      Correct Answer: Shorter tube

      Explanation:

      V = Ļ€ p r4 / 8 Ī· lwhereĀ V = discharge volume flow (m3/s)p = pressureĀ difference between the ends of the pipe (N/m2, Pa)r = internal radius of pipe (m)l = length of pipe (m)Ī· = viscosity of fluid

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 41 - 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 42 - 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

  • Question 43 - 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 44 - Which of the following are responsible for the 4th heart sound? ...

    Incorrect

    • Which of the following are responsible for the 4th heart sound?

      Your Answer:

      Correct Answer: Ventricular hypertrophy

      Explanation:

      The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 45 - Which of the following causes an increase in venous return? ...

    Incorrect

    • Which of the following causes an increase in venous return?

      Your Answer:

      Correct Answer: An increase in the negative intra-thoracic pressure

      Explanation:

      During inspiration, intrathoracic pressure becomes more negativeĀ and intra-abdominal pressure more positive. This increases the venous pressure gradient from abdomen to thorax and promotes filling of the central veins.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 46 - The posterior aspect of the interventricular septum is supplied by: ...

    Incorrect

    • The posterior aspect of the interventricular septum is supplied by:

      Your Answer:

      Correct Answer: A branch of the right coronary artery

      Explanation:

      The posterior aspect of the heart is supplied by the posterior interventricular artery which is a branch of the right coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 47 - 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 48 - The a-wave is created by: ...

    Incorrect

    • The a-wave is created by:

      Your Answer:

      Correct Answer: Regurgitation of some blood to the great veins when the atria contracts in atrial systole

      Explanation:

      The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 49 - What is the function of the BK channel on the vascular smooth muscle...

    Incorrect

    • What is the function of the BK channel on the vascular smooth muscle membrane?

      Your Answer:

      Correct Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel

      Explanation:

      BK channels, also known as large-conductance calcium-activated potassium channels, play a critical role in regulating vascular smooth muscle tone. When BK channels open, they allow a large efflux of potassium ions (K+) out of the cell. This efflux of K+ causes the membrane potential to become more negative (hyperpolarization), which in turn leads to the closure of voltage-gated calcium channels. The closure of these calcium channels reduces the influx of calcium ions (Ca2+) into the smooth muscle cells, resulting in decreased intracellular calcium levels and subsequent relaxation of the smooth muscle.

      Thus, BK channels promote smooth muscle relaxation by hyperpolarizing the membrane and reducing the activity of voltage-gated Ca2+ channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 50 - Which of the following regulates the calcium release channels? ...

    Incorrect

    • Which of the following regulates the calcium release channels?

      Your Answer:

      Correct Answer: Calstabin 2

      Explanation:

      Ca2+ is released from the SR through a Ca2+ release channel, a cardiac isoform of the ryanodine receptor (RyR2), which controls intracytoplasmic [Ca2+] and, as in vascular smooth-muscle cells, leads to the local changes in intracellular [Ca2+] called calcium sparks. A number of regulatory proteins, including calstabin 2, inhibit RyR2 and, thereby, the release of Ca2+ from the SR.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 51 - Why does arterial blood pressure drop during pregnancy? ...

    Incorrect

    • Why does arterial blood pressure drop during pregnancy?

      Your Answer:

      Correct Answer: Progesterone relaxes vascular smooth muscle

      Explanation:

      Progesterone relaxes vascular smooth muscle thus resulting In a decrease in total peripheral resistance. This accounts for the increase in the cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 52 - The triangle with the heart at its centre, using limb leads is called:...

    Incorrect

    • The triangle with the heart at its centre, using limb leads is called:

      Your Answer:

      Correct Answer: Einthoven

      Explanation:

      The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 53 - 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 54 - 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 55 - Myocyte action potentials ā€“ Choose the false statement: ...

    Incorrect

    • Myocyte action potentials ā€“ Choose the false statement:

      Your Answer:

      Correct Answer: Repolarisation is due to net k+ influx

      Explanation:

      Final repolarization (phase 3) to the resting membrane potential (phase 4) is due to closure of the Ca2+ channels and a slow, delayed increase of K+ efflux through various types of K+ channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 56 - Sinus bradycardia may be caused by disease of which of the following: ...

    Incorrect

    • Sinus bradycardia may be caused by disease of which of the following:

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      Disease of the right coronary artery may cause sinus bradycardia and AV nodal block.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 57 - 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 58 - Which of the following structures of the cardiac conduction system is located in...

    Incorrect

    • Which of the following structures of the cardiac conduction system is located in the right posterior portion of the interatrial septum?

      Your Answer:

      Correct Answer: AV node

      Explanation:

      AV node is located at the right posterior portion of the interatrial septum.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 59 - The celiac trunk consists of which arteries? ...

    Incorrect

    • The celiac trunk consists of which arteries?

      Your Answer:

      Correct Answer: Left gastric, common hepatic, splenic

      Explanation:

      The celiac trunk is the first major branch of the abdominal aorta. It is 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12). There are three main divisions of the celiac artery:- left gastric artery- common hepatic artery- splenic artery

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 60 - In cardiac muscle, which of the following is directly responsible for the release...

    Incorrect

    • In cardiac muscle, which of the following is directly responsible for the release of Ca2+ stored in the sarcoplasmic reticulum (calcium-induced calcium release)?

      Your Answer:

      Correct Answer: Ryanodine receptor (RyR)

      Explanation:

      Ryanodine receptor (RyR) is a ligand-gated Ca2+ channel with Ca2+ as its natural ligand. In skeletal muscle, Ca2+ entry from ECF by this route is not required for Ca2+ release. Instead, the DHPR that serves as the voltage sensor unlocks release of Ca2+ from the nearby SR via physical interaction with the RyR. The release is amplified through ca-induced ca release. However, in cardiac muscle, it is the influx of extracellular Ca2+ through the voltage-sensitive DHPR in the T system that triggers ca-induced ca release trough the RyR at the SR.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 61 - Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which...

    Incorrect

    • Calcium induced calcium release occurs in the sarcoplasmic reticulum by activation of which receptors

      Your Answer:

      Correct Answer: Ryanodine receptors

      Explanation:

      Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca2+ stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). CICR occurs when the resulting Ca2+ influx activates ryanodine receptors on the SR membrane, which causes more Ca2+ to be released into the cytosol.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 62 - 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 63 - 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, Ehlersā€“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 64 - With regards to the cardiac cycle which of the following is true ...

    Incorrect

    • With regards to the cardiac cycle which of the following is true

      Your Answer:

      Correct Answer: Right atrial systole occurs before left atrial systole: as below

      Explanation:

      Cardiac cycle: The first event in the cycle is atrial depolarization (a P wave on the surface ECG) follows by RIGHT ATRIAL and then LEFT ATRIAL contraction. Ventricular activation (QRS) follows after a short interval (the PR interval). LEFT VENTRICULAR contraction starts shortly thereafter RIGHT VENTRICULAR contraction begins. At the end, the aortic valve closure is followed by pulmonary valve closure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 65 - 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 66 - 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 67 - Cross-bridges between actin and myosin filaments contain: ...

    Incorrect

    • Cross-bridges between actin and myosin filaments contain:

      Your Answer:

      Correct Answer: Calcium ions

      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 causes 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 68 - Which of the following is true of the Natriuretic hormones? ...

    Incorrect

    • Which of the following is true of the Natriuretic hormones?

      Your Answer:

      Correct Answer: They are released in response to hypervolemia

      Explanation:

      Natriuretic hormones are vasodilators released in response to hypervolemia.

      Natriuretic hormones (NH) include three groups of compounds: the natriuretic peptides NPs (ANP, BNP and CNP), the gastrointestinal peptides (guanylin and uroguanylin), and endogenous cardiac steroids. These substances induce the kidney to excrete sodium and therefore participate in the regulation of sodium and water homeostasis, blood volume, and blood pressure (BP). In addition to their peripheral functions, these hormones act as neurotransmitters or neuromodulators in the brain.

      Atrial natriuretic peptide (ANP) plays a crucial role in blood pressure regulation by inducing natriuresis and diuresis in the kidney, inhibiting renin secretion, aldosterone production, and promoting vasorelaxation. Ā Two paracrine factors derived from endothelial cells play important roles in modulating ANP secretion. Endothelin, a potent vasoconstrictor, stimulates ANP secretion and augments stretch induced ANP secretion. The dramatic increase in ANP release produced by cardiac ischemia appears to be mediated in part by endothelin. Nitric oxide (NO), an important vasodilator, is also produced by endothelial cells and inhibits ANP secretion.

      Brain natriuretic peptide (BNP) shares ANP’s receptor but is primarily associated with antifibrotic effects in ventricular remodeling, serving as a biomarker for heart failure and myocardial infarction.

      C-type natriuretic peptide (CNP) acts locally in an autocrine/paracrine manner, exerting potent cardiovascular effects, including vasorelaxation and vascular remodeling post-injury. NPs also demonstrate diverse effects beyond cardiovascular and renal systems, such as bronchodilation, anti-inflammatory actions, and metabolic effects on adipose tissue and long bones.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 69 - In the cardiac cycle, all of the following are true except: ...

    Incorrect

    • In the cardiac cycle, all of the following are true except:

      Your Answer:

      Correct Answer: Mitral valve is closed by contraction of papillary muscles

      Explanation:

      Mitral valve is closed by contraction of papillary muscles: This statement is incorrect. The mitral valve closes due to the pressure difference between the left ventricle and the left atrium at the onset of ventricular systole. The papillary muscles contract to prevent prolapse of the valve into the atrium but do not cause the valve to close.

      The left ventricular volume is maximal at the end of atrial systole: This statement is true. At the end of atrial systole, the atria have pushed the remaining blood into the ventricles, making the ventricular volume maximal (end-diastolic volume).

      The left ventricular pressure is maximal just before the aortic valve opens: This statement is true. Left ventricular pressure peaks just before the aortic valve opens, as the ventricle contracts to overcome the pressure in the aorta.

      The ejection fraction is about 55%: This statement is true. The ejection fraction, which is the percentage of blood ejected from the ventricles with each contraction, is typically around 55%.

      The ā€˜aā€™ wave is due to atrial systole: This statement is true. The ā€˜aā€™ wave on the venous pressure curve corresponds to atrial systole, reflecting the increased pressure from atrial contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 70 - Currents caused by opening of which of the following channels contribute to the...

    Incorrect

    • Currents caused by opening of which of the following channels contribute to the repolarization phase of the action potential of the ventricular muscle fibers?

      Your Answer:

      Correct Answer: Potassium channels

      Explanation:

      Depolarization occurs due to opening of the voltage gated sodium channels. Repolarization occurs due to opening of the voltage gates potassium channels causing an out flux of potassium ions, decreasing the membrane potential towards resting potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 71 - 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 72 - 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 73 - Myocardium requires more oxygen to expel blood in: ...

    Incorrect

    • Myocardium requires more oxygen to expel blood in:

      Your Answer:

      Correct Answer: A stenotic aortic valve

      Explanation:

      In aortic valve stenosis, increased ventricular pressure Is needed to expel the blood into the aorta. Increased pressure means increased contractility hence increase O2 consumption by the heart muscles.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 74 - 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 75 - Which heart sounds are matched correctly? ...

    Incorrect

    • Which heart sounds are matched correctly?

      Your Answer:

      Correct Answer: All of the above

      Explanation:

      In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S1) and second heart sound (S2), produced by the closing of the atrioventricular valves and semilunar valves, respectively. In addition to these normal sounds, a variety of other sounds may be present including heart murmurs, adventitious sounds, and gallop rhythms S3 and S4. S3 is thought to be caused by the oscillation of blood back and forth between the walls of the ventricles initiated by blood rushing in from the atria. The reason the third heart sound does not occur until the middle third of diastole is probably that during the early part of diastole, the ventricles are not filled sufficiently to create enough tension for reverberation. S4 when audible in an adult is called a presystolic gallop or atrial gallop. This gallop is produced by the sound of blood being forced into a stiff or hypertrophic ventricle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 76 - Which membrane bound protein in the sarcoplasmic reticulum regulates calcium return from the...

    Incorrect

    • Which membrane bound protein in the sarcoplasmic reticulum regulates calcium return from the cytosol to the sarcoplasmic reticulum?

      Your Answer:

      Correct Answer: Phospholamban

      Explanation:

      Phosphorylation of phospholamban increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the sarcoplasmic reticulum (SR), that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 77 - 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 78 - Which structure forms the major part of the sternocostal surface of the heart?...

    Incorrect

    • Which structure forms the major part of the sternocostal surface of the heart?

      Your Answer:

      Correct Answer: Right ventricle

      Explanation:

      The anterior (sternocostal) surface is formed mainly by the right ventricle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 79 - Where would one find pericytes around endothelial cells? ...

    Incorrect

    • Where would one find pericytes around endothelial cells?

      Your Answer:

      Correct Answer: Post-capillary venules

      Explanation:

      Pericytes release a wide variety of vasoactive agents which regulate the flow through the junction between endothelial cells.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 80 - Why is the sub-endocardial portion of the left ventricle the most common site...

    Incorrect

    • Why is the sub-endocardial portion of the left ventricle the most common site for ischaemic damage and myocardial infarction?

      Your Answer:

      Correct Answer: No blood flow occurs during systole

      Explanation:

      The subendocardium receives the least amount of blood from the coronary arteries. 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
      0
      Seconds

  • Question 81 - How does pregnancy affect the cardiac output of a patient? ...

    Incorrect

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

      Your Answer:

      Correct Answer: Increased cardiac output due to increase in heart rate and stroke volume

      Explanation:

      Cardiac Output increases to a similar degree as the blood volume. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state. Steady rises are shown on Doppler echocardiography, from an average of 6.7 litres/minute at 8-11 weeks to about 8.7 litres/minute flow at 36-39 weeks; they are due, primarily, to an increase in stroke volume (35%) and, to a lesser extent, to a more rapid heart rate (15%). There is a steady reduction in systemic vascular resistance (SVR) which contributes towards the hyperdynamic circulation observed in pregnancy

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 82 - The Sinoatrial node in the majority of people is supplied by the? ...

    Incorrect

    • The Sinoatrial node in the majority of people is supplied by the?

      Your Answer:

      Correct Answer: Right coronary artery

      Explanation:

      In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 83 - 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 84 - Absolute refractory period in a cardiac action potential graph occurs during. ...

    Incorrect

    • Absolute refractory period in a cardiac action potential graph occurs during.

      Your Answer:

      Correct Answer: All of the above

      Explanation:

      Absolute refractory period (ARP): the cell is completely unexcitable to a new stimulus and occurs from phase 0 – 2 i.e. depolarisation, early repolarisation and plateau phase.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 85 - The major factor in controlling coronary artery blood flow is considered to be?...

    Incorrect

    • The major factor in controlling coronary artery blood flow is considered to be?

      Your Answer:

      Correct Answer: Metabolites of oxygen consumption

      Explanation:

      There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 86 - Which of the following is first to rise following myocardial infarction? ...

    Incorrect

    • Which of the following is first to rise following myocardial infarction?

      Your Answer:

      Correct Answer: Myoglobin

      Explanation:

      Myoglobin, is a sensitive indicator of muscle injury and is first to rise following MI within two hours but is nonspecific.Troponin and CK-MB both begin to rise approximately three hours after MI. The cardiac troponins T and I which are released within 4ā€“6 hours of an attack of MI and remain elevated for up to 2 weeks, have nearly complete tissue specificity and are now the preferred markers for assessing myocardial damage.Lactate dehydrogenase (LDH) begins to rise approximately 12 hours after MI.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 87 - 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 88 - Cholinergic nerves from the vagus innervate the SA and AV nodes via which...

    Incorrect

    • Cholinergic nerves from the vagus innervate the SA and AV nodes via which receptor in the heart?

      Your Answer:

      Correct Answer: M2 receptor

      Explanation:

      M2 receptor is found in the heart. M3 and M4 are associated with smooth muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 89 - The amount of a substance taken up by an organ (or whole body)...

    Incorrect

    • The amount of a substance taken up by an organ (or whole body) per unit time is = (the arterial level - the venous level) * the blood flow. This statement describes?

      Your Answer:

      Correct Answer: The Fick principle

      Explanation:

      The essence of the Fick principle is that blood flow to an organ can be calculated using a marker substance if the following information is known:- Amount of marker substance taken up by the organ per unit time- Concentration of marker substance in arterial blood supplying the organ- Concentration of marker substance in venous blood leaving the organ

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 90 - The heart rate can be accelerated by: ...

    Incorrect

    • The heart rate can be accelerated by:

      Your Answer:

      Correct Answer: Exercise and thyroid hormones

      Explanation:

      The firing of the SA node will increase due to exercises and as the thyroid hormone has a chronotropic effect on the heart, it too will result in an increase in the heart rate via stimulation of the adrenergic receptors of the heart. As during exercise the sympathetic nervous system is activated, it will directly have an positive chronotropic effect on the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 91 - When observing a JVP, which of the following would lead to prominent v...

    Incorrect

    • When observing a JVP, which of the following would lead to prominent v waves?

      Your Answer:

      Correct Answer: Tricuspid regurgitation

      Explanation:

      The v wave corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return. In Tricuspid regurgitation there is additional blood from the regurgitant flow and thus this leads to a more prominent V wave.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 92 - What is cardiac output? ...

    Incorrect

    • What is cardiac output?

      Your Answer:

      Correct Answer: Product of stroke volume and heart rate

      Explanation:

      Cardiac output is the product of stroke volume and heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 93 - In a normal heart rate at rest, the left ventricular end-diastolic volume is...

    Incorrect

    • In a normal heart rate at rest, the left ventricular end-diastolic volume is ā€¦.

      Your Answer:

      Correct Answer: 100-130 ml

      Explanation:

      In cardiovascular physiology, end-diastolic volume (EDV) is the volume of blood in the right and/or left ventricle at end load or filling in (diastole) or the amount of blood in the ventricles just before systole. Because greater EDVs cause greater distention of the ventricle, EDV is often used synonymously with preload, which refers to the length of the sarcomeres in cardiac muscle prior to contraction (systole). End-diastolic volume: Right = 144 mL(Ā± 23mL) & Left = 142 mL (Ā± 21 mL).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 94 - Which one of the following is a risk factor for torsade de pointes?...

    Incorrect

    • Which one of the following is a risk factor for torsade de pointes?

      Your Answer:

      Correct Answer: Hypothermia

      Explanation:

      The following is a list of factors associated with an increased tendency toward torsades de pointes:- Hypokalaemia (low blood potassium)- Hypomagnesemia (low blood magnesium)- Hypocalcaemia (low blood calcium)- Bradycardia (slow heartbeat)- Heart failure- Left ventricular hypertrophy- Hypothermia- Subarachnoid haemorrhage- Hypothyroidism

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 95 - The bradycardia that occurs in patients with raised intracranial pressure is a result...

    Incorrect

    • The bradycardia that occurs in patients with raised intracranial pressure is a result of the?

      Your Answer:

      Correct Answer: Cushing reflex

      Explanation:

      When intracranial pressure is increased, the blood supply to RVLM neurons is compromised. This results in an increase in their discharge as a result of hypoxia and hypercapnia. The resultant rise in systemic arterial pressure (Cushing reflex) tends to restore the blood flow to the medulla.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
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  • Question 96 - 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
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      Seconds

  • Question 97 - 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 98 - The ā€˜cā€™ wave in JVP corresponds more closely with: ...

    Incorrect

    • The ā€˜cā€™ wave in JVP corresponds more closely with:

      Your Answer:

      Correct Answer: Isovolumetric contraction

      Explanation:

      The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections (peaks) and two downward deflections (troughs) have been described:The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 99 - Myocardial fibers have a resting membrane potential of approximately: ...

    Incorrect

    • Myocardial fibers have a resting membrane potential of approximately:

      Your Answer:

      Correct Answer: -90mv

      Explanation:

      The resting membrane potential of the mammalian heart is about -90 mv.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

  • Question 100 - The process by which depolarization of the muscle fiber initiates contraction is called?...

    Incorrect

    • The process by which depolarization of the muscle fiber initiates contraction is called?

      Your Answer:

      Correct Answer: Action potential

      Explanation:

      This process is known as an action potential. Upon generation of an action potential when depolarization reaches threshold, it spreads throughout the muscle fiber, resulting in generation of an excitation-contraction coupling leading to contraction of the muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      0
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (5/12) 42%
Medicine (5/12) 42%
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