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  • Question 1 - Regarding cardiac muscle contractility, the afterload refers to: ...

    Correct

    • Regarding cardiac muscle contractility, the afterload refers to:

      Your Answer: The resistance against which blood is expected

      Explanation:

      The afterload for the left ventricle is the aortic pressure. Hence it is this pressure that offers resistance against which the blood is to be expelled from the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      104
      Seconds

  • Question 2 - 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: Po4

      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
      • Physiology
      12.9
      Seconds

  • Question 3 - 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: Vasoconstriction directly

      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
      • Physiology
      24.4
      Seconds

  • Question 4 - The end- diastolic ventricular volume is about? ...

    Correct

    • The end- diastolic ventricular volume is about?

      Your 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
      • Physiology
      7.1
      Seconds

  • Question 5 - 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: Calmodulin

      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
      • Physiology
      19
      Seconds

  • Question 6 - Which factors increase the end-diastolic volume? ...

    Incorrect

    • Which factors increase the end-diastolic volume?

      Your Answer: Raised intra-pericardial pressure

      Correct Answer: Constriction of veins

      Explanation:

      End diastolic volume is also known as preload. It is the amount of blood the heart contracts against. Constriction of veins will decrease venous pooling and increase venous return, hence increasing the end diastolic volume. Standing will increase venous pooling hence decreasing venous return and end diastolic volume. Raised intrapericardial pressure will also decrease venous return and hence end diastolic volume.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      28
      Seconds

  • Question 7 - Endothelial cells are attached to adjacent cells by adherent junctions via: ...

    Correct

    • Endothelial cells are attached to adjacent cells by adherent junctions via:

      Your 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
      • Physiology
      19.2
      Seconds

  • Question 8 - The Plateau phase in myocyte action potentials does all of the following except:...

    Incorrect

    • The Plateau phase in myocyte action potentials does all of the following except:

      Your Answer: It directly determines the strength of cardiac contraction

      Correct Answer: It allows early reactivation of the myocytes

      Explanation:

      The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. 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 (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      47.6
      Seconds

  • Question 9 - Which of the following results in the resting membrane potential of a myocyte?...

    Correct

    • Which of the following results in the resting membrane potential of a myocyte?

      Your 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      20.5
      Seconds

  • Question 10 - The postextrasystolic potentiation of myocardial contractility is due to: ...

    Correct

    • The postextrasystolic potentiation of myocardial contractility is due to:

      Your 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
      • Physiology
      19.8
      Seconds

  • Question 11 - The term cardiac output refers to the amount of blood pumped by the...

    Correct

    • The term cardiac output refers to the amount of blood pumped by the heart in one minute. The rate in women is around 5 L/min, whereas in men is somewhat higher, around 5.5 L/min. Which of the equations below best describes cardiac output?

      Your Answer: Stroke volume x heart rate

      Explanation:

      Cardiac output (CO) is calculated by multiplying stroke volume (SV) by heart rate (HR): CO = HR x SV As a result, both stroke volume and heart rate are exactly proportional to cardiac output. There will be an increase in cardiac output if the stroke volume or heart rate increases, and a reduction in cardiac output if the stroke volume or heart rate lowers.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      25.3
      Seconds

  • Question 12 - What is the most common cardiac defect seen in patients with Down’s syndrome?...

    Correct

    • What is the most common cardiac defect seen in patients with Down’s syndrome?

      Your Answer: Atrioventricular septal defect

      Explanation:

      The rate of congenital heart disease in new-borns with Down syndrome is around 40%. Of those with heart disease, about 80% have an atrioventricular septal defect or ventricular septal defect with the former being more common. Mitral valve problems become common as people age, even in those without heart problems at birth.[3] Other problems that may occur include tetralogy of Fallot and patent ductus arteriosus.[38] People with Down syndrome have a lower risk of hardening of the arteries

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      21.4
      Seconds

  • Question 13 - B1 adrenergic stimulation produces: ...

    Correct

    • B1 adrenergic stimulation produces:

      Your 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
      • Physiology
      14.2
      Seconds

  • Question 14 - Which one of the following is a cause of a soft second heart...

    Correct

    • Which one of the following is a cause of a soft second heart sound?

      Your Answer: Aortic stenosis

      Explanation:

      Second heart sound (S2) forms the dub of lub-dub and is composed of components A2 and P2. •    loud: hypertension•    soft: AS•    fixed split: physiological split (normally occurs during inhalation), right bundle branch block, pulmonary stenosis, and atrial septal defect.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      30.3
      Seconds

  • Question 15 - 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: Left ventricle

      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
      • Physiology
      27.3
      Seconds

  • Question 16 - The basic unit of contraction in myocytes is: ...

    Correct

    • The basic unit of contraction in myocytes is:

      Your Answer: Sarcomere

      Explanation:

      Sarcomere is the organelle where calcium is stored to be released during contraction of the muscle. It is the basic unit of contraction in striated muscle fibers. As myocytes are also striated muscles, sarcomeres also forms the basic unit of contraction. The impulses travel along the membrane and via its interaction with the dihydropyridine receptors it releases the stored calcium.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      10.6
      Seconds

  • Question 17 - 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: Coronary cardiac shunt vessels

      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
      • Physiology
      36.8
      Seconds

  • Question 18 - Which part of the ECG represents ventricular repolarisation? ...

    Correct

    • Which part of the ECG represents ventricular repolarisation?

      Your Answer: T wave

      Explanation:

      Ventricular repolarisation is denoted by the T wave.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      10.7
      Seconds

  • Question 19 - The celiac trunk consists of which arteries? ...

    Incorrect

    • The celiac trunk consists of which arteries?

      Your Answer: Right gastric, common hepatic, superior mesenteric

      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
      • Physiology
      15.7
      Seconds

  • Question 20 - Activation of nitric oxide synthesis by endothelial cells is triggered by: ...

    Correct

    • Activation of nitric oxide synthesis by endothelial cells is triggered by:

      Your 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
      • Physiology
      15.1
      Seconds

  • Question 21 - Dicrotic notch is produced by which valves? ...

    Incorrect

    • Dicrotic notch is produced by which valves?

      Your Answer: Pulmonary and aortic

      Correct Answer: Aortic

      Explanation:

      The graph of aortic pressure throughout the cardiac cycle displays a small dip (the incisure or dicrotic notch) which coincides with the aortic valve closure. The dip in the graph is immediately followed by a brief rise (the dicrotic wave) then gradual decline.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      14.1
      Seconds

  • Question 22 - 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: 1 mm ST depression in 2 limb leads

      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
      • Physiology
      4
      Seconds

  • Question 23 - 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
      • Physiology
      24.8
      Seconds

  • Question 24 - Regarding the myofilament molecules, which of the following contains binding sites for calcium...

    Correct

    • Regarding the myofilament molecules, which of the following contains binding sites for calcium that helps to initiate contraction?

      Your Answer: Troponin c

      Explanation:

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

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      10.8
      Seconds

  • Question 25 - 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: ATP hydrolysis

      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
      • Physiology
      34.7
      Seconds

  • Question 26 - Afferent fibers from the baroreceptors of the great arteries form branches of which...

    Correct

    • Afferent fibers from the baroreceptors of the great arteries form branches of which cranial nerves?

      Your 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
      • Physiology
      16.8
      Seconds

  • Question 27 - What type of intercellular connection found between cardiac muscle fibers allow for the...

    Correct

    • What type of intercellular connection found between cardiac muscle fibers allow for the spread of excitation from one cell to another?

      Your 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
      • Physiology
      12.8
      Seconds

  • Question 28 - In a normal heart rate at rest, the left ventricular end-diastolic volume is...

    Correct

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

      Your 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(± 23mL) & Left = 142 mL (± 21 mL).

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      11.3
      Seconds

  • Question 29 - What is troponin? ...

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      23.7
      Seconds

  • Question 30 - Heart rate can be slowed by: ...

    Correct

    • Heart rate can be slowed by:

      Your Answer: Grief

      Explanation:

      Grief stimulates the parasympathetic nervous system, resulting in a decrease in the heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      7.5
      Seconds

  • Question 31 - The following determines the strength of contraction ...

    Incorrect

    • The following determines the strength of contraction

      Your Answer: Depolarization

      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
      • Physiology
      16.3
      Seconds

  • Question 32 - Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s...

    Correct

    • Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s syndrome?

      Your Answer: Aortic aneurysm

      Explanation:

      Marfan syndrome (MFS) is a genetic disorder of connective tissue. The degree to which people are affected varies. People with Marfan’s tend to be tall, and thin, with long arms, legs, fingers and toes. They also typically have flexible joints and scoliosis. The most serious complications involve the heart and aorta with an increased risk of mitral valve prolapse and aortic aneurysm.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      20
      Seconds

  • Question 33 - 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: Isovolumetric ventricular relaxation

      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
      • Physiology
      22.5
      Seconds

  • Question 34 - 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: The left ventricle

      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
      • Physiology
      21.6
      Seconds

  • Question 35 - According to Starling's law of the heart: ...

    Incorrect

    • According to Starling's law of the heart:

      Your Answer: Energy of contraction is proportional to the pressure in the left ventricle

      Correct Answer: The extent of the preload is proportional to the end-diastolic volume

      Explanation:

      Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      45.1
      Seconds

  • Question 36 - The V wave in the jugular pulse is caused by: ...

    Correct

    • The V wave in the jugular pulse is caused by:

      Your Answer: Atrial filling

      Explanation:

      The V wave indicates the rise in the atrial pressure due to filling of the atria with blood before the tricuspid valve opens during the diastolic phase of contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      3.2
      Seconds

  • Question 37 - Where are the baroreceptors of the great arteries located? ...

    Incorrect

    • Where are the baroreceptors of the great arteries located?

      Your Answer: In the smooth muscle

      Correct Answer: In the adventitia

      Explanation:

      Baroreceptors are located in the adventitia of the great arteries.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      13.7
      Seconds

  • Question 38 - 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 impaired renal function

      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
      • Physiology
      20
      Seconds

  • Question 39 - Where would one normally find venous valves? ...

    Incorrect

    • Where would one normally find venous valves?

      Your Answer: Brain

      Correct Answer: Saphenous vein

      Explanation:

      The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      18
      Seconds

  • Question 40 - Digoxin causes: ...

    Incorrect

    • Digoxin causes:

      Your Answer: Na/k ATPase stimulation

      Correct Answer: Increase in cytosolic calcium concentration

      Explanation:

      Digoxin is a positive inotrope which inhibits NA/K ATPase, increases cardiac contractility and can cause hypokalaemia.

    • This question is part of the following fields:

      • Cardiovascular
      • Physiology
      3.5
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (21/40) 53%
Physiology (21/40) 53%
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