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740+ Physiology Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .

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Chapter: Cardiovascular
1.

Regarding ECG changes, which is CORRECT?

A. hypernatraemia is associated with low voltage complexes
B. the first change in hyperkalaemia is prolongation of QRS
C. with hypokalaemia, the resting membrane potential decreases
D. in hyperkalaemia, the heart stops in systole
E. in hypercalcaemia, myocardial contractility is enhanced
Answer» E. in hypercalcaemia, myocardial contractility is enhanced
discuss
2.

Regarding jugular pressure waves:

A. the ‘v’ wave denotes the increased atrial pressure due to the bulging of the tricuspid valve during isovolumetric ventricular contraction
B. in tricuspid insufficiency, there is a giant ‘A’ wave with each ventricular systole
C. atrial premature beats produce an ‘A’ wave
D. the ‘v’ wave occurs during systole
E. a giant ‘C’ wave (‘cannon wave’) may be seen in complete heart block
Answer» C. atrial premature beats produce an ‘A’ wave
discuss
3.

What factor does not alter cardiac output?

A. standing up
B. sleeping
C. eating
D. exercising
E. pregnancy
Answer» B. sleeping
discuss
4.

What is the O2 consumption of a beating heart at rest?

A. 2ml/100g/min
B. 9ml/g/min
C. 2ml/g/min
D. 2L/100g/min
E. 9ml/100g/min
Answer» E. 9ml/100g/min
discuss
5.

Regarding percentages of blood volume in the body:

A. the heart has 5%
B. the pulmonary circulation has the greatest percentage
C. the venous circulation has 35%
D. the aorta has 2%
E. capillaries have 20%
Answer» D. the aorta has 2%
discuss
6.

What is a biological action of endothelin?

A. dilates vascular smooth muscle
B. produces bronchodilation
C. increase GFR and renal blood flow
D. evokes positive inotropic and chronotropic effects on myocardium
E. inhibits gluconeogenesis
Answer» D. evokes positive inotropic and chronotropic effects on myocardium
discuss
7.

What inhibits gene transcription for endothelin-1 secretion:

A. nitric oxide
B. angiotensin II
C. insulin
D. growth factors
E. catecholamines
Answer» A. nitric oxide
discuss
8.

Regarding NO synthase:

A. it synthesises nitrous oxide from arginine
B. there are 2 isoforms
C. it is inactivated by haemoglobin
D. NOS-1 is activated by cytokines
E. NOS-2 is in endothelial cells
Answer» C. it is inactivated by haemoglobin
discuss
9.

What factor dilates the arterioles?

A. decreased local temperature
B. myogenic theory of autoregulation
C. angiotensin II
D. increased discharge of noradrenergic vasomotor nerve
E. histamine
Answer» E. histamine
discuss
10.

Which is NOT a baroreceptor site?

A. right atria at the entrance of SVC and IVC
B. aortic arch
C. left atria at the entrance of the pulmonary veins
D. pulmonary circulation
E. carotid body
Answer» E. carotid body
discuss
11.

Regarding cerebrospinal fluid:

A. the total volume of CSF is 300mL
B. CSF is absorbed through the choroid plexus
C. the average CSF pressure is 220m-CSF
D. CSF has a higher pH than plasma
E. it contains very low levels of cholesterol relative to plasma
Answer» E. it contains very low levels of cholesterol relative to plasma
discuss
12.

Which substance has equal concentrations in CSF and plasma?

A. Ca2+
B. K+
C. Na+
D. PCO2
E. glucose
Answer» C. Na+
discuss
13.

Which vessel has the lowest PO2?

A. maternal artery
B. maternal vein
C. uterine vein
D. umbilical vein
E. umbilical artery
Answer» E. umbilical artery
discuss
14.

During exercise:

A. diastolic BP increases more than systolic BP
B. regional blood flow to the brain doubles
C. cardiac output may increase 15-fold
D. after exercise, BP takes longer to return to normal than heart rate
E. O2 consumption of skeletal muscle may increase 100-fold
Answer» E. O2 consumption of skeletal muscle may increase 100-fold
discuss
15.

Atrial systole:

A. causes a decrease in atrial pressure
B. causes the ‘A’ wave of the jugular pulse
C. causes the ‘C’ wave of the jugular pulse
D. causes the ‘V’ wave of the jugular pulse
E. causes the dicrotic notch of the aortic pulse
Answer» B. causes the ‘A’ wave of the jugular pulse
discuss
16.

The depolarisation of cardiac muscle cells is characterised by:

A. a slow depolarisation, a plateau then a rapid repolarisation
B. initial depolarisation due to a slow Na+ influx
C. repolarisation due to K+ efflux through two types of K+ channels
D. a plateau phase due to slowly opening Na+ channels
E. calcium efflux during the plateau phase
Answer» D. a plateau phase due to slowly opening Na+ channels
discuss
17.

Regarding cardiac electrical properties:

A. all cardiac cells have the same resting membrane potential
B. cholinergic fibres act predominantly by blocking tonic sympathetic input
C. discharge rates of pacemaker tissue does not change significantly with temperature
D. the bundle of HIS is not the most rapidly conducting part of the conducting system
E. the last parts of myocardium to depolarise normally do not include the septum
Answer» D. the bundle of HIS is not the most rapidly conducting part of the conducting system
discuss
18.

Abnormalities causing ECG changes in myocardial infarction include:

A. delayed repolarisation early on
B. delayed depolarisation
C. increased resting membrane potential
D. TQ segment elevation
E. current flow away from the infarct
Answer» B. delayed depolarisation
discuss
19.

Features of the venous system include all of the following EXCEPT:

A. total volume is approximately 55% of the total vascular volume
B. compliance approximately 25 times the arterial side
C. total volume of venules is twice the total capillary volume
D. valves in the cerebral circulation
E. substantial venoconstriction in response to noradrenaline
Answer» D. valves in the cerebral circulation
discuss
20.

Arteriolar constriction is caused by:

A. serotonin
B. ANP
C. NO
D. K+
E. histamine
Answer» A. serotonin
discuss
21.

Regarding the inputs into the vasomotor centre:

A. baroreceptors causes stimulation
B. chemoreceptors cause inhibition
C. baroreceptors provide significant input below 70mmhg mean arterial pressure
D. atrial stretch receptors inhibit the vasomotor centre
E. direct inputs include pO2
Answer» D. atrial stretch receptors inhibit the vasomotor centre
discuss
22.

CSF:

A. volume is about 600ml
B. normal pressure is 5-10cm CSF
C. has a higher concentration of creatinine than plasma
D. has a higher concentration of urea than plasma
E. is formed solely in the choroid plexus
Answer» C. has a higher concentration of creatinine than plasma
discuss
23.

Regarding the conduction system of the heart:

A. the right bundle branch (of HIS) divides into anterior and posterior fasicles
B. the AV node contains P cells
C. myocardial fibres have a resting membrane potential of -60mV
D. action potential in the SA and AV nodes are largely due to Na+ influx
E. there are two types of K+ channels in pacemaker tissue – transient and long acting
Answer» B. the AV node contains P cells
discuss
24.

During systole:

A. the peak left ventricular pressure is 160mmHg
B. contraction of the atria propels 70% of the ventricular filling
C. the period of isovolumetric ventricular contraction is 0.5sec????
D. the end systolic ventricular volume is about 50mL
E. coronary blood flow to subendocardial portions of the left ventricle occur only in systole
Answer» D. the end systolic ventricular volume is about 50mL
discuss
25.

Regarding cardiac output:

A. “energy of contraction is proportional to the initial length of the cardiac muscle fibre” is Fick’s Law of the heart
B. cardiac index is the correlation between resting cardiac output and height
C. sleep decreases cardiac output
D. basal O2 consumption by the myocardium is 2ml/g/min
E. standing normally decreases the length of ventricular cardiac muscle fibres
Answer» E. standing normally decreases the length of ventricular cardiac muscle fibres
discuss
26.

Effects of electrolyte changes:

A. PR interval increases in hyperkalaemia
B. in hyperkalaemia, the heart stops in systole
C. hypercalcaemia causes prolongation of the ST segments
D. hypernatraemia is associated with low voltage electrocardiographic complexes
E. magnesium counteracts digitalis toxicity
Answer» E. magnesium counteracts digitalis toxicity
discuss
27.

Which statement is TRUE regarding cardiac muscle?

A. cardiac muscle fibres are multinucleated
B. they are smaller than skeletal muscle fibres
C. Ca2+ release is triggered by membrane repolarisation
D. the elastic ‘Titin” protein component is greater than in skeletal muscle, adding stiffness
E. the amount of Ca2+ in the sarcoplasmic reticulum is decreased by catecholamine stimulation
Answer» B. they are smaller than skeletal muscle fibres
discuss
28.

Which statement regarding cardiac “work” is FALSE?

A. the energy applied to the blood stream is defined as kinetic plus potential
B. potential energy involves consideration of energy stored in elastic arterial walls and gravity
C. there is an exchange between kinetic and potential energy
D. the largest drop in energy occurs at the level of the precupillary sphincters
E. the higher resistance in smaller calibre vessels corresponds to greater energy losses
Answer» D. the largest drop in energy occurs at the level of the precupillary sphincters
discuss
29.

Which statement about blood flow is FALSE?

A. cardiac output = stroke volume x heart rate
B. the volume of blood pumped through the lungs equals the volume entering the heart
C. Poiseville’s Law predicts the effects of pressure and resistance on cardiac output
D. the resistance of the systemic circulation is 5 to 10 times the pulmonary vascular resistance
E. with constant pressure, a vessel with radius ‘2X ‘ has 16 times the flow of vessel with radius ‘X’
Answer» B. the volume of blood pumped through the lungs equals the volume entering the heart
discuss
30.

Regarding haemodynamic principles, which statement is FALSE?

A. viscosity of blood with haematocrit of 40 is three times that of water
B. ‘arterial’ blood volume is 10-15% total volume
C. ‘elastance’ measures a vessel’s stiffness or recoil
D. aging causes increased elastance and therefore decrease in resting (unstressed) arterial volume
E. an increase in total peripheral resistance leads to increased arterial volume and BP
Answer» D. aging causes increased elastance and therefore decrease in resting (unstressed) arterial volume
discuss
31.

Considering conduction rates in myocardial cells, which statement is TRUE?

A. Perkinje fibres are subepicardial and are the largest fibres, 4-7 times the width of other fibres
B. Perkinje fibres are ‘fast fibres’, and can conduct a wave of depolarisation at a speed of 4m/sec
C. the duration of the action potential and refractory period in fast fibres is shorter than slow fibres
D. initial depolarisation occurs in fast fibres with a rapid influx of Ca2+ ions from the sarcoplasmic reticulum
E. none of the above statements are true
Answer» B. Perkinje fibres are ‘fast fibres’, and can conduct a wave of depolarisation at a speed of 4m/sec
discuss
32.

With respect to splanchnic circulation:

A. the liver is approximately 50% blood by volume
B. zone 3 of the hepatic acinus is well oxygenated
C. abdominal viscera receive at 30% cardiac output
D. liver receives blood from hepatic artery (1000???ml/min) and hepatic ??? vein (500ml/min)
E. muscular layer of intestinal wall has higher flow of mucosal layer
Answer» C. abdominal viscera receive at 30% cardiac output
discuss
33.

Blood pressure:

A. the sounds of Korotkoff when taking blood pressure are caused by laminar flow
B. the diastolic pressure in resting adults correlates to the muffling of Korotkoff sound
C. pressures obtained by palpation of auscultation methods are usually 2-5mmHg higher
D. if cuff is inflated for some time, it can give falsely low BP readings
E. sounds of Korotkoff occur when velocity of flow through constriction exceeds critical velocity
Answer» E. sounds of Korotkoff occur when velocity of flow through constriction exceeds critical velocity
discuss
34.

Coronary circulation:

A. left coronary artery has greater flow in 50% of people
B. thebesian veins connect arterioles to the heart chambers
C. cusps of the aortic valve occlude orifices of coronary arteries during LV ejection
D. coronary flow at rest is 250ml/min
E. at rest, heart extracts 50% O2 / unit of blood delivered
Answer» D. coronary flow at rest is 250ml/min
discuss
35.

Which statement is FALSE regarding CVS?

A. the primary function of the CVS uses convection
B. secondary function involves heat control
C. the heart is two pumps operating in parallel
D. the same volume of blood passes through each semilunar valve over time
E. the Frank Starling mechanism is used in balancing the output of both ventricles
Answer» C. the heart is two pumps operating in parallel
discuss
36.

Regarding the heart, which is TRUE?

A. the right and left ventricles perform the same amount of work, because the same volume of blood is pumped by each
B. the cross sectional shape of both ventricles is approximately cylindrical
C. the right ventricle pumps by a bellows type mechanism
D. the left ventricle pump action is via reducing cross-sectional area, as a function of radius cubed
E. in pulmonary disease the right ventricle hypertrophies and assumes a crescented shape in cross section
Answer» C. the right ventricle pumps by a bellows type mechanism
discuss
37.

Which is FALSE? Stroke Volume varies with changes in:

A. ventricular contractility
B. arterial pressure
C. end diastolic volume of ventricle
D. blood viscosity
E. right ventricle compared to left
Answer» E. right ventricle compared to left
discuss
38.

Regarding pressure in circulation, which is FALSE?

A. kinetic energy = M.V2(mass x velocity2)2
B. hydrostatic (gravitational) pressure = potential energy
C. the pressure in a foot vein may be 150 cm??? greater than at aortic root (in upright posture)
D. the same pressure differential applies in arterial system, (in upright posture)
E. the greatest pressure drop occurs in the capillaries
Answer» E. the greatest pressure drop occurs in the capillaries
discuss
39.

Regarding volumes in each compartment, which is FALSE?

A. 3% in LV and aorta
B. 15% in arterial system
C. 7% in capillaries
D. 50% in venous system (systemic)
E. 40% in pulmonary circulation
Answer» E. 40% in pulmonary circulation
discuss
40.

Regarding pressures, which is FALSE?

A. lateral (static) pressure is reduced but prolonged by elastic arteries
B. static pressure increases with gravitation (hydrostatic) pressure increases
C. static pressure does not include kinetic energy
D. greater resistance to flow through a segment of circulation leads to greater loss of energy through that segment
E. kinetic energy becomes more significant in a narrowed segment and converts back to potential energy when the tube widens
Answer» B. static pressure increases with gravitation (hydrostatic) pressure increases
discuss
41.

Regarding flow, which is FALSE?

A. flow is proportional to pressure gradient
B. flow is inversely proportional to resistance
C. Poiseville’s Law relates flow to pressure gradient and factors that influence resistance
D. Poiseville’ Law demonstrates that resistance to flow is largely determined by viscosity and length of tube and radius x 4
E. if radius of a vessel is halved, the flow may be reduced to 1/16th of previous flow
Answer» D. Poiseville’ Law demonstrates that resistance to flow is largely determined by viscosity and length of tube and radius x 4
discuss
42.

Which statement about factors affecting blood pressure is FALSE? Factors that increase blood pressure are:

A. increased heart rate
B. increased blood volume
C. pressure rises in increased cardiac output until the amount entering the arterial system equals the amount leaving
D. increased total peripheral resistance
E. increased end systolic volume
Answer» E. increased end systolic volume
discuss
43.

Regarding blood pressure, which is TRUE?

A. M.A.P. = pulse pressure / 2 + diastolic pressure
B. elastance increases progressively with age
C. increase in arterial blood pressure causes a subsequent increase in stroke volume
D. increased sympathetic stimulation may sometimes lead to decreased cardiac output
E. pulse pressure increases with age because of decreased arterial elastance
Answer» B. elastance increases progressively with age
discuss
44.

Regarding red blood cells, all are true EXCEPT:

A. erythropoiesis is stimulated by anaemia and hypoxia
B. after splenectomy, malaria has a higher mortality
C. normal adult haemoglobin is designated α2 β2
D. about 5% of adult haemoglobin is haemoglobin A2 (α2 δ2)
E. G6PD deficiency increases red cell susceptibility to lysis by drugs and infection
Answer» D. about 5% of adult haemoglobin is haemoglobin A2 (α2 δ2)
discuss
45.

Regarding the function of the heart:

A. at increased heart rates, diastole is shortened more than systole
B. the pericardial sac normally contains about 50ml of fluid
C. during the cardiac cycle, left ventricular ejection begins before right ventricular ejection
D. during expiration, the aortic valve closes before the pulmonary valve
E. the end—diastolic ventricular volume is about 170ml
Answer» A. at increased heart rates, diastole is shortened more than systole
discuss
46.

Regarding flow in vessels:

A. velocity is greatest closest to blood vessel walls
B. turbulence is almost always present at a Reynold’s number greater than 2,000
C. probability of turbulence in a vessel is directly related to twice the radius
D. flow in vessels is directly related to the fourth power of the ?????
E. turbulence is related to increasing radius
Answer» C. probability of turbulence in a vessel is directly related to twice the radius
discuss
47.

Which of the following does not increase the length of ventricular cardiac muscle fibres?

A. increased total blood volume
B. increased venous tone
C. increased pumping action of skeletal muscle
D. increased negative intrathoracic pressure
E. increased intrapericardial pressure
Answer» E. increased intrapericardial pressure
discuss
48.

Which of the following does not cause a systolic murmur?

A. aortic stenosis
B. anaemia
C. mitral insufficiency
D. tricuspid stenosis
E. normal flow in children
Answer» D. tricuspid stenosis
discuss
49.

Timing of events in the cardiac cycle:

A. right atrial systole begins after left atrial systole
B. the pulmonary closes after the aortic in inspiration
C. right ventricular ejection starts after left ventricular ejection
D. right ventricular systole starts after left ventricular systole
E. right and left atrial systole are synchronous
Answer» B. the pulmonary closes after the aortic in inspiration
discuss
50.

Starling’s Law of the heart:

A. is an example of hetermeric regulation
B. is an example of homomeric regulation
C. is explained by troponin / tropomyosin overlap
D. relates stroke volume to cardiac output
E. bears little relation to in vivo regulation of the heart
Answer» A. is an example of hetermeric regulation
discuss

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