Cardio vascular system: (Physiology practice multiple choice questions for FCPS, MRCP, USMLE, and PLAB)

1) S.A. node is the pacemaker of heart because of

a. location in the right atrium     

b. neural  control

c. natural leakiness to Na+          

d. Natural leakiness to k+

Ans. c

2) Absolute refractory period in the heart

a. corresponds to the duration of relaxation       

b. lasts till half of cardiac contraction

c. shorter than refractory period in skeletal muscle         

d.   lasts till cardiac contraction

Ans. d

3) First heart sound occurs during the period of

a. isometric relaxation  

b. isotonic relaxation

c. isovolumetric contraction       

d. isovolumetric relaxation

Ans. c

4) Which of these vessels does not have sympathetic control

a. cerebral          

b. splanchnic

c. cardiac             

d. cutaneous

Ans. a

5) Blood brain barrier is made up of

a. astrocytes     

b. oligodendrocytes

c. oligodendroglia           

d. microglia

Ans. a

6) Positive bathmotropic effect on heart is produced by

a. stimulation of vagus nerve     

b.  stimulation of sympathetic nerves

c. atropin            

d. sectioning of vagus

Ans. b

7) Mary's law denotes relationship between heart and

a. contractility and conductivity                

b. rate and contraction

c. rate and BP   

d. contraction and BP

Ans. c

8) Which of the following conducting systems has the slowest conducting velocity

a. SAN  

b. atrial muscle

c. purkinje fibres             

d. AVN

Ans. c

9) In heart, within physiological limits the force of contraction is directly proportional to the

a. pacemaker activity    

b. a-v nodal delay

c. initial length of the cardiac muscle      

d. respiratory rate

Ans. c

10) The diacrotic notch on aortic pressure curve is caused by

a. closure of mitral valve              

b. closure of tricuspid valve

c. closure of atrial valve                

d. closure of pulmonary valve

Ans. c

11) The PR interval of ECG corresponds to

a. ventricular repolarization        

b. ventricular repolarization

c. atrial repolarization and conduction through AV node               

d. repolarization of AV node and bundle of His

Ans. c

12) Increased vagal tone causes

a. hypertension               

b. tachycardia

c. bradycardia   

d. increase in cardiac output

Ans. c

13) Which of the following is not increased during exercise

a. Stroke volume             

b. total peripheral resistance

c. systolic BP      

d. heart rate

Ans. b

14) Which of the following takes longest time to return to normal after 1L of blood is removed from a normal individual

a. number of RBC's in peripheral blood

b. plasma volume

c. renin secretion            

d. blood pressure

Ans. a

15) When a pheochromocytoma suddenly discharges a large amount of epinephrine into the circulation the patients heart rate would be expected to

a. increase because epinephrine has a direct chronotropic effect on the heart   

b. increase because of increased parasympathetic discharge to the heart

c. decrease because the increase in blood pressure stimulates the carotid and aortic baroreceptors        

d. decrease because of increased tonic parasympathetic discharge to heart

Ans. a

16) In  a patient with mitral stenosis one would expect to hear

a. continuous murmur  

b. a systolic murmur loudest over the base of heart

c. a diastolic murmur loudest over the apex of heart      

d. a diastolic murmur loudest over the base of heart

Ans. c

17) The 's' wave in ECG is below isoelectric line because of

a. repolarization of ventricles    

b. change in direction of the impulse when the base of the ventricles are getting depolarised

c. depolarisation of apex of heart            

d. repolarisation of apex of heart

Ans. b

18) Which of the following is least likely to cause hypertension

a. chronically increased secretion of adrenal medulla     

b. treatment with OCP

c. chronically increased secretion of thyroid gland            

d. chronically increased secretion by zona glomerulosa of adrenal cortex

Ans. c

19) Lymph flow from the foot is

a. increased when an individual rises from the supine to standing position           

b. increased by massaging the foot

c. increased when capillary permeability is decreased    

d. decreased by exercise

Ans. b

20) The pressure in the radial artery is determined by

a. the degree of constriction of brachial vein      

b. the rate of discharge in sympathetic nerve fibres to the arm

c. pressure in the hepatic portal vein     

d. pressure in the brachial vein

Ans. b

21) The 'T' wave in ECG is above the isoelectric line because of

a. depolarisation of ventricles    b. depolarisation of bundle of His

c. change in the direction of repolarisation from the wave of depolarization of the ventricles      

d. repolarisation of purkinje fibres

Ans. c