Circulation 1

Question 1

Electrocardiogram is the record of :

Answer 1

Potential changes of cardiac muscle fibers

Question 2

P wave is due to :

Answer 2

Depolarization of atria

Question 3

QRS complex is due to :

Answer 3

Depolarization of ventricles

Question 4

T wave is due to :

Answer 4

Repolarization of ventricles

Question 5

Significance of electrocardiography is identification of :

Answer 5

Heart rate, Heart rhythm, Ischemic heart diseases

Question 6

Rhythmicity & Automaticity is the ability of the heart to :

Answer 6

Generate regular excitation waves Independent

Question 7

SA node is normal :

Answer 7

Primary pacemaker

Question 8

SA node is the normal primary pacemaker of the heart as it has the highest rate of discharge is :

Answer 8

100/min

Question 9

AV node rate of discharge is :

Answer 9

40-60/min

Question 10

AV node is the :

Answer 10

Secondary pacemaker of the heart

Question 11

His-Purkinje fibers rate of discharge is :

Answer 11

20-40/min

Question 12

Heart lies in the thorax behind :

Answer 12

Sternum

Question 13

Name 4 chambers of heart :

Answer 13

Rt atrium, Rt ventricle, Lt atrium, Lt ventricle

Question 14

Rt & Lt atria are separated by :

Answer 14

Inter-atria septum

Question 15

Rt & Lt ventricles are separated by :

Answer 15

Inter-ventricular septum

Question 16

Name 4 valves of heart :

Answer 16

Tricuspid valve (between Rt atrium & Rt ventricle) ,
Bicuspid(mitral) valve (between Lt atrium & Lt ventricle) ,
Pulmonary valve (at beginning of pulmonary trunk) ,
Aortic valve (at beginning of aorta)

Question 17

The atria walls are thinner than :

Answer 17

Ventricles walls

Question 18

The right ventricle wall is thinner than :

Answer 18

Left ventricle

Question 19

Heart is covered by :

Answer 19

Pericardium

Question 20

Heart is blood supplied by :

Answer 20

Rt & Lt Coronary arteries

Question 21

Nerve supply of heart ;
sympathetic supply :
parasympathetic (vagus) supply :

Answer 21

sympathetic: Atria & Ventricles
parasympathetic: Atria only

Question 22

Histologically, Heart wall consists of 3 layers ;
inner :
middle :
outer :

Answer 22

inner: Endocardium
middle: Myocardium
outer: Epicardium

Question 23

Specialized cardiac muscle fibers responsible for :

Answer 23

Generation & Conduction

Question 24

SA node present in the upper lateral wall of :

Answer 24

Right atrium

Question 25

AV node present in lower part of :

Answer 25

Inter-atrial septum

Question 26

Which specialized cardiac muscle fiber passes down from Atria to Ventricles ?

Answer 26

AV Bundle of His

Question 27

Right & Left bundle branches pass down on either side of :

Answer 27

Inter-ventricular septum

Question 28

Purkinje fibers pass in the wall of :

Answer 28

Ventricles

Question 29

Heart functions as :

Answer 29

Muscular pump

Question 30

Cardiac contraction called :

Answer 30

Systole

Question 31

Cardiac relaxation called :

Answer 31

Diastole

Question 32

Arteries carry blood away from heart, Large arteries have :

Answer 32

Thick elastic walls

Question 33

Capillaries are microscopic vessels, that may contain :

Answer 33

Pores

Question 34

Veins carry blood back to heart, They have :

Answer 34

Thin walls

Question 35

Systemic circulation is the passage of oxygenated blood from Lt ventricle to Aorta to body, then venous blood returns through :

Answer 35

SVC & IVC

Question 36

Pulmonary circulation is the passage of deoxygenated blood from Rt ventricle to Pulmonary artery to lungs then returns back through :

Answer 36

Pulmonary vein

Question 37

SA node (heart pacemaker) generates :

Answer 37

Electrical impulses

Question 38

Inter-nodal atrial bundles transmit impulses through atria to :

Answer 38

AV node

Question 39

Bundle of His transmits impulses to :

Answer 39

Rt & Lt bundle branches

Question 40

Rt & Lt bundle branches transmit impulses to :

Answer 40

Purkinje fibers

Question 41

Purkinje fibers transmit impulses through :

Answer 41

Wall of the ventricles

Question 42

Excitability to the ability to :

Answer 42

Respond to stimuli

Question 43

Resting membrane potential (RMP) of the contractile muscle fibers :

Answer 43

-90 mV

Question 44

Depolarization (phase 0) is due to opening of :

Answer 44

Na+ voltage gated channels so rapid inflow of Na+

Question 45

Depolarization (phase 0) is till the membrane potential is :

Answer 45

+20 mV

Question 46

Repolarization (phase 1) is small repolarization due to :

Answer 46

Outflow of K+

Question 47

Repolarization (phase 2) slows & form a Plateau due to :

Answer 47

K+ Outflow & Ca++ Inflow

Question 48

Repolarization (phase 3) is complete rapid repolarization till reaching RMP -90 due to :

Answer 48

Outflow of K+

Question 49

Calcium inflow from :

Answer 49

Extracellular fluid via voltage gated calcium channels

Question 50

Calcium release from :

Answer 50

Sarcoplasmic reticulum

Question 51

Calcium binds to :

Answer 51

Troponin moving Tropomyosin away from actin Active site allowing binding of Myosin head

Question 52

Myosin head pulls :

Answer 52

Actin filament

Question 53

Relaxation occurs by :

Answer 53

Pumping intracellular calcium