The number of action potential generated by SAN:

(1) 70–75 times per minute.

(2) 50–72 times per minute.

(3) Exact 70 times per minute.

(4) not more than 60 times per minute.

'Bundle of His' is a part of which one of the following organs in humans?

1. Heart

2. Kidney

3. Pancreas

4. Brain

SAN is responsible for

(1) initiating and maintaining a random contractile ability of heart

(2) initiating and maintaining a rhythmic contractile ability of heart

(3) maintaining a random contractile ability of heart

(4) Initiating a rhythmic contractile ability of heart

What does the depolarization of ventricles initiate?

(1) Atrial Diastole

(2) Atrial systole

(3) ventricular systole

(4) Joint Diastole

Which of the following sequences best represents the pathway of an action potential through the Heart's conduction system?

(i) Sino-atrial (SA) node

(ii) Purkinje fibres

(iii) Bundle of His

(iv) Atrio-ventricular (AV) node

(v) Right and left bundle branches

1. (i),(iv),(iii),(ii),(v)

2. (iv), (i),(iii),(v),(ii)

3. (iii),(iv),(i),(ii),(v)

4. (i),(iv),(iii),(v),(ii)

Normal activities of the human heart are regulated:

1. Intrinsically

2. By the autonomic nervous system

3. By the brain stem

4. By the diencephalon

Which one of the following is wrong with respect to nodal tissue.

(1) auto excitable

(2) not localized to a single chamber.

(3) equal ability to excite throughout nodal tissue.

(4) structural changes are observed throughout nodal musculature in different chambers of the heart.

The action potential of ventricular side and to the entire ventricular musculature is conducted by–

(1) AVN, AV bundle and Bundle of His

(2) SAN, AVN, AV bundle and Bundle of His

(3) SAN, AV bundle and Bundle of His

(4) Only by Bundle of His

Depolarisation and repolarisation actually initiate ___________ in different chambers of heart?

(1) contraction and relaxation

(2) relaxation and contraction

(3) thickening and thinning

(4) thinning and thickening

The action potential causes ______ and then the ______ to undergo ______ followed by ______.

(1) ventricles, atria, contraction, relaxation

(2) atria, ventricles, contraction, relaxation

(3) ventricles, atria, relaxation, contraction

(4) atria, ventricles, relaxation, contraction