In open circulatory system, blood is pumped through

(1) Sinuses to large vessels

(2) Large vessels to sinuses

(3) Cavities to organs

(4) Spaces to large vessels

Consider the following statement with respect to heart:

(i) It has the double walled membranous bag.

(ii) Human heart has four chambers: two larger atria and two median ventricles.

(iii) Human heart is mesodermal in origin and is situated in abdominal cavity.

(iv) There is no clear separation between atria and ventricles.

How many of the statements given above are correct?

(1) 2

(2) 3

(3) 1

(4) all are wrong

Inter atrial septa are:

(1) thin muscular

(2) thick muscular

(3) thin fibrous

(4) thick fibrous

Which one is incorrect in the following:

(1) Inter atrial septa – thin and muscular

(2) Atrio– ventricular septa – thick and fibrous

(3) Inter ventricular septa – thick and muscular

(4) Pericardium – muscular

SAN is present in __________ while AVN is present in __________.

(1) Right upper corner and left lower corner of both the atria.

(2) Right upper corner and left lower corner of right atrium.

(3) Right upper corner and left lower corner of left atrium.

(4) Right upper corner and left median corner of left atrium

Bundle of His includes:

(1) Purkinje fibres + left AV bundle

(2) Purkinje fibres + right AV bundle

(3) Purkinje fibres + right and left AV bundle

(4) SA node + AV node + AV bundle

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 duration of cardiac cycle is–

(1) 0.8 second

(2) 0.5 second

(3) 0.3 second

(4) 0.4 second

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.

The route of action potential in heart is

(1) SA node – AV node – AV bundle

(2) AV node – SA node – bundle of his – AV bundle

(3) SA node – AV node – AV bundle – Bundle of His

(4) SA node – AV node – Purkinje fibres