1. Rate of heartbeat is determined by
a) SA node
b) AV node
c) Purkinje fibres
d) Papillary muscles
Explanation: Rate of heartbeat is determined by SA node
2. In amphibia, the heart has
a) Two auricles and two ventricles
b) Two auricles and one ventricle
c) One auricle and two ventricles
d) One auricle, one ventricle and one sinus venosus
Explanation: In amphibia, the heart has two auricles and one ventricle
3. SA node is called the pace maker of the heart. Why?
a) It can change contractile activity generated by AV node.
b) It delays the transmission of impulse between the atria and ventricles.
c) It gets stimulated when it receives neural signal.
d) It initiates and maintains the rhythmic contractile activity of heart
Explanation: It initiates and maintains the rhythmic contractile activity of heart
4. Sino-Atrial node (SAN) can generate impulses
a) 70–75 \[min^{-1}\]
b) 50–55 \[min^{-1}\]
c) 35–40 \[min^{-1}\]
d) 90–100 \[min^{-1}\]
Explanation: 70–75 \[min^{-1}\]
5. The impulse of heartbeat originates from
a) SAN
b) AVN
c) Vagus nerve
d) Cardiac nerve
Explanation: SAN
6. Rate of heart is determined by
a) SAN
b) AVN
c) Purkinje fibres
d) Bundle of His
Explanation: Rate of heart is determined by SAN
7. Bundle of HIS is a group of
a) Ganglia
b) Nerve fibres
c) Muscular fibres
d) Connective tissue
Explanation: Bundle of HIS is a group of muscular fibres.
8. Bundle of HIS found in
a) Right atrium
b) Left atrium
c) Both (a) and (b)
d) Interventricular septum
Explanation: Interventricular septum
9. An atrioventricular valve prevents the back flow or leakage of blood from the
a) Right ventricle into the right atrium
b) Left atrium into the left ventricle
c) Aorta into the left ventricle
d) Pulmonary vein into the right atrium
Explanation: Right ventricle into the right atrium
10. How many double circulation are normally completed by the human heart in one minute?
a) 8
b) 16
c) 36
d) 72
Explanation: 72