Body Fluids and Circulation

Question 1

The number of action potentials generated by sino-atrial node (SAN) in a healthy human is _______ per minute.

Accepted Answer

70 – 75. The sino-atrial node is the pacemaker, and each action potential it generates produces one heartbeat. A healthy resting heart rate is about 70–75 beats per minute, so that is the SAN's firing rate.

Answer

28 - 30

Answer

100 - 110

Answer

120 - 140

Question 2

Which of the following statements is incorrect?

Accepted Answer

Fibrinogen is produced from fibrin. The conversion runs one way only: the enzyme thrombin converts the inactive plasma protein fibrinogen into fibrin threads, which mesh to form the clot. Option D reverses that, which is why it is the incorrect statement.

Answer

Blood coagulates in response to an injury

Answer

Blood clot consists of fibrins

Answer

Fibrin is produced from fibrinogen

Question 3

The opening between the right atrium and the right ventricle is guarded by _________.

Accepted Answer

tricuspid valve. The right atrioventricular opening carries a valve of three cusps, hence tricuspid. The left side has the two-cusped bicuspid or mitral valve, and semilunar valves guard the exits into the pulmonary artery and aorta.

Answer

bicuspid valve

Answer

semilunar valve

Answer

sino-atrial node

Q1.The number of action potentials generated by sino-atrial node (SAN) in a healthy human is _______ per minute.

Q2.Which of the following statements is incorrect?

Q3.The opening between the right atrium and the right ventricle is guarded by _________.