Question

Name the following

(i) The part inside the heart that initiates heartbeat.

(ii) The structure that holds the heart valves in position.

Answer 1

Heart:

• The heart is the main pumping organ found in most animals.
• It pumps blood to all parts of the body.
• The heart has four chambers namely - left auricle, right auricle, left ventricle, and right ventricle.
• It has four valves namely - tricuspid, pulmonary semilunar, mitral, and aortic semilunar valve.

(i) SA node:

1. The Sino-Atrial node is a band of muscles or a myocardial structure found at the opening of the vena cava.
2. It generates electrical impulses which stimulate contraction.
3. It initiates the cardiac cycle hence the heartbeat.

(ii) Chordae tendineae:

1. The thread-like bands of fibrous tissues that are attached to the edges of heart valves are called chordae tendineae.
2. Chordae tendineae serves as an anchor and help to attach the heart valves in position.

The part inside the heart that initiates the heartbeat is SA node.

The structure that holds the heart valves in position is chordae tendineae.