Chapter 14 (Transport) F.Sc 1st Year Biology Short Questions

What are coronary arteries?

At the base of aorta, first pair of arteries, the coronary arteries, arise, and supply blood to the heart.

How many branches are given off by aorta before descending down?

Aorta forms an arch, and before descending down gives three branches . supplying blood to head, arms and shoulders.

Name the branches of iliac arteries and body parts supplied by them.

Each iliac artery divides into two arteries i.e., femoral and sciatic arteries supplying blood to legs.

What is ventricular systole? or How lub and dub sounds are made?

When the ventricles receive blood from atria, both ventricles contract simultaneously and the blood is pumped to pulmonary artery and aorta. The tricuspid and bicuspid valves close, and lub sound is made. Ventricular systole ends, and ventricles relax at the same time, semilunar valves at the base of pulmonary artery and aorta close simultaneously, and ‘dub sound is made.

What is sino-atrial node or pace maker? What is the function of pace maker?

The stimulus for contraction of the heart originates in a specific region called the sino-atrial node (S-A node) or pace maker at the upper end of right atrium, Pacemaker is responsible for initiating the impulses which trigger the heart beat rate.

What is composition of S-A node?

The S-A node consists of a small number of diffusely oriented cardiac fibres, possessing few myofibrils and few nerve endings from the autonomic nervous system.

What is electrocardiogram?

It is an electrographic interpretation of the electrical flow of impulses in the heart, and is taken by E.C.G. (electrocardiograph) machine.

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