Question

Bundle of His is:
(a) Nervous tissue supplying ventricles
(b) Nervous tissue supplying the heart
(c) Muscular tissue supplying atria
(d) Muscular tissue supplying ventricles

Answer 1

Hint: A bundle of his was discovered by Wilhelm His Jr. and is a part of the heart electrical conduction system. The heart electrical conduction system helps in the generation of electrical impulses which later on passes to another part of the heart leading to the distribution of blood all over the body.

Complete answer:
Bundle of His or Atrioventricular bundle is specialized muscle cells of the heart that helps in the transmission of the electrical impulse to Purkinje fibers of ventricles from the AV node.
The electrical conduction functions of the heart functions in the following way:
- At first, an impulse is generated by the SA node which is present in the right atrial wall of the heart and this impulse spreads across the atria and contracts it.
- This contraction moves the blood from the atria to the ventricle and this impulse gets converged at the AV node which delays the impulse to about 120ms.
- This impulse then passes from the AV node to the Purkinje fibers that are located in the wall of the ventricles. Bundle of His help in the distribution of this impulse throughout the wall of ventricles causing the contraction of ventricles.
- As a result of this, blood flows to the pulmonary artery and aorta.
So, the correct answer is, ‘Muscular tissue supplying ventricles’.

Note:
- The heart is formed during the 3^rd week of the gestation period and is derived from the mesoderm.
- Bundle of His prevents the lateral spread of the propagated impulse.