Question

The internal lining of walls of hollow organs is made up of one of the following types of muscular tissue.
I. Cardiac
II. Smooth
III. Striated
A. I only
B. II only
C. III only
D. I and II
E. II and III

Answer 1

It is an involuntary non- striated muscle.

Complete answer: Cardiac muscle is the muscle that is found only in the heart.
Smooth muscle is a non- striated muscle. It is found in the walls of hollow organs such as stomach, intestines, urinary bladder, uterus etc.
Striated muscle tissue has repeating functional units called sarcomeres. It is of two types- cardiac muscle and skeletal muscle. It contains T-tubules which enables the release of calcium ions from the sarcoplasmic reticulum.

Additional information: In skin the smooth muscle cells cause goosebumps in response to cold temperature or fear.
1. Smooth muscles are divided into- single unit and multi-unit smooth muscle.
2. Most of the smooth muscles are single units which means that the whole muscle contracts or relaxes. Single unit smooth muscles are present on the urinary tract, digestive system etc.
3. Multi-unit subunit is present in the trachea, large elastic arteries and in the iris of the eye.
4. Smooth muscle cells are known as myocytes.
5. Elasticity is an important function of smooth muscles. It is able to stretch itself whenever necessary.
6. Smooth muscles contract in a peristaltic fashion in the digestive tract. It rhythmically forces foodstuff through the digestive tract as the result of phasic contraction.

So, the answer is B. II only, which means smooth muscle.

Note: In some special smooth muscles, renin is secreted in response to osmotic and pressure changes. Renin helps in regulating the renin-angiotensin system to regulate blood pressure.