Question

Which one of the following is correct pairing of a body part and the kind of muscle tissue that moves it?

• A. Heart wall- involuntary unstriated muscle
• B. Biceps of upper arm- Smooth muscle fibres
• C. Abdominal wall- Smooth muscle
• D. Iris- Involuntary smooth muscle

Answer 1

The correct option is D Iris- Involuntary smooth muscle

There are three types of muscles found in human body, namely skeletal muscle, smooth muscle and cardiac muscle. Skeletal muscles are also called as striated muscles. They are attached to the bone and helps in the movement of skeleton. These muscles are voluntary muscles as they are under voluntary control of somatic nervous system. Examples of skeletal muscle are muscles of arms and legs, muscles of abdomen and back. Smooth muscles are involuntary muscles as they are not controlled voluntarily. They are also called as unstriated muscles as they do not have stripes appearance as in case of skeletal muscle. Examples of smooth muscles include walls of stomach, oesophagus, bronchi and iris. Involuntary smooth muscle of iris helps to adjust pupil size. Cardiac muscles are found only in the walls of the heart. These are involuntary muscles.

Thus, the correct answer is option D.