Question

Which one of the following is correct pairing of a body part with the kind of muscle tissue present in it?

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

Answer 1

The Correct Option is C

The question is about identifying the correct pairing of a body part with the type of muscle tissue it contains. Let's examine the given options one by one:

1. Biceps of upper arm ? Smooth muscle fibres: The biceps of the upper arm contains skeletal muscle tissue, which is striated and voluntary. Therefore, this pairing is incorrect.
2. Abdominal wall ? Voluntary smooth muscle: Smooth muscles are involuntary, whereas skeletal muscles, which are voluntary, are found in areas like the abdominal wall. This makes the pairing incorrect as smooth muscles are not voluntary.
3. Iris? Involuntary smooth muscle: The iris of the eye contains smooth muscle fibres. These muscles control the size of the pupil and are indeed involuntary. Hence, this is the correct pairing.
4. Heart wall ? Involuntary unstriated muscle: The heart wall consists of cardiac muscle, which is striated and involuntary. Thus, referring to the heart muscle as unstriated is incorrect.

By analyzing each option, it is clear that option 3, "Iris? Involuntary smooth muscle", is the correct pairing. Muscles in the iris are smooth muscles that allow for involuntary adjustments in pupil size.

Conclusion: The correct answer is Iris? Involuntary smooth muscle, which accurately matches the structure of the iris with its muscle type.