Question

Which muscles act involuntarily?
(i) Striated muscles
(ii) Smooth muscles
(iii) Cardiac muscles
(iv) Skeletal muscles

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (iii) and (iv)
• D. (i) and (iv)

Answer 1

The correct option is B

(ii) and (iii)

The correct option is B.

The explanation for the correct option:

1. Smooth muscles are found in the body's visceral organs such as the urinary bladder, uterus, respiratory tract, and so forth and they are involuntary muscles.
2. Cardiac muscles, on the other hand, are found in the heart and assist in the rhythmic contraction and relaxation of the auricles and ventricles.
3. Involuntary movements are defined as cardiac movements that are not controlled by the human body.

The explanation for the incorrect option:

Option A:

Striated muscles move according to our will and are voluntary in action whereas cardiac muscles are involuntary muscles.

Option C:

Cardiac muscles are involuntary muscles whereas skeletal muscles, on the other hand, are related to bones and function in bodily motions such as walking and running because they are under the direct control of an individual, these are voluntary movements.

Option D:

Striated and skeletal muscles move according to our will and are voluntary in action.

Final answer: (ii) and (iii) Smooth muscles and Cardiac muscles act involuntarily.