Question 1

Smooth muscle tissue is responsible for peristalsis in the sigmoid colon.

Smooth muscle is the type of muscle tissue responsible for involuntary movements in the digestive tract, including peristalsis, which propels contents through the sigmoid colon.

A) Smooth

Smooth muscle is specialized for involuntary control and is found in the walls of hollow organs, including the intestines. It enables rhythmic contractions, known as peristalsis, which help in moving food and waste through the digestive system, particularly in the sigmoid colon.

B) Skeletal

Skeletal muscle is under voluntary control and is responsible for movement of the skeleton. It does not participate in peristalsis, as it functions primarily in actions that require conscious control, such as walking or lifting.

C) Cardiac

Cardiac muscle is found exclusively in the heart and is responsible for pumping blood throughout the body. It does not play a role in peristalsis or any movement within the digestive tract, including the sigmoid colon.

D) Striated

Striated muscle is a term often used to describe skeletal muscle due to its striped appearance, but it refers specifically to voluntary muscles. Like skeletal muscle, striated muscle does not facilitate peristalsis, which is an involuntary process carried out by smooth muscle.

Conclusion

Smooth muscle tissue is the definitive answer for the question since it is the only type of muscle responsible for involuntary movements such as peristalsis in the sigmoid colon. The other options—skeletal, cardiac, and striated muscles—do not contribute to the peristaltic process and are characterized by different functions and control mechanisms.