Figure 24-2 The Wall of the Small Intestine

Use Figure 24-2 to answer the following questions:
-Contraction of the muscle layer labeled "9" causes the digestive tract to
A) constrict.
B) shorten.
C) dilate.
D) fold for increased surface area.
E) secrete enzymes.

Question

Figure 24-2 The Wall of the Small Intestine
 
Use Figure 24-2 to answer the following questions:
-Contraction of the muscle layer labeled "9" causes the digestive tract to
A) constrict. 
B) shorten. 
C) dilate. 
D) fold for increased surface area. 
E) secrete enzymes.

Quizplus · Accepted Answer

The muscle layer labeled "9" is the muscularis externa, which is responsible for peristalsis, the rhythmic contractions that move food through the digestive tract. Peristalsis involves constriction of the muscle layer, which propels the food forward.

Figure 24-2 the Wall of the Small Intestine