Question

7. What type of motility pattern increases mechanical digestion?

A - segmentations in the small intestine

B - peristalsis in the colon

C - haustral churning in the large intestine

D - retropropulsion in the antrum

Answer 1

Answer) option D-retropropulsion in the antrum

Explanation - Mostly mechanical digestion takes place in the mouth(oral cavity) and stomach.

Stomach consists of 4 parts - cardiac part, fundus, body, pylorus(pylorus divided into pyloric antrum and pyrolic canal)

Mechanical digestion means breakdown of large food particles into smaller particles.

Chemical digestion takes place with help of digestive enzymes.

In stomach both mechanical and chemical digestion takes place.

Gastric emptying of food to the duodenum occurs due to the contraction of pyloric antrum.

As retropropulsion of food by pyloric antrum to the body of stomach f takes place,so that food goes back to the stomach. Then food is mixed thoroughly with the gastric juice of the stomach by the churning movements of its muscular wall and the product formed is called chyme. This chyme represents smallest particles of the food, so retropropulsion helps in the increase in mechanical digestion.

Other options are incorrect -

As mechanical digestion not takes place in the small intestine, large intestine and colon. In these structures, the motility pattern helps in the chemical digestion (not mechanical digestion).