Which of the following is a factor affecting intestinal motility?

Hormonal control is a significant factor affecting intestinal motility because hormones play a crucial role in regulating the movement of the intestines. Various hormones, such as gastrin, cholecystokinin, and secretin, can stimulate or inhibit intestinal contractions, influencing digestion and the transit of food through the digestive tract. For example, the release of gastrin increases gastric motility, while cholecystokinin stimulates the contraction of the gallbladder and promotes the movement of food through the intestines.

In contrast, while the presence of digestive enzymes can aid in the breakdown of food, it does not directly impact the mechanics of motility. The structure of intestinal villi primarily serves to increase surface area for absorption rather than influencing motility directly. Lastly, types of nutrients may affect the rate at which digestion occurs but are not direct regulators of motility like hormones are. Therefore, hormonal control is the primary factor involved in actively regulating the contractions and movements of the intestinal walls during digestion.