Biology, Eighth Edition (Raven)

Chapter 48: The Digestive System

Hormones and Gasric Secretion

Why is the secretion of gastric fluids controlled both locally and through the central nervous system? The smell and taste of food begin the process of gastric secretion. The stomach is prepared in advance for the food that will arrive shortly. Once the food arrives in the stomach the amount of gastric fluid can be increased proportionately to the amount of food. Thus the central nervous system is starting up the system and local effects are fine-tuning the amount of secretion.

View the animation below, then complete the quiz to test your knowledge of the concept.


1.	Which of the following does NOT stimulate the secretion of HCl in the stomach?

		A)	the smell of food
		B)	the taste of food
		C)	the distention of the stomach as it fills with food
		D)	secretin
		E)	all of the above stimulate secretion of HCl in the stomach

2.	Secretin is released from the duodenum in response to

		A)	hydrochloric acid in chyme.
		B)	sodium hydroxide in chyme.
		C)	the hormone gastrin.
		D)	partially digested protein.
		E)	partially digested carbohydrate.

3.	Which of the following hormones is produced by the stomach?

		A)	insulin
		B)	secretin
		C)	pepsin
		D)	trypsin
		E)	chymotrypsin

4.	When chyme enters the duodenum, gastric secretion increases.

		A)	True
		B)	False

5.	Gastrin functions to increase the production of HCl in the stomach.

		A)	True
		B)	False