The digestive system is controlled by both the nervous system and hormones. The sympathetic and parasympathetic nervous systems regulate digestive activity through nerves like the greater splanchnic, lumbar splanchnic, and sacral splanchnic nerves (sympathetic) and the vagus nerves (parasympathetic). Key hormones that control digestion include gastrin, secretin, cholecystokinin, and GIP. These hormones stimulate or inhibit processes like gastric juice secretion, bile production, and pancreatic juice secretion. Digestion is regulated in three phases: cephalic, gastric, and intestinal phases which involve neural and hormonal responses to prepare the GI tract for digestion and movement of food.

1. By: Safana Sadiq

2. 
The digestive system is controlled by both:
 Nerves, and
 Hormones

3. Neuronal control of
digestion

Autonomic Nervous System
SNS PNS
Digestive system Digestive system activity
activity

4. Sympathetic nerves that regulate digestion are:

 The greater splanchnic nerves
 The lumbar splanchnic nerves, and
 The sacral splanchnic nerves

5. 
The parasympathetic nerve that regulates
digestion are the vagus nerves.

6. Hormones that control digestion are:

 Gastrin
 Secretin
 Cholecystokinin
 Glucose insulinotropic peptide (GIP)

7. Effects of gastrin

 Stimulates gastric juice secretion
 Stimulates smooth muscle contraction
 Relaxation of pyloric sphincter

8. Effects of secretin

 Stimulates bicarbonate secretion
 Stimulates bile production
 Inhibits gastric juice secretions and gastric motility

9. Effects of cholecystokinin

 Stimulates bile release
 Stimulates pancreatic juice secretion
 Relaxation of the hepatopancreatic ampulla and
opening of hepatopancreatic sphincter

10. Effects of GIP

 Stimulates the pancreas to begin release of insulin

11. The 3 phases of digestive
regulation

 Cephalic phase
 Gastric phase
 Intestinal phase

12. Cephalic Phase

 Neuronal response:
Stimuli that arouse digestion relayed to
hypothalamus
Nerve impulse initiated in vagus nerve
Impulse innervates nerve network of GI tract
Contraction of sm ms & secretion of gastric juice
promoted

13. Gastric Phase

The stimuli that initiates gastric phase includes:
 Distension of the stomach
 Low acidity
 Presence of peptides

14. Gastric Phase

 Neural response: gastric juice secretion & smooth
muscle contraction promoted
 Hormonal response: gastrin production promoted
 General effect: stomach and small intestine prepare
for digestion of chyme , and gastric emptying is
promoted

15. Intestinal Phase

 Neural response:
 gastric secretion & gastric motility are inhibited
 Intestinal secretion, sm ms contraction, bile &
pancreatic juice production are promoted

16. Intestinal Phase

 Hormonal response: production of secretin, CCK &
GIP is promoted
 General effects : gastric emptying is retarded to
allow adequate time for digestion in the SI. And
intestinal digestion and motility are promoted.

17. Reference

http://www.cliffsnotes.com/study_guide/t
opicArticleId-277792,articleId-27770.html
http://www.aboutgastro.com/digestive-
system/regulation-of-digestive-process