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REGULATION OF DIGESTION By: Safana Sadiq

Regulation of digestion

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Page 1: Regulation of digestion

REGULATION OF DIGESTION

By: Safana Sadiq

Page 2: Regulation of digestion

The digestive system is controlled by both: Nerves, and

Hormones

Page 3: Regulation of digestion

Autonomic Nervous System

SNS PNS

Neuronal control of digestion

Digestive system activity

Digestive system activity

Page 4: Regulation of digestion

Sympathetic nerves that regulate digestion are:

The greater splanchnic nerves

The lumbar splanchnic nerves, and

The sacral splanchnic nerves

Page 5: Regulation of digestion

The parasympathetic nerve that regulates

digestion are the vagus nerves.

Page 6: Regulation of digestion

Hormones that control digestion are:

Gastrin

Secretin

Cholecystokinin

Glucose insulinotropic peptide (GIP)

Page 7: Regulation of digestion

Stimulates gastric juice secretion

Stimulates smooth muscle contraction

Relaxation of pyloric sphincter

Effects of gastrin

Page 8: Regulation of digestion

Stimulates bicarbonate secretion

Stimulates bile production

Inhibits gastric juice secretions and gastric motility

Effects of secretin

Page 9: Regulation of digestion

Stimulates bile release

Stimulates pancreatic juice secretion

Relaxation of the hepatopancreatic ampulla and opening of hepatopancreatic sphincter

Effects of cholecystokinin

Page 10: Regulation of digestion

Stimulates the pancreas to begin release of

insulin

Effects of GIP

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Cephalic phase

Gastric phase

Intestinal phase

The 3 phases of digestive regulation

Page 12: Regulation of digestion

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

Cephalic Phase

Page 13: Regulation of digestion

The stimuli that initiates gastric phase includes:

Distension of the stomach

Low acidity

Presence of peptides

Gastric Phase

Page 14: Regulation of digestion

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

Gastric Phase

Page 15: Regulation of digestion

Neural response:

gastric secretion & gastric motility are inhibited Intestinal secretion, sm ms contraction, bile &

pancreatic juice production are promoted

Intestinal Phase

Page 16: Regulation of digestion

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.

Intestinal Phase