1. Hormones of the Digestive System

2. Hormone Basics
Hormones are secreted into the blood stream and must circulate the body before reaching target location
Hormones turn things on (stimulate) or off (inhibit)
Hormones are regulated by hypothalamus in the brain
Endocrine glands are gland that secrete hormones

4. GASTRIN: Secretion: By “G cells” of stomach lining
Stimulus: Stomach distention and acid pH of chyme causes gastrin to be produced.
Action:
1. increases HCl production in stomach
2. increases gastric motility
3. stimulates growth of gastric mucosa
4. contract lower esophageal sphincter
5. relaxes pyloric sphincter
6. relaxes ileocecal sphincter

6. SECRETIN: Secretion: By (S) cells in the small intestine.
Stimulus: Acid chyme in small intestine causes secretion of secretin
Actions:
stimulate secretion of pancreatic juice and bile that is rich in bicarbonate ions.
inhibit production of HCl in stomach
promote growth and maintenance of the pancreas
enhance effects of Cholecystokinin (CCK)
Increases rate of bile secretion by liver

8. CHOLECYSTOKININ (CCK):
Secretion: Enteroendocrine cells in the small intestine mucosa (Crypts of Lieberkuhn)
Stimulus: Chyme rich in amino acids, triglycerides and fatty acids enter the small intestine.
Actions:
increases secretion of pancreatic juice rich in digestive enzymes
opens the Sphincter of Oddi (from common bile duct)
contracts the gallbladder
Inhibits gastric secretion and motility
May reduce hunger

10. Gastric Inhibitory Peptide (GIP):
Secretion: Enteroendocrine cells in the small intestine
Stimulus: Chyme rich in glucose enter the small intestine.
Actions:
Stimulates release of insulin by beta cells of pancreas
Inhibits gastric secretion and motility
Stimulates glucose use by skeletal muscle cells

12. Hormonal control in the Digestive system Pancreas and Islets of Langerhans
Endocrine cells make up 1% of the pancreas and are observed as Islets of Langerhans:
1. Alpha Cells: Secrete Glucagon (increases blood sugar)
2. Beta Cells: Secrete Insulin (decreases blood sugar)
3. Delta Cells: Secrete Human Growth Hormone- Inhibiting Hormone (inhibit secretion of both glucagon and insulin and slows rate of nutrient absorption)
4. F-Cells: Secrete Pancreatic Polypeptide (inhibit secretion of digestive enzymes and inhibits contraction of the gallbladder)

16. Hunger Hormones
Hunger – a feeling of discomfort or weakness caused by a lack of food
Satiety – a feeling of fullness

18. Hunger Hormones

19. Hunger Hormones Case Study
Work as a table team to answer the questions in the case study
What are some of the issues that are occurring in his body? How might his digestive organs be involved?

20. Case Study
What is the difference between type 1 and type 2 diabetes?

21. Case Study
Flow Chart

22. Case Study
Flow Chart