Hormones of the digestive system.ppt

Physiology

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:Enteroendocrinecells in the small
intestine mucosa (Crypts of Lieberkuhn)
Stimulus:Chymerich 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