17. INHIBITION OF ACID SECRETION
Stomach secretes acids at mealtime
Antrum contents approaches Ph 2.0
D cells secrete somatostatin
Inhibition of gastrin & histamine release
Inhibition of acid production
18. C. Secretion of the Small
Intestine
1.
Crypt of Lieberkuhn
-secrete enterokinase and amylase
-has two types of cells
1.Goblet cells - secrete
mucus
2. Enterocytes – secrete
water and electrolytes
19. Stimulation of Acid
Secretion
Brunner’s Gland
-duodenal gland
-secrete large amount of alkaline mucus in
response to
1. tactile or irritating stimuli
2. vagal stimulation
3. GI hormone-secretin
21. Digestive Enzymes
1.
2.
Peptidase-split small peptides into AA
Four enzymes that split disaccharide into
monosaccharide
a. sucrase
b. maltase
c. isomaltase
d. lactase
3.
Intestinal lipase-split neutral fats into glycerol
and FA
22. HorMones
1.
2.
Gastrin- stimulates gastric glands to secrete
pepsinogen and hydrochloric acid
-presence of peptides and amino acids
in gastric lumen
Secretin- signals the secretion of sodium
bicarbonate in the pancreas
-stimulates bile secretion in the liver
-acidic pH in the lumen of small
intestine
23. HorMones
3.
4.
Cholecystokinin- stimulates the release of
digestive enzymes in the pancreas
-emptying of bile in the gall bladder
-presence of fatty acids and amino
acids in the small intestine
Gastric Inhibitory Peptide- decrease the
stomach churning
-slowing the emptying of the stomach
-presence of fat and glucose in small
intestine
24. HorMones
5.
6.
Motilin- increase the migrating myoelectic
component of gastrointestinal motility
-secretion is associated with fasting
Ghrelin- appears to be a strong stimulant for
appetite and feeding
-secretion peaks prior to feeding and
diminishes with gastric filling
26. Secretion of Sodium Bicarbonate
Carbon dioxide combines with water through
carbonic anhydrase to form carbonic acid
Carbonic acid dissociates into bicarbonate
(actively transported into lumen) and hydrogen
Hydrogen ion exchanged for sodium ion
Sodium ion diffuses into lumen
Sodium and bicarbonate attract water, forming
bicarbonate solution
27.
28. Secretion of Pancreatic Enzymes
1.
Zymogen granules
a. inactive zymogen -attack membranes
eg. Proteases
b. active zymogen -do not attack membranes
eg. Lipase, amylase