1. DIGESTIVE ENZYMES AND
HORMONES
Jessica C. Largado
Camille Lee R. Mananggit

2. Functions of Secretory
Glands
1.
2.
Secretion of digestive enzymes
Production of mucus
 Lubrication
 Protection of alimentary tract

3. A. SALIVARY SECRETION
Saliva-mixed secretion of salivary glands
MAIN SALIVARY GLANDS
Parotid
1.
Submaxillary or Mandibular
2.
sublingual
3.

4. Sublingual gland

5. Major Types of Secretion
1.
Serous secretion- ptyalin or salivary amylase
-starch splitting enzyme

6. Major Types of Secretion
2.
Mucus secretion- mucus
-for lubrication

7. B. GASTRIC SECRETION
Components:
1. pepsinogen-active form of pepsin
-protein digestion
2. mucus- lubricated ingested food
-protects mucosa
3. HCO3- protects mucosa against acid and pepsin
4. Intrinsic factor- absorption of Vit B12
5. Rennin- milk coagulation
6. Gastric lipase- hydrolyze fats

8. Types of Glands
1.
2.
Cardiac Gland
-secrete mucus
Fundic gland
-gastric/oxyntic gland

9. Types of Glands
-has five types of cells
1. parietal cells-secrete HCl
2. chief cells or peptic cells-secrete
pepsinogen
3.mucous cells-secrete mucus
4. endocrine D cells-secrete
somatostatin
5. entero-chromaffin-like cellshistamine

10. Types of Glands
3.
Pyloric gland-has G cells

11. Types of Glands
Cardiac gland
Fundic gland

12. Types of Glands
Pyloric gland

13. Types of Glands

14. Types of Glands

15. Stimulation of Acid Secretion
Gastrin
-from G cells
-stimulated by
protein products in
the stomach
1.

16. Stimulation of Acid
Secretion
2.
3.
Acetylcholine
-released from cholinergic neurons
-stimulates acid production in the same way as
gastrin
Histamine
-released from ECL cells
-directly contacts the parietal cells

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

20. Stimulation of Acid
Secretion

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

25. D. EXOCRINE PANCREAS
1.
2.
Endocrine-hormone secreting
Exocrine- enzyme and bicarbonate secreting
parts

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

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

29. Secretion of Pancreatic
Enzymes
2.
Proteolytic enzymes
1. trypsin
2. chymotrypsin
3. carboxypeptidase
4. ribonucleases
5. deoxyribonuclease

30. Regulations of Pancreatic Secretion
1.
2.
Nervous Regulation
Hormonal Regulation
Cholecystokinin (CCK)
1.
2.
Secretin

31. THANK YOU!!!!
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