1. Chap 19 The Digestive System
Memmler’s A&P
Chap 19
The Digestive System

2. Digestion p410 Every body cell needs a constant supply of nutrients.
The food we eat is too large to enter the cells. It must be digested, or broken down into particles small enough to cross the plasma membrane, before it is usable.

3. Functions of digestive system p410
Digestion
Absorption
Elimination

4. Digestive system p410 The digestive tract Accessory organs
Salivary glands
Liver
Gallbladder
Pancreas

5. Wall of the digestive tract p410
Where absorption happens
From innermost layer to outermost layer:
Mucous membrane
Submucosa
Smooth muscle
Serous membrane
visceral peritoneum

6. The Peritoneum p411
Serous membrane that lines the wall of the abdominal cavity and covers the outer surface of abdominal organs
Parietal peritoneum
Visceral peritoneum

7. Digestive Tract p412 Mouth Pharynx Esophagus Stomach Small intestine
Large intestine

8. Mouth p412 Oral cavity Functions Ingestion Mastication Saliva
Deglutition

9. The Pharynx p413
The throat
Uvula
Epiglottis

10. The Esophagus p414 Smooth muscle Mucosa
Lubricates food with mucus and moves it to the stomach with peristalsis
Esophageal hiatus
Hiatal hernia

11. The Stomach p414
3 smooth muscle layers for mixing food with digestive juices
Rugae
Gastric juice
Hydrochloric acid
Pepsin
Chyme

12. The Small Intestine p414
Functions: digestion and absorption of nutrients
Sections of small intestine
Duodenum
Jejunum
Ileum
Special features
Villi
Lacteals

13. Wall of small intestine 411, 416

14. The Large Intestine p415 Functions: Sections: Reabsorption of water
Storage of food wastes
Elimination
Growth of Vit K and some B vitamins by normal flora
Sections:
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anus

15. Accessory organs p417
Liver
Gallbladder
Pancreas
Salivary glands

16. The liver p418 Manufactures bile Storage glycogen Modification of fats
Stores some vitamins and iron
Formation plasma proteins
Destruction of old RBCs
Synthesis of urea
Detoxification of blood

17. The Gallbladder p418 Stores bile Secretes bile into the duodenum
Function of bile: emulsification of fat
Secretes bile into the duodenum

18. The Pancreas p418
Produces enzymes that digest fats, proteins, carbohydrates
Releases sodium bicarbonate to neutralize chyme
Secretes into the duodenum

19. Enzymes and digestion p418
Catalysts to speed digestion
Pancreatic amylase: splits carbohydrates into monosaccharides
Trypsin: splits proteins into amino acids
Lipase: splits fats into glycerol and fatty acids

20. The role of water p419 Hydrolysis: splitting by means of water.
7 liters of water a day are secreted into the digestive tract in addition to what is eaten or consumed by drinking
Water dilutes food and digestive juices for easier passage through the digestive tract.

22. Absorption p420
Absorption site: villi in the mucosa of the small intestine
Each villus contains blood vessels and a lacteal
After absorption, nutrients go to the liver via the hepatic portal system

23. Control of digestion p420
Regulation is by the Autonomic Nervous System
Parasympathetic nervous system promotes digestion and peristalsis
Sympathetic nervous system inhibits peristalsis, digestion, and mucus production

24. Hunger and appetite p421 Hunger Appetite Anorexia
desire for food because nutrition is needed to fuel cells
Appetite
desire for food without relationship to the need for food
Anorexia
loss of appetite

25. Digestive system disorders p422
Peritonitis
Gastroesophageal reflux disease (GERD)
Nausea
Vomiting
Diarrhea
Flatus
Peptic ulcer
Appendicitis
Constipation

26. Constipation p424
Hard stools or difficulty with defecation

27. Cancer p424 Colon or rectal cancer can be detected by colonoscopy.
Occult blood

28. Liver diseases p
Cirrhosis: active liver cells are replaced by scar tissue
Jaundice: damage to liver can cause bile pigment to accumulate in the blood
Stool becomes light clay colored
Skin and sclera become yellow
Hepatitis: inflammation of liver (can be caused by drugs, alcohol, or infection.

29. Disease of gallbladder p426
Gallstones: cholelithiasis
Inflammation of gallbladder: cholecystitis
Surgical removal of gallbladder: cholecystectomy

30. Aging and digestive system p426
Receptors for taste and smell deteriorate, loss of appetite
Decrease in saliva
Poor gag reflex
Tooth loss
Poor absorption
Slowed peristalsis
Constipation