Alimentary System

Question 1

Digestive tract functions (5)

Answer 1

1. Prehension: grasping of food with the lips or teeth
2. Mastication: chewing, mechanical grinding and breaking down of food
3. Chemical digestion: of food
4. Absorption: of nutrients and water
5. Elimination: of waste (defecation)

Question 2

Mucosa

Answer 2

Lining of GI tract, epithelium and loose connective tissue

Question 3

Submucosa

Answer 3

Des er connective tissue; may contain glands

Question 4

Muscle layer

Answer 4

Outside the submucosa

Question 5

Serosa

Answer 5

Outer most layer of stomach; thin, tough connective tissue

Question 6

Mesentery (hint: it leads to the stomach)

Answer 6

• Sheets of connective tissue
• Suspend digestive tube in the abdomen from the dorsal body wall
• Contains blood and lymph vessels and nerves that supply the GI tract

Question 7

digestive tract structure (7)

Answer 7

1. mucosa
2. submucosa
3. muscle layer
4. serosa
5. mesentery
6. skeletal muscle
7. smooth muscle

Question 8

skeletal muscle (GI tract)

Answer 8

• mouth. pharynx, the cranial part of the esophagus, and the external anal sphincter
• allows the processes of shewing, mixing saliva with food and initiation of swallowing

Question 9

smooth muscle (GI tract)

Answer 9

• wall of the majority of the esophagus, the stomach, the small intestine, the large intestine, and the internal anal sphincter
• primarily arranged in circular and longitudinal layers. - contraction of circular muscle fibers narrows the tract. - contraction of longitudinal fibers shortens the tract

Question 10

digestive enzymes

Answer 10

1. Amylase - enzyme in saliva of omnivores (breaking down starches)
2. Lipase - enzyme that digests fats
3. Sodium bicarbonate and phosphate buffers found in saliva of cattle: neutralize acids normally formed in the rumen

Question 11

list the five areas of the monogastric stomach

Answer 11

1. cardia - opening from esophagus
2. fundus - distensible blind pouch, expands as more food is swallowed
3. body - distensible middle section. contains parietal, chief, mucous cells
4. pyloric antrum - grinds up swallowed food
5. pyloris - muscular sphincter, regulates movement of chyme from the stomach into the duodenum

Question 12

gastrin

Answer 12

produced by the G cells in the antrum of the stomach
- increases the production of HCl
- inhibits muscle activity of the fundus

Question 13

cholecystokinin (CCK)

Answer 13

• release in response to large amounts of fats or proteins in duodenum
• decreases contraction of the antrum, body, and fundus

Question 14

secretin

Answer 14

released from duodenum in response to excess stomach acid in the small intestine
- can cause fundus to relax
- can inhibit peristalsis of the body and antrum of the stomach to slow gastric emptying

Question 15

enterogastric reflex

Answer 15

distension of the intestine or increased acidity in the duodenum inhibits stomach contraction
- delays gastric emptying