Lecutre 18 And 19 - The Gastrointestinal System

Question 1

The Gastrointestinal Tracts

Answer 1

• Oral Cavity
• Esophagus
• Stomach
• Small Intestine
• Colon
• Rectum

Question 2

4 Basic Processes

Answer 2

Motility - Throughout the GI tract
Secretion - Saliva, antibodies, digestive enzymes, bile and bicarbonate
Digestion - breaking down food to smaller components
Absorption - Water and Nutrients

Question 3

Cephalic Phase

Answer 3

• Chemical and Mechanical digestion begins in the mouth
• Chewing
• secretions in response to stimuli ( sight, smell taste) prepares the GI tract for food processing

Question 4

Salivary Secretion

Answer 4

• under autonomic control
• Softens and lubricates food
• Provides enzymes: Amylase and some lipase

Question 5

Pancreas

Answer 5

• digestive enzymes
• released in inactive form and activated in small intestine by the duodenum to form trypsin for protein digestion

Question 6

Gallbladder

Answer 6

Stores bile - fat digestion

Question 7

Small Intestinal Mucosa

Answer 7

Villi increase surface area to promote nutrient absorption

Question 8

Type of Secretions into the lumen (3 types)

Answer 8

1. Bicarbonate: from cells in the intestinal epithelium ad in pancreatic secretions
2. Digestive enzymes: from the pancreas
3. Bile acids: from the liver and gallbladder

Question 9

Digestive enzymes anchored on the luminal surface of small intestine epithelial cells

Answer 9

1. Disaccharides
2. Amino Peptidases

Question 10

Carbohydrates

Answer 10

Polysaccharides and disaccharides
Maltose = 2 glucose
Sucrose = fructose and glucose
Lactose = galactose + glucose
Starch = glucose + glucose + glucose

Question 11

Emulsifying Fat - Making fat soluble with bile

Answer 11

Bile salts are amphipathic - hydrophilic and lipophilic

Question 12

Hedonic Hunger or Eating

Answer 12

the drive to eat or obtain pleasure in the absence of an energy deficit

Question 13

Homeostatic Hunger or Eating

Answer 13

Increases motivation to eat following depletion of energy stores