Digestive System

Question 1

Explain nutrient acquisition in animals:
1) Selection of energetic compounds thru digestive activities (3)
2) Specific digestive processes allowing for isolation, absorption and cellular breakdown of energetic compounds (2)
3) Increased efficiency of energetic compounds (5)

Answer 1

2-4

Question 2

How gastrointestinal tract surface area is increased in:
- Agnathan (Lamprey)
- Chondrichthian (Shark)
- Actinopterygian (Gar/Ray-finned fishes)
- Amphibian (Salamander), Reptile (Turtle), Mammal (Pig)
- Avian (Chicken)

Answer 2

Spiral valve
Pyloric ceca
Crop, proventriculus, ceca
6

Question 3

Digestion phases:
- Cephalic
- Gastric
- Intestinal

Answer 3

8

Question 4

Lining in gastric lumen; what do these cells secrete?
- Mucous cell
- Parietal cell
- Chief cells
- Enteroendocrine cell (G cells, enterochromaffin-like cells)

Answer 4

Mucin
HCl
Pepsinogen, lipase
Gastrin, histamine

Question 5

Steps of stomach digestion after cephalic stimuli (6)

Answer 5

• Acetylcholine (ACH), gastrin-releasing peptide (GRP)
• Gastrin, G-cells
• Parietal, ECL
• H+
• Chief cell, pepsinogen, pepsin
• Feedback, D-cells, somatostatin (SST), G-cells, peptides/amino acids

11-14

Question 6

What do cells in intestinal mucosa layer do?
- Enteroendocrine cells
- Enterocytes
- Goblet cells
- Paneth cells

Where is bile created/stored + what does it do?

Answer 6

Secrete hormones and peptides to act locally and systemically
Nutrient and water absorption
Secrete mucins that form mucus
Secrete antimicrobial factors
16

Created in liver, stored in gall bladder
Contains salts that emulsify dietary fats to break them down into smaller droplets
17

Question 7

Intestinal digestion
- H+ (Chyme) -> S cells -> Secretin -> ? (2)
- Fat glucose -> K cells -> Gastric inhibitory peptide (GIP) -> ? (2)
- Digested nutrients -> I cells -> cholecytokinin (CCK) -> ? (3)
- Vagus nerve + H cells -> Vasoactive intestinal peptide (VIP) -> ? (2)
- L cells -> Glucagon-like peptide 1 (GLP-1/2) -> ? (2)
- D call -> Somatostatin (SST) -> ?

Answer 7

S and K cells: 18-19
I cells: 23-24
H cells: 28
L cells: 29
D cells: 32

Question 8

Serotonin
- Come from what cells + where (2)
- Play significant role in? (2)
- Steps to make serotonin (3)

Answer 8

34

Question 9

Gut microbiota
- Consist of what (6)
- Found where (2)
- Role + signal to where
- Primary metabolites currently studied
- Secondary bile salts and Lipopolysaccharide (LPS) do what

Answer 9

Short chain fatty acids (SCFA); acetate, proprionate, butyrate
35-36

Question 10

Substance P
- What stimulates it
- What does it do? (2)

Answer 10

Vagal stim
Vasodilator hypotensive (increase absorption), intestinal peristalsis (move nutrients thru gut)
39