Gastrointestinal Physiology

Question 1

types of breakdown

Answer 1

1. chemical: stomach
2. mechanical: in the stomach and mouth
3. enzymatic: small intestine

Question 2

accessory organs and their functions

Answer 2

• liver:
• gallbladder: stores bile from liver
• pancreas:

Question 3

peristalsis

Answer 3

autonomic nervous system controls waves of muscular contraction to move substances through gut

Question 4

location and components of enteric nervous system (ENS)

Answer 4

myenteric plexus:
- located all throughout the tract, in between longitudinal and circular SM layers
- controls GI motility

submucosal plexus:
- also along the entire tract, below circular SM and above epithelium
- local control of secretion, absorption, contraction

Question 5

hepatic portal system

Answer 5

blood from abdominal parts of the GI system and the spleen pass through liver before returning to heart

Question 6

pH vs transit time

Answer 6

pH general increases as you go down (is very acidic and then is neutralized), while transit time increases

Question 7

mucosal lining

behaviour throughout tract

Answer 7

changes as we go through the tract

Question 8

purpose of villi

Answer 8

increased surface area = increased absorption

Question 9

lower esophagial sphincter

Answer 9

stops backflow of acid from stomach into esophagus

Question 10

chyme

Answer 10

a fine, dispersed mix of food and secretions

Question 11

pancreas

Answer 11

exocrine function: produces lots of digestive enzymes
- enzymes produced in inactive form: trypsinogen, chymotrypsinogen, pro-elastase
–> trypsinogen gets activated at the brush border

Question 12

zymogen

Answer 12

inactive precursor of an enzyme