GI Overview

Question 1

Digestive tract
Aka
Accessory organs

Answer 1

Mouth to Anus
Alimentary canal
Teeth/tongue/salivary glands/ liver/gall bladder/pancreas

Question 2

Function of the GI tract

Must have

Requires

Answer 2

supply CV system with usable nutrients

Digestion (breakdown of large non diffusible molecules into absorbable units)

Enzymes to aid/speed chemical rxns

Question 3

Molecules move via

Transport occurs by

Answer 3

simple diffusion
carrier mechanisms (facil diffusion, active transport)

Question 4

Motility
Mostly_____, except for

Secretion

Answer 4

muscular contraction of GI tract for propulsion and mixing
Involuntary, chewing/swallowing/defecation

Digestive juices secreted into lumen of GI tract and hormones

Question 5

Digestion

Absorption

Answer 5

Breakdown of stuff via chemical rxns, governed by temp/enzymes

Transport of digestion products into blood (via SI)

Question 6

Endocrince secretions

Answer 6

Gastrin, secretin, CCK, GIP, motilin

Question 7

Layered organization

Blood and lymph vasculature

Answer 7

Absorptive cells lining the lumen, with neural and muscular components below

Abundant to transport absorbed nutrients

Question 8

Mucosa has

ME contractions
Myenteric plexus

Answer 8

microvilli on membane, villi on folds to inc SA

Move food through tract, mixing food
Fibers and ganglia of both SNS and PNS

Question 9

Enteric NS

Allows for

Answer 9

site where PNS fibers synapse with PG neurons that innervate SM

Many S PG nerves synapse on neurons

Local regulation of the GI tract

Question 10

ENS coordinates

Modified bt

Answer 10

digestion, secretion, motility to optimize absorption

Info from CNS and local chemical/mechanical sensors

Question 11

Kallikrein

Bradykinin

Answer 11

causes breakdown of kininogen to bradykinin

causes local vasodilation to inc blood flow to the actively secreting gland