1. STRUCTURE Oral/Esop Stomach Small Int Colon/Rectum
ENS no/yes (distal) yes yes yes
Oral/Esop Stomach Small Int Colon/Rectum
Muscle Skeletal (prox) Smooth Smooth smooth
Smooth (distal) (skeletal sphincter)
Glands Salivary/none Gastric Glands (pits) Duodenal Crypts&single cell (fundus vs antrum) Pancreas Biliary
Crypts&single cell
STRUCTURE

2. CONTROLS Oral/Esop Stomach Small Int Colon/Rectum
Neural yes yes yes yes
Control CNS>ENS CNS~ENS ENS>CNS CNS~ENS/CNS>ENS
Endocrine No Yes Yes Some/No
Control Gastrin CCK + Gastrin/CCK
Secretin Secretin +
CCK +/ Gastrin +/--
PYY, PP--
Paracrine No yes yes yes
Control Histamine Serotonin + Serotonin +
Prostaglandin +/-
Somatostatin ---
CONTROLS

3. Motility & Secretion Oral/Esop Stomach Small Int Colon/Rectum
Motility peristalsis peristalsis peristalsis, antiperistalsis peristalsis, mixing
(1 & 2) adaptive relaxation segmentation, bursts antiperistalsis receptive relaxation Mass movement&defecation
Interdigestive no yes yes yes/no
MMC/Secretion
Secretion Saliva/none HCl HCO3, Cl, H20 electrolyte
HCO intrinsic factor Panc Enzymes mucous
Amylase pepsin mucous
lipase lipase bile
mucous
Motility &
Secretion

4. ABSORPTION Oral/Esop Stomach Small Int Colon/Rectum
Epithleium very tight very tight very leaky (duod) very tight
to tight (ileum)
Absorption none Little (ROH) Nutrient (duod-jej) H20 & electrolyte/none
IF-B12 (ileum) SCFA
Bile salt (ileum)
H20 & electrolyte
ABSORPTION

5. ORAL PHASE sight sound smell Afferent Efferent
HCl
Pepsin
Gastrin
HCO3
Enzyme
Bile
Ctxn
Rlxn
Thickness ≈ activity level

6. GASTRIC PHASE sight Afferent Efferent Gastrin
sound
smell
HCl
Pepsin
Gastrin
HCO3
Enzyme
Bile
Ctxn
peristalsis/segmentation
AAs
Rlxn
Thickness ≈ activity level

7. INTESTINAL PHASE Afferent Efferent Inhibition H+ SSN Secretin CCK GE
HCl
Pepsin
Gastrin
HCO3
Enzyme
Bile
segmentation
peristalsis
Ctxn H+
SSN
Secretin
CCK GE
Inhibition aa
ffa
Thickness ≈ activity level