What are the four basic layers of cells in the GI tract?
- 1) mucosa
- 2) submucosa
- 3) muscularis externa
- 4) serosa or adventitia
What are the three mucosa layers?
- 1) epithelium
- 2) Lamina Propria: LCT, BV, LV, II Capillaries
- 3) Muscularis mucosa: smooth muscle
What is the enteric nervous system called in the submucosa?
Submucosa (Meissner's) plexus
What is the enteric nervous system called in the muscularis externa?
Myenteric (Auerbach's) plexus
What are the two layers of the muscularis externa?
- 1) outer circular layer
- 2) inner longitudinal layer
What organs have a serosa and what organs have an adventitia?
- Serosa = intraperitoneal
- Adventitia = retroperitoneal
What two places in the GI tract contain submucosal glands?
Espohagus & Duodenum
In what layer are the esophageal glands proper located?
What are the three muscle types that make up the ME in the esophagus?
- upper 1/3 = skeletal
- middle 1/3 = skeletal + smooth
- lower 1/3 = smooth
How many layers of Smooth Muscle are in the ME of the stomach?
How to characterize the pits and glands throughout the stomach: Cardiac, Fundus, Pyloric
- Cardiac: Pits = medium (~1/2 MM)/ Glands = coiled
- Fundus: Pits = short (~1/3 MM) / Glands = longest
- Pyloric: Pits = long (1/2 - 2/3 MM)/ Glands = branched
What type of system makes up an active parietal cell?
Tubulovesicular system (a lot of microvilli, open intracellular canaliculi)
From the outer epithelium to the inside, name the cells lining the stomach pit and gland:
- 1) epithelium: surface mucous cells
- 2) Neck: mucous neck cells, regenerating stem cells
- 3) body: parietal, DNES, Chief
What two chemicals are released by parietal cells?
- 1) HCL
- 2) Intrinsic factor Vitamin B-12
What do chief cells release?
- gastric lipase
What do DNES cells secrete and where to?
- CCK, Secretin
- Secrete basally either paracrine or endocrine (may be neurotransmitter as well)
3 Epithelial cells common to villi and glands
- 1) surface absorptive cells - enterocytes
- 2) Goblet cells
- 2) DNES
Epithelial cells common to intestinal glands:
- 1) Paneth Cells: secrete to lumen, red staining, regulated secretion
- 2) Regenerative stem cells
What are the four cells present in the intestinal glands of the colon?
- 1) Surface absorptive
- 2) Goblet
- 3) DNES
- 4) Regenerative stem cells
Since there are no lacteals in the colon, where does the lymph drain?
Submucosa into LV
What is the name for the three unique outer longitudinal layers of the colon?