Esophagus/Stomach Histo

Question 1

GI Mucosa

Answer 1

3 components: Lining epithelium, Underlying lamina propria, thin muscularis mucosae

Question 2

GI Submucosa

Answer 2

Dense irregular CT with neurovasculatur and lymphatics.

Glands may also be present

Question 3

GI Muscularis Externa

Answer 3

Two layers of smooth muscle: inner circular layer and outer longitudinal layer

Contraction of circular layer constricts the lumen

Contraction of the longitudinal layer shortens the tube

Neurovascular plexuses reside between layers

Question 4

GI Adventitia/Serosa

Answer 4

When digestive tube is suspended by a mesentery/peritoneal fold, the adventitia is covered by mesothelium forming the serosa layer

Without mesothelium covering have an adventitia

Organs may have an adventitia and/or serosa, depending on location

Question 5

GI Innervation

Answer 5

1) Extrinsic component-parasympathetics and sympathetics

2) Intrinsic/Enteric Component

Question 6

Intrinsic (Enteric) Innervation

Answer 6

Two plexuses oif sensory and motor neurons linked by interneurons:

1) Submucosal plexus of Meissner
2) Myenteric plexus of Auerbach, between the inner circular and outer longitudinal layer (muscularis externa)

Question 7

Stimuli and input from ANS

Answer 7

1) peristaltic contractions of muscularis externa and movemnts of muscularis mucosae
2) Secretory activity of the mucosal and submucosal glands

Preganglionic axons of parasympathetic increase motility

Postganglionic axons of sympathetics decrease motility