Lymph drainage, nerve supply, and structural features of the GI tract (Dave's notes)

Question 1

What is the first stage of gut lymphatic drainage? What occurs to this in the terminal ilium?

Answer 1

Lymphatic networks along the peripheral arcades, intermediate mesenteric nodes and superior mesenteric nodes.

Terminal ileum doesnt drain into the superior mesenteric nodes, but towards the ileocolic nodes.

Question 2

What are the five stages of small bowel lymphatic drainage?

Answer 2

1. Lymphoid follicles
2. 3 stations:
   - Juxta-intestinal nodes (along peripheral arterial arcardes)
   - intermediate mesenteric nodes (along jejunal and ileal arteries)
   - superior mesenteric nodes (along length of SMA)
3. Along arterial course back towards the arterial main branch.
   - Superior mesenteric lymph nodes
   - Prox D2 -> coeliac LN)
   - terminal ileum -> ileocolic LN)
4. Drains upwards eventually to the cisterna chyli

Question 3

All parts of the gut are supplied by ……… and ……… nerves

Answer 3

sympathetic and parasympathetic

Question 4

Sympathetic nerves are….. and their action is ……..

Answer 4

post ganglionic - inhibitory

Question 5

Parasympathetic nerves are ….. and their action is ….

Answer 5

preganglionic - excitatory

Question 6

What structures do the sympathetic and parasympathetic nerves travel with?

Answer 6

The arterial supply to the gut

Question 7

What additional nerve supply exists in the gut?

Answer 7

• The myenteric or Auerbach’s plexus is between the two muscle layers of the gut
• The submucous or Meissners plexus is submucosal

These function without extrinsic nerve supply

Question 8

From whence is the epithelial lining of the gut derived?

Answer 8

Endoderm

Question 9

The gut can be described as what sort of tube with what coverings?

Answer 9

A muscular tube with a mucous membrane lining and a peritoneum covering

Question 10

The muscular layers of the gut consist of what?

Answer 10

An inner circular and an outer longitudinal later. The upper one third of the oesophagus is striated muscle that is gradually replaced by visceral muscle

Question 11

The mucous membrane consists of what three layers?

Answer 11

The epithelium
The lamina propria (connective tissue layer)
The muscularis mucosa (thin layer of visceral muscle)