GI Review

Question 1

Layers of GI luman (deep to surface)

Answer 1

• Mucosa (w/ circular folds, mucosal galnds, mucosal epithelium with lamina propria)
• Submucosa (artery, veins, lymph vessels follow into circular folds)
• Muscularis externa (circular, then longitudinal muscle layer)
• Serosa (visceral peritoneum)

Question 2

3 factors influencing digestion

Answer 2

• Local factors (pressure from volume, chemicals, pH)
• CNS- myenteric reflexs (the long game of peristalsis)
• Hormonal control

Question 3

3 parts of small intestine

Answer 3

• Duodenum- “mixing bowl”, receives chime, 25cm
• Jejunum- bulk of chemical digestion and nutrients absoption 2.5m long
• Ileum- final small intestine section 3m

Question 4

What produces bile?

Answer 4

Liver!

• About a liter a day
• Closely linked to bilirubin production from break down of RBC in liver

Question 5

What stores bile and what stimulates its release?

Answer 5

Stored in Gallbladder and released when CCK hormone (from duodenum) stimulates contraction. Flows down cystic duct to common bile duct and released into duodenum.

Question 6

Three key bits of Mesentery?

Answer 6

• Lesser omentum- between stomach and liver
• Falciform- stabilizes liver relative to diaphragm and abd wall
• Greater omentum- hangs from stomach anteriorly

Question 7

What are mesenteries and why are they there?

Answer 7

• Are double sheets of the peritoneal membrane.
• Stabilize postions of attached organs, preventing entanglement of intestines
• Provide route to digestive tract for blood vessels, lymph and nerves

Question 8

Two layers of the peritoneum?

What kind of membrane? And what service does it provide?

Answer 8

parietal- inner surface of body wall
visceral- encloses enclosed organs of the abdominopelvic cavity.

Serous membrane allows organs to slide across one another without damage to themselves or walls of the cavity.

Question 9

which organs are retroperitoneal?

Answer 9

kidneys and pancreas

not in peritoneum