Intestine

Question 1

What are the functions of the SI?

Answer 1

-Digestion & ABSORPTION (Jejunum > Ileum)
Consists of: Carbs, Fat, protein, folate, iron, calcium, water & electrolytes (minor)
-Vit. B12 absorption @ ileum > jéjunum

Question 2

Characteristics of Jejunum

Answer 2

• Begins @ duodenojejunal flexure
• Located in LUQ
• Blood supply is SMA
• Lymphatic to Sup. mesenteric nodes via mesenteric nodes
• Thicker walls: mucosal folds(Pilcae circulares) increase SA
• Has more Blood supply for better absorption = Darker red in color
• Distal arcades = Longer vasa recta

Question 3

Characteristics of Ileum

Answer 3

• Terminates @ ileocecal opening
• Located in RLQ
• Blood supply is SMA
• Lymphatics to sup. mesenteric nodes via mesenteric nodes
• Linked with hernias
• Less pilcae circulares
• Smaller diameter
• Proximal arcades = shorter vasa recta

Question 4

Blood Supply to SI

Answer 4

• SMA branches:
• Jejunal (LUQ)
• Ileal (RLQ)
• Ileocecal (main branch to lleal from SMA)
• Right colic (branches off ileocecal)
• Middle colic (branches off SMA @ Sup. pos)

Question 5

Characteristics of Large Intestine

Answer 5

• Begins @ the ileocecal juntion & ends @ rectum
• Haustrations: distinct to LI & help with segmentation/movement
• Taenia coli: Contract lengthwise to produce the Haustra (produce ANTI peristalsis)
• Appendicies epiplocae:omental in nature are small fat distributions throughout colon
• absorption: water/electrolytes
• Secrete: K+, Bicarb, Mucus
• Motility: antiperistalsis, segmentation, Mass movement

Question 6

Cecum & Appendix

Answer 6

• Cecum is retroperitoneal
• Appendix has a mesentery (mesoappendix) = intraperitoneal & is posterior to retro cecum
• Localize appendix by following the tanea coli which point towards it

Question 7

Sigmoid Colon

Answer 7

• S-Shaped most distal portion of the LI
• Very mobile
• Blood supply IMA–>sigmoid

Question 8

What the flexures of the LI?

Answer 8

• Hepatic flexure on right side (ascending)

- Splenic flexure on left side (descending)

Question 9

Large Intestines by sections

Answer 9

• Ascending colon: Retroperitoneal
• Transverse colon: Intraperitoneal
• Descending colon: Retroperitoneal
• Sigmoid colon: Intraperitoneal

Question 10

What is Volvulus?

Answer 10

• Ascending colon is abnormally mobile

- May result in rolling over on itself producing an obstruction circulatory

Question 11

SMA & IMA

Answer 11

• SMA is @ the level of L1
• IMA is prone to arteriosclerosis
• Marginal branches are used to bypass blood flow between SMA/IMA

Question 12

Esophageal varices?

Answer 12

• Arise from high portal hepatic blood pressure
• Azygous (right of esophagus)
• Left Gastric (upper part of stomach)

Question 13

Rectal varices?

Answer 13

• Arise from high portal hepatic blood pressure
• Superior rectal vein (portal)
• Internal iliac (systemic)

Question 14

Caput medusae

Answer 14

• Arise from high portal hepatic blood pressure
• Portal vein
• umbilical vein

Question 15

GI tract Lymphatic Drainage

Answer 15

1. Local LN
2. Pre-aortic LN
3. Para-aortic LN (on aorta)
4. Intestinal trunks
5. Cisterna Chyli (Post. to stomach)
6. Thoracic duct (Left subclavian)