Chapter 93 Colon

Question 1

What is the vascular supply to the cecum?

Answer 1

Ileocolic artery

Question 2

What is the vascular supply to the ascending colon?

Answer 2

• ileocolic
• right colic

Question 3

What is the vascular supply to the transverse colon?

Answer 3

• right colic
• middle colic

Question 4

What is the vascular supply to the descending colon?

Answer 4

Proximal:
- middle colic
- left colic
Distal/terminal:
- cranial rectal

Question 5

What are the stages of wound heaing in the colon?

Answer 5

Lag (First 3-4 days)
Proliferative (4-14 days)
Maturation (17-onward)

Question 6

What happens during the lag phase of wound healing?

Answer 6

• fibrin clot forms
• predmoninant cell type is neutrophil
• mucous plays role in plugging wound gap and preventing leakage

Question 7

What is the most critical phase of colonic wound healing?

Answer 7

Lag phase, dehiscence most likely to occur first 72-96 hours

Question 8

What happens during the proliferative phase of wound healing?

Answer 8

• fibroblasts proliferate and produce immature collagen
• angiogenesis
• type III collagen 30-40% of granulation tissue
• rapid gain in wound bursting strength

Question 9

What happens during the maturation phase of wound healing?

Answer 9

Reorganization and remodeling of collagen

Question 10

Why is the submucosa the supporting layer of the colon?

Answer 10

High collagen content
Type I 68%
Type III 20%
Type V 12%

Question 11

What cells are collagen produced from in the GI tract?

Answer 11

Smooth muscle cells and fibroblasts

Question 12

What % of normal strength is a colonic wound after 48 hours? 4 months?

Answer 12

48 hours = 30%
4 months = 75%

Question 13

What local factors negatively effect colonic wound healing?

Answer 13

• hypoperfusion
• poor wound apposition
• wound tension
• infection
• distal obstruction

Question 14

What happens when PaO2 to a wound is <40mmHg? <10mmHg?

Answer 14

<40mmHg - collagen formation will not occur
<10mmHg - angiogenesis and epithelial hyperplasia will fail, wound will not heal

Question 15

What are three different methods for improving colonic wound healing?

Answer 15

1. Vascularized tissue wraps (eg. omentoplasty)
2. Colonic reinforcement (eg. PSIS)
3. Cytokines (eg. VEGF)

Question 16

What type of antibiotics are recommended for coliforms and anaerobes?

Answer 16

• cefoxitin
• cefazolin
• cefuroxine
• metronidazole

Question 17

What vessels branch off the cranial mesenteric artery to supply the large intestines?

Answer 17

• ileal
• ileocolic
• right colic
• middle colic

Question 18

What vessels branch off the caudal mesenteric artery to supply the colon?

Answer 18

• left colic
• cranial rectal