5: SI And LI Histo

Question 1

Plicae circulares

Answer 1

Transverse mucosal folds with a submucosal core; cant lay flat if distended

Question 2

Where are plicae circulares located?

Answer 2

Jejunum, less visible in ileum

Question 3

Intestinal villi

Answer 3

Mucosal folds in lumen covering SI

Question 4

Two cell types on SI villi

Answer 4

Enterocytes, goblet cells

Question 5

Enterocytes

Answer 5

Produce enzymes for digestion and absorption

Question 6

Core of intestinal villi

Answer 6

Loose CT, microvasculature, a lacteal

Question 7

LI major function

Answer 7

Absorption: water, Na, vitamins, minerals + sedatives, anesthetics, steroids

Question 8

Hallmark of LI

Answer 8

Intestinal glands, goblet cells, and NO villi

Question 9

Tenia coli

Answer 9

Three flat bands of longitudinal fibers running from cecum to rectum

Question 10

Are haustra fixed?

Answer 10

No, they appear and disappear

Question 11

Anal canal anatomy

Answer 11

Contains columns with mucosal folds and anal sinuses between the columns

Question 12

Circumanal glands

Answer 12

Large apocrine glands surrounding anal orifice

Question 13

Three zones of the anal canal histo

Answer 13

1. Colorectal zone: simple columnar ep (identical to rectum)
2. Anal transition zone: simple columnar ep -> stratified squamous ep
3. Squamous zone: stratified squamous ep continuous with perianal skin