Histo of Small and Large Intestines

Question 1

Main portions of the small intestine?

Answer 1

Duodenum
Jejunum
Ileum

Question 2

Principal site for digestion of food and absorption of digested products?

Answer 2

Small intestines

Question 3

What are the transverse folds in the intestines called and what are layers are they made of?

Answer 3

Plicae Circularae

- Submucosal and Mucosal layers

Question 4

What project off of the Plicae Circulares?

Answer 4

Villi

Question 5

Intestinal villi project off of the folds of plicae circularae, what type of epithelium are they?

Answer 5

Simple columnar epithelium

Question 6

What type of cells make up the simple columnar epithelium on the intestinal villi?

Answer 6

Enterocytes and scattered goblet cells

Question 7

Each intestinal villi also contains a white core, what is that called?

Answer 7

Lacteal

Question 8

What is the function of enterocytes?

Answer 8

Produce enzymes for digestion and absorption

Question 9

What is the function of goblet cells?

Answer 9

Produce mucus coating for protection from abrasion

Question 10

What is located on individual cells of the intestinal villi to increase absorption?

Answer 10

Microvilli

Question 11

On what cell are microvilli located?

Answer 11

Enterocytes of the villi of the plicae circulares

Question 12

What is the innervation of the small and large intestines?

Answer 12

Submucosal plexus of Meissner AND

Myenteric plexus of Auerbach

Question 13

Where will you find the myenteric plexus of auerbach?

Answer 13

Between the inner circular layer and outer longitudinal layer of the muscularis externa

Question 14

What type of epithelium are intestinal glands?

Answer 14

Simple columnar

Question 15

What are the cell types found in intestinal glands?

Answer 15

Paneth cells
M cells
Intestinal stem cells
Enteroendocrine cells

Question 16

Another word for the intestinal gland?

Answer 16

Crypt

Question 17

Describe paneth cells

Answer 17

Found at base of intestinal gland

• Will stain eosinophilic in cytoplasm
• Functions in innate immunity

Question 18

Describe intestinal stem cells

Answer 18

Found in niches at base of intestinal gland

- Differentiate into different cell types such as goblet cells or enteroendocrine cells or enterocytes

Question 19

Main function of M cells?

Answer 19

Highly specific antigen transporting cells

Question 20

Where will you find M cells?

Answer 20

Overlying Peyer’s Patches

Question 21

Main function of Enteroendocrine cells?

Answer 21

Secrete hormones that aid in digestive function

Question 22

2 types of Enteroendocrine cells?

Answer 22

Closed - not open to lumen

Open - apical end contacts lumen

Question 23

Epithelial type found in the small intestines?

Answer 23

Simple columnar

Question 24

Defining features of the Duodenum?

Answer 24

Simple columnar epithelium with scattered goblet cells

- DUODENAL GLANDS FOUND IN SUBMUCOSA

Question 25

Defining features of the Jejunum mucosal and submucosal layers?

Answer 25

NONE - simple columnar epithelium with scattered goblet cells, long villi and lymphoid nodules (mucosa) - NO submucosal glands

Question 26

Defining features of the Ileum?

Answer 26

Simple columnar epithelium with scattered goblet cells, PEYER'S PATCHES, Paneth cells at base of glands - NO submucosal glands

Question 27

Describe the duodenum mucosal layer

Answer 27

Simple columnar epithelium with scattered goblet cells

Question 28

Describe the duodenum submucosal layer

Answer 28

DUODENAL GLANDS! - neutralize acidic chyme

Question 29

Describe the jejunum mucosal layer

Answer 29

Simple columnar epithelium with scattered goblet cells, long villi, long lacteal and lymphoid nodules

Question 30

Describe the jejunum submucosal layer

Answer 30

NO SUBMUCOSAL GLANDS

Question 31

Describe the ileum mucosal layer

Answer 31

Simple columnar epithelium with scattered goblet cells, PEYER'S PATCHES, Paneth cells at base of glands

Question 32

What are peyer's patches?

Answer 32

Lymphoid nodules found in the ileum mucosal layer

Question 33

Describe the ileum submucosal layer

Answer 33

NO SUBMUCOSAL GLANDS

Question 34

How can you tell you are at the Gastroduodenal junction?

Answer 34

Noticeable presence of duodenal submucosal glands deep to the muscularis mucosase

Question 35

What makes up the large intestine?

Answer 35

``` Cecum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum Anal canal ```

Question 36

Main function of large intestine?

Answer 36

Absorb water, vitamins, minerals, sedatives, anesthetics, steroids

Question 37

Does the large intestine have villi?

Answer 37

NO

Question 38

What are the main hallmarks of the large intestine?

Answer 38

NO villi, lots of goblet cells making up the intestinal glands of simple columnar epithelium with colonocytes

Question 39

Describe the mucosal layer of the large intestine

Answer 39

Simple columnar epithelium with colonocytes and lots of goblet cells - lamina propria and muscularis mucosae are also present

Question 40

Describe the submucosal layer of the large intestine

Answer 40

Dense irregular CT, well vascularized

Question 41

What is different about the outer longitudinal layer of the muscularis externa in the large intestine?

Answer 41

Organized into taeniae coli that will form the haustra of the large intestine

Question 42

What is the haustra of the large intestine?

Answer 42

It's segmented appearance

Question 43

Hirschsprung's Disease

Answer 43

Aganglionosis in the distal colon | = portion of distal colon is not innervated by a plexus!

Question 44

What gene mutation causes Hirschsprung's Disease?

Answer 44

RET gene mutation that causes insufficient migration of NCC

Question 45

Most common site of Hirschsprung's Disease?

Answer 45

Short-segment disease - confined to rectosigmoid region

Question 46

Symptoms of Hirschsprung's Disease?

Answer 46

Constipation, poor feeding, progressive abdominal distention

Question 47

What 3 things will you find in the anal canal?

Answer 47

Anal columns Anal sinuses Anal glands

Question 48

What are anal columns?

Answer 48

Mucosal folds

Question 49

What are anal sinuses?

Answer 49

Depressions between the anal columns

Question 50

What are circumanal glands?

Answer 50

Apocrine glands surrounding the anal orifice

Question 51

What are the 3 anal canal zones on a histo image?

Answer 51

Colorectal zone Anal transition zone Squamous zone

Question 52

What epithelium is in the colorectal zone?

Answer 52

Simple columnar

Question 53

What happens at the anal transition zone?

Answer 53

Simple columnar transitions into stratified squamous epithelium

Question 54

What type of epithelium is at the squamous zone?

Answer 54

Stratified squamous