Lecture 33/34/35 11/9/23 & 11/13/23

Question 1

What are the four layers of the tubular GI tract?

Answer 1

-mucosa
-submucosa
-muscularis
-serosa

Question 2

What are the general characteristics of GI mucosa?

Answer 2

-stratified squamous, cuboidal, or columnar
-lamina propria contains vessels and loose connective tissue
-may contain muscularis mucosa

Question 3

What is the role of the muscularis mucosa?

Answer 3

helps agitate villi and get them moving

Question 4

What are the general components of GI submucosa?

Answer 4

-blood vessels
-lymphatic vessels
-submucosal ganglia/nerves
-collagen
-adipose
-glands
-lymphoid tissue

Question 5

Which layer the GI tract holds suture the best?

Answer 5

collagen within the submucosa

Question 6

What are the general characteristics of the GI muscularis?

Answer 6

-inner circular + outer longitudinal layers
-myenteric plexus between the two layers
-mostly smooth muscle

Question 7

What are the general characteristics of GI serosa?

Answer 7

-peritoneal surface of abdominal organs
-covered by mesothelial cells when in cavities
-covered by adventitia when not in cavities
-single layer of simple squamous

Question 8

What are the characteristics of esophageal mucosa?

Answer 8

-stratified squamous
-variably keratinized
-can have a herringbone pattern in cats

Question 9

What is the main characteristic of esophageal submucosa?

Answer 9

some parts contain esophageal glands

Question 10

What is the main muscle type found within the esophageal muscularis?

Answer 10

skeletal muscle (+/- smooth muscle)

Question 11

What are the characteristics of the esophageal adventitia?

Answer 11

-blends with and anchors to surrounding mediastinal connective tissue
-no serosa or mesothelial cells on outside of esophagus

Question 12

What type of mucosa is found in the forestomachs of ruminants?

Answer 12

keratinized stratified squamous epithelium

Question 13

What is the defining “texture” of the rumen?

Answer 13

papillae

Question 14

What is the defining look/texture of the reticulum?

Answer 14

honeycomb/net appearance

Question 15

What is the defining “look” of the omasum?

Answer 15

leaves/book page appearance

Question 16

How do glandular stomachs differ between species?

Answer 16

-entire stomach is glandular in dogs and cats
-abomasum is glandular in ruminants
-pigs have pars esophagea portion which is squamous
-horses and rodents have glandular aborad stomach and orad stratified squamous stomach

Question 17

What are the characteristics of the stomach mucosa cardia?

Answer 17

-branched tubular mucous glands
-few chief and parietal cells

Question 18

What are the characteristics of the stomach mucosa fundus?

Answer 18

-contains mucous/neck cells, parietal cells, and chief cells
-site of HCl and pepsinogen secretion

Question 19

What are the characteristics of parietal cells?

Answer 19

-appear pink
-secrete HCl

Question 20

What are the characteristics of chief cells?

Answer 20

-appear purple/blue
-secrete pepsinogen

Question 21

What are the characteristics of the stomach mucosa pylorus?

Answer 21

-branched tubular mucous glands
-no parietal or chief cells

Question 22

What are the characteristics of the stomach muscularis?

Answer 22

-has inner circular and outer longitudinal layers
-inner circular layer of pylorus is very thick and forms pyloric sphincter

Question 23

What are the characteristics of the small intestine mucosa?

Answer 23

-villi increase surface area
-crypts between the villi
-crypt cells proliferate rapidly
-only part of alimentary canal with villi
-cells at tips of villi are most differentiated and constantly sloughed

Question 24

Which cell types make up the small intestine epithelium?

Answer 24

-enterocytes (simple columnar w microvilli)
-goblet cells

Question 25

Which structures are found in the small intestine lamina propria?

Answer 25

-lacteals (lymphatic vessels in villi)
-lymphocytes and plasma cells

Question 26

What are the characteristics of the small intestine submucosa?

Answer 26

-contains Brunner’s glands (duodenum only)
-contains Peyer’s patches/GALT

Question 27

What is the role of Brunner’s glands?

Answer 27

secrete alkaline mucus to combat low pH of stomach digesta

Question 28

How are Peyer’s patches distributed throughout the small intestine?

Answer 28

-ileum has the most
-duodenum has the least

Question 29

Which plexus is found within the submucosa?

Answer 29

Meisner plexus

Question 30

What are the characteristics of the large intestine mucosa?

Answer 30

-no villi, only crypts
-lots of goblet cells
-water absorption occurs here
-capillaries, lymphocytes, and plasma cells within lamina propria

Question 31

Where in the large intestine is gut associated lymphoid tissue most abundant?

Answer 31

cecum

Question 32

What are the characteristics of the rectal mucosa?

Answer 32

-similar to rest of large intestine but with more goblet cells
-makes abrupt transition to stratified squamous epithelium at the anus (mucocutaneous junction)

Question 33

What are the characteristics of the anal sacs?

Answer 33

-lined by keratinized stratified squamous epithelium
-surrounded by apocrine glands
-contain keratin and apocrine secretions

Question 34

What are the characteristics of the rectal muscularis?

Answer 34

-thick inner and outer layers
-form anal sphincters
-internal sphincter contains smooth muscle
-external sphincter contains skeletal muscle

Question 35

Where does the rectal serosa change to adventitia?

Answer 35

at the mucocutaneous junction/caudally

Question 36

What is the function of the anal sacs?

Answer 36

to provide lubrication during defecation

Question 37

Where are the anal glands located?

Answer 37

within the dermis of the rectum