Histology of Digestive System

Question 1

what are the associated or accessory digestive organs

Answer 1

tongue, teeth, salivary glands, pancreas, liver, gallbladder

Question 2

what are the 4 main tissue layers of the digestive system from the lumen outward

Answer 2

• mucosa
• submucosa
• muscularis externa
• serosa/adventitia

Question 3

the lamina propria is in what tissue layer of the digestive system ?

Answer 3

mucosal layer

Question 4

what main tissue layer has an inner circular layer and an outer longitudinal layer ? what is the purpose of each ?

Answer 4

Muscularis externa

• inner circular - constricts lumen in peristalsis
• outer longitudinal - dilates lumen in peristalsis

Question 5

where is the myenteric nerve plexus found, and what is its function

Answer 5

found b/w inner circular and outer longitudinal layers of the muscularis externa
-its the brain function of dig. system that controls peristalsis movements

Question 6

what is the muscle tissue of the lumen in the proximal 1/3 of the esophagus ? middle 1/3 ? distal 1/3 ?

Answer 6

proximal 1/3 - skeletal muscle
middle - mixed
distal 1/3 - smooth muscle

Question 7

the mesothelium can be found in what major layer of the digestive system

Answer 7

serosa

Question 8

what type of epithelium is the mucosal lining in the esophagus ?

Answer 8

nonkeratinized stratified squamous epithelium

Question 9

what layer would the esophageal glands (proper) be found in the GI system

Answer 9

submucosal layer throughout esophagus

Question 10

what layer would esophageal cardiac glands be found ?

Answer 10

lamina propria of mucosal layer in distal esophagus

Question 11

what is the function of the stomach

Answer 11

• physical breakdown
• chemical breakdown of lipids and proteins
• 10 % absorbtion

Question 12

what type of epithelium is the mucosal lining of the stomach ?

Answer 12

simple collumnar epithelium

Question 13

how many individual layers are w/in the muscularis externa in the esophagus ? stomach ?

Answer 13

esophagus - 2

stomach - 3

Question 14

what are the 3 layers of the muscularis externa in the stomach from the lumen outward

Answer 14

inner oblique
middle circular
outer longitudinal

Question 15

what anatomical region of the stomach would you find gastrin glands ? what do they do ?

Answer 15

fundus/body of the stomach in the mucosal layer

-secrete HCl and pepsinogen

Question 16

how do secretions from glands w/in the mucosal layer reach the lumen ?

Answer 16

secretions travel through gastric pits and then into lumen

glands are located at base of pit

Question 17

how can you tell the difference b/w cardiac glands and pyloric glands

Answer 17

both at base of gastric pits BUT

-gastric pits leading to pyloric glands are much longer

Question 18

what are the folds w/in the stomach called

Answer 18

rugae

Question 19

all glands w/in the stomach NEVER go past or extend into what tissue layer

Answer 19

muscularis externa

Question 20

what are the 3 parts of the fundus of the stomach

Answer 20

isthmus, neck, and base

Question 21

what special cells will you find in the isthmus of the (fundus) stomach

Answer 21

stem cells

Question 22

what special cells will you find in the neck of the (fundus) stomach

Answer 22

mucous neck cells, parietal cells

Question 23

what is the function of mucous surface and mucous neck cells

Answer 23

secrete mucous and adsorption

Question 24

what is the function of parietal cells and where are they found

Answer 24

in the neck of the fundus of the stomach

-secrete HCl and intrinsic factor for absorption

Question 25

what special cells will you find in the base of the (fundus) stomach

Answer 25

- chief cells | - G cells (enteroendocrine)

Question 26

what is the function of chief cells and where can you find them

Answer 26

base of the fundus - secrete pepsinogen (break down proteins) - sectrete gastric lipase (break down fats)

Question 27

what is the function of G cells and

Answer 27

base of the fundus | -secrete gastrin which stimulates parietal cells to secrete HCl

Question 28

where does 90 percent of absoprtion in the body take place

Answer 28

small intestine

Question 29

what are plicae circularis

Answer 29

small circular folds of the small intestine designed to increase surface area -composed of a villus w/ multiple microvilli at surface

Question 30

what does the small intestine digest

Answer 30

nucleic acids

Question 31

the epithelial mucosal lining of the small intestine is what ?

Answer 31

simple collumnar epitheliu

Question 32

what are crypts of Lieberkuhn and where are they found

Answer 32

intestinal glands found in small intestine at base b/w the villi in the mucosal layer or in mucosal layer of large int. -Never extend into submucosa

Question 33

where would you find more goblet cells the small intestine or large

Answer 33

large intestine cuz they are water absorbative cells

Question 34

how many individual layers of the muscular externa is there in the small int.

Answer 34

2 - inner circular - outer longitudinal

Question 35

what are Brunner's glands and where can they be found

Answer 35

glands in duodenum in the submucosal layer | -produce alkaline mucous to buffer stomach pH

Question 36

what are paneth cells and where can they be found

Answer 36

-secrete lysozymes for digestion of bacterial cell walls and regulate normal bacterial flora -found in the crypt of lieberkuhn in mucosal layer of small int./

Question 37

what are fingerlike projections of the small intestine designed for adsorption

Answer 37

villi

Question 38

in the ileum of the small intestine, aggregations of lymph follicles in the lamina propria and submucosa are referred to as ?

Answer 38

Peyer's patches

Question 39

what are the specialized cells in ileum overlying the peyers patches and what is their purpose

Answer 39

M (microfold) cells | -present antigens

Question 40

the absorptive cells in the small intestine are called

Answer 40

enterocytes

Question 41

the adsorptive cells in the large intestine are called

Answer 41

colonocytes

Question 42

what is the tenia coli and what part of GI tract is it found

Answer 42

band of smooth muscle in the muscularis externa layer of the large intestine

Question 43

why are paneth cells not found in the large intestine

Answer 43

Because we need bacteria in the large intestines and paneth cells KILL bacteria

Question 44

what is the function of the pancreas

Answer 44

98%- exocrine gland to secrete enzymes to surface | 2 % - endocrine gland

Question 45

where at in the distal part of the GI tract would you find a shift in the mucosal epithelial lining from simple collumnar epithelium to nonkeratinzed stratified squamous epithelium

Answer 45

recto-anal junction

Question 46

where would you find islets of langerhans

Answer 46

pancreas

Question 47

where does the liver recieve blood from

Answer 47

25 % - oxygenated blood from hepatic artery | 75 % - deoxygenated nutrient-rich blood from hepatic portal vein

Question 48

the liver is what shape anatomically

Answer 48

6 sided hepatic lobules

Question 49

what are the type of cells that make bile

Answer 49

hepatocytes

Question 50

what are the large phagocytic cells lining the sinusoids of the liver

Answer 50

Kupffer cells (type of macrophage)

Question 51

explain the path of blood from when it enters the liver to final destination in the hear

Answer 51

enters then to liver sinusoids - --> central vein -----> hepatic vein - ------->inferior vena cava ----------> right atrium of heart

Question 52

what is at each of the 6 corners of the liver

Answer 52

portal triad