Gastrointestinal

Question 1

funtions of alimentary mucosa?

Answer 1

1) secertion
2) absorption
3) barrier
4) immunologic

Question 2

basic organization of alimentary canal layers? (deep to superficial)

Answer 2

1) mucosa
thin layer of muscle
2) submucosa
3) muscularis externa
4) serosa

Question 3

3 projections in mucosa?

Answer 3

1) plicae cicularis = submucosal folds
2) villi = mucosal projections
3) microvilla =projections of apical surface of cells

Question 4

glycocalyx found on what type of mucosa projection?

Answer 4

microvilla

*glycocalyx is the glycoprotein layer on the apical surface of absorptive cells

Question 5

extramural galnds deliver to ____ only?

what glands are scattered throughout canal?

Answer 5

small intestine

mucosal and submucosal glands

Question 6

peyers patch?

Answer 6

diffuse lymph tissue/nodules found in SI (type of GALT)

Question 7

muscluaris externus muslces?

Answer 7

inner=tighti=circle/spiral
outer=loose=length/shorten
*together responsible for peristalsis
*separated by C.T. layer that houses the myenteric plexus from enteric nervous system

Question 8

enteric nervous system

Answer 8

• Part 1 in submucosa =meissner’s plexus

* Part 2 in muscularis externa in the CT between the two layers of muscle = myenteric plexus

Question 9

List the 5 sphincters

Answer 9

1) pharyngoesophageal sphincter =prents entry of air into esophagus
2) inferior esophageal sphincter = prevents gastric reflux
3) pyloric = junction of stomach and duodenum
4) ileocecal = junction of small and large intestine
5) internal anal sphincter = surrounds anal canal

Question 10

adventitia

Answer 10

point of digestive tract attachment for the portions that are directly affixed to the cavity wall by CT

Question 11

serosa is a serous membrane consisting of ______?

Answer 11

mesothelial layer that is continuous with mesentary of abdominal cavity

Question 12

mucosa lining the esophagus is special and different from skin how?

Answer 12

it is NON-keratinized stratified squamous epithelium with no cross-linking that allows for expansion as food passes

Question 13

what are the 3 gastric glands in the stomach? what do they secret?

Answer 13

• cardiac and pyloric secrete mucous to protect stomach epithelium
• fundic glands secrete most digestive products

Question 14

3 parts of stomach?

Answer 14

1) cardiac = near esophageal oriface
2) pyloric = junction of stomach and SI
3) fundic region = largest, body of stomach

Question 15

stomach is lined by what type of cell? what makes them special?

Answer 15

simple columnar epithelium
*have surface mucous cells that have LARGE apical cup of mucinogen granules that release bicarbonate and potassium to protect epithelium from low pH

Question 16

what does the parietal, chief and enteroendocrine cells of stomach do?

Answer 16

• parietal = scattered, produce HCL and intrinsic factors
• cheif cells= DEEP, pepsin
• enteroendocrine cells= gastrin, bile and sense whats (endo and exo) happening in stomach digestively

Question 17

what is super special about parietal cells?

Answer 17

they have an extensive intracellular canalicular system to increase surface area with numerous microvilli to facilitate proton pump activity (scattered, produce HCL and intrinsic factors)

Question 18

5 types of cells in intestinal epithelium?

Answer 18

1) entercytes= absorption
2) goblet= mucin secretion
3) paneth cells= maintain mucosal innate immunity
4) enteroendocrine= produce paracrine and endocrine hormones (gastrin, bile, sense what is happening in digestive tract)
5) M cells= cover lymph nodules

Question 19

explain M cells

Answer 19

• facilitate passage of microorganisms to underlying lymph tissue
• envaginated at basament lamina to allow lymphocytes to enter closer to lumen
• M cell sourronds lymph tissue
• **have smooth surface compared to microvilli

Question 20

crypts of lieberkuhn

Answer 20

glands found in mucosa of LI, house stem cells that in base of gland and repopulate the mucosa every 5 days

Question 21

principle function of large intestine?

Answer 21

absorption of electrolytes and water; elimination of waste

*very little nutrient re-absorption

Question 22

what cell does the LI lack that the SI has?

Answer 22

paneth cells= maintein immunity, secrete ani-microbial lysozymes and alpha-defensins

Question 23

What is the bulk of the cells found in pancreas? what do they do?

Answer 23

B (beta) cells= control plasma glucose levels by releasing insulin = ENDOCRINE function

Question 24

what is the endocrine function of pancreas and the 3 cells associated with it?

Answer 24

*regulate blood glucose
alpha= secrete glucagon
beta= secrete insulin
delta= secrete somatostatin

Question 25

how do you ID the exocrine and endocrine parts of pancreas? Islets are exo or endo?

Answer 25

``` LARGE dark purple areas= exocrine light small (round) purple areas= endocrine= **islets of Langerhan** ```

Question 26

explain acinar cells, intercalated duct, cetroacinar cells and pancreatic duct?

Answer 26

* Exocrine function of pancreas to release digestive enzymes * acinar cells are TRIANGULAR and surround intercalated duct system * intercalated ducts drain into main pancreatic ducts that drain into duodenum * centriacinar cells are FLAT cells that mark the beginning of intercalated ducts, considered to be part of acinar cells

Question 27

hepatopancreatic ampulla and sphincter?

Answer 27

where the pancreas empties into the duodenum and controls bile flow

Question 28

what layer of tissue is the gallbladder missing?

Answer 28

submucosa | *stright from mucosa to muscularis externa

Question 29

what increases and decreases bile flow?

Answer 29

* increase= hormones cholecystokinin, gastrin, motilin to aid digestion * decrease= steroid hormones * released by enteroendocrine cells

Question 30

what is the smallest branch of biliary tree?

Answer 30

bile canaliculi

Question 31

cholangiocytes

Answer 31

monitor bile flow and regulate bile content via PRIMARY cilia that acts as mechonosensor

Question 32

biliary tree

Answer 32

from hepatocytes to gallbladder to intestine

Question 33

lots of catalase found?

Answer 33

in hepatocytes and peroxisomes to dergade hydrogen peroxide

Question 34

kupffer cells

Answer 34

are phagocyte cells that monitor sinusoides that receive blood