Histology: Gastrointestinal System

Front 1

describe digestive system purposes

Back 1

digest food, break it down, make to useable form, absorb nutrients and process, make waste

Front 2

general organization of digestive system

Back 2

epithelial lined tube some glands are built in to the tube, others are separate structures, Salivary glands
Pancreas,
Liver &Gallbladder

Front 3

organization of gut tube (very important!!)- layers of gut

Back 3

lined with epi, bsmt membrane, lamina propria (CT also called mucosa), thin sheet of smooth muscle, submucosa with loose CT (all big nerves run thru here), meissner's plexus, circular muscle, myenteric plexus, longitudinal muscle, adventita

Front 4

muscularis mucousa

Back 4

thin sheet of SM sitting under mucosa

Front 5

serosa

Back 5

thin layer of epithelial surrounding

Front 6

epis in oral cavity

Back 6

stratified squamous non cornified epithelium

Front 7

esophagus

Back 7

wet epi., non-corn, strat sq., specialized mucosal glands in 1st layer of CT (lamina propria) or submucosa, musclular layer - top 1/3 skeletal, next 1/3 mixed, final 1/3 SM. Delivers stuff to stomach

Front 8

retrothoracic cavity?

Back 8

parts of espophagus

Front 9

stomach layers

Back 9

columnar epithelium with deep pits of gastric glands, lamina propria, muscularis mucosae, submucosa, extra oblique layer of SM, circula, longitudinal muscle, serosa

Front 10

stomach regions

Back 10

cardiac,fundus, pyloric

Front 11

cardiac region of stomach

Back 11

glands producing mucous

Front 12

fundus regions

Back 12

most complicated glandular epithelium makes HCL, etc

Front 13

pyloric region

Back 13

secretory region making mostly mucous

Front 14

parietal cells of stomach

Back 14

cells-oxyphil- eosinophilic
Secrete hydrochloric acid
Secrete intrinsic factor-a glycoprotein that
binds to vitamin B12 to enhance absorbtion by
intestinal epithelial cells
Secretory activity of parietal cells regulated by gastrin
released by enteroendocrine cells in glands of pylorus

Front 15

chief cells in stomach

Back 15

basophilic
Secrete pepsinogen-an inactive precursor form of pepsin.
Acid environment of the gastric fluid cleaves pepsinogen
to liberate pepsin-a potent proteolytic enzyme.

Front 16

surface mucous cells

Back 16

Protective mucous carpet traps bicarbonate,
K+, Na+ and Cl- ions to generate local alkaline
environment

Front 17

layout of layers of fundus

Back 17

gastric pit, lower down- neck with stem cells, then parietal cells and deeper in gland chief cells (makes pepsinogen)

Front 18

Breakdown of pepsinogen

Back 18

Pepsinogen released into environment by chief cells, stomach acid cleaves and makes pepsin (protein proteolytic enzyme)

Front 19

Describe mucosa in stomach

Back 19

surface epis with pits, tubes of epithelia, lamina propria, lighter staining and darker staining cells

Front 20

Describe Higher mag fundular body cells

Back 20

Eosinophilic packed with mitochondria lighter staining parietal cells, darker staining chief cells basophilic making proteins. chief tends to be in deeper parts of glands

Front 21

Pyloric region

Back 21

distal part stomach links to gut tube. epithelium with bsmt membrane, lamina propria (submucosa), 3 layers of muscle still, serosa

Front 22

pyloric sphincter

Back 22

sphincter that squeezed down between pyloric region and intestine

Front 23

job of intestine

Back 23

absorption

Front 24

how does intestine absorb?

Back 24

lots of modifications for increased surface area

Front 25

plica circulares

Back 25

folds of mucosa to increase SA

Front 26

villi

Back 26

fingers of epithelium to increase SA

Front 27

microvilli

Back 27

brush border to increase SA

Front 28

Layers of small intestine (duodenum)

Back 28

simple columnar epi., microvilli into lumen, crypts just under imaginary midline, lamina propria, muscularis mucosae, submucosa with bruners glands, muscularis externa, serosa.

Front 29

bruners glands

Back 29

Alkaline bicarbonate secretion to neutralize acidic material from stomach

Front 30

duct from pancreas and gall bladder

Back 30

big duct carrying assorted products from gall bladder and pancreas to help break down food

Front 31

describe enterocytes

Back 31

Microvilli to increase luminal cell surface area for absorption
Enzymes associated with microvilli-glycosidases,peptidases,
and enzymes that break down lipids
Additional cytoplasmic enzymes and transporters to move products to circulation

Front 32

presence of enterocytes, goblet cells and enteroendocrine cells in sm intestine?

Back 32

enterocytes most abundant, goblet - variable in amount, Gastroendocrine or Enteroendocrine cells-
scattered

Front 33

describe goblet cells

Back 33

mucous-mechanical and bacteriocidal protection

Front 34

gastroendocrine cells

Back 34

diffuse neuroendocrine system (DNES)
diffusely scattered among the epithelial cells lining the gut tube.
Collectively, the largest endocrine organ in the body

Front 35

Cholecystokinin (CCK)

Back 35

release triggered by presence of fat ingestion
Stimulates gallbladder contraction&secretion of bile
(bile salts help break down fat-detergent action).

Front 36

secretin

Back 36

produced by cells of duodenum when lumenal pH of duodenum < 4.5
Stimulates bicarbonate secretion by Brunner’s glands
Reduces acid secretion by parietal cells in stomach

Front 37

Gastrin

Back 37

produced by “G-cells” in pyloric region of stomach
Stimulates production of acid by parietal cells

Front 38

paneth cells

Back 38

cells-secrete lysozyme and other bactiocidal molecules, make lots of lysozyme to break down

Front 39

what sheds into gut lumen

Back 39

Terminally differentiated cells shed into gut lumen

Front 40

jejunum layers (small intestine)

Back 40

simple columnar ep. with villi, lamina propria, muscularis mucosae, NO Brunners gland in submucosa, muscularis externa, serosa

Front 41

what gives moth eaten appearance in slide of small intestine?

Back 41

all the plumbing is located in submucosa giving this appearance

Front 42

Layers of ileum (sm intestine)

Back 42

simple columnar epi, lamina p, muscularis mucosa, submucoas, muscle externa, serosa

Front 43

diffuse lymphoid tissue in ileum

Back 43

Lymphocytes
Antigen-presenting cells
Stromal (framework) cells most is in submucosa, but flows into lamina propria

Front 44

large intestine layers

Back 44

simple, columnar ep, lamina propria, muscularis mucosae, submucosa, muscularis externa, serosa, teniae coli (bundles of smooth muscle)

Front 45

purpose of pits in LI

Back 45

water absorption

Front 46

why no villi and many goblet cells in LI?

Back 46

No villi b/c absorption is mostly done, goblet for more lubrication

Front 47

appendix of LI

Back 47

simple columnar epi. (no villi, but with crypts), lamina propria, muscularis mucosae, submucosa (with massive diffuse lymphoid tissue-often with many primary and secondary follicles), muscularis externa, serosa