Gi Tract Microanatomy

Front 1

the digestive tract can be seen to be made up of what 4 distinct layers?

Back 1

1. mucosa (mucous membrane)

2. submucosa

3. muscularis externa

4. serosa (or adventitia)

Front 2

the 4 distinct later of the digestive tract vary depending upon the __of the different __?

Back 2

upon the functions of the different regions of the tract

Front 3

the mucosa has what three layers or parts?

Back 3

1. epithelium with its basal lamina

2. lamina propria

3. muscularis mucosae

Front 4

the mucosa epithelium with its basal lamina is derived from ___?

Back 4

derived from endoderm

Front 5

the mucosa epithelium with its basal lamina, is an epithelium type that reflects___?

Back 5

reflects function

Front 6

the lamina propria of the mucosa layer is a ___containing?

Back 6

a loose connective tissue, containing blood vessels, nerves, lymphatics, lymphoid tissue and in some regions, glands

Front 7

the mucosa muscularis mucosae typically is __layers of ___? a ___and a ____?

Back 7

typically two layers of smooth muscle, a thin inner circular layer and an outer longitudinal layer

Front 8

the muscularis mucosae of the mucosa separates the __from the __?

Back 8

the mucosa from the submucosa

Front 9

the submucosa is typically a ___connective tissue?

Back 9

a dense irregular connective tissue

Front 10

the submucosa contains?

Back 10

blood vessels, lymphatics, a nerve plexus (the submucosal Meissner's plexus), and in some regions glands and lymphoid tissue

Front 11

the submucosa contains a nerve plexus, the ___? this is part of the ___system, and is ___derived?

Back 11

the submucosal Meissner's plexus, part of the enteric nervous system, neural crest derived

Front 12

the muscularis externa is typically an ___and an ___of___?

Back 12

typically an inner circular and an outer longitudinal layer of smooth muscle

Front 13

between the inner circular and outer longitudinal layers of smooth muscle of the muscularis externa is the ___?

Back 13

myenteric (aurbach's) plexus

Front 14

the myenteric (aurbach's) plexus is part of the ___system, and is ___derived?

Back 14

part of the enteric nervous system and is neural crest derived

Front 15

what distinctive layer of the digestive tract is the myenteric (auerbach's) plexus found in?

Back 15

in between the two smooth muscle layers of the muscularis externa

Front 16

the serosa or adventitia is a layer of ___with ___?

Back 16

layer of loose connective tissue with blood vessels, lymphatics and nerves

Front 17

in the case of the serosa, the layer of loose CT with blood vessels, lymphatics and nerves is covered by?

Back 17

by mesothelium

Front 18

in the case of adventitia, the layer of loose CT with blood vessels, lymphatics and nerves is surrounded by and blends into?

Back 18

into the adjacent connective tissue of the abdominal wall

Front 19

in the esophagus the mucosa layer has what type of epithelium?

Back 19

stratified squamous non-keratinized epithelium

Front 20

in the esophagus, the lamina propria of the mucosa has ___at its lower end near the stomach?

Back 20

has esophageal cardiac glands

Front 21

esophageal cardiac glands secrete ___which has a __pH? this secretion functions to?

Back 21

secrete mucus which has a neutral pH

-functions to protect the esophagus from regurgitated acid

Front 22

in the esophagus, the muscularis mucosae (smooth muscle) of the mucosa layer is ___than other parts of the tract and is unique because it is only ___?

Back 22

is thicker than other parts, and is only longitudinally oriented smooth muscle cells (instead of typically inner circular layer and outer longitudinal layer)

Front 23

the esophageal cardiac glands of the lamina propria of the mucosa layer in the esophagus are located in the part of the esophagus close to the?

Back 23

to the esophagogastric junction (terminal part of the esophagus)

Front 24

what is GERD?

Back 24

excessive gastric reflux in pyrosis or what is more commonly described as heartburn

Front 25

persistent reflux (as with GERD) can cause __of the epithelium?

Back 25

can cause metaplasia of the epithelium; there is a change from a stratified squamous epithelium to a simple columnar epithelium

Front 26

incidence of Barret's esophagus is increasing, particularly among?

Back 26

among males

Front 27

___are risk factors for GERD/Barret's esophagus?

Back 27

alcohol and smoking

Front 28

as with all epithelial metaplasia, Barret's esophagus can undergo transformation into a ___, ___?

Back 28

a malignancy, adenocarcinoma

Front 29

GERD (gastroresophageal reflux disorder) is when an ___allows ___?

Back 29

when an incompetent esophageal valve allows acid to rise into the esophagus

Front 30

in chronic cases of GERD, the lining of the esophagus can ___ or worse, become __?

Back 30

can change (metaplasia) or worse, become eroded

Front 31

over the entire length of the esophagus, the submucosa layer contains groups of ___called __?

Back 31

groups of small mucus-secreting glands called esophageal glands proper

Front 32

esophageal glands proper in the submucosa layer of the esophagus secrete a mucus that is slightly __and functions to ___?

Back 32

that is slightly acidic, and functions to lubricate the lumen of the esophagus

Front 33

esophageal glands proper in the submucosa layer of the esophagus tend to be most numerous in the ___region of the esophagus?

Back 33

in the upper half of the esophagus (book says)

lowermost region (slides say)?

Front 34

the esophageal muscularis externa has two muscular layers, an ___and an__?

Back 34

an inner circular layer and an outer longitudinal layer

Front 35

the esophageal muscularis externa is unique in the fact that?

Back 35

based on the region of the esophagus, the type of muscle present differs

Front 36

region of esophagus, upper, middle and lower can be identified by muscle types in the?

Back 36

in the muscularis externa layer

Front 37

the upper third of the esophagus has a muscularis externa composed of?

the middle third?

the lower third?

Back 37

upper third- composed of skeletal muscle only

middle third- mixture of skeletal and smooth

lower third- smooth muscle only!

Front 38

the esophageal adventitia or serosa depends on its position in regards to the diaphragm; so its ___above the diaphragm, and ___below the diaphragm?

Back 38

adventitia above the diaphragm

serosa below the diaphragm

Front 39

the adventitia of the esophagus (above diaphragm) is ___containing ___?

Back 39

loose connective tissue containing longitudinally-oriented blood vessels, nerves and lymphatics

Front 40

the serosa of the esophagus (below the diaphragm) is on the __part of the esophagus just before the __?

Back 40

the free part of esophagus, just before the stomach is covered with mesothelium

Front 41

the stomach has what 4 grossly identifiable regions? and what are the histological identifiable regions?

Back 41

grossly: cardia, fundus, body, pylorus

histological: cardiac (cardia), pyloric (pylorus), fundic (fundus)

Front 42

what are rugae? these are called __by gross anatomists?

Back 42

longitudinal folds of mucosa and submucosa seen in the empty stomach; called magenstrasse by gross anatomists

Front 43

the stomach (gastric) mucosa layer is characterized by?

Back 43

by gastric pits or foveae (numerous openings)

Front 44

in the mucosa layer of the stomach (gastric) the epithelium is?

Back 44

simple columnar epithelium with mucus secreting cells--surface mucous cells (NOT GOBLET CELLS)

Front 45

in the mucosa layer of the stomach (gastric) the lamina propria is ___containing ___?

Back 45

loose CT with lymphatic tissue; containing branched tubular gastric glands that open into the gastric pits

Front 46

in the mucosa layer of the stomach (gastric) the muscularis mucosae is composed of?

Back 46

an inner circular, and an outer longitudinal smooth muscle layers

Front 47

gastric glands are located in the ___layer of the stomach?

Back 47

in the lamina propria of the mucosa layer

Front 48

the gastric glands are ___specialized?

Back 48

regionally specialized

(cardia glands in the cardiac region, pyloric glands in the pyloric region, fundus glands in the fundus and body region)

Front 49

the gastric glands in the cardia region of the stomach (cardiac gastric glands) are mainly ___cells?

Back 49

mainly mucus-secreting cells

Front 50

the gastric glands in the fundus and body region of the stomach (fundus gastric glands) are ___gastric glands that open up (empty) into __gastric pits?

Back 50

long gastric glands, that empty into short gastric pits

Front 51

the gastric glands in the pyloric region of the stomach (pyloric gastric glands) are __glands that empty into __pits?

Back 51

short glands that empty into deep pits

Front 52

what are the different gastric epithelial cells? (cells found in fundic gastric glands)

Back 52

-surface cells

-undifferentiated cells

-mucus neck cells

-parietal or oxyntic cells

-chief or zymogenic cells

Front 53

surface cells secrete?

Back 53

secrete mucus (visible mucus b/c of its cloudy appearance)

Front 54

what does the mucus secreted by surface cells do?

Back 54

it forms a thick, viscous, gel-like coat that adheres to the epithelial surface; thus protecting against abrasion from rougher components of chyme

Front 55

undifferentiated cells at the __of glands, give rise to?

Back 55

at the neck of glands, give rise to the other cell types

Front 56

mucous neck cells in the neck region of glands have a different secretion than the ___?

Back 56

than the surface mucus-secreting cells (there's is soluble compared with the insoluble/cloudy mucus produced by surface mucus-secreting cells)

Front 57

parietal or oxyntic cells, located mainly in the ___part of gastric glands, are ___shaped, very __cells?

Back 57

mainly in the upper part of gastric glands, are round or pyramidal shaped, very eosinophilic cells

Front 58

chief or zymogenic cells, located in the __portions of the gastric glands, are very ___cells?

Back 58

in the lower portions of the glands, are very basophilic

Front 59

parietal cells elaborate ____? they contain ___which dissociates ?

Back 59

elaborate hydrochloric acid

-their cytoplasm contains carbonic anhydrase which dissociated H2CO3 into H+ and HCO3-, and that H+ combines with Cl- to from HCl in the lumen

Front 60

it is improper to say that parietal cells ___?

Back 60

secrete HCl

Front 61

parietal cells actively transports ___across their ___? and ___is actively transported across the ___and passively across the ___to enter the lumen of the canaliculus?

Back 61

transports H+ across their apical membranes

Cl- is actively transported across the basal membrane and passively crosses the apical membrane to enter the lumen

Front 62

parietal cells secrete ___which is needed for___?

Back 62

secrete intrinsic factor which is needed for absorption of vitamin B12

Front 63

parietal cells are very___?

Back 63

acidophilic

Front 64

parietal cells are characterized by?

Back 64

-intracellular canaliculi

-numerous mitochondria

-very little rER

Front 65

lack of intrinsic factor due to such conditions as ___can lead to ___?

Back 65

such conditions as atrophic gastritis can lead to pernicious anemia

Front 66

B12 deficiency can lead to ___?

Back 66

central nervous system degeneration

Front 67

B12 deficiency can lead to CNS degeneration, for example it can cause ___? thus can occur in ___since B12 is not found in ___?

Back 67

can cause subacute combined degeneration of the spinal cord; can occur in very strict vegetarians since B12 is not found in vegetables and fruits

Front 68

subacute combined degeneration of the spinal cord (caused by B12 deficiency) presents as ___? it may present like?

Back 68

presents as a burning sensation in soles of feet and other sensory disturbances

-may present like multiple sclerosis

Front 69

chief (zymogenic) cells are located in the ____of the gastric glands?

Back 69

in the lower portions

Front 70

chief (zymogenic) cells are very ___because of their high content of___?

Back 70

very basophilic because of their high content of RER

Front 71

chief (zymogenic) cells have ___granules and release ___?

Back 71

have secretory (zymogen) granules and release pepsinogen

Front 72

pepsinogen (released from ___) becomes ___ in the very __envrionment of the?

Back 72

released from chief (zymogenic) cells, becomes pepsin in the very acidic environment of the lumen

Front 73

chief (zymogenic) cells are characterized by?

Back 73

lots of RER, and secretory (zymogen) granules

Front 74

gastric enteroendocrine cells produce __that does what?

Back 74

produce gastrin that stimulates acid production

Front 75

all enteroendocrine cells secrete their products where?

Back 75

into lamina propria

Front 76

the muscularis externa layer of the stomach is made up of what?

Back 76

3 layers of smooth muscle; an inner oblique layer, a middle circular layer, and an outer longitudinal layer

Front 77

what forms the pyloric sphincter?

Back 77

the middle circular smooth muscle layer of the gastric muscularis externa

Front 78

plicae circulares (valves of____)?

Back 78

valves of Kerkring

Front 79

plicae circulares in the mucosa layer of the small intestine (valves of Kerkring) have a core of?

Back 79

core of submucosa

Front 80

vili in the mucosa layer of the small intestine have a core of? and has a central__?

Back 80

core of lamina propria ; has central lymphatic vessel or lacteal

Front 81

absorptive cells with microvilli in the mucosa of the small intestine, have a core of?

Back 81

core of microfilaments (actin filaments)

Front 82

crypts of lieberkuhn are intestinal glands found within the __?

Back 82

within the lamina propria of the mucosa layer of the small intestine

Front 83

there are ___cells in the base of the crypts of Lieberkuhn?

Back 83

paneth cells

Front 84

paneth cells in the base of crypts of Lieberkuhn have large ___granules, which contain ___which is a?

Back 84

large eosinophillic granules, which contain lysozyme an antibacterial enzyme that breaks down bacterial cell walls

Front 85

the mucosa layer of the ___contains other cells types, such as goblet cells and enteroendocrine cells?

Back 85

of the small intestine

Front 86

enterocytes are?

Back 86

-intestinal absorptive cells; epithelial cells with microvilli

Front 87

goblet cells are?

Back 87

single cell mucous gland; unicellular mucin-secreting glands

Front 88

paneth cells secrete?

Back 88

antimicrobial substances

Front 89

paneth cells primary function?

Back 89

to maintain mucosal innate immunity by secreting antimicrobial substances

Front 90

enteroendocrine cells secrete?

Back 90

various paracrine and endocrine hormones

Front 91

M (microfold) cells are ___that cover__?

Back 91

are modified enterocytes that cover lymph nodules of lamina propria

Front 92

cell types of the small intestine?

Back 92

-enterocytes

-goblet cells

-paneth cells

-enteroendocrine cells

-M(microfold) cells

Front 93

the small intestine is specialized for?

Back 93

for absorption

Front 94

what are the three levels of folding that increase the absorptive surface area of the small intestine?

Back 94

-plicae circulares

-villi

-microvilli

Front 95

plicae circulares are permanent ___and as such, they have a core of?

Back 95

permanent submucosal folds and as such, they have a core of submucosa

Front 96

Villi are ___shaped or finger-like projections of ___? they have a core of?

Back 96

leaf-shaped or finger-like projections of mucosa

-core of lamina propria

Front 97

microvilli are cellular ___, with a core of ?

Back 97

cellular projections, with a core of microfilaments

Front 98

after absorption, glycerol, monoglycerides and fatty acids are resynthesized into ___that are converted into __? they are then released into the ___and carried away by__?

Back 98

resynthesized into triglycerides that are converted into chylomicrons; they are released into the lamina propria and carried away by capillaries and lymphatic lacteals (contained in the intestinal vili)

Front 99

triglycerides are broken down into ___so they can be absorbed?

Back 99

into glycerol, monoglycerides and long and short chain fatty acids

Front 100

microvili of the small intestine create a ___on the apical region of the cells?

Back 100

striated border

Front 101

the lamina propria of the mucosa layer of the small intestines is ___containing___?

Back 101

loose CT

contains lymphocytes, mast cells, macrophages

has blood vessels and central lacteals

Front 102

the submucosa layer of the small intestine contains glands where?

Back 102

ONLY in the duodenum

Front 103

the submucosa layer of the small intestines is ___contianing?

Back 103

dense irregular CT

-only in duodenum contains glands

-contains nerve plexus (Meissner's plexus)

Front 104

the muscularis externa of the small intestine is made up of ___and between layers there is a ?

Back 104

made up of an inner circular and an outer longitudinal smooth muscle layers

-between layers there is a nerve plexus and postganglionic neurons (Auerbach's plexus)

Front 105

M cells (microfold cells) are specialized ___cells that cover __?

Back 105

specialized epithelial cells that cover Peyer's patches

Front 106

how to M cells (microfold cells) function in the GALT as immune monitoring?

Back 106

-they phagocytose microorganisms and macromolecules from the intestinal lumen and present the antigens to CD4+ T lymphocytes in the lamina propria

Front 107

plasma cells in the ___secrete ___; thus they function in the GALT as monitoring immune?

Back 107

in the lamina propria secrete IgA

Front 108

what does the IgA that plasma cells in the lamina propria do?

Back 108

its bound to a secretory component in enterocytes and transported to the lumen

Front 109

GALT has a monitoring function through what type of cells? (immune function of the GI tract)

Back 109

-M cells (microfold cells) and plasma cells

Front 110

the duodenum has leaf-shaped ___, and a typical intestinal epithelium meaning?

Back 110

leaf-shaped vili, meaning the epithelium has columnar cells with microvili, and goblet cells

Front 111

the duodenum has short simple tubular glands that are called ___within the ___?

Back 111

crypts of Lieberkuhn within the lamina propria

Front 112

in the Duodenum, ___are found in the submucosa (i.e. outside the muscularis mucosa)?

Back 112

Brunner's glands

Front 113

when chyme, material from stomach, enters the duodenum, ____secrete an ____to buffer acidic chyme? this optimizes ___for__?

Back 113

Brunner's glands secrete an alkaline secretion to buffer acidic chyme; this optimizes pH for pancreatic enzymes

Front 114

enteroendocrine cells of the duodenum secrete?

Back 114

cholecystokinin (CCK), gastric inhibitory protein (GIP) and secretin

Front 115

cholecystokinin (CCK) secreted from enteroendocrine cells in the duodenum stimulates ___and inhibits ___?

Back 115

stimulates gallbladder contractions, pancreatic enzyme secretion, and pancreatic bicarbonate secretion

inhibits gastric emptying

Front 116

gastric inhibitory protein (GIP) secreted from enteroendocrine cells in the duodenum shuts off__in the __?

Back 116

shuts off acid production in the stomach

Front 117

secretin, secreted from the enteroendocrine cells in the duodenum stimulates ___and inhibits?

Back 117

stimulates pancreatic secretion

inhibits gastric acid production

Front 118

at the gastroduodenal junction, you can see the pyloric sphincter, which is a thickening of?

Back 118

of the inner, circular layer of the muscularis externa

Front 119

at the gastroduodenal junction there is a transition from __mucosa to __mucosa? so here, one finds __and for the first time__?

Back 119

transition from pyloric mucosa to intestinal mucosa; here one finds villi, and for the first time, goblet cells

Front 120

if one follows the muscularis mucosa into the duodenum, one sees that there are ___ within the __?

Back 120

glands within the submucosa

Front 121

the jejunum has the most well-developed ___of the small intestine? the vili are ___, and there are more ___than the duodenum?

Back 121

most well-developed plicae circulares

vili are rounded-finger like

more goblet cells than duodenum

Front 122

the ileum has __vili? and more ___than jejunum and duodenum?

Back 122

club-like villi, more goblet cells

Front 123

the ileum contains ___(___) in the lamina propria of the mucosa layer?

Back 123

peyer's patches (lymphoid nodules)

Front 124

paneth cells reside at the base of ?

Back 124

of the crypts of Lieberkuhn

Front 125

paneth cells have secretory granules which have ___within them?

Back 125

antibacterial enzymes

Front 126

what are the functions of the large intestine (colon)?

Back 126

to absorb water, compact feces, and lead to its elimination

Front 127

the function of the large intestine (to absorb water, compact feces, and lead to its elimination) is reflected in __with rather meager ___and lots and lots of ___to provide_?

Back 127

reflected in absorptive cells with rather meager microvilli and lots and lots of goblet cells to provide lubrication for the movement of the stool

Front 128

the large intestine DOES NOT have?

Back 128

villi

Front 129

the large intestine (colon) has crypts of Lieberkuhn containing many?

Back 129

many goblet cells

Front 130

in the large intestine (colon) there ARE NO ___in the crypts of Lieberkuhn, but there are some?

Back 130

no paneth cells, but there are some enteroendocrine cells

Front 131

the muscularis externa of the large intestine (colon) is made up of ____?

Back 131

inner circular smooth muscle layer, and an outer longitudinal smooth muscle layer composed of three distinct longitudinal bands called the teniae coli

Front 132

the outer longitudinal smooth muscle layer of the muscularis externa in the large intestine (colon) is composed of ___called the __?

Back 132

composed of three distinct longitudinal bands called the teniae coli

Front 133

haustra coli in the large intestine are __?

Back 133

sacculations

Front 134

the appendix was once believed to be a __organ, it is now viewed as a ___organ?

Back 134

once believed a vestigial organ, now viewed as a lymphoid organ

Front 135

the appendix is characterized by a mucosa like that of the __and numerous ___amognst?

Back 135

a mucosa like that of the colon and numerous secondary lymphoid nodules amongst diffuse lymphoid tisse

Front 136

the appendix, although has mucosa like that of the colon, it DOES NOT have?

Back 136

teniae coli

Front 137

the internal sphincter of the rectum and anal canal is __ muscle and is a thickening of?

Back 137

smooth muscle;of the inner circular layer of the muscularis externa

Front 138

the internal sphincter of the rectum and anal canal relaxes under the influence of the ___and tightens under ___?

Back 138

relaxes under influence of the parasympathetic nervous system and tightens under sympathetic control

Front 139

the external sphincter of the rectum and the anal canal is ___muscle, innervated by the ?

Back 139

skeletal muscle, innervated by the inferior anal (rectal) nerves, which are branches of the pudendal nerve (S2, S3, S4)

Front 140

at the anorectal junction, a transition from a ___epithelium to a ___epithelium occurs?

Back 140

from a simple columnar epithelium to a stratified squamous non-keratinzed epithelium

Front 141

the the anal orifice, there is a second transition from ___epithelium to __epithelium?

Back 141

from stratified squamous non-keratinized to stratified squamous keratinized