Stomach and Esophagus Flashcards
What are the components of the ailmentary canal?
oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anal canal
what are the principal organs associated with the ailmentary canal?
tongue, teeth, salivary glands, pancreas, liver, gallbladder
What is the function of the mucosa epithelium of the ailmentary canal?
protective, secretory, or absorptive
what does the lamina propria of the mucosa layer of the ailmentary canal contain? (tissue/cells)
loose CT with many capillaries; often contains diffuse or nodular lymphatic tissue referred to as gut - associated lymphatic tissue (GALT); may contain glands continuous with epithelium (mucosal glands)
what does the muscularis mucosae layer of the alimetary canal contain? (in the mucosa layer)
thin layer of smooth muscle, sometimes with inner circular and outer longitudinal components
Why type of tissue is found in the ailmentary canal submucosa?
coarse collagenous CT (dense irregular) with blood vessels, lymphatic vessels, and nerves
AND ganglion cells of the submucosal plexus = Meissners
where does the submucosa layer of the ailmentary canal contain glands?
only in the esophagus and duodenum
Describe the muscle layers in the muscularis externa layer of the ailmentary canal
usually two layers: inner circular and outer longitudinal, which provide for luminal and longitudinal constriction, respectively;
the stomach has 3 layers (inner oblique layer is added)
Where is the ganglia of myenteric (Auerbach’s) plexus found?
between the (inner) circular and (outer) longitudinal layers of the muscularis externa layer of the ailmentary canal
what is the function of the ganglia myenteric? what system do they belong to?
belong to the intrinsic enteric component of the autonomic nervous system;
Function = integrated networks regulate peristaltic muscular contractions and secretory functions of mucosal and submucosal glands
what is the outermost layer of the ailmentary canal?
serosa or adventitia (fibrosa)
Describe the serosa layer of the ailmentary canal
outer layer of connective tissue covered by a simple squamous epithelium called mesothelium
Describe the adventitia fibrosa layer of the ailmentary canal. where is it found?
when the organ (ie: esophagus) is NOT suspending in the peritoneal cavity, there is no medothelial covering = adventitia fibrosa
what is the function of the oropharynx? what does it transmit?
provides access to esophagus; carries both air and food
Describe the mucosa layer of the oropharynx
epithelium = stratified squamous non-keratinized
lamina propria = loose CT with elastic fibers, some mucous glands and a prominent elastic layer that sends fibers into muscle layer to anchor mucosa
Describe the submucosa layer of the oropharynx
typically not present
Describe the muscularis externa layer of the oropharynx:
inner circular and out longitudinal layers of skeletal muscle
Describe the outermost layer of the oropharynx
= adventitia (fibrosa) = tough fibroelastic CT
what is the function of the esophagus
muscular tube that delivers food and liquid from pharynx to stomach
Describe the mucosa layer of the esophagus
- epithelium = stratified squamous non-keratinized
2. Lamina propria = loose CT + mucosal or cardiac glands present near the ends of esophagus
Describe the glands found in mucosa of the esophagus (histology)
found in the lamina propria of the mucosa; simple branched tubular glands similar to those in the upper or cardiac region of the stomach
Describe the muscularis mucosae in the esophagus
single layer of longitudinally oriented SMOOTH muscle
what type of tissue is found in the submucosa of the esophagus?
coarse collagenous connective tissue (dense irregular) + submucosal glands (esophageal glands proper)
Are there any glands found in the submucosa of the esophagus? if yes, describe them
compound tubuloalveolar glands with variable distribution;
secrete product to the surface via a duct;
mostly MUCUS, but some serous cells producing lysozyme
what is the product of the glands found in the submucosa of the esophagus?
mostly mucus, but some serous glands producing lysozyme
What are the layers found in the muscularis externa of the esophagus?
inner circular layer and outer longitudinal layer
what type of muscle is found in the muscularis externa of the esophagus?
Upper 1/3 = skeletal muscle; transitions into smooth muscle in the lower 1/3;
this transition reflects voluntary to involuntary swallowing
Describe the adventitia (fibrosa) of the esophagus
Loose CT that blends with adjacent structures
What is the function of the stomach?
expanded muscular portion of digestive tube that mixes and partially digests food, producing a pulpy fluid mixture (chyme)
what is chyme? where is it produced?
mixture of food + gastric juices in the stomach
What is the esophagogastric junction?
an abrupt change in the eptihelial lining from stratified squamous to simple columnar
what type of epithelium is found in the stomach? what is its function?
simple columnar; functions in secretions and absortion
How are the different regions of the stomach distinguished?
via the histology of their mucosal glands
Describe the histological characterisitc of the cardia of the stomach
has cardiac glands in the mucosal glands
Describe the histological characteristic of the body and fundus of the stomach
presence of gastric/fundus glands in the mucosa
Describe the histological characteristic that defines the pylorus of the stomach
pyloric glands
What are the 3 major characteristics of the stomach mucosa?
- Ruga (termporary submucosal folds)
- Mammilated gastric areas (thickened mucosal for increased surface area for secretion)
- Gastric pits (holes from ruga to gastric pit)
What are Rugae? what is their function?
temporary longitudinal submucosal folds; serve to accommodate expansion and filling of the stomach
Note: since the submucosa golds, the overlying mucosa temporarily folds as well
What are the mamilated/ gastric areas? where are they located?
small bulges of the mucosa of the stomach that is thickened;
provide increased surface area for secretion
What are gastric pits? where are they found?
holes found in the mucosa of the stomach;
the mucosal glands empty into them
what type of cells line the surface of the gastric pits? what do they produce?
surface mucous cells which produce a thick, cloudy mucus
What is the function of the mucos cells that line the gastric pits? (what is the function of the mucus that they secrete?)
secrete a thick mucous film that has a high BICARB (HCO3) content and protects the eptihelium from the acidity of the gastric contents
Describe the lamina propria of the stomach
- mucosal glands are each surrounded by loose CT that contains blood vessels, lymphocytes, plasma cells, eosinophils, mast cells, and macrophages
- Muscularis mucosae (deep to glands)
Describe the muscularis mucosae of the stomach (location, function)
located in the lamina propria deep to the mucosal glands;
extends smooth muscle cells up between the glands (contraction of smooth muscle aids in emptying the glands)
Are there any glands present in the submucosa of the stomach? if so, describe them
No glands present
Describe the submucosa of the stomach
Dense irregular CT;
NO GLANDS
Nerves and ganglion cells of submucosal (Meissner’s plexus)
Describe the Muscularis Externa of the stomach (how many layers/what are they, function)
3 layers of SMOOTH muscle: inner oblique, middle circular, outer longitudinal
function: contractions churn and homogenize food as gastric secretions are added
where is the myenteric plexus found?
between the circular and longitudinal layers of muscularis externa of the stomach
Describe the outer tissue layer of the stomach
Serosa: CT that is covered with a mesothelium
Where are the cardiac glands found? what type of cells do they contain?
located in the cardiac region of the stomach; contain primarily mucous cells
Where are the gastric glands found? what do they produce? describe the characteristic histology associated with the gastric glands
located in the fundus of the stomach;
produce gastric juices;
The fundus/body has a characteristic two-tone staining appearance due to distribution of multiple cell types
Where are pyloric glands found? what type of cells do they contain?
located in the pyloric region of the stomach; contain primarily mucous cells
