GI Histology Flashcards
layers of GI tract; histology of specific regions
define submucosal plexus
collection of ganglia, interneurons of ENS responsible for regulating epithelial fxn & circular smooth muscle fxn
define myenteric plexus
collection of ganglia, interneurons of ENS responsible for regulating longitudinal & circular smooth muscle fxn
Name the layers of digestive tract from superficial to deep
serosa => muscularis externa => submucosa => mucosa
What are the 3 layers of the mucosa
epithelium;
lamina propria;
muscularis mucosa
what is unique about the esophageal muscle?
1st 1/3 is skeletal;
2nd 1/3 is mixed skeletal and smooth;
3rd 1/3 is smooth
for the stomach, what is unique about the layers of the digestive tract?
stomach smooth muscle contains oblique layer bw submucosa & circular layer of smooth muscle
what are the major histo characteristics of the esophagus?
nonkeratinized stratified squamous epithelium; skeletal muscle in muscularis externa (upper 1/3); smooth muscle (lower 1/3)
major histo characteristics of stomach (body and fundus)
Rugae=> shallow pits; deep glands
major histo characteristics of pylorus
deep pits; shallow branched glands
major histo characteristics of small intestine
villi, plicae, crypts
major histo characteristics of duodenum
Brunner glands
action of the brunner glands of duodenum
discharge alkaline secretion
major histo characteristics of jejunum
villi;
well developed plica;
crypts
major histo characteristics of ileum
Payer patches=> aggregations of lymph nodules
major histo characteristics of large intestine
lacks villi; crypts
mucosal cell types at surface of body and fundus of stomach
mucous cells;
chief cells;
parietal cells;
enteroendocrine (EE) cells
function of mucous cells
secrete mucus; form protective layer against acid;
tight jxns bw cells contribute to acid barrier of epithelium
functions of Chief cells
secrete pepsinogen and lipase precursor
function of parietal cells
secrete HCl and intrinsic factor
function of EE cells in body and fundus of stomach
secrete variety of peptide hormones
mucosal cell types at surface of pylorus
mucous cells;
parietal cells
EE cells
function of EE cells in pylorus
high concentration of gastrin
mucosal cells types of small intestine at the surface
columnar absorptive cells
mucosal cells types of duodenum at the surface
goblet cells;
paneth cells;
EE cells
mucosal cells types of jejunum at the surface
goblet cells;
paneth cells;
EE cells
mucosal cells types of ileum at the surface
M cells found over lymphatic nodules and payer patches
mucosal cells types of large intestine at the surface
mainly mucus secreting and absorptive cells
functions of columnar absorptive cells
contain numerous microvilli that greatly increase luminal surface area, facilitating absorption
functions of Goblet cells
secrete acid glycoproteins that protect mucosal linings
functions of paneth cells
contains granules that contain lysozyme=> may help regulate intestinal flora
functions of EE cells of duodenum and jejunum of small intestine
high concentration of cells that secrete cholecystokinin and secretin
functions of M cells
endocytose and transport antigen from lumen to lymphoid cells
functions of mucus secreting and absorptive cells of large intestine
transports Na+ (actively) and water (passively) out of lumen
