Gastrointestinal Tract Flashcards
Pharynx (Function)
Carry food and air
Pharynx (Composition)
Mostly Stratified squamous non keratinized. The resp area is pseudostratified rep epithelium
three areas of the pharynx
nasopharynx - behind nasal cavity
orpharynx - behind the oral cavity
Layrngopharynx - behind larynx
Canal General Organization
Mucosa - Lining Epithelium, lamina propria, muscluaris mucosase
Submucosa - Dense irregular usually has meisners plexus
Muscluaris Externa - inner circular and outer longitudinal with auerbachs plexus in between
Serosa or adventitia - seroa has underlying connective tissue and mesothelium
adventitia just connective tissue
Esophagus ( special chracteristics of Layers)
Lining - stratifies squamous nonkeratinized
Lamina propria - see MALT, lymph nodules
also see esophageal cardiac glands distal in esophagus
musclaris mucosae not present in oral cavity
Submucosa - has manty elastic fibers and has esophageal glands proper
Muscularis externa slowly swtiches from skeltal to smooth (from upper 1/3 to lower
Thoracic - has adventitia
ABdmonial - serosa covers
Esophogeal Cardiac Gands
Distal in esophagus in order to protect from fluids in reflux
Esophageal Galnds proper
in the submucosa layer and they function to lube wall faciliateate food and keep moist
Gastro esophogeal Junction
Abrupt change in epithelium from sratified squamous non keratinizedd to simple squamou to columnar
Gastroesophogeal sphincter
physiologic sphincter that has increase in tone in the inner circular layer of mucslaris externa
not an increase in bulk so it not as effective as an anatomical sphincter and stuff can back up
Stomach gross anatomy sections
Cardia - adjacent to espohagus near heart
Fundus - extend above where esophagus enters
Body - large main section
PYlorus is where stomach tapers
3 histological regions
the body and fundus become the gastric section
Rugae
transient folds in tstomach to increase surface area
Layers of the stomach
lining epithelium - has simple columnar epithelium
lamina propria - surrounds gastric pits, MALT and lymph nodules
Muscularis Mucosa - normal for outflow
Submucosa - contains blood vessels. may see GALT
Muscluaris externa - has three layers with inner oblique middle circular and outer longtidudinal
Serosa - is covers entire stomach
Gastric Pits
branching 3-7 projections in glands. They extend thorugh the lamina propria to the level of the muscularis mucosae
Parts of the gastric pits
isthmus - the narrow passage where glands connect glands
Neck 0 the the branch point of pits
Base- the main tube of the gland
6 Cell types of simple columnar lining epithelium
Surface Mucous Mucous Neck Stem Cells Enteroendocrine Cells Pariatel Cells Chief Cells
Surface Mucous Cells of Stomach
in luminal surface and gastric pits, have apical mucigen granules and basal nucleus
Function is to release mucin which mixes with water to form buffer blanket
Mucous Neck Cell of Stomach
located in isthmus and neck of pitws in teh cardiac pyloric and gastric section of stomach
apical mucigen and basal nuclues. The funciton is same as surface mucous but its a different secretion
Stem Cells of Stomach
location is in all parts of stomach
columnar, release reneweal of all stomach epithelial
Enteroendocrine cells of stomach
at the base of pits in all cells
basally located secretory granules
function is to release hormones to blood
Parietal Cells of stomach
location thorughout gastric pits and few in cardiac pits
large triangular shape with intracellular canaliculi and microvilli for surface area for pumps
very eosionpihillic because mitochondria
function is to pump h and cl seperately to make HCL
cheif cells of stomach
location - base of gastric pits
structure - basophilic because of rough er
release apical granules of pepsinogen which convertes for digestion
also secrete gastric lipase
what cells are in the what sections of the stomach
gastric (fundus and body) - has them all
cardiac - has all but chief and only some parieatal
Pyloric - has not parieetal or chief
pyloric sphincter
between stomach and duadenum formed by thickening of muddle circular layer of muscluars externa. isssss a thickening not tone so anatomical sphincter
Small Intestine regiosn
duadenum jejunum and ileum
3 absorption featres of small intesting
villi - evaginations of mucosa along the circulares. lined with simple columnar with a lamina propria core wtih blood vessels
plicae circulares - series of perminant cicular folds of mucosa snd submucosa
Microvilli - located at apical aspect of enterocytes for increase contact
LAyers of the small intestine
Lining Epithelium - 6 cell types all simple columnar have villi
lamina propria - core of each villis surround crypts, contain fenestrated capillaries lactea smooth mucsle MALT and nodueles
Muscularis mucosa - move villi
Submucossa - has lymph vessels (See differences in each section)
Musculares Externa - normal
Serosa - covers majority
Adventitia - where duadenum is in contact with abdominal wall
Lieberkuhn
intestinal glands or crypts
what are the six cell types in lining epithelium of small intestine
enterocytes, goblet cells enteroendocrine paneth cells M Cells Stem Cells
Enterocytes of SI
absorption. line luminal surface of villi, mirgrate from crypt and mature
Have mircrovvili covered in glycocalyx
absorption - transprot nutrients to the circulation.
Secrete glycoprotein alaso for digesion
aslo secrete water for maintain chyme
KNOW THE SECRETORY ROLE
Goblet Cell of SI
location - ling lumen of villi and crypts among the enterocytes increase as go from duadenum Structure - goblet shape with apical accumulation of mucigen granules function - secrete granules mucin apical to combine with water to form mucous product to lube and protect
enteroendocrine of SI
scatters al over.
Basal secretory granules
release hormones to blood
Paneth Cells of SI
base of crypt only in small intesting
apical eosinophilic granules,
Function - have lysozyme to digest cell wall of bacteria
M Cells of SI
over large lymph nodules
Structure - apical microfolds, and basal intracellular pockets
immune cells migrate here thorugh discontinous basement membrane
Function - endocytose and transport antigens to immune cells in pocket
Stem cells of SI
location base of crypts, replace all epithelial cells
Submucosa differences in histology of SI
Duadenum - has additional mucous glands called brunner glands - neutralize acidic chyme
Jejunum- no unique
Ileum -has large peyers patches nodules from submucosa to lamina propria
know these
Ileocecal Valve
Thick extension of inner circular layer at junction of ileum and cecum
Transition to large intesting histology
abrupt transition from villi to no villi
Appendix
extends from cecum, four layers (mucosa submucosa, musclaris externa and serosa)
Increase in lymph nodes and no absorbtive function
Layers of cecum and colon
mucosa
lining epithelium - simple columnar no villi see tubular glands, five cell types
lamina propria - abundant immune cells many capillaries, no lymph vessels like SI ***** slow metastisis
muscularis muscous - helps mucus
submucosa - with blood and lymph vessels
lymph tissue extendinf from lamina propria in to tsubmucosa
muscularis externa - has inner circular layer and then 3 spaces muscluar bands called teniae coli
serosa - covers intraperiotneal portions
adventitia - located where intestine is in contact with ab wall
lieberkuhn in large intestine
into the lamina propria these are tubes again in the cecum and colon
Five cell Types In LI
absorbtive goblet enteroendocrine stem cells m cells
absorbtive cells in LI
in luminal surface, aka colonocytes, short microvilli and absorb water and na
goblet cells of LI
luminal surface and glands cyrpts
goblet shaped
release mucos to lube and protect
enteroendocrine of LI
in cyrpts, basal secretion of hormone to bloof
Stem cells of LI
replace all cells
M Cells of LI
located over the lymph noted have the basal pockets and the microfolds on apical
Transport antigents in to nodes
teniae coli
3 equally spaces muscluar bands helping movement in the muscularis externa
Rectum
dilated distal portion of large intestine
deeper crypts with more goblet cells
no teniae coli
adventitia only
Anal Canal
Simple columnar - stratified cuboidal to stratifeid squamus non keratinized - becomes keratinized at anus
all adventitia
Internal and external anal sphincter
internal - thickening of the inner circular layer
external - skeletal muscle
