9/24 Histology of digestive system Flashcards
what is the general type of epithelium in the oral cavity?
stratified squamous: both deratinized (ortho and para) and non-keratininzed
what is the embriological origin of the oral cavity
derived from ectoderm, like skin, not endoderm like the rest of the gut
what is the average turn over of the stratified squamous of the oral cavity
1-2 weeks
the underlying connective tissue
lamina propria
How and why is there a large immune pressence in the oral cavity
many lymphocytes and the tonsils, 3X10^9 PMNs enter lamina propria everyday, and small mixeed sero/mucous salivary glands. all to take care of small immune responses to the large number of pathogens in the mouth
what covers the back of the toungue
lymphatic tissue, and the palatine tonsil
the structure near the back of the tounge wear most taste happens
circumvallate papilla
the structures on the majority of the dorsal surface of the toungue that taste
fungiform papilla
the structures of the dorsal of the tounge that cover most of the surface
filiform papilla
The layers of the tounge in the microscope
stratisfied epithelium; loose or dense connective tissue (lamina prpria) then striated skeletal muscle and adipose tissue
why do you have skeletal muscle tissue in the tounge
moves food back, and requeired for normal speech. arranged in all kinds of orientations
The most common form of cell on the dorsal surface of the tounge
filiform papillae
the moat that surrounds the circumvallate papillae
crypt
why does the circumvallate papillae have crypt
has glandular structures to wash material out to allow constant tasting of new things
the glands that wash out the crypt
Von Ebner’s gland: serous glands, they appear as globular structure in the connective tissue with ducts associated with the crypt
what is the purpose of saliva
lubricate the mouth w/mucous secretion. amylase in serous secretion (digest carbs). Helps prevent infection!
purpose of the salivary glands
Make saliva; get infected (mumps, and impacted ducts); growth factors; make haptocorrin.
how does salive act as defensive agent?
secrete lactoferrin (iron binding protien against bacteria), lysozyme (desolve bacteria cell walls), and defensins (anti-biotic protiens) and transport IgA (binds to pathogens)
what is haptocorrin?
a vitamin B12 binding protein
why would the saliva produce growth factors?
maybe to promote wound healing in the mouth and in other parts of the body when you lick wounds
cells that secrete in a serous fashion and are a spherical gland
Serous acinus
Glands that produce mucous
mucous tubule
combinded serous and mucous cells in a singe duct
mucous tubule and serous demilune
the course of mucous and serous once produced form serous acinus/demilune and mucous tubule
glands connected to intercalated ducts, striated ducts, and interlobular ducts
what ducts are found in the parenchyma of the secretory units
the glands and the intercalated ducts and striated ducts are in the parenchyma of the glands
the section of the duct that is in the stroma
the interlobular ducts
ducts in the stroma or connective tissue
interlobular ducts
what do the smooth muscle aorudn the interlobular duct do
Myoepithelial cells contract to push out saliva
what type of cells are the intercalated ducts
cuboidal cells
type of cells in striated duct
colomnar
describe the histological appearence of the serous secreting cells (serous demilune)
they are in a semi-circle of dark staining cells with prominate nucleus connected to a light stained area of duct
describe the histological appearance of the mucous secreting cells
they are light staining cells along the ducts with no clear nucleus
need special staining of anti-myosin to see well
the myoepithelial cells that squeez out the spit
describe the intercalated duct
cuboidal
describe the striated ducts
colomnar cells
how does striated duct cells control hemiostasis
recover sodium and chloride from the saliva, but don’t really recover much water, use a Na,K-ATPase to pump
histology of the interlobular ducts
may even be stratified columnar, surrounded by dense irregular connective tissue.
what is the general plan of the gut?
4 layers!
what are the 4 layers of the general plan of the gut?
Mucosa; Submucosa; Muscularis externa; Serosa (adventitia)
what are the layers of the mucosa?
the epithelium, lamina propria, musclaris mucosae
what are the sublayers of the muscularis externa?
circular muscle, myenteric plexus (nerves); longitudinal muscle
how does the mucosa change from the stomach to the intestine to the colon?
stomach has no villus, but has pits, intestine has villus, colon has no villi and no pits.
describe the mucosa layer of the gut
epithelium, lamina propria is hard to see, lined with muscularis mucosa at the bottom of the epithelium