Histology Flashcards
What is covered by (non kreatinis) stratified squamous epithelium in the upper GI tract
oropharynx and laryngopharynx
What is the difference between two thirds of the anterior tongue and the posterior third?
anterior - strat sqaumous epithelium, thin on underside (ventral) surface and with papillae on dorsal surface
posterior - smooth stratified sqaumous epithelium lacks papillae
What are papillae
buds on surface of tongue that increase surface area for the taste buds
What are the 4 different types of papillae
- fungiform
- circumvallate
- foliate
- filiform - NO TASTEBUDS but used to mechanically manipulate food
What does the ring of lymphoid tissue in the pharynx give rise to?
all the different types of tonsils
What are the six different layers of the tract?
1) mucosa (first 3) - epithelium
2) lamina propria - loose connective tissue
3) muscularis mucosae - thin layer of smooth muscle
4) submucosa - dense irregular connective tissue
5) muscularis externa - inner circular and outer longitudinal layer
6) serosa or adventitia - outer layer of connective tissue
is the transition to different types of epithelium smooth?
no very abrupt and can change when moving to a different organ almost instantaneously
What are gastric pits and gastric glands?
- a hole in the flat surface of the stomach
- glands - these lie at the bottom of the gastric pits
What are the pits lined by?
lined by surface mucous cells
In gastric glands, what is the function of a chief cell and a parietal cell?
- C - digestive enzyme secreting cell
- P - hydrochloric acid producing cell
How does the mucosa differ in the cardia, body and pylorus of the stomach?
(columnar epithelium)
cardia - deep gastric pits that branch into tortuous glands
body - shallow gastric pits with long straight gastric glands
pylorus - deep gastric pits with branched glands at a greater density than cardia
what does the oblique layer of the muscularis externa of the stomach do?
aids in the churning action of stomach
describe the surface view of the small intestine
finger like projections (villi) and between them there are drilled down pits - crypts of lieberkuhn (simple columnar)
What are the 3 regions of the small intestine? how are brunners glands stimulated
duodenum - contains brunners glands receives acidic partially digested food called chyme. Brunners glands secrete alkaline material to neutralise the chyme
jejunum - tallest villi
ileum - shorted villi and aggregations of lymphoid follicles called peyer’s patches
describe these cells: enterocytes, goblet cells, paneth cells, enteroendocrine cells and stem cells
- enterocytes - most numerous, tall columnal cells with brush border so are principle absorptive cell
- goblet cells - produce mucous and lubricate passage of material
- paneth - defensive function and regulate bacterial flora - base of liebarkuhn
- enteroendocrine - hormones that control secretion and motility
- stem - divide to replenish epithelium
What are the two main types of cells in the large intestine?
- absorptive cells - removal of salts and thereby water
- goblet cells - secretion of mucous to lubricate colon
How are the cells of the large intestine arranged?
test tube racks - (simple columnar) straight tubular glands that extend down to muscularis mucosae
Where is the outer longitudinal smooth muscle found in the large intestine?
3 muscular strips called teniae coli
where is the appendix found?
blind ending hollow extension of the cecum - lymphoid tissue tends to die with age
what does parenchyma mean?
cells that carry out the function of an organ
What are parenchyma liver cells composed of?
glandular epithelial cells
What are some functions of the parenchymal liver cells?
syntheis and secretion of bile, detoxification, synthesis cholesterol
What is the histology of the liver?
covered by collagenous connective tissue capsule - covered by a layer of mesothelial cells
Describe its structure:
- made up of segments called lobules - a wee bit like a hexagon
- each lobule - branch of a hepatic vein in the centre of it and portal triads at each corner
