Lecture 3: Histology 2 (Chamier/Baekey) Flashcards
6 surface area modifications of the small intestine
- length and convolution
- plicae circulares
- villi and crypts
- epithelial cells on surface of villi
- microvilli project from epithelial cells
- polysaccharides of membrane glycoproteins
Which parts of the small intestine are plicated?
duodenum and jejunum
which tunic layers comprise the plicae circularis?
tunica mucosa and tunica submucosa
which tunic layers comprise the villi and crypts of the small intestine?
tunica mucosa
what structures lie within the villi and crypts of the small intestine?
veins, arteries, lacteals, and lymphatics
fx of microvilli
greatly increase the surface area of small intestine lining cells. Uses glycocalyx to increase adsorption of pancreatic enzymes and enhance digestion and absorption at the cell surface
what are enterocytes?
lining cells of small intestine surface mucosa
GALT =
gut associated lymphoid tissue. Contains migrating lymphocytes and is a major component of the immune system
What type of cells reside in the surface mucosa of the small intestine?
- lining cells/enterocytes
- goblet cells
- enteroendocrine cells
What type of cells reside in the crypts of lieberkuhn of the small intestine?
- lining cells
- goblet cells
- enteroendocrine cells
- paneth cells
- basal cells
fx of paneth cells
are filled with granule cells that may have antimicrobial properties
what are peyer’s patches?
large lymphoid aggregations in the intestine. Most prominent in the ileum. Are GALT
T or F: paneth cells do not migrate
T
T or F: small intestine has greater capacity than large intestine to repair itself
T
main functions of large intestine
- microbial activity (mainly in the cecum)
- absorption of water, electrolytes, vitamins (mainly in the colon)
- secretion of lubricating mucus
- peristalsis
peristalsis is important for:
mixing and propulsion of ingesta from the body
surface area is increased in the large intestine via
longitudinal plications (small intestine uses mainly circular folds)
T or F: small intestine has greater blood supply than large intestine
T
fxs of hepatocytes
1) secrete bile salts/acids, excrete bile pigments
2) synthesize sugars, plasma proteins, clotting factors, lipids, urea, ketone bodies
3) store lipids, vitamins, glycogen
4) transform toxins, drugs, hormones
5) metabolize lipids, proteins, carbs
how do bile salts travel from central vein of hepatocyte to the bile duct?
via bile canaliculi
Describe the organization of hepatocytes
Plates of hepatocytes are arranged in radial patterns, are surrounded by interlobular connective tissue, and are separated by sinusoids.
- central vein in the center of each plate
- portal triads in the interlobular connective tissue
- 1 hepatocyte is assoc. with multiple sinusoids and canaliculi*
what are the 3 components of a portal triad?
interlobular bile duct, hepatic artery, and hepatic portal v.
importance of hepatic artery with respect to hepatic vasculature
- supplies O2 and metabolic substrates
- supplies 1/5 of the sinusoidal volume
importance of hepatic portal v. with respect to hepatic vasculature
- brings substances from small intestine and spleen
- supplies 4/5 of the sinusoidal volume
drainage pathway from central vein to hepatic veins
central v. –> sinusoids –> sublobar vv. –> hepatic vv.
main fxs of the gallbladder
storage, concentration, and acidification
type of epithelium of tunica mucosa of gall bladder
simple columnar
tunica muscularis of gall bladder has smooth or striated m.?
smooth
pathway of bile from bile canaliculi to duodenum or gall bladder
bile canaliculi –> biliary ductules –> interlobar bile ducts –> intrahepatic ducts –> hepatic ducts –> cystic ducts –> gall bladder OR bile duct –> duodenum
cell types of the pancreas
- serous acinar cells
- centroacinar cells
- cuboidal epithelium
- goblet cells
fx of serous acinar cells in the pancreas
secrete zymogen granules containing enzymes that are released into the duct system
fx of centroacinar cells in the pancreas
line acinus/adenomeres (collections of acinar cells that secrete into a common intralobular duct)
fx of cuboidal epithelium in the pancreas
lines intralobular and interlobular secretory ducts
fx of crop
An esophageal diverticulum that is used for storage of feed, and later regurgitation to young. Lies before the thoracic inlet
what is a proventriculus?
a bird’s “stomach.” Undergoes acidic and enzymatic digestion
the ventriculus includes what structure in birds?
the gizzard
the cloaca is a common opening for:
- GI
- urinary
- genital
- Bursa of Fabricius (organ involved in hematopoiesis)
vent
outer opening of the cloaca
koilin
a carb-protein complex that lines and protects the muscles of the gizzard
T or F: the cecum is paired in birds
T
