Histology Flashcards
what type of epithelium is Bowmans capsule
simple squamous epithelium
what are the 2 layers of Bowmans capule
parietal (outer) and visceral (inner) - podocytes
what are the 3 layers that separate the blood from the glomerular filtrate
- capillary endothelium - has pores
- basal lamina
- podocytes (Bowmans capsule) -
describe the structure of podocytes
have interdigitating cell processes forming filtration slits
what is special about the basal lamina in renal corpuscle
- thicker than usual
- forms a major part of the filtration component
mesangial cells
- scattered mesangial cells produce a connective tissue core called a mesangium
- these cells have several functions: support and removal of debris
- have contractile properties - resemble smooth muscle cells
what is the function of the renal corpuscle
production and collection of glomerular filtrate
what is the basal lamina like in the proximal convuluted tubule
large BL invaginations to increase surface area
proximal or distal convuluted tubules
proximal - they have an indistinct apical border
function of the loop of Henle
- create hyperosmotic environment in medulla - salts lost into interstitial spaces between tubes
- permeability to ions varies in differenet areas
describe the histology of the loop of henle
- simple squamous epithelium in the thin limb, with nuclei protruding into the lumen (tl)
- simple cuboidal epithelial cells in the thick limb, with abundant mitochondria (TAL)
vasa recta
- thin walled blood vessels taht dip down into the medulla from cortex, and then climb back into cortex
- collectively called vasa recta
- branch from efferent arterioles
- run parallel to the loop of Henle
proximal or distal convuluted tubule
distal - no brush border
medullary rays
in the cortex, groups of straight tubules (straight segments of proximal and distal tubules and collecting ducts) run perpendicular to the surface of the kidney
what are the collecting ducts lined by
simple columnar epithelium
describe the epithelium changes in the nephron
- bowmans capsule - simple squamous
- proximal convuluted tubule - simple cuboidal with brush border
- loop of Henle - simple squamous
- thick ascending loop of Henle - simple cuboidal with mitochondria
- distal convuluted tubule - simple cuboidal
- collecting duct - simple columnar
what is the duct of Bellini
also known as papillary duct
describe the collecting and papillary duct drainage
- medullary collecting ducts form papillary collecting ducts
- these converge to form a central duct near the apex of each renal pyramid
- the papillary duct exits the renal pyramid at the renal papilla
- renal filtrate is drained into minor calyx as urine
- major calyx etc
what does the juxtaglomerular apparatus compose of
- macula densa
- juxtaglomerular cells
- extraglomerular mesangial cells
macula densa function
sense sodium ions
juxtaglomerular cell function
secrete renin, modified smoth muscle cells
what are Extraglomerular mesangial cells also called
lacis cells
what does urothlium line
also called transitional epithelium
condicting parts of urinary tract - renal pelvis onwards
what are teh cells at the surface of the urothelium called
umbrella cells - domed
what is the structure of the urothelium cells like facing the lumen
thickened and inflexible membrane:
- variability in thickness of cells represents different states of distension
- apical surface cells have a thickened membrane to provide an impermeable barrier
urothelium
- umbrella cells
- capillary
- lamina properia
- smooth muscle
compare the proximal and distal ureter
star shaped to allow expansion
epithelium in urethra in males
- prostatic (bladder to prostate) - transitional
- membranous (prostate to bulb of penis) - transitional changes to stratified columnar
- penile - stratified columnar which changes to stratified squamous near the tip
