L17 - kidney and urinary histology Flashcards
what are medullary rays ( or pyramids )
bundles of collecting tubules/ducts
function of medullary rays
drain nephrons
what is a lobe
medullary pyramid and the region of cortex it connects to
what is the functional unit of the kidney
nephron (glomerulus to ureter)
renal corpuscle and renal tubule
what does the renal corpuscle consist of
glomerulus and bowmans capsule
what does renal tubule consist of
PCT
LOH
DCT
CT
where is the renal corpuscle
cortex
is the afferent or efferent arteriole bigger and which direction do they take the blood
afferent biggest
afferent towards glomerulus efferent away
does PCT / DCT / CT have the biggest lumen
CT
what cells line the bowmans capsule
parietal cells
what are the 3 layers of the glomerular filter
- capillary endothelium (fenestrated)
- glomerular basement membrane (thick)
- podocytes
describe podocytes
branching cells that go from
primary - secondary - tertiary - pedicels
which wrap around the BM
what are pedicels
finger like projections of podocytes with gaps in-between called filtration slits
role of glomerular basement membrane
prevents large material crossing into filtrate
contains -ve proteins which repel other -ve proteins in the plasma (which is most proteins)(minimising protein lost into filtrate)
order of nephron
afferent arteriole glomerulus bowmans space PCT LOH(thin descending -thin ascending -thick ascending) DCT CT CD
describe PCT epithelium
simple tall columnar with tall microvilli
describe DCT epithelium
simple cuboidal no microvilli
what is found in PCT epithelium
microvilli
vesicles (transport of absorbed material to capillary side)
mitochondria
lysosomes
how does epithelium change from PCT through the LOH
simple columnar (PCT)
squamos (thin descending)
cuboidal (thick ascending limb)
what is the juxtaglomerular apparatus
specialisation of afferent arteriole and DCT
what lines the DCT?
macula densa
where are juxtaglomerular cells located
adjacent to afferent arteriole
where is the macula densa
adjacent to the JMA lining the DCT
how does epithelium change from collecting tubule - CD
cuboidal to columnar
what cells are found in collecting tubules
principle cells
intercalated cells
what is the epithelium in ureter
transitional
describe the structure of ureter
2 layers of smooth muscle, outer circular inner longitudinal
what epithelium in bladder
transitional
describe layers of bladder
- epithelium (highly folded to allow stretch)
- inner longitudinal
- outer circular
- outermost longitudinal
what do renal veins drain into
inferior vena cava
what drives filtration at glomerulus
starling forces
what are starling forces?
pressure differences between hydrostatic (out of capillaries) and oncotic pressure
the juxtaglomerular complex consists of what cells
- juxtaglomerular cells
- macula densa
- mesangial cells
- lacis cells
function of juxtaglomerular cells
secretere renin - renin angiotensin system
function of macula densa cells
reabsorb Na
function of lacis cells
store and secrete erythropoietin
what are mesangial cells and what is their function
specialised smooth muscle cells that can contract to reduce GFR (glomerular filtration rate)
function of principle cells (DCT)
reabsorb Na
secrete k+
function of intercalated A cells (DCT)
reabsorb K+
reabsorb HCO3-
secrete H+
function of intercalated B cells
secrete HCO3- in response to alkalosis
