Structural basis of the kidney function Flashcards
general process of filtration
under high pressure - force subsatnces out
don’t want cells to leave
afferent high pressure - bigger vessel than efferent - pressure gradient, squeeze fluid out
how is the glomerulus organised for filtration
specialised basement membrane
fenestrated endothelium capillaries
podocytes with individual feet - feet interlock = filter
many capillaries = high surface area
blood flow and pressure for the kidney
arterioles come of the aorta
short distance
high pressure
composition of filter from the glomerulus
isotonic - same conc as plasma minus the cells
where does the filtrate go from the glomerulus
from urinary pole of corpuscle
to the PCT
components of the renal corpuscle
bowmans capsule
glomerulus
podocytes
where is the blood supply of the renal corpuscle
vascular pole
what is filtered out in the glomerulus
ions and molecules <50000 molecular weight
what is the bowman’s capsule
where the filtrate is collected
summary of reabsorption
material to be absorbed is retained in PCT ions glucose AA small proteins water
structure of the PCT
vesicles - to absorb brush border - increase SA lots of mt cuboidal epithelium tight junctions interdigitations of lateral membrane - increase SA aquaporins
functions of PCT
reabsorption of 70% glomerular filtrate Na uptake - basolateral Na pump water and anions follow Na glucose uptake by Na/glucose co-transporter - requires energy aa by Na/aa co transporter protein by endocytosis
summary of creating a hyper-osmotic ECF
function of loop of henle and vasa recta counter current mechanism
Henle’s loop
gets thin
different lengths - different concentrations of ions in the medulla
vasa recta - capillaries
descending limb of the loop of henle
passive osmotic equilibrium
thin
simple squamous epithelium
few mt
ascending limb
Na and Cl actively pumped out - many mt V water impermeable TJ- don't want water to enter no aquaporins - no permeability = hyperosmotic ECF cuboidal epithelium
vasa recta
blood vessels are arranged in loop
blood in rapid equilibrium with ECF
loop structure stabilises hyperosmotic
allow fluid to be taken away from the area
adjustment of ion content of urine
principally a function of DCT
control levels of Na, K, H, NH4
distal convoluted tubule structure
invaginations no brush border some mt shorter that pct in invag - Na, K, NH4 pump and mt cuboidal epithelium few microvilli
function of the DCT
osmotic re-equilibration - by vasopressin
adjustment of Na+/K+/H+/NH4+ - aldosterone
anti-hypertensive drug
sprionolactone
interfere with osmotic re-equilibration
excrete more Na and control Bp
concentration of urine
collecting duct
movement of water down osmotic gradient into ECF
controlled by vasopressin
ECF is hyperosmotic fluid - used to concentrate urine
depends on aquaporin 2 in apical membrane
rapidly reabsorbed through the base - aquaporin 3
control by ADh
little active pumping - fewer mt
drains into minor calyx at pailla of medullary pyramid
minor and major calyces, and pelvis have urinary epithelium
kidney and bp
near aorta - detect bp
make bp controlling hormone - aldoseterone
structure of the cells of the collecting duct
TJ - don’t want movement of fluid - got urea and creatine etc in
