Physiology 3 Flashcards
the basal lamina is the same as the basement membrane of the capillary: T or F
T
gaps between podocytes are called…
filtration slits
the basement membrane is made up of what 2 structures?
collagen
glycoproteins
why does the basement membrane repel plasma proteins?
it is negatively charged and thus will repel negative plasma proteins
name the 3 filtration barriers of the glomerulus
glomerular capillary endothelium
basement membrane
filtration slits
name the 3 layers that make up the glomerular membrane (inner to outer)
endothelial cells in lumen
basement membrane
filtration slits
the pressure of blood in the capillary is known as?
glomerular capillary BP
biggest determinant of net filtration pressure?
glomerular capillary BP
blood pressure is constant in the glomerular capillary T or F
T
“oncotic” should make you think…
plasma proteins
name the 4 forces that determine the net filtration pressure
glomerular capillary BP
bowmans capsule hydrostatic pressure
bowman’s capsule oncotic pressure
capillary oncotic pressure
what does the capillary oncotic pressure do?
tries to attract fluid from bowman’s capsule into lumen of capillary
why is bowman’s capsule oncotic pressure negative?
no plasma proteins formed in tubular fluid of bowman’s capsule
how do you work out the net filtration pressure?
(GCBP + BCOP) - (COP + BCHP)
normal net filtration pressure?
10mmHg
main determinant of GFR?
GCBP
normal GFR?
125ml/min
what controls extrinsic regulation of GFR?
sympathetic control via baroreceptor reflex
if blood pressure in the glomerulus is increased, what would happen to the GFR?
it would increase too
how can the glomerulus control how much blood flows through it?
it can alter the diameter of the afferent arteriole
how does sympathetic control reduce GFR?
causes vasoconstriction of blood vessels so will constrict the afferent arteriole
MABP is?
93mmHg
increased GFR will increase or decrease the amount of salt in the tubular fluid?
increase
what do macula densa cells do when they sense salt in the tubular fluid?
release vasoconstrictive substances to bring GFR back to normal
what effect would a kidney stone have on GFR and how?
would decrease it by increasing bowman’s capsule fluid pressure
burns have what effect on GFR?
increase it
what is plasma clearance?
the volume of plasma cleared of a particular substance per minute
what kind of substance is inulin (NOT insulin)?
polysaccharide
inulin clearance = GFR T or F
T
how does inulin enter the urine?
filtration only (not by secretion or reabsorption)
where is the main area of filtration in the kidney?
glomerulus
clearance of urea is less than the GFR T or F
T
a substance is said to be reabsorbed if clearance is more/less/equal to/than the GFR?
less
a substance is said to be neither reabsorbed nor secreted if clearance is more/less/equal to/than the GFR?
equal to
a substance is said to be secreted into the tubule if clearance is more/less/equal to/than the GFR
more
best way to estimate GFR?
creatinine
