B5-036 Renal Physiology I Flashcards
blood enters the glomerulus via
afferent arteriole
blood exits the glomerulus via
efferent arteriole
all the glomeruli are located in the
cortex
3 layers of the glomerular filtration membrane
- endothelial cells
- basement membrane
- podocytes
space between podocytes
slit diaphragm
- plasma without proteins
- only ions and small molecules
renal ultrafiltrate
is albumin normally able to filter through the membrane?
no, too big
the charge of albumin is […] than hemoglobin
more negative
this is why hemoglobin can filter and albumin cannot
are positive or negative ions more favorable for filtration?
positive
basement membrane is negatively charged
the basement membrane is […] charged
negatively
why positively charged ions filter better
infection can cause loss of […] at the basal membrane
negative charge
causes leakage of proteins in the urine
damage to the GBM will cause […] decreasing plasma oncotic pressure
hypoproteinemia
will cause edema
what is beneficial about the biphasic curve of pressures along the nephron?
maintains high hydrostatic pressure for filtration
hydrostatic pressure - oncontic pressure =
filtrating pressure
sites of major resistance within nephron
2
afferent and efferent arterioles
hydrostatic pressure > oncotic pressure in the glomerular capillaries, thus…
filtration
oncotic pressure > hydrostatic pressure in peritubular capillaries, thus…
absorption
describe forces involved in ultrafiltration
major force: hydrostatic pressure of glomerular capillary bed PGC
opposed by: hydrostatic pressure of tubule PBS
colloid osmotic pressure of blood (PGC)
normal PUF=
10 mmHg
PUF= PGC - PBS - IIGC
besides the pressure […] and […] of the GBM are important factors
surface area
permeability
together= KUF
normal KUF=
12 ml/min/mmHg
GFR=
equation and normal value
KUF x PUF
normal about 120
main pressure that can be changed to regulate filtration
hydrostatic pressure
increased pressure in glomerulus causes […] filtration
more or less
more
obstruction of the renal arteries will […] hydrostatic pressure
decrease
cause low GFR
obstruction of the ureter will […] the pressure in the glomerulus
increase
decreased GFR due to increased capsule pressure
changes in resistance of afferent and efferent arterioles causes changes in
GFR
describe the changes to pressures
afferent constriction
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: decrease
peritubular capillary pressure: decrease
renal blood flow: decrease
describe the changes to the pressures
afferent dilation
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: increase
peritubular capillary pressure: increase
renal blood flow: increase
describe the changes to the pressures
efferent constriction
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: increase
peritubular capillary pressure: decrease
renal blood flow: decrease
describe the changes in the pressures
efferent dilation
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: decrease
peritubular capillary pressure: increase
renal blood flow: increase
describe the changes in the pressures
afferent-efferent constriction
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: no change
peritubular capillary pressure: decrease
renal blood flow: decrease
describe the changes in the pressures
afferent-efferent dilation
glomerular capillary pressure:
peritubular capillary pressure:
renal blood flow:
glomerular capillary pressure: no change
peritubular capillary pressure: increase
renal blood flow: increase
autoregulation of RBF and GFR is done via
2 mechanisms
- tubuloglomerular feedback
- myogenic response
if you transplant a kidney, innervation is not maintained but […] is
autoregulation
describe the myogenic response
- increase in blood pressure
- arteriolar smooth muscles stretch
- arteriolar muscle contraction
- increases resistance
- net result: little change in RBF