Renal physiology Flashcards
what two factors are needed to calculate osmolality
molar concentration of the solution
number of osmotically active particles present
What is the osmolality of body fluids
300
TBW of males and females
males 60%
females 50%
TBW = ICF and ECF - concentrations?
ICF 67%
ECF 33%
separated by plasma membrane
ECF compartments
plasma 20%
interstitial fluid 80%
What tracers are used for
TBW
ECF
plasma
3h2o
inulin
labelled albumin
NaCl high concentration in ECF or ICF
K concentration higher in ECF or ICF
ECF
ICF
What charge does the glomerular membrane have
negative
what are the three filtration barriers
glomerular capillary epithelium - endothelium with large pores - barrier to RBCs
glomerular BM
foot processes of podocytes
extrinsic regulation of GFR is controlled by what
sympathetic control via baroreceptor reflex
increase ABP leads to what
vasodilatation of afferent arterioles - increase in BP gc and an increase GFR
what is Kf and what effect does this have on the GFR
surface area available for filtration
a decrease leads to a decrease in GFR
net filtration pressure
10mmHg
Why is inulin not used for measuring GFR
endogenous - has to be infused
Normal RPF
650
what is used to measure RPF
PAH- para amino hippuric acid
what is the transport max for glucose
2mmol/min
how much of water and salt is reabsorbed in the proximal tubule
approx 67%
Vasa recta when dipping down what happens to the osmolality
wen returning what happens
increase in osmolality due to loss of water and gain of NaCl
decrease in osmolality due to gain of water and loss of NaCl
What is the receptor that binds to ADH called
type 2 vasopressin receptor
where is ANP released from and how
Atrial natriuretic hormone/peptide
stored in atrial heart cells - increase in plasma volume causes atrial cells to be stretched and for ANP to be released
what does ANP lead to
decrease in BV
increased excretion of Na and diuresis leading to a decrease in plasma volume
what is the difference between water diuresis and osmotic diuresis
water - increase in urine volume but no increase in salt excretion
osmotic - increase in urine volume due to an increase in salt excretion
what is an octeopeptide that is synthesised by nerve cells
ADH
