Kidney Function 1 Flashcards
4 main functions of kidney
- water sodium balance
- ion control, K+, CA2+, Mg2+
- acid-base balance
- excretion
3 things to take away from the lecture:
autoregulation
clearance
macula densa
is acid-base balance only done by kidney?
nope. in conjunction with lungs
what happens if ion concentrations get out of hand?
could be deadly and sudden death from nerve, muscle, brain damage
uraemia is what?
chronic renal failure due to a general plethora of products
what does Renin do?
hormone what regulates BP and Na+
Vitamin D3 has homey hydroxyl compared to calciferol?
3OH vs. 1OH
what does formation of concentrated urine do? what is min vs. max?
excrete toxins and waste
30mOsm/L - 1200 mOsm/L
what is formation of dilute urine do?
remove excess water
85% of glomeruli are what?
superficial cortical glomeruli SCGs
what are JM glomeruli?
juxtamedullary glomeruli: deep penetrating loops of HEnle into medula
SCGs are what?
superficial cortical glomeruli with shallow penetrance of loops of Henle
more loops of henle deeper or superficially?
superficially due to 85% of glomeruli being SCGs
juxtamedullary glomeruli account for concentration gradient, where is it higher? lower?
300 at superficial
1200 in deepest papilla part of medulla
Expand these acronyms: PCT, tDLH, tALH, TAL, DT, CD
proximal convoluted tubule thin descending loop of henle thin ascending loop of henle Thick ascending loop of henle Distal Tubule collecting duct
where does the TAL attach to parent glomerulus?
end of TAL attaches between efferent and afferent arteriole
how many nephrons per kidney?
1 million
how many L out of daily 180L of filtrate goes back into efferent arteriole?
178L
what is renal blood flow per minute? per kidney?
1L/min, 500ml per kidney
filtration fraction is?
20% or 0.2
what is normal haematocrit?
40
if renal plasma flow is 600ml, what is total GFR? GFR per kidney?
total GFR is 125ml or 60ml per kidney
how much cardiac output needed to run the renal filtration system?
20%
describe the efferent renal arteriole
artery to capillary to artery to capillary to vein
Na+ or K+ more important for secretion?
K+
macula densa cells close to the arteriole make what? does what?
Renin which ends up vasoconstricting
macula densa detect Na+ feeback via paracrine mediators such as? what does it adjust?
prostaglandins and adenosine
alters afferent arteriole tone to adjust resistance and keep glomerulus constant at 50mmHg
epithelial granular cells near afferent arteriole make what?
Renin
What is myogenic response/reflex?
if too much stretch on afferent arteriole, is contracts to mitigate any dilating force
Creatinine level is equated roughly the same as the?
GFR
3 components of filtration in Bowman’s Capsule?
filtration slits
basal lamina
fenestrations
what is hallmark of advanced diabetes?
albumin in the urine as the basal lamina degenerate, lose negative charge and ability to repel
what is normal hydrostatic pressure in glomerular capillary?
50mmHg
what is normal hydrostatic pressure in Bowman’s capsule?
10mmHg
what is normal oncotic pressure in glomerular capillary?
25-40mmHg
what is normal oncotic pressure in Bowman’s capsule?
0mmHg
what is the normal net filtration pressure across bowman’s capsule?
10mmHg into nephron
Angiotension II preferentially constricts which arteriole?
efferent arteriole
which arteriole does autoregulation occur at?
afferent arteriole
BP can vary between what and still maintain normal GFR?
80-180mm Hg
what happens if low sodium? how do you maintain BP?
macula densa detects, triggers Renin to increase BP via unknown mechanism
what are the 3 drivers of renin release?
sympathetic
decreased BP
decreased NaCl
Renin affects afferent or efferent?
efferent
what happens if Na+ too high?
releases thromboxane and adenosine which constricts afferent
Renal clearance of a substance equation is?
Urine Volume / plasma concentration
Inulin is a marker for what?
GFR
how much Glucose clearance per minute in nephron?
0mL/min
penicillin reabsorbed?
nope. freely filtered and even secreted
