102814 physio review Flashcards
ICF is what percent of body weight?
40%
ECF is what percent of body weight?
20%
osmolarity of ECF and ICF in the body is
280-300 mOsm/liter
what does glomerular filtrate contain in terms of salt and organic substance concentration?
same concentration of most salts and organic substances found in plasma
what are the physical forces causing filtration by glomerular capillaries?
glomerular hydrostatic pressure
glomerular colloid osmotic pressure
Bowman’s capsule hydrostatic pressure
GFR is usually
125 ml/min
efferent plasma flow is usually
575 ml/min
what are the determinants of glomerular filtration rate?
ultrafiltration coefficient and driving force
ultrafiltration coefficient
product of hydraulic permeability (Lp) and surface area of the glomerular capillary membranes
in diabetes mellitis, why is ultrafiltration coefficient reduced?
because glomeruli become sclerotic and there are less glomeruli contributing to the total glomerular capillary area
as arterial pressures change, what happens to renal blood flow? to GFR?
they stay the same within 80-150 mmHg of arterial pressure. this is because of autoregulation of renal blood flow and GFR
what happens to urine output with increases in arterial pressure?
it increases (due to pressure natriuresis. the mechanism for pres natr is unknown)
how can GFR and RBF be autoregulated?
myogenic mechanism
tubuloglomerular feedback
what is the ultimate effect of macula densa feedback in the case of decreased arterial pressure?
decrease afferent arteriolar resistance
increase efferent arteriolar resistance
NE’s effect on GFR
decreases GFR
epinephrine’s effect on GFR
decreases GFR
endothelin’s effect on GFR
decreases GFR
angiotensin II’s effect on GFR
no change or decreases
endothelial derived NO’s effect on GFR
increases GFR
prostaglandin’s effect on GFR
increase
myoglobin’s filterability by glomerular capillary
0.75 (as it’s a small protein)
albumin’s filterability by glomerular capillary
0.005 (larger protein)
angiotensin II increases Na and water reabsoprtion where
proximal tubule
angiotensin II increases hydrogen ion secretion where
proximal tubule
diabetics can have what with regards to urine?
proteinuria
what happens in the thin descending loop of henle
reabsorption of water
what happens in thin ascending loop of henle
impermeable to water
passive reabsorption of sodium
permeable to urea-urea secretion
thick ascending loop of Henle
reabsorbs 25% of filtered Na by Na/K/2Cl transport
lumen positive potential drives paracellular reabsorption of Na, K, Mg, Ca
impermeable to water
dilutes tubular fluid
what sodium transporters are in the thick ascending loop of Henle
Na/H (sodium reabsorption, H secretion)
Na/K/2Cl (all reabsorbed)
furosemide works where?
thick ascending loop of Henle at the Na/K/2Cl transporter
early distal tubule
reabsorbs Na, Cl, Ca, Mg
not permeable to water
thiazide diuretics sensitive segment (works at Na/Cl transporter)
what transporters are there in the early distal tubule
Na/Cl (both reabsorbed)
late distal tubule and cortical collecting duct
reabsorbs Na, secretes K (these two are coupled and regulated by aldosterone)
regulated by aldosterone
water permeability regulated by ADH
where do K sparing diuretics work?
late distal tubule and cortical collecting duct at the reabsoprtion of sodium and secretion of potassium
what transporter is in the principal cell of late distal tubule and cortical collecting duct
ENaC (epithelial sodium channel)-reabsorbs sodium
medullary collecting duct
reabsorbs Na-similar to principal cells
ADH stimulated water reabsorption
urea reabsorption
angiotensin II acts where and does what
primarily proximal tubule
increases Na and water reabsorption. increases H+ secretion
where does ADH work? what does it do?
principal cells of late distal tubule and collecting duct, inner medullary collecting duct
increases water reabsorption
where does ANP work and what does it do?
distal tubule and collecting duct
decreases Na reabsoprtion
PTH works where and does what?
proximal tubule-decreases PO4 reabsoprtion
thick ascending loop of Henle and distal tubule-increases Ca reabsoprtion
