KIDNEY PHYSIOLOGY REVIEW TEST
3 things that the kidney regulate - CORRECT ANSWERS-Kidney regulates the body fluid
osmalality, electrolyte balance, acid/base balance.
Why is regulation of body fluid osmolality important? - CORRECT ANSWERS-Important for normal
functioning of the cardiovascular system, change in osmolality affect cells.
Describe positive balance/negative balance - CORRECT ANSWERS-intake> out-take, intake<out-
take
What are the end products of metabolism secreted by the kidney? (5 main ones) - CORRECT
ANSWERS-urea (from amino acids, uric acid (purines), creatinine (from muscle creatine), end
products of hemoglobin metabolism, and metabolites of hormones.
How is the kidney an endocrine organ? what does it secrete? - CORRECT ANSWERS-The kidney
secrete renin, calcitrol, and erythropoietin.
What is calcitrol? - CORRECT ANSWERS-calcitrol is a hormone secrete by the kidney which
facilitates absorption of calcium in the GI tract, important for bone where calcium gets deposited.
What is erythropoietin? - CORRECT ANSWERS-hormone secreted by the kidney which stimulates
red blood cell formation by the bone marrow.
How is renal blood flow (RBF) controlled in the bowman's capsule and why? - CORRECT
ANSWERS-RBF is controlled by the endothelial cells of the capillaries which can produce
vasocontrictors like endothelin or vasodilators like NO and increase/decrease vascular resistance.
What is the relationship between input and output in the kidney? Explain with an equation. -
CORRECT ANSWERS-Input=output, input is done solely by the renal artery, and output by the
renal vein and the urine.
Pa x RPFa = (U x V) + Pv x RPFv
Concentration of substance x in the renal artery time the renal plasma flow of the artery is equaled
to the sum of the concentration of the urine times the flow of the urine and the concentration of the
substance x in the vein times the flow of the vein.
What is the principle of clearance of the kidney?
What is filtered load? - CORRECT ANSWERS-it allows us to calculate how a substance is cleared
in the system and is only dependent on the renal artery intake and the excretion intake.
Cx= Ux x V/ Pxa
FL= Plasma concentration of x x GFR.
,If you wanted to determine if the kidney was functioning properly what test would you want to use
and why?
Describe stages or renal disease based on creatine levels. - CORRECT ANSWERS-GFR
creatinine, excretion of creatining= production of creatinine in skeletal muscle. or UcrxV= PcrxGFR
With high GFR (early renal disease), small drops in GFR contribute to small changes in GFR
whereas with chronic renal disease small drops of GFR contribute to large increase to serum
creatinine
If you want to use a substance to calculate the GFR what 4 critical tests must that substance pass?
- CORRECT ANSWERS-The substance must be
1) freely filtered across the glomerulus into the bowman's space.
2) not be reabsorbed or secreted by the nephron
3) not be metabolized or produced by the kidney
4) not alter the GFR
What is the filtration fraction? What is the equation?
What is fractional excretion? - CORRECT ANSWERS-The filtration fraction is the amount of plasma
that is actually filtered in the glomerulus as opposed to the amount of plasma that enters the
glomerulus.
Filtration fraction is defined by Ff= GFR/RPF
FEx= UxV/Flx
What is a critical sign (because it could the first and only) of kidney disease? - CORRECT
ANSWERS-Glomerular filtration rate.
What forces drive filtration across the glomerular capillaries? - CORRECT ANSWERS-Starling
forces
What is the glomerulus able to filter? What about its structure makes this type of filtration possible? -
CORRECT ANSWERS-The glomerulus does bulk filration. It is fenestrated encircled by podocytes
and only let neutral molecules 20A or less go through. Molecule between 20-42 are filtered to
varying degree. The glomerulus also have a strong negative charge that repels like negative
charges restricting the filtration of most proteins.
How does the glomerulus hold proteins? - CORRECT ANSWERS-In addition to size, the
glomerulus filtration barrier is made of negatively charged glyocoproteins which repel the negatively
charged proteins.
What pressures oppose filtration in the glomerulus? - CORRECT ANSWERS-Hydrostatic pressure
in the bowman's capsule
and oncotic pressure in the capillaries.
What happens to the different pressures involved in the ultrafiltration as you go across the
glomerular capillaries? - CORRECT ANSWERS-First oncotic pressure in the bowman's capsule is 0
because there are no proteins in the bowman's capsule. Hydrostatic pressure in the glomerular
, capillaries will decrease slightly because of the resistance to flow, oncotic pressure will increase
because proteins concentration is increased as water moves out, and the hydrostatic pressure in
the bowman's capsule is decreased.
What equations define the GFR in the glomerulus? What is GFR?
What happens if the clearance of substance x is less than GFR? - CORRECT ANSWERS-GFR = kf
[(Pgc-Pbs)-sigma(Pigc-Pibc)] n ml/min
GFR is the sum of filtration rate of all nephrons in the kidney.
Most likely substance x is reabsorbed.
What is kf? - CORRECT ANSWERS-Measure of intrinsic permeability of the glomerular capillary
and the glomerular surface area available for filtration.
What can you do to manipulate the hydrostatic pressure of the capillary? - CORRECT ANSWERS-
Manipulte resistance in the afferent arteriole, the efferent arterioles and blood pressure.
How does changes in afferent arteriolar resistance affect hydrostatic pressure in the glomerular
capillaries? - CORRECT ANSWERS-Increasing afferent arteriolar resistance, decreases flow to the
capillaries and decrease hydrostatic pressure.
Decrease in afferent arteriolar resistance, increase flow to the capillaries, increasing pressure.
How does change in efferent arteriolar resistance affect hydrostatic pressure in the glomerular
capillaries? - CORRECT ANSWERS-Increasing resistance to the efferent arteriolar resistance,
causes increased hydrostatic pressure due to increase resistance in the glomerular capillaries.
Decrease resistance, leads to decreased pressure due to decreased resistance.
How do you calculate renal blood flow? - CORRECT ANSWERS-Aortic pressure-renal venous
pressure/ renal vascular resistance.
What are the two mechanisms responsible for autoregulation of both RBF and GFR? - CORRECT
ANSWERS-Myogenic mechanism which is a pressure sensitive system.
And tubuloglomerular feedback which senses osmolarity.
What is tubuloglomerular feedback? What are the components and functions of the juxtaglomerular
apparatus. - CORRECT ANSWERS-It is one of the mechanism regulating autoregulation of RBF
and GFR, the other being myogenic mechanism sensing pressure. feedback loop in which the
concentration of NaCl in tubular fluid is sensed by the macula densa of the juxtaglomerular
apparatus.
Juxtaglomerular apparatus: macula densa (part of the TALH) + juxtaglomerular cells (produce renin)
+ extraglomerular mesangial cells (similar to monocytes, surround and provide support for
glomerular capillaries, secrete prostaglandins and cytokines, contractile, phagocytic)
Generally what is the effect of increase sympathetic tone on the GFR and the RBF? - CORRECT
ANSWERS-Increased release of NE and E binds to alpha 1 adrenergic receptors causing
vasoconstriction decreasing RBF and GFR.
3 things that the kidney regulate - CORRECT ANSWERS-Kidney regulates the body fluid
osmalality, electrolyte balance, acid/base balance.
Why is regulation of body fluid osmolality important? - CORRECT ANSWERS-Important for normal
functioning of the cardiovascular system, change in osmolality affect cells.
Describe positive balance/negative balance - CORRECT ANSWERS-intake> out-take, intake<out-
take
What are the end products of metabolism secreted by the kidney? (5 main ones) - CORRECT
ANSWERS-urea (from amino acids, uric acid (purines), creatinine (from muscle creatine), end
products of hemoglobin metabolism, and metabolites of hormones.
How is the kidney an endocrine organ? what does it secrete? - CORRECT ANSWERS-The kidney
secrete renin, calcitrol, and erythropoietin.
What is calcitrol? - CORRECT ANSWERS-calcitrol is a hormone secrete by the kidney which
facilitates absorption of calcium in the GI tract, important for bone where calcium gets deposited.
What is erythropoietin? - CORRECT ANSWERS-hormone secreted by the kidney which stimulates
red blood cell formation by the bone marrow.
How is renal blood flow (RBF) controlled in the bowman's capsule and why? - CORRECT
ANSWERS-RBF is controlled by the endothelial cells of the capillaries which can produce
vasocontrictors like endothelin or vasodilators like NO and increase/decrease vascular resistance.
What is the relationship between input and output in the kidney? Explain with an equation. -
CORRECT ANSWERS-Input=output, input is done solely by the renal artery, and output by the
renal vein and the urine.
Pa x RPFa = (U x V) + Pv x RPFv
Concentration of substance x in the renal artery time the renal plasma flow of the artery is equaled
to the sum of the concentration of the urine times the flow of the urine and the concentration of the
substance x in the vein times the flow of the vein.
What is the principle of clearance of the kidney?
What is filtered load? - CORRECT ANSWERS-it allows us to calculate how a substance is cleared
in the system and is only dependent on the renal artery intake and the excretion intake.
Cx= Ux x V/ Pxa
FL= Plasma concentration of x x GFR.
,If you wanted to determine if the kidney was functioning properly what test would you want to use
and why?
Describe stages or renal disease based on creatine levels. - CORRECT ANSWERS-GFR
creatinine, excretion of creatining= production of creatinine in skeletal muscle. or UcrxV= PcrxGFR
With high GFR (early renal disease), small drops in GFR contribute to small changes in GFR
whereas with chronic renal disease small drops of GFR contribute to large increase to serum
creatinine
If you want to use a substance to calculate the GFR what 4 critical tests must that substance pass?
- CORRECT ANSWERS-The substance must be
1) freely filtered across the glomerulus into the bowman's space.
2) not be reabsorbed or secreted by the nephron
3) not be metabolized or produced by the kidney
4) not alter the GFR
What is the filtration fraction? What is the equation?
What is fractional excretion? - CORRECT ANSWERS-The filtration fraction is the amount of plasma
that is actually filtered in the glomerulus as opposed to the amount of plasma that enters the
glomerulus.
Filtration fraction is defined by Ff= GFR/RPF
FEx= UxV/Flx
What is a critical sign (because it could the first and only) of kidney disease? - CORRECT
ANSWERS-Glomerular filtration rate.
What forces drive filtration across the glomerular capillaries? - CORRECT ANSWERS-Starling
forces
What is the glomerulus able to filter? What about its structure makes this type of filtration possible? -
CORRECT ANSWERS-The glomerulus does bulk filration. It is fenestrated encircled by podocytes
and only let neutral molecules 20A or less go through. Molecule between 20-42 are filtered to
varying degree. The glomerulus also have a strong negative charge that repels like negative
charges restricting the filtration of most proteins.
How does the glomerulus hold proteins? - CORRECT ANSWERS-In addition to size, the
glomerulus filtration barrier is made of negatively charged glyocoproteins which repel the negatively
charged proteins.
What pressures oppose filtration in the glomerulus? - CORRECT ANSWERS-Hydrostatic pressure
in the bowman's capsule
and oncotic pressure in the capillaries.
What happens to the different pressures involved in the ultrafiltration as you go across the
glomerular capillaries? - CORRECT ANSWERS-First oncotic pressure in the bowman's capsule is 0
because there are no proteins in the bowman's capsule. Hydrostatic pressure in the glomerular
, capillaries will decrease slightly because of the resistance to flow, oncotic pressure will increase
because proteins concentration is increased as water moves out, and the hydrostatic pressure in
the bowman's capsule is decreased.
What equations define the GFR in the glomerulus? What is GFR?
What happens if the clearance of substance x is less than GFR? - CORRECT ANSWERS-GFR = kf
[(Pgc-Pbs)-sigma(Pigc-Pibc)] n ml/min
GFR is the sum of filtration rate of all nephrons in the kidney.
Most likely substance x is reabsorbed.
What is kf? - CORRECT ANSWERS-Measure of intrinsic permeability of the glomerular capillary
and the glomerular surface area available for filtration.
What can you do to manipulate the hydrostatic pressure of the capillary? - CORRECT ANSWERS-
Manipulte resistance in the afferent arteriole, the efferent arterioles and blood pressure.
How does changes in afferent arteriolar resistance affect hydrostatic pressure in the glomerular
capillaries? - CORRECT ANSWERS-Increasing afferent arteriolar resistance, decreases flow to the
capillaries and decrease hydrostatic pressure.
Decrease in afferent arteriolar resistance, increase flow to the capillaries, increasing pressure.
How does change in efferent arteriolar resistance affect hydrostatic pressure in the glomerular
capillaries? - CORRECT ANSWERS-Increasing resistance to the efferent arteriolar resistance,
causes increased hydrostatic pressure due to increase resistance in the glomerular capillaries.
Decrease resistance, leads to decreased pressure due to decreased resistance.
How do you calculate renal blood flow? - CORRECT ANSWERS-Aortic pressure-renal venous
pressure/ renal vascular resistance.
What are the two mechanisms responsible for autoregulation of both RBF and GFR? - CORRECT
ANSWERS-Myogenic mechanism which is a pressure sensitive system.
And tubuloglomerular feedback which senses osmolarity.
What is tubuloglomerular feedback? What are the components and functions of the juxtaglomerular
apparatus. - CORRECT ANSWERS-It is one of the mechanism regulating autoregulation of RBF
and GFR, the other being myogenic mechanism sensing pressure. feedback loop in which the
concentration of NaCl in tubular fluid is sensed by the macula densa of the juxtaglomerular
apparatus.
Juxtaglomerular apparatus: macula densa (part of the TALH) + juxtaglomerular cells (produce renin)
+ extraglomerular mesangial cells (similar to monocytes, surround and provide support for
glomerular capillaries, secrete prostaglandins and cytokines, contractile, phagocytic)
Generally what is the effect of increase sympathetic tone on the GFR and the RBF? - CORRECT
ANSWERS-Increased release of NE and E binds to alpha 1 adrenergic receptors causing
vasoconstriction decreasing RBF and GFR.
