Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/147

Click to flip

147 Cards in this Set

  • Front
  • Back
6. (normal) Plasma oncotic pressure in
glomerular capillary

G S L

(normal ) Oncotic pressure of Bowman’s space
Greater than .. Normally the oncotic pressure (protein
concentration) of bowman’s space is zero,
because normally proteins do not pass through
the filtration barrier
7. Hydrostatic pressure at final segment of
glomerular capillary

G S L

Hydrostatic pressure at initial segment of
peritubular capillary
Greater than…There will always be a pressure drop across the capillaries, so the pressure as the blood enters the efferent arterioles must be greater than the pressure of the blood as it leaves the efferent arteriole
8. Oncotic pressure at the initial segment of the
glomerular capillary

G S L

Oncotic pressure at the initial segment of
peritubular capillary
Less than.. Since water leaves the glomerular capillaries,
but proteins do not, the proteins will become
more concentrated by the time the blood exits
the glomerular capillaries. The increased
oncotic pressure of the peritubular capillaries
favors reabsorption of water and solutes into
those capillaries
9. Hydrostatic pressure at beginning of
glomerular capillary

G S L

Hydrostatic pressure in Bowman’s space
Greater than.. The hydrostatic pressure difference between
glomerular capillaries and Bowman’s space
favors filtration
10. Hydrostatic pressure at the final segment of
the glomerular capillary

G S L

Oncotic pressure at the final segment of the
glomerular capillary
Greater than.. Because the oncotic and hydrostatic pressures
in Bowman’s space are normally zero (oncotic)
or very small (hydrostatic), the forces that
determine filtration in the glomerular capillary
are primarily the capillary hydrostatic and the
capillary oncotic pressure (hydrostatic favors
filtration, and oncotic opposes it). Filtration
occurs along the entire length of the
glomerular capillary, so the hydrostatic pressure must be greater than the oncotic pressure, even at the end of the capillary
11. The fluid in Bowman’s space contains
A. proteins in the same concentration as in the glomerular capillary plasma
B. electrolytes in the same concentration as in glomerular capillary plasma
C. only solutes that will be eliminated in the urine
D. only electrolytes, and no other solutes
E. all solutes at a higher concentration than in the glomerular capillary plasma
B. Filtration is by bulk flow, and there is no barrier to electrolytes, water, and small solutes, including both waste products and essential nutrients. On the other hand, there is a barrier to nearly all proteins. The solutes present in the fluid of Bowman’s space will be present in the same concentration as in the plasma, since any difference in solute concentration would be quickly corrected by the free movement of water.
12. Which of the following would initially increase the GFR:
A. lower than normal concentration of albumin in the plasma (“hypoalbunemia”)
B. significant loss of nephrons, as in renal disease
C. hemorrhage, accompanied by significant decrease in mean arterial pressure
D. increased activity in sympathetic nerves
E. vasodilation of the efferent arterioles
A. Plasma oncotic pressure opposes filtration, so decreased plasma oncotic pressure will increase GFR.
Significant loss of nephrons, as in renal disease does what to the GFR?
Since GFR measures the filtration rate of the total tissue, reducing the tissue will reduce the GFR, at least initially (there is often compensation that can return the GFR back to normal)
GFR does what?
measures the filtration rate of the total tissue
hemorrhage, accompanied by significant decrease in mean arterial pressure does what to the GFR?
tends to decrease GFR because the afferent arterioles, and also efferent arterioles, will constrict in response to the increased sympathetic nerve activity..
increased activity in sympathetic nerves does what to the GFR?
tends to decrease GFR because the afferent arterioles, and also efferent arterioles, will constrict in response to the increased sympathetic nerve activity..
vasodilation of the efferent arterioles does what to GFR?
vasodilation of the efferent arterioles will increase RBF, but decrease GFR.
13. Dilation of the efferent arterioles would result in an initial increase in
A. hydrostatic pressure in Bowman’s space
B. hydrostatic pressure in the glomerular capillaries
C. GFR
D. blood flow through the glomerular capillaries
E. Both C and A
13. D. Blood flow would increase (as it does with vasodilation anywhere in the circulatory system).
Dilation of the efferent arterioles would result in an initial_______ in hydrostatic pressure in the glomerular capillaries
decrease
Dilation of the efferent arterioles would result in an initial _______ in GFR
decrease
Dilation of the efferent arterioles would result in an ____________ in hydrostatic pressure in Bowman’s space
no change
14. Autoregulation in the kidney
A. maintains a high RBF even during hemorrhage
B. is mediated primarily by reflexes in the sympathetic nervous system
C. is mediated in part by intrinsic activity in the afferent arteriolar smooth muscle
D. is mediated primarily by a change in the oncotic pressure of Bowman’s space
E. is a reflex unique to the kidney
14. C. Autoregulation is due to local effects, not sympathetic nervous
Does Autoregulation in the kidney maintain a high RBF even during hemorrhage?
During hemorrhage, the afferent arterioles are maximally dilated, but still cannot maintain RBF
Is Autoregulation in the kidney mediated primarily by reflexes in the sympathetic nervous system?
Autoregulation is due to local effects, not sympathetic nervous system
Is Autoregulation in the kidney mediated primarily by a change in the oncotic pressure of Bowman’s space?
Oncotic changes in the Bowman’s space (the ultrafiltrate) are not part of this reflex
Is Autoregulation in the kidney a reflex unique to the kidney?
There are other organ systems with autoregulation – both the heart and the brain
15. Tubuloglomerular feedback compensation to a decrease in arterial blood pressure will include all of the following EXCEPT
A. compensation is initiated by a decrease in the delivery rate of NaCl in the tubular fluid near macula densa cells
B. compensation includes release of a signal by the macula densa cells
C. the macula densa signal will produce relaxation in the afferent arteriolar smooth muscle
D. the result of compensation will be a decrease in GFR.
15. D. Tubuloglomerular feedback is the feedback from the macula densa cells onto the smooth muscle of the afferent arteriole.
What type of feedback helps maintain a constant rate of delivery of NaCl to the macula densa, and therefore, to the rest of the tubule.
Tubuloglomerular feedback
If the GFR of Tubuloglomerular feedback is high, then the delivery rate will be ……and the reflex will compensate by……?
high

reducing the GFR.
The compensation of reducing the GFR when Tubuloglomerular feedback is high is mediated by?
vasoconstricting the afferent arteriole, thus lowering the GFR.
If the GFR of ubuloglomerular feedback delivery rate is low, what happens?
afferent arteriole will dilate, and GFR will increase.
The reflex from GFR of Tubuloglomerular feedback delivery is mediated by?
signals sent from the macula densa to the smooth muscle of the afferent arteriole.
Although the macula densa cells also directly affect JG release of renin, the tubuloglomerular reflex refers to ?
the local effect of locally delivered NaCl in the tubule on the afferent arteriole for that same tubule.
16. During hemorrhage,
A. Fluid shifts from the intracellular to the extracellular compartment
B. GFR is maintained at a normal level by autoregulation
C. Increased sympathetic nerve activity decreases renal plasma flow
D. renin secretion decreases
E. Na+ and water excretion increase
16. C
During hemorrhage, does fluid shifts from the intracellular to the extracellular compartment?
No. Hemorrhage is an iso-osmotic loss of ECF, so there would be no shift from intracellular to extracellular compartments
During hemorrhage, is GFR is maintained at a normal level by autoregulation?
No. Severe drops in blood pressure are outside the limits of autoregulation, so GFR would fall
During hemorrhage, does renin secretion decreases?
No. Renin secretion increases, not decreases
During hemorrhage, does Na+ and water excretion increase?
No. Restoring ECF and therefore blood pressure will only occur if the loss of Na+ and water from the extracellular compartment is reduced, not increased
17. An increase in mean arterial pressure would produce all of the following EXCEPT:
A. GFR would increase initially
B. The rate of NaCl delivery in tubular fluid at the macula densa would increase
C. afferent arterioles would be stretched
D. JG cells would be stretched
E. renin secretion by the JG cells would increase
17. E

An increase in mean pressure will increase hydrostatic pressure, and produce an initial increase in GFR. There would also be an increased rate of delivery of NaCl to the macula densa (because the GFR increase), the arterioles would be stretched by the pressure. JG cells are embedded in the wall of the afferent arteriole, and they also would be stretched, and do sense that stretch. However, the increased stretch of the JG cells, the increased delivery of NaCl to the macula densa would both decrease the secretion of renin (remember that ultimately, renin increases will increase systemic blood pressure).
Would renin secretion would increase or decrease

Increased NACl sensed by macula densa cells
Decrease

Increased Na+ sensed by macula densa cells results from an increased GFR. The macula densa cells, in addition to having an effect on afferent arteriolar smooth muscle, also have an effect on the JG cells. The increased NaCl sensed by macula densa cells will result in a decrease in renin secretion, and this will decrease the aldosterone, and finally the Na+ reabsorption by the tubules.
Would renin secretion would increase or decrease?

Increased sympathetic nerve stimulation
increase

Sympathetic nerves directly stimulate renin secretion from JG cells; an increase in nerve stimulation will increase renin release. Sympathetic stimulation will tend to increase during a fall in blood pressure.
Would renin secretion would increase or decrease

Decreased stretch sensed by JG cells
Increase

The JG cells are positioned around the afferent arteriole, and will be stretched when pressure in that arteriole increases, and stretched less when the pressure in the arteriole decreases. Decreased stretch sensed by the JG cells therefore corresponds to a decreased pressure in the arteriole. The JG cells will secrete more renin, which will help restore pressure.
Would renin secretion would increase or decrease

Increased levels of ANP
Decrease

ANP is released by cells of the atrium in response to stretch of the atrium (by the blood filling the atrium). ANP inhibits renin release.
19. PAH is used to measure renal plasma flow because
A. it is distributed within the plasma, and within the cytoplasm of the blood cells
B. all of the PAH that enters the glomerular capillaries is filtered
C. PAH is entirely reabsorbed
D. the PAH that does not get filtered enters the tubules by way of secretion
E. it has no effect on tubuloglomerular feedback
19. D. the PAH that does not get filtered enters the tubules by way of secretion
PAH will enters?
the arteries of the kidney, and the glomerular capillary.
In the peritubular capillaries, all of the PAH present will …………….., so that the blood leaving the peritubular capillaries, and entering the renal veins, will contain_______.
be secreted
no PAH
Within the glomerular capillary, some of the PAH will be …………..while the rest will continue into…………..
filtered and enter the tubular fluid

the efferent arteriole, and the peritubular capillaries
Inulin PAH
Plasma .6 mg/dl .004 mg/ml
Urine 3.0 mg/ml 1.2 mg/ml
Urine flow = 2ml/min

20. The excretion rate of PAH is
A. 2.4mg/min
B. 2.4mg/ml
C. 1.2mg/min
D. 1.2mg/ml
E. .004 mg/ml
A. Excretion rate of anything is = (concentration in the urine) * (rate of urine flow) = (mg/ml * ml/min), the excretion rate of PAH = (1.2mg/ml) * (2ml/min) = 2.4mg/min.. Excretion rate should always have the units of mass/time
Inulin PAH
Plasma .6 mg/dl .004 mg/ml
Urine 3.0 mg/ml 1.2 mg/ml
Urine flow = 2ml/min
excretion rate 27 = 2.4mg/min

21. The renal plasma flow for this individual is:
A. 100 ml/min
B. 600 ml/min
C. 2 ml/min
D. 60 ml/min
E. 125 ml/min
21. B..

Calculating RPF:
amount in = p[PAH] * RPF = amount out = u[PAH] * V
RPF = (U[PAH] * V)/ P[PAH]
You just calculated the excretion rate (U[PAH] *V) in problem 27 = 2.4mg/min
RPF = (2.4mg/min)/ (.004mg/ml)
= 600ml/min

Flow rate should always have the units of volume/time
PAH is the substance we use to measure RPF for 2 reasons:
First: it is filtered, and that filtered material is excreted (not reabsorbed),

Second: the PAH that was not filtered is secreted as it passes through the peritubular capillaries, and ends up excreted.
Inulin PAH
Plasma .6 mg/dl .004 mg/ml
Urine .3 mg/ml 1.2 mg/ml
Urine flow = 2ml/min

22. The GFR for this individual is:
A. 125 ml/min
B. 600 ml/min
C. 2 ml/min
D. 60 ml/min
E. 100 ml/min
E. GFR is calculated either from creatinine or inulin values. In this case, you were given values for inulin. The calculation is the same as above: the amount in/ time = amount out/time. In this case, the amount in/time is the filtration rate or GFR. The amount out/time is the excretion rate of inulin.

Amt in/time = P[inulin] * GFR
Amt out/time = U[inulin] * V
GFR= (.3 mg/ml * 2ml/min)/( .6mg/dl)
= 1dL/min or 100ml/min

The GFR is a flow rate, and should have the units of volume/time, just as the RPF
Inulin PAH
Plasma .6 mg/dl .004 mg/ml
Urine .3mg/ml 1.2 mg/ml
Urine flow = 2ml/min
RPF = 600ml/min

23. The hematocrit for this individual is 40. What is the renal blood flow?
Recall from Lecture 1 that the plasma volume = (1-hematocrit%) * blood volume

Similarly, renal plasma flow = (1-hematocrit%) renal blood flow

So renal blood flow = renal plasma flow / (1-hematocrit%)

Using the answer from question 21, RPF = 600ml/min

Renal blood flow = (600ml/min)/ .6 = 1000ml/min or 1L/min

Blood volume should be > plasma volume because blood includes both the plasma and the cells
24. You inject PAH intravenously, but some of the solution enters the interstitium. The calculated RPF will be greater than or less than the actual value?
This problem is similar to question 30, problem set 1, in that you need to think about the what happens to a volume measurement when some of the indicator escapes into another compartment. In this case, PAH is normally confined to the plasma compartment, so that the flow rate measured is the plasma volume per minute. If some of the PAH actually enters the interstitium, then the plasma concentration you measure will be lower than it should be, and you will underestimate the plasma volume, and the plasma flow rate.
25. Using inulin will yield a more accurate measurement of GFR than using creatinine because
A. creatinine is not freely filtered
B. inulin is entirely reabsorbed
C. creatinine is slightly secreted
D. inulin is slightly secreted
E. inulin is both reabsorbed and secreted
C. Both inulin and creatinine are freely filtered, but creatinine is slightly secreted, so inulin will give the more accurate result.
Kidneys do what to maintain water and electrolyte balance?
filter the plasma, then return all of the nutrient, and enough of the water and electrolytes
All of these processes to maintain water and electrolyte balance done by the Kidneys depends on _________________________ that is maintained by the kidney through the cooperative events of ____________________________________
the water and electrolyte balance

glomerular function, tubular secretion, and tubular reabsorption.
Understanding the normal function of the kidney requires ………. and ……………………..
an understanding of the relationship between renal blood flow and glomerular filtration,

a quantitative understanding of renal transport processes and how they are determined.
Filtration is the formation of?
the ultrafiltrate
With permselectivity, what determines the size of charged and uncharged molecules normally capable of being filtered?
The slit size (between processes of the podocytes) and molecular composition of the basal lamina
Net filtration pressure =

ΔP is called Hydrostatic pressure difference
ΔP (transcapillary hydrostatic pressure) – Δπ (transcapillary oncotic pressure)
ΔP = formula
Pgc-Pbs = (hydrostatic pressure in glomerular capillary – hydrostatic pressure in Bowman’s space)
Δπ is called?
Oncotic pressure difference
Δπ = formula
Oncotic pressure difference= πgc – πbs = (oncotic pressure in glomerular capillary – oncotic pressure in Bowman’s space)
Oncotic pressure is usually zero within?
Bowman’s capsule
Oncotic pressure rises as the blood finishes going through the glomerular capillaries and enters the efferent arteriole.. why?
Water has entered Bowman’s space
The net force favors filtration along the entire length of the capillaries: How does this differ from other capillaries?
Different than normal (?)
The hydrostatic pressure in the glomerular capillaries is regulated by?
two separate sets of arterioles:
afferent and efferent
Where are two major drops in resistance in Hydrostatic pressure:
across the afferent arteriole, and across the efferent arteriole.
Arterioles are a primary target for factors changing _______.
total resistance.
How does this pattern of pressure drop compare to the site of pressure drops in the rest of the vascular system?
???
Filtration is favored in what capillary system?
Glomerular capillaries
Reabsorption is favored in what capillary system?
Peritubular capillaries
Filtration rate for entire kidney = formula
Kf [(Pgc – Pbs) - πgc] =GFR
Kf [(Pgc – Pbs) - πgc] =GFR =
The volume of filtrate formed per unit time is the GFR.
Kf of the Filtration rate for entire kidney is the?
filtration coefficient; includes the total surface area for filtration,
Kf of the filtration rate for entire kidney decreases if?
substantial numbers of nephrons no longer function.
The excretion of salt and water is greatly affected by?
changes in GFR, so the regulation of GFR is crucial to kidney function. GFR is not constant
The excretion of salt and water is greatly affected by changes in GFR, so the regulation of GFR is crucial to?
kidney function.
GFR is or is not constant
Is not constant
During each pass through the kidney, how much blood is filtered
only a fraction
Filtration fraction = formula
GFR/RPF
Normally, renal plasma flow (RPF)is about ?? mL/min.
600 mL/min.
Typical GFR= about ? mL:/min
125
If renal plasma flow (RPF)is about 600mL/min. and typical GFR= about 125 mL:/min, what does this mean?
This means that, of the 600mL/min entering the
afferent arterioles, 125mL/min are filtered and enter the
tubules, while the remaining 485mL/min enter the efferent
arterioles.
Filtration fraction = formula
and avg. amount filtered
GFR/ RPF

about 20%
A young woman suffers from severe back pain, and her physician discovers a large kidney stone (crystal of calcium oxalate) blocking one of her ureters. What effect would this kidney stone have on her GFR?
The GFR will decrease because ΔP (Hydrostatic pressure difference) will decrease because PBS (hydrostatic pressure in Bowman’s space) increased
The smooth muscle of arterioles is a target of ………… & …………. that
change …….
various neural and hormonal signals

the resistance of the arterioles.
The resistance of afferent and efferent arterioles can be _____, with different effects on ??, ??, & ??
independently regulated

RBF (renal blood flow) and GFR, and filtration fraction (FF)
Increase afferent arteriole resistance (vasoconstrict afferent arteriole smooth muscle) will have what effects on RBF, PGC, and GFR?
RBF - Decrease
Pgc - Decrease
GFR - Decrease
Δ afferent arteriole resistance, what two will have the same effects: RBF, PGC, & GFR
RBF and GFR
With Δ efferent arteriole resistance, what two will have the opposite effect on each other: RBF, PGC, & GFR
RBF and GFR
Any restriction or resistance will do what to the RBF?
Will restrict RBF
2. Increase efferent arteriole resistance (vasoconstrict efferent arteriole smooth muscle) will have what effects on RBF, PGC, and GFR?
RBF - Decrease
Pgc - Increase
GFR - Increase
3. Decrease efferent arteriole resistance (vasodilate efferent arteriole smooth muscle) will have what effects on RBF, PGC, and GFR?
RBF - Increase
Pgc - Decrease
GFR - Decrease
Decrease afferent arteriole resistance (vasodilate afferent arteriole smooth muscle) will have what effects on RBF, PGC, and GFR?
RBF - Increase
PGC - Increase
GFR - Increase
Changes of both afferent and efferent arteriolar resistance often affect?
Major hormones that influence RBF and GFR
What is the Stimulus, Action at kidney, Effect on RPF, & Effect on GFR of Atrial natriuretic peptide (ANP)?
Stimulus: increased blood volume

Action at kidney: Vasodilation (afferent>efferent)

Effect on RPF: Increased effect

Effect on GFR: Increased effect
What is the Stimulus, Action at kidney, Effect on RPF, & Effect on GFR
of Sympathetic nerve?
Stimulus: decreased ECF (extracellular fluid volume)

Action at kidney: Vasoconstriction (afferent>efferent)

Effect on RPF: Decreased effect

Effect on GFR: Decreased effect
What is the Stimulus, Action at kidney, Effect on RPF, & Effect on GFR of Angiotensin II (high dose)?
Stimulus: decreased ECF (extracellular fluid volume) and increased renin
Action at kidney: Vasoconstriction (afferent>efferent)
Effect on RPF: Decreased effect
Effect on GFR: Decreased effect

ECF = extracellular fluid volume
renin is secreted by?
Juxtaglomerular cells
rennin catalyzes the conversion of _____ to ________ .
angiotensin I
angiotensin II
an increase in renin secretion will __________ angiotensin II
increase
Changes in GFR have significant changes in the excretion of?
Na+ and other solutes
Changes in GFR have significant changes in the excretion of Na+ and other solutes. However, GFR normally does not vary as widely as the mean arterial pressure due to?
intrinsic mechanisms within the kidney
Within this range of autoregulation, the RPF, GFR, and FF are ______, even though the mean arterial blood pressure ________.
constant

is changing
When the GFR is increased, what happens toward macula densa cells?
Increased rate of NaCl to Mecula Densa cells
What happens during a hemorrhage?
Decrease in blood volume, and blood pressure but no change in osmolality of ECF or ISF.


Increase in smooth muscle contraction, especially at afferent arteriole (due to high levels, related to severe blood loss)
During a hemorrhage, what is the process from sympathetic outflow to sympathetic outflow to aldosterone
Huge increase in sympathetic outflow will decrease RBF and GFR;

Huge increase in sympathetic outflow will directly increase in renin secretion (JG cells);

An increase in renin secretion will increase angiotensin II and increase aldosterone

increased angiotensin II and increased aldosterone will increase Na+ reabsorption
During a hemorrhage, Decrease in RPF and GFR will _______ in Na+ and water excretion
Decrease
During a hemorrhage, a decrease in ECF volume will _______ ANP (atrial natriuretic peptide)
Decrease
During a hemorrhage, large decreases in ECF volume will _________ vasopressin (ADH)
Increase
an increase in renin secretion will __________ angiotensin II
increase
Changes in GFR have significant changes in the excretion of?
Na+ and other solutes
Changes in GFR have significant changes in the excretion of Na+ and other solutes. However, GFR normally does not vary as widely as the mean arterial pressure due to?
intrinsic mechanisms within the kidney
Within this range of autoregulation, the RPF, GFR, and FF are ______, even though the mean arterial blood pressure ________.
constant

is changing
When the GFR is increased, what happens toward macula densa cells?
Increased rate of NaCl to Mecula Densa cells
What happens during a hemorrhage?
Decrease in blood volume, and blood pressure but no change in osmolality of ECF or ISF.


Increase in smooth muscle contraction, especially at afferent arteriole (due to high levels, related to severe blood loss)
During a hemorrhage, what is the process from sympathetic outflow to sympathetic outflow to aldosterone
Huge increase in sympathetic outflow will decrease RBF and GFR;

Huge increase in sympathetic outflow will directly increase in renin secretion (JG cells);

An increase in renin secretion will increase angiotensin II and increase aldosterone

increased angiotensin II and increased aldosterone will increase Na+ reabsorption
During a hemorrhage, Decrease in RPF and GFR will _______ in Na+ and water excretion
Decrease
During a hemorrhage, a decrease in ECF volume will _______ ANP (atrial natriuretic peptide)
Decrease
During a hemorrhage, large decreases in ECF volume will _________ vasopressin (ADH)
Increase
The kidneys receive almost __% of the cardiac output.
20%

far more than is necessary to supply the metabolic needs of renal cells.
All of the blood entering the kidney flows through ……….., and a fraction of this blood is filtered during …………
the glomerular capillaries

the passage through the glomerulus
…………….. is a crucial element in kidney function, and in the quantitative analysis of kidney function.
Conservation of mass
What is a good rule of thumb for measuring kidney fuction?
Amount in = Amount out

(Conc. in the volume * volume/time ) going in = (conc. in the volume * volume/time ) going out
Amount in = formula
Pa[x] * RPFa Pa[x] = concentration in plasma in renal artery;
What is this formula?

Pa[x] * RPFa Pa[x]
concentration in plasma in renal artery;

RPFa = renal artery plasma flow
RPF = formula
related to renal blood flow in the following way
Volume of plasma = (1-hematocrit) * volume of blood
RPF = (1-hematocrit)* RBF
There is only one way for substances to enter the kidney, but there are two possible ways for substances to exit the kidney. What are the two possible ways?
Plasma Flow & Glomerular filtration rate
Amount out = Formula
Pv[x] * RPFv + U[x]* V

Pv[x] = plasma concentration in renal vein;
RPFv= renal venous plasma flow
U[x] = urine concentration
V= urine flow rate
The conservation of mass of plasma flow (RPF) means that
(input) = (output)

Input (X) of RPF formula via the renal artery

= P[x] * RPF mg/dL * dL/hour
Output of RPF =
urine + renal vein
Output distribution will depend on whether:
the solute is reabsorbed (into capillaries, and therefore entering venous
drainage),

secreted (leaving capillary and entering tubule) or

simply excreted without additional reabsorption or secretion
What if Input (X) of RPF formula were freely filtered, and entirely secreted
Output would be?
urine only
if Input (X) of RPF formula were freely filtered, what would the formula be?
Input (X) of RPF formula (freely filtered) = U[x] * V

V= volume urine/hour
= mg/dL * dL/hour
What does this formula mean?
P[x] * RPF = U[x] * V
In = Out

In: P[x] * RPF

Out: U[x] * V
What is the formula for RPF?
RPF= (U[x] * V) / P[x]
What is PAH?
PAH (p-aminohippurate) is an organic substance, not
endogenous, but extremely useful in determining RPF.
At low concentrations PAH is essentially entirely secreted __________, so that all of the PAH entering the kidney is removed, and the concentration of PAH in the renal vein is ____
by the tubules

0.
What is the RPF from the following variables?

P[PAH] = 2.0 mg/dL

U[PAH] = 226mg/dL

V= 5.3ml/min
RPF = (U[x] * V) / P[x]

226 mg/dL x 5.3ml/min x (1dL/100ml) / 2.0 mg/dl =

11.98 mg/dL / 2.0 mg/dL = 5.99 dL/min
In order to measure GFR, we can apply conservation of mass, and use a substance, y that is ........
filtered by each nephron, but is neither reabsorbed nor secreted:
By conservation of mass of GFR,

Amount in = ??

Amount in = amount filtered = ??

Amount out equation = ??

GFR = ??
amount out

P[y] * GFR

U[y] * V

U[y] * V / P[y]
In order to measure GFR, we can apply conservation of mass,and use a substance, y that is filtered by each nephron, but is neither reabsorbed nor secreted: What is one good example of substance Y?
Inulin: one substance that fulfills these requirements. It is not endogenous, inert, and eliminated solely via the urine without any additional secretion by the tubules.
What is the GFR from the following variables?

P[ in] = 94.7 mg/dL
U[in] = 3500 mg/dL
V= 2.3ml/min
GFR = ??
GFR= U[in] * V / P[in]

3500 mg/dl x 2.3 ml/min x (1 dL/100 mL) / 94.7 mg/dL = .805 mg/min / 94.7 mg = .85 mg/min = 85 ml/min
Practically, inulin is difficult to use in a clinical setting because it requires IV administration for a period long enough to excrete a reasonable volume of urine. Instead, clinical measurements of GFR are estimated from?
an endogenous substance, creatinine.
What is creatinine?
Creatinine is a waste product related primarily to muscle activity.
Creatine is synthesized in ........ , and excreted ........... . It is taken up by skeletal muscle, and reversibly converted to .............:
the liver

into the plasma

phosphocreatine
Creatine <~> phosphocreatine
Involves?
Creatine kinase and ATP converts to ADP+Pi
The reaction Creatine <~~> phosphocreatine is coupled to the formation of ……… and the pool of phosphocreatine acts as ……….
ATP,

a high energy storage for muscle.
Creatine is metabolized to a waste product, ________ and is then released into the blood.
Creatinine
The plasma levels of creatinine are fairly constant for an individual, and are generally related to ?
Creatinine

the muscle mass of the individual (although there can be transient changes due related to diet)
What are the plasma levels of creatine in males and females
Males: 62-121 mM/L

Females 44-110 mM/L