Keef other transport Flashcards
(blank) is the highest rate at which the renal tubules can transfer a substance either from the tubular luminal fluid to the interstitial fluid or from the interstitial fluid to the tubular luminal fluid.
transport maximum (TM)
(blank) reach a maximum where they can no longer move substances anymore
transporters
What substance has the highest transport maximum?
glucose
What substance as the lowest transport maximum?
sulfate
Do you normally have glucose in your urine?
no
Where does glucose get reabsorbed into our body?
in the proxial tubule
Do you need energy to get glucose out of the tubule?
yes
To get glucose into the peritubular capillary do you need energy?
no, done via faciliated diffusion
What is the equation for reabsorption rate?
Tx=Filtered load - excretion rate
Tx= reabsorption rate
What is the equation for excretion rate?
Ux * V
Ux= substance concentration in urine times urine flow rate
What is the equation for filtered load?
GFR times concentration of substance in plasma
What is the typically urine flow rate?
What is the typically GFR?
1.2
120
What percent of stuff is filtered?
20%
If you are below the Tm what percent of substance of glucose will be present in the urine?
Above tm?
None
Some amount will be present
What is the relationship between filtration rate and plasma concentration of glucose?
directly proportional (i.e freely filtered)
What is splay?
the point at which glucose may be present in urine before the TM is reached
What does the reabsorption rate vs Plasma concetration graph show you?
shows you the Tm when the graph plateaus by showing that at a particular plasma concentration you resorption rate becomesconstant even with increasing plasma concentration (i.e you cannot reabsorb anymore)
The excretion rate vs plasma concentration graph of glucose will tell you what?
at a certain plasma concentration you will get excretion into urine
The difference between filtered load and the excretion rate is the rate of (blank)
net reabsorption or net secrion
If the filtered load is greater than the excretion rate, there has been net (blank) of the substance
reabsorption
If the filtered load is less than the excretion rate, there has been net (blank) of the substance.
secretion
Sodium is an example of a substance with net (blank)
reabsorption
PAH is an example of a substance with net (blank)
secretion
If you use sodium-glucose co transporter 2 (SCLT2) inhibitors and non selectiveblockers what will happen to your glucose reabsorption?
you will have a lot less and you will excrete a lot of glucose
If you have more glucose in the proximal tubule, what will happen to sodium?
you will have more sodium in the proximal tubule
If macula densa sense a decrease in NaCl what will happen?
you will get increased GFR via constriction of efferent and dialation of afferent
Why do you pea a lot when you have diabetes?
Mellitus: Increased osmolality of glucose ions reduces water reabsorption
Insipidous: Problems reabsorbing water
If you have a substance with a clearance rate less than inulin then you will (blank) that substance.
reabsorb
If you have a substance with a clearance rate higher than inulin then you will (blank) that substance
excrete it easily
(blank) is constant regardless of concentration it will always be cleared out making GFR 125.
inulin
What is probenecid?
a synthetic compound that promotes increased excretion of uric acid and is used to treat gout.
( a transport blocker)
What is p-amino hippurate?
an organic anion secreted by proximal tubule
What kind of organic molecule are secreted by the proximal tubule?
organic anions and organic cations
PAH is used as an (blank) with other molecules and is used to find (blank)
exchanger
renal plasma flow
The filtered load of PAh increases in (blank) proportion to the plasma PAh concentration.
direct
Secretion of PAh occurs from peritubular capillary blood into tubular fluid (urine) via (blank) in the proximal tubule.
carriers
At low plasma concentration of PAH the secretion rate (blank) as the plasma concentration increases.
Once the carriers are saturated further increases in plasma PAH concentration do not cause further (blank) in the secretion rate ( TM)
increases
increases
Exceretion of Pah is the (blank) of filtration across the glomerular capillaries plus secretion from peritubular capillary in blood.
sum
The curve for excretion is steepest at (blank) plasma PAH concentrations (lower than at Tm). Once the Tm for secretion is exceeded and all of the carries for secretion are saturated, the excretion curve (blank) to the curve for filtration.
low
flattens and becomes parallel
RPF is measured by the clearance of PAH at plasma concentrations of PAH that are (blank) than at Tm
lower
If you are below the TM of PAH what percentage will be excreted and what percent will be cleared from plasma?
100% for both (your excretion rate will be low but your clearance rate will be high)
If you are above the Tm of PAH what percent will be cleared from the plasma?
less than all of it. (your excretion rate will be high but clearance rate low)
Renal plasma flow is 5 times greater than what?
GFR
Which has the highest clearance?
Urea, Inulin, PAH, glucose, creatinine, potassium
PAH > creatinine > inulin > urea > potassium > glucose
The concentration of PAH and Inulin in the collecting tubule is what?
585 times that of plasma
125 times that of plasma
What is the equation for filtration fraction?
GFR/RPF
(blank) occurs due to buildup of uric acid.
gout
Uric acid is both (blank) and (blank) in the nephron.
reabsorbed and secreted
When you get too much uric acid absorbed due to wacky transporters you will get (blank)
gout
ALthough urea must be eliminated every day (blank) percent is reabsorbed
60%
What are 3 factors that affect passive reabsorption of urea?
Tubular area
Urea permeability
concentration gradient
As (blank) rate increase, urea reabsorption decrease
tubular flow rate (i.e drink more water : ) )
(blank) increases the urea permeability of the inner medullary collecting ducts.
ADH
How is urea reabsorbed from the proximal tubule?
How is Na involved in its reabsorption?
passively
Na reabsorption increases water reabsorption which creates a gradient for urea by concentrating the tubule and allowing the urea to follow the water
The distal tubule, cortical collecting ducts and outer medullary collecting ducts are (blank) to urea thus no urea is reabsorbed by these segments.
impermeable
The clearance of urea is dependent upon (blank) whereas that of inulin is not.
If flow is slow then you will have (blank). If flow is fast you will have (blank)
tubular flow
Reabsorption
Clearance (excretion)
If you have a basic substance in your body and you want to urine trap it, how do you do it?
If you have an acidic substance in your body and you want to trap it in your urine how do you do it?
you make your urine more acidic
You make your urine more basic
What moves more easily across membranes, charged or uncharged ion?
uncharged
If you want to excrete drug and you change the ph of your urine to do this, why do you also want to add a osmotic diuretic to this concoction?
It keeps water from leaving the tubule so you can maintain your gradient and keep peeing your drug out
What is the app. Fractional excretion of: Sodium Inulin Creatinine Glucose PAH Uric acid Potassium
Na=0.4 % Inulin-100% Creatine-120% Glucose-0% PAH-500% Uric acid-10% Potassium-10-20%
