intro phisiology Flashcards
What are the processes of the nephron?
Filtration
at the glomerulus
Reabsorption
from tubule lumen
into blood
Secretion
from blood/cells
into tubule lumen
Excretion
from body as part
of urine
What is molecules are diffused frothe glomerulus to the bowmans capsule?
most inorganic ions and
low molecular weight organic solutes is the
same as in plasma
no protein or diavalent molecules
What decides GF flow into bowmans capsule? What is the equation?
Net filtration pressure
NFP = [(HPgc + OPcs) – (HPcs + OPgc)]
What is GFR? what is noral GFR?
GFR = volume of fluid filtered into all the Bowman’s capsules of both kidneys
per unit time
125 ml / min [~1 can of Coke® every 3 minutes!]
180 L / day [volume of blood is only ~5L…]
What is Filtration fraction eqal to?
Filtration Fraction (FF) = GFR/RPF
RPF= Renal plasma flow
How much of filtrate volume is excreted?
1%
What is concentration in renal physio?
Concentration = Quantity / Volume
What is the filtered load? what is it equal to?
Defined as the amount (mass quantity) of a substance that is filtered across all the glomeruli per unit time how much is going into the nephron
Filtered load = plasma concentration x GFR
(quantity / time) = (quantity / volume) x (vol / time)
What is renal handling?
Renal handling* of any substance refers to some combination of the basic renal processes
How much is ultimately being excreted?
How is quantity of solute excreted determined?
Filtered load (F) - quantity reabsorbed (R) + quantity secreted (S)= quantity of solute excreted (E)
How To Determine If A Solute Molecule That Was Filtered Was Also Reabsorbed Or Secreted…
Is quantity excreted < quantity filtered?
Net reabsorption of the solute x
Is quantity excreted > quantity filtered?
Net secretion of the solute x
Is quantity excreted = quantity filtered?
No net reabsorption or secretion of solute x
Compare the Quantity Filtered and
the Quantity Excreted:
Quantity filtered = [x]pl x GFR
Quantity excreted = [x]ur x V
[x]pl = plasma concentration, mg/ml
[x]ur = urine concentration, mg/ml
V: urine flow rate, ml/min
What is the function of the nephron?
Main function is to recover (reabsorb) most of solutes and water filtered at glomerulus
secretes a variety of ions and solutes (“wastes”)
Transepithelial transport!
What is the function of the PCT?
Obligatory salt and water reabsorption
Reabsorbs essentially all the filtered organic nutrients
Secretes H+/Reabsorbs HCO3-
Secretes organic ions Secretes ammonia (NH3)
Which channels are found in the PCT?
AQP1
SGLT 1/2 (GLUT2)
NHE3
What is the function AQP1 in the PCT?
Reabsorbs most of the filtered H2O, Na+(Cl-), HCO3-, K+,
Ca++, PO42-, urea
What is the function of SGLT 1/2 (Glut 2) in PCT?
Reabsorbs essentially all the filtered organic nutrients
What is the function of NHE3 in PCT/
Secretes H+/Reabsorbs HCO3-
What is the function of loop of henle?
Continue obligatory water and
salt reabsorption*
Plays key role in developing medullary osmotic gradient**
Differential permeabilities in descending vs ascending limbs
Which channels are found in the descending loop and function? What is the function?
AQP1-Permeable to water (AQP1), Impermeable to solutes
Which channels are found in the Ascending loop and function? What is the function?
NKCC-Impermeable to water, ; permeable
to salt (NKCC in TALH)
Diluting segment
What is the DCT segments?
early distal tubule
Late distal tubule
What is the function of the early tubule?
somewhat similar to TALH
Impermeable to water
Permeable to salt: NCC
Diluting segment
TALH: thick ascending limb of Henle
What is the function of Late distal tubule?
tubule is similar to CCD Variable permeability to water Hormonal fine tuning of Na+, K+ and water balance
CCD: cortical collecting duct
What is the collecting system divided into?
late distal tubule*
and cortical collecting tubule= CCT
What is the function of CCT?
What are the. Channels found in the CCT?
Hormonal fine tuning of Na+, K+
and water balance
ENaC, ROMK, AQP2
What is the cell type of CCT?
What is the function of these cells?
Principal cells – involved in hormonally controlled Na+ and water reabsorption and K+ secretion.
Intercalated cells – involved in acid/base regulation and K+ reabsorption.
What is the function of the inner medullary collecting duct?
has a single cell type that is hybrid of above
Hormonal fine tuning of Na+, K+
and water balance
What are the parts of the nephron?
Cortex
medulla
What parts are found in the cortex?
proximal tubule,
distal tubule,
connecting tubule
cortical collecting duct for all
What parts are found in the medulla?
loop of Henle of juxtamedullary nephrons
medullary collecting duct
What are the segments of the nephron?
Bowans capsule PCT Loop of henle DCT Collecting duct Connecting tubule initial tubule
What is the bowans capsule? what does it make up?
beginning of the nephron; surrounds the glomerular capillaries. Together, Bowman’s capsule and its glomerulus make up the Renal Corpuscle. [Cortical]
What are the parts of the loopof henle?
thin descending limb (DLH) and an ascending limb that has both thin (tALH) and thick (TALH) segments.
What is the last segment of the DCT called?
Connecting Tubule (CNT) and Initial Collecting Tubule (ICT)
which are more physiologically and embryologically related to the collecting duct
What is the blood flow into the glomerulus?
Aorta Renal artery segmental artery Lobar artery interlobar artery arcuate artery interlobular artery affrerent aterioles Glomerulus
What is the blood flow from the glomerulus?
Glomerulus Efferent aterioles (peritubular cappalaries and vasa recta) interloblar veins arcuate veins interlobar vein renal vein IVC
