pathophysiology 3rd and 4th powerpoint stuff
as water is reabsorbed _____ rises
Cl-
in the renal tubules what does NH3 form with a proton
NH4+
antiporter membrane proteins
Na+ co-transport with protons
what are the major osmotically active solutes in the plasma and glomerular filtrate
Na+ salts
Na+ and Cl- are transported from the lumen into the cell by a
Na-Cl cotransporter
urea circulation is responsible for concentrating solutes such as
NaCl and Creatinine level in urine
excretion formula
excreted= filtered - reabsorbed + secreted
in osmotic diuresis, increased urine flow results from _________ of osmotically active solute
excretion
is PAH endogenous or exogenous?
exogenous
clearance ratio
clearance of substance divided by GFR (cx/GFR)
reabsoprtion of HCO3- leads to what?
fall in tubular fluid mainly bc of H+ secretion
t/f there is an endogenous substrate that can be used to estimate renal plasma flow
false
t/f the proximal tubule can establish steep gradients for small ions and water
false. distal nephron
if clearance ratio is greater than 1 solute is _____ and it is actively secreted from the _______________ into the tubular fluid
filtered peritubular capillaries
cellular mechanism for proximal tubule H+ and HCO3- transport
filtered HCO3- and secreted H+ from the tubular cell forms H2CO3 wirh help of luminal carbonic anhydrase H2CO3 dissociates to CO2 and H2O
if clearance ratio is less than 1, solute is _______ but ______
filtered but reabsorbed (sodium)
autoregulatory response
filtration fraction increases in order to maintain gfr at constant level
total kidney clearance is dependent on contributions of
glomerular filtration secretion in the proximal tubule reabsorption in distal tubule
a high GFR causes ______ to occur
glycosuria
an increase in splay causes a ______ in glucose threshold
decrease
if absorption of urea/water is stopped in the collecting duct what happens to the osmolarity of the medulla?
decreases and concentration of mechanisms collapse
where are aquaporins found
descending limb of loop of henle distal convulated tubule collecting duct cells
ADH secretion deficiency leads to what disorder?
diabetes insipidus
the _____ nephron has a tight epithelium
distal
5-15% if the filtered K+ reaches the
distal nephron
Which of the following adrenoreceptors are located on the renal vasculature? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a α1-adrenoreceptors b β1-adrenoreceptors
a
second site of sodium chloride and potassium reabsorption is the
ascending loop of henle
Which of the following cells express postjunctional β1-adrenergic receptors? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a Afferent arterial smooth muscle cell b Proximal tubule epithelial cells c juxtaglomerula (JG) cells
b
energy for the natrium reabsorption derives from the __________
basolateral sodium-potassium pump
why does the earliest part of the distal convulated tubule has an osmolality of 100 compared to 285 in plasma?
bc more solute than water is reabsorbed by the loop of henle
why does a reduced tmg lower the threhold?
bc tubules have a diminished capacity to reabsorb glucose
in case of alkalosis, Bicarbonate can do what
be secreted to balance the acid-base homeostasis
distal tubule has active ____ transport via a _______ sensitive Na-Cl-co-transporter
sodium thiazide
aldosterone is responsible for reabsorption of ___ and ____ into the vascular compartment
sodium and water
what does aldosterone regulate?
sodium and water reabsorption and potassium secretion
if clearance ratio >1
solute filtered, actively secreted from peritubular capillaries into tubular fluid (eg potassium)
if clearance ratio < 1
solute filtered, but reabsorbed (eg. sodium)
if clearance ratio = 1.0 ...
solute handled like inulin and renal clearance is = GFR
in the DCT, fluid is _______
hypotonic
urine at the end of TAL is
hypotonic
thick ascending loop of henle is _______ to water and transports _____ into the interstitium of the kidney
impermeable electrolytes
a diuresis is an _______ in urine output
increase
when plasma osmolality is increased plasma avp levels
increase
ADH is released in response to three stimuli
increased blood osmolality decreased blood volume thirst
at low plasma PAH concentrations, the rate of secretion ________ linearly with the plasma
increases
the para-aminohippurate ratio in proximal tubular fluid _______ more steeply than the inulin concentration ratio bc of PAH secretion
increases
aldosterone regulates water absorption by doing what
increasing sodium uptake from the tubular fluid into the blood but potassium is excreted
if clearance ratio is 1 solute is handled like ____ and its renal clearance is equal to
inulin GFR
the _____ form passively penetrates cell membranes with difficulty
ionized
25-35% of the filtered K+ is reabsorbed in
loop of henle
active secretion of urea occurs in
loop of henle
What type of connective tissue is the renal Fascia?
loose connective tissue
water permeability of DCT is _____
low
if ADH is absense the permeability of collecting ducts for water is _____
low, urine will not be concentrated
a reduced tmg _________ the threshold
lowers
30% of the filtered sodium is reabsorbed using a _____________ mechanism
luminal Na-K-2Cl-cotransport
renal clearance units
ml/min
PAH is secreted by what
only proximal tubules
urinary excretion of glucose, glucosuria produces what?
osmotic diuresis
What is amiloride?
potassium sparing diuretic
in renal tubules the secondary phosphate binds a _____ and the result is H2pO4-
proton
renal excretion of ______ is a major factor in
protons
para-aminohippurate (PAH)
provides a measure of function proximal secretory tissue
the ______ tubule has a leaky epithelium
proximal
the tmpah is directly related to the number of functioning _____ tubules
proximal
Where is HCO3- reabsorbed?
proximal convoluted tubule
what nephron segment is responsible for complete reabsorption of glucose and amino acids
proximal tubular fluid
60-70% of the filtered K+ is reabsorbed in the
proximal tubule
reabsoprtion of urea occurs
proximal tubule collecting ducts
volume depletion causes a __________ in cardiac output and renal plasma flow
reduction
what do intercalated cells do?
regulate acid-base homeostasis regulate reabsorption of K+
TAL: prevention of a passive waterflow with watertight junctions leads to a high osmotic pressure in the _________
renal medulla
the clearance of pah =
renal plasma flw
filtration fraction
represents fraction of renal plasma flow that gets filtered by glomerulus
If clearance ratio is ___, then either the solute is too large to be filtered (protein) or it is filtered and 100% reabsorbed
0
normal GFR is approximately ___ mL/min
120
______ % of the filtered sodium is reabsorbed in distal tubule
10
the threshold concentration for glucose greater than 200 mg/dl is
10 mmol/l
ammonium excretion can be ______ increased in case of acidosis
10-fold
at what concentration does kidney start to excrete in individuals with glucose more than 200 mg/dl?
180 mg/dl
_____ of primary urine with electrolytes are reabsorbed
2/3
about ______ % of renal plasma flow becomes gfr
20%
_____% of filtered calcium is reabsorbed in the proximal tubule with paracellular absorption
60%
Normal renal plasma flow is _________ ml/min
600
____% of filtered solutes and water are reabsorbed along PCR
70
phosphate dissociates in the blood to
80% in HPO42-
glucose threshold depends on three factors
GFR TMg amount of splay
in the collecting duct, intercalated cells are responsible for
H+ and HCO2- transport
Acid secreting intercalculated cells have vacuolar what localized to the apical membrane
H+- ATPase and H+-K+-ATPase
in intercalcalated cells cof collecting duct secretion _______ exits the cells in exchange for _______
HCO3- Cl-
aldosterone promotes what hormone secretion
K+
what is the primary function of the collecting duct principal cell
K+ secretion
organic cations can______ H+
RELEASE
Which of the following renal adrenoreceptors activation by the sympathetic nerve directly increases renin secretion? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a β1-adrenoreceptors b α1-adrenoreceptors
a
organic anions can _____ H+ i
accept
aldosterone is produced by
adrenal cortex
K+ reabsorption and excretion is controlled by
aldosterone
how can luminal sodium channels be inhibited?
amiloride
excretion rate
amount of substance excreted into the urine per unit of time
filtered load
amount of substance in plasma that is filtered at glomerulus per unit of time
the descending limb of the loop of henle is water ________ and the ascending limb is water ___________
highly water permeable water impermeable
at high filtered glucose loads the rate of glucose reabsorption reaches a _______ ________ value
constant maximal value
how is NH3 formed in the kidney
deamination of glutamine by the tubular cells and can diffuse into tubular lumen
in the proximal tubule the solvent drag enables paracellular absorption of h2o and cl due to
electrolyte concentrations between tubule lumen and renal interstitium
a low gfr leads to a ______ threshold
elevated
in diabetes mellitus plasma glucose levels are abnormally ________ so more glucose is filtered than can be reabsorbed
elevated
excretion
elimination via urine
if the collecting ducts do not have ADH what happens?
fluid leaving distal tubules remains hypotonic distal tubules cortical and outer medullary collecting ducts are impermeable to water medullar collecting duct reabsorbs nacl and is permeable to water/urea large amounts of hypotonic urine flow into renal pelvis daily
TAL of henle transporting electrolytes into interstitium of kidney produces a ___________ of the interstitium
high osmotic pressure interstitium
s1 segment of the proximal tubule is characterized by
high-flux low affinity glucose transport
fluid from PCT is ______ to plasma
isomotic
tubular fluid entering the loop of henle is ______ to plasma, but fluid leaving the loop is _______
isotonic hypoosmotic
the tmpah provides a measure of the _____ ______ ______ secretory tissue
mass of proximal
symporter membrane protein
na co transport with glucose, galactose, phosphate, sulfate, or amino acids
Furosemide inhibits Na-k-2cl cotrasnporter and leads to a massive _______ and loss of _______
natriuresis potassium, calcium, magnesium
H2PO4- can is be reabsorbed?
no
can NH4+ be reasbsorbed?
no
when cl moves out of the late PCT what does the potential created favor
passive na reabsorption
in the DCT, when AVP is present the cortical collecting ducts become water ______ and water is passively reabsorbed into cortical interstitial fluid
permeable, High blood flow in cortex carries this water away so cant detect lowering of cortical tissue osmolarity
mechanisms of acid-base homeostasis
phosphate excretion reabsorption of bicarbonate ammonia excretion
the s3 segment is characterized by
reverse low flux high affinity glucose transport system
what is splay?
rounding of the glucose reabsorption curve
at high plasma PAH concentrations the secretory carriers are ______
saturated
at tmgo the tubule glucose carriers are all ______ and trasnport glucose at _______ rate
saturated maximal
in case of too high glucose this mechanism is subject to
saturation and glycosuria results
on the luminal side of the proximal tubule epithelium sodium enters the cell via
symporter membrane protein antiporter membrane protein
renal clearance
the volume of plasma thats completely cleared each minute of any substance that finds its way into urine
_____ inhibit sodium reabsorption is distal tubule and lead to a mild ______ w/o loss of calcium
thiazides diuresis
t/f changes in kidney function will change plasma concentrations of drugs
true
t/f if the non-ionized form is lipid soluble it can diffuse thru the lipid bilauer of cell membranes down conc gradients
true
in the proximal tubule, when water is reabsorbed and cl rises, what type of concentration gradient is created
tubular fluid to plasma concentration gradient that favors cl- diffusion out of tubule lumen
what causes splay?
tubular heterogeneity
why does the tubular glucose reabsorption not abruptly attain tmg when plasma glucose is elevated
tubular heterogeneity glucose carrier does not have an infinitely high affinity
the constant maximal value that high flitered glucose reaches is called
tubular transport minimum for glucose