Questions derived From bRS Phys Flashcards by Dylan Weaver

At steady state, ECF and ICF osmolarity are?

The same

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What happens in the infusion of Isotonic NaCl?

ECF volume increases (no change occurs in osmolarity and therefor no shift of water to ICF)

Plasma [protein and hematocrit] decreases

Arterial blood pressure increases

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What changes occurs in diarrhea (loss of isotonic fluid)

ECF volume decreases (but no change occurs in the osmolarity, so water does not shift from ICF)

Plasma [protein and. Hematocrit] increase

Arterial blood pressure decreases

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What occurs in excessive NaCl intake?

Osmolarity of ECF increases

Water shifts from ICF to ECF (causing ICF osmolarity to increase)

ECF volume increases and ICF volume decreases

Plasma [protein and hematocrit] decrease bc of the increase in ECF volume

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What happens in sweating in a desert? (Hyperosmotic volume contraction)

ECF osmolarity increases (more water than salt lost in sweat)

ECF Volume decreases -> water shifts from ICF to ECF -> ICF osmolarity increases to equal ECF

ICF volume decreases

Plasma [protein] decreases (hematocrit concentration stays the same due to the loss of fluid from RBC’s)

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What happens in Syndrome of inappropriate antidiuretic hormone? (Gain of water)

Osmolarity of ECF decreases

ECF volume increases, water shifts to cells, ICF osmolarity decreases, ICF volume increases

Plasma protein concentration decreases

(Hematocrit remains same bc water shifts into RBC’s)

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What happens in adrenocortical insufficiency (loss of NaCL)

Aka hyposomotic volume contraction

Osmolarity of ECF decreases
Water shifts into cells, ecf volume dcreases, ICF osmolarity decreases, ICF volume increases

Plasma [protein] increaases

Hematocrit concentration increases

Arterial blood pressure decreases

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Vasoconstriction of renal arterioles occurs due to ?

Activation of sympathetic nervous system

Angiotensin II

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What causes vasodilation of renal arteries ?

Prostaglandins E2 and I2, bradykinin
Nitric Oxide
Dopamine

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Autoregulation of renal blood flow is accomplished by ?

Changing renal vascular resistance

(Myogenic mechanism - stretch reflex)

(Tubuloglomerular feedback - macula densa senses increased load and causes constriction in nearby afferent arteriole)

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RBF is constant over a blood pressure range of ?

80-200mmHg

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What happens to BUN and creatinine when GFR decreases?

They both increases

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In prerenal azotemia (hypovolemia) BUN increases ____ than serum creatinine and there is a _______ BUN/creatinine ratio

Increased

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Normal filtration fraction ?

0.20

FF = GFR/RPF

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Increases in filtration fraction leads to ?

Increased protein concentration of peritubular capillaries and increased reabsorption in the proximal tubule

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Decrease in filtration fraction leads to ?

Decreases in concentration of protein in the peritubluar capillaries and a decrease in reabsorption in the proximal tubule

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The glomerular barrier consists of ?

The cappillary endothelium

Basement membrane

Filtration slits of the podocytes

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What causes increases in Bowmans space hydrostatic pressure?

Constriction of the ureters

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Increases in glomerular capillary protein concentration cause ______ in net ultrafiltration pressure and GFR

Decreases

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______ in the proximal tubule reabsorbs glucose from tubular fluid into the blood

Na-Glucose cotransport

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RPF is measured by the clearance of PAAH at plasma concentrations of PAH that are ______ than at Tm

Lower

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Parathyroid hormone causes ______ and increased urinary ______

Phosphaturia

.cAMP

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The ______ and _____ reabsorb more than 90% of the filtered calcium by passive processes that are coupled to Na reabsorption

Proximal tubule and thick ascending limb

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_____ % of plasma calcium is filtered

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Loop diuretics (Furosemide) cause ____ urinary calcium excretion

Increased [urinary calcium is linked to Na reabsorption in the loop of henle. Inhibiting Na reabsorption therefore also inhibits Ca reabsorption]

The _________ and _________ reabsorb 8% of the filtered calcium by an active process

Distal tubule and collecting duct

How does PTH increase calcium reabsorption in the kidney?

By activating adenylate cyclase in the distal tubule.

Thiazide diuretics _____ calcium reabsorption in the early distal tubule

Increase

In the thick ascending limb, Mg and Ca ______ for reabsorption, therefore, hypercalcemia causes an increase in Mg Excretion and vice versa

Compete

Hyperosmotic urine is produced when circulating _____ levels are high

ADH

Gradient of osmolarity from the cortex to the papilla. Composed primarily of NaCl and urea. Established by countercurrent multiplication and urea recycling. Maintained by countercurrent exchange in the vasa recta

Corticopapillary osmotic gradient

Countercurrent multiplication in the loop of henle is dependent on?

NaCl reabsorption in the thick ascending limb and countercurrent flow in the descending and ascending limbs of the loop of Henle (It is augmented by ADH which stimulates NaCl reabsorption in the thick ascending limb)

The presence of ADH ______ the size of the corticopapillary osmotic gradient

Increases

The capillaries that supply the loop of henle

Vasa recta

Maintain corticopapillary gradient by serving as osmotic exchangers. Blood from this equilibriates osmotically w/ the interstitial fluid of the medulla and papilla

Vasa recta

When producing concentrated urine, _____ of the filtered H2O is reabsorbed isosmotically (with Na, Cl, Bicarb, gluc) in the proximal tubule

2/3

The thick ascending limb of the loop of henle, with high ADH (making hyperosmotic urine) is called the ______

Diluting segment

In High ADH (hyperosmotic urine) the thick ascending limb of the loop of henle reabsorbs ______ by _______, and is impermeable to _______

NaCl Na-K-2Cl cotransporter H2O

The TF/Posm after the thick ascending limb in high ADH (hyperconcentration of urine) has a TF/Posm that is ___ 1.0

TF/Posm < 1.O

The early distal tubule in situations of high ADH is ______ to water

Impermeable

ADH ______ the H2O permeability of the principal cells in the late distal tublule

Increases

ADH ______ the H2O permeability of the principal cells of the collecting ducts in high ADH scenarios

Increases

Hyposmotic urine is produced when ?

Circulating ADH levels are low or ADH is ineffective

______ stimulates both countercurrent multiplication and urea recycling

ADH

In the absence of ADH what happens to water in the proximal tubule /?

The same as in situations of high ADH About 2/3 of the filtered water is absorbed isosmotically in the proximal tubule

In no ADH, what happens in the thick ascending limb of the loop of henle ?

Same as w/ in Presence of ADH (but not as much as in it ) NaCl reabsorbed w/o water and the tubular fluid becomes dilute

What happens in the early distal tubule in no ADH

Same as w/ presence of ADH NaCl is reabsorbed w/o H2O and tubular fluid is further diluted

What happens in the late distal tubule and collecting ducts in the absence of ADH ?

The cells here are impermeable to water in the absence of ADH Even though fluid flows thru the corticopapillary osmotic gradient, the osmotic equilibration does not occur Osmolarity of final urine dilut

What part of the nephron is free water produced in ?

The diluting segments The thick ascending limb and the early distal tubule

In the absence of ADH, Ch2o is _____-

Positive

In the presence of ADH, Ch2o is

Negative

Ch2o =

V - Cosm

Urine that is isosmotic to plasma (Ch2o = 0) is produced when treatment with ?

Loop diuretics Because these will inhibit NaCl reabsorption in the thick ascending limb. Inhibiting both dilution in the thick ascending limb and production of the corticopapillary osmotic gradient, therefore, the urine cannot be diluted during high water intake or concentrated during water deprivation

What can lead to the production of urine that is hyposmotic to plasma ?

High water intake Central diabetes insipidus Nephrogenic diabetes insipidus (These all lead to low or innefective ADH )

What can cause urine that is hyperosmotic to plasma ?

(High ADH) Water deprivation SIADH

An acid produced from carbon dioxide Can be excreted by the body by ventilation

Volatile acid

An acid such as lactic acid or sulfuric acid that accumulates in the body as a result of digestion, dz, or metabolism. Must be excreted from the body by organs other than the lungs (urine)

Nonvolatile acids

Reabsorption of filtered HCO3- occurs primarily in the _____-__

Proximal tubule

Increases in Pco2 result in ______ rates of HCO3- reabsorption

Increased

ECF volume expansion results in________ HCO3- reabsorption

Decreased

ECF volume contraction results in _______ HCO3- absorption

Increased

Angiotensin II ______ Na-H exchange and thus _______ HCO3- reabsorption

Stimulates Increases

Fixed H produced from the catabolism of protein and phospholipid is excreted by which two mechanism?

Titratable acid and NH4

H-ATPase is _____ by aldosterone

Increased

NH3 is produced in renal cells from ______

Glutamine

Hyperkalemia ______ NH3 synthesis

Inhibitis