↑ ADH → ↑ AQP-2 channels → ↑water reabsorption Results in ↑ intravascular volume → ↑VR, CO, BP Results in ↓ urine volume, ↑ urine concentration

RENAL Flashcards by Nancy Urayani

body fluid “60-40-20” RULE

60% of BW: Water
40% of BW: ICF
20% of BW: ECF (INTERSTITAL FLUID 15%, PLASMA 5%)

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Marker for Total Body Water

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MArker for ECF

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Marker for plasma

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Marker for IF

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MArker for Intercellular fluid

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Explain thr volume and concentration changes across compartments during LOss of Isotonic fluid ie Diarrhea

ECF volume: decrease

ECF osmolarity : no change

ICF volume: no change

ICF osmolarity: no change

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Explain the volume and concentration changes across compartments during excess fluid ie Infusion of isotonic fluid

ECF volume: increase

ECF osmolarity : no change

ICF volume: no change

ICF osmolarity: no change

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Explain the volume and concentration changes across compartments during volume contraction ie Loss in dessert

ECF volume: decrease

ECF osmolarity : no change

ICF volume: no change

ICF osmolarity: no change

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Explain the volume and concentration changes across compartments during Volume expansion ie Excessive NaCl intake

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Explain the volume and concentration changes across compartments during Adrenal sufficiency ie decrease Aldosterone secretion

Aldosterone: inc Na reabsorption along with water.

Decrease aldosterone levels would reselt in salt and water wasting

ECF volume: decrease

ECF osmolarity : no change

ICF volume: no change

ICF osmolarity: no change

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Explain the volume and concentration changes across compartments during SIADH

ECF volume: increase

ECF osmolarity : decrease

ICF volume: increase

ICF osmolarity: decrease

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by excessive unsuppressible release of antidiuretic hormone (ADH). Unsuppressed ADH causes an unrelenting increase in solute-free water being returned by the tubules of the kidney to the venous circulation

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Workhorse of the Nephron

PCT

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Reabsorption in the PCT

66% of filtered Na, K, H20

100% of filtered glucose and amino acids

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most susceptible to hypoxia and toxins

PCT

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Loop of HEnle

Descending Limb

permeable to water

Impermeable to solutes

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loop of henle

Ascending limb

permeable to solutes
impermeable to water

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where does NA K 2Cl transport located

Thick ascending limb of henle also called Diluting segment

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Also called Cortical diluting segment and the site for macula densa

Early Distal tubule

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Site of action of Aldosterone

Late distal tubule

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Cells contain in the LAte Distal TUbule

Principal cells and Intercalated cells

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Pricipal cells REABSORB AND SECRETE?

reabsorb : Na

Secrete: K

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Intercalated cells reabsorb and secrete?

reabsorb : K

Secrete: H

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Role of ADH

↑ ADH → ↑ AQP-2 channels → ↑water reabsorption

Results in ↑ intravascular volume → ↑VR, CO, BP
Results in ↓ urine volume, ↑ urine concentration

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Movement from Glomerular Capillaries to Bowman’s Space

GLomerular filtration

Movement from Tubules to Interstitium to Peritubular Capillaries

(Tubular) Reabsorption

Movement from Peritubular Capillaries to Interstitium to Tubules

(Tubular) Secretion

Define Excretion

Excretion = (Amount Filtered) – (Amount Reabsorbed) + | (Amount Secreted)

Point were Substance start to appear in the urine and nephrons exhibit saturation

Renal Threshold

All excess substance appear in the urine and All nephrons exhibit saturation

Renal Transport Maximum

Management for overdose with acidic drug

overdose with an ACIDIC drug (e.g. ASA), ALKALINIZE the urine so that the weak acid will be in its water-soluble (charged) form. **WEAK ACIDS:** ``` HA Form (lipidsoluble) and A- Form (water-soluble) ``` * A- Formpredominates: less back diffusion,ncreased excretion of weak acids (e.g., ASA excretion increased by alkalinizing urine)

Management overdose with basic drug

If you overdose with an ALKALINE/BASIC drug (e.g., morphine), ACIDIFY the urine so that the weak base will once again be in its water-soluble (charged) form). **WEAK BASES:** **BH+ Form (watersoluble) and B Form (lipid-soluble)** **• B form predominates, more “back-diffusion”,decreased excretion of weak bases**

Volume of plasma cleared of a substance per unit of time (in mL/min or mL/24 hour)

Clearance

principle behind tubular processing

involves two parameters: renal threshold and renal transport maximum.. for examlpe, glucose is 100% and reabsorbed. suposed na madami kang intake ng glucose( 200mg/dl) , some of your nephrons will eventualy be saturated over time. when renal transport maximum is achieve (\>375mg/dl), at this point glucose will start to appear in urine. In english: the higher the plasma conc, the higher the glucose filtered and excreted in the urine :) As for the case ng PAH, filtered, secreted not reabsorb. never sya magkakaroon ng renal threshold or transport maximum kasi never masasaturate yung nephron kasi naeexcrete nga kasi sya all the time

TRUE OR FALSE: If substance has high clearance: most will be found in the urine

true

If substance has low clearance: most will be found in the blood

true

Reason why PAH hs the highest clearance

Reason: Filtered and Secreted, not reabsorbed

Used to estimate for Renal Blood Flow (RBF) and Renal Plasma Flow (RPF)

PAH

Relative clearances in order

PAH \> K \> inulin \> urea \> Na \> glucose, amino acids and HCO3-

Substance with low clearances

Lowest Clearance: Protein, Na, Glucose, amino Acids, HCO3- and Cl * Reason: Not filtered (protein), or filtered but mostly reabsorbed (everything else listed above) o Normally not found or found in small amounts in the urine

Substances were clearance is equal to gfr

inulin, creatinine filtered but not secreted not reabsorbed

substance that is more concentrated at the end of PCT that at the start of PCT:

Creatinine Crea Clearance = Crea excreted/plasma crea concentration

Marker for Kidney function (glomerular marker)

Creatinine

Directly proportional to pressure difference between renal artery and renal vein; inversely proportional to resistance of renal vasculature? and 25% of cardiac output

renal blood flow

True or false: **vasodilation** of renal arterioles **increses RBF**

TRUE

Substance that cause Vasodilation of Renal Arterioles:

PGE2, PGI2, bradykinin, NO, dopamine

True or false: Vasoconstriction of Renal Arterioles:Increases

false: decreases

True or false : ANP **vasoconstrict** Afferent Arterioles and to a lesser extent **vasodilates** Efferent Arterioles. Net effect: increases RBF

false ANP: **vasodilates** Afferent Arterioles and to a lesser extent **vasoconstricts** Efferent Arterioles. Net effect: **increases RBF**

Estimated by PAH Clearance

Renal Plasma Flow (RPF)

True or false : PAH Clearance underestimates true RPF by 10% due to RPF to kidney regions that do not filter and secrete PAH

TRUE

A patient is infused with para-aminohippuric acid (PAH) to measure renal blood flow (RBF). She has a urine flow rate of 1 mL/min, a plasma [PAH] of 1 mg/mL, a urine [PAH] of 600 mg/mL, and a hematocrit of 45%. What is her “effective” RBF? (A) 600 mL/min (B) 660 mL/min (C) 1091 mL/min (D) 1333 mL/min

``` CPAH = UPAH × V/PPAH = 600 mL/min CPAH = RPF since clearance of PAH is used to estimate RPF RBF = RPF/ (1 – hematocrit) RBF = (6000mL/min)/ (1-0.45) RBF = 600mL/min/0.55 RBF = 1091 mL/min ```

renal blood flow formula

RBF= RPF/ 1- hematocrit

Amount filtered in the glomerular capillaries per unit time

GFR Normal Value: 125mL/min or 180L/day

T/F : GFR **Determined by Starling Forces at the level of the glomerular capillary (glomerulus)**

TRUE

T/F : BUN and Creatinine increase when GFR increases o

FALSE: DECREASES

T/F In pre-renal azotemia (e.g. Hypovolemia), CREATININE increases more than BUN and Crea/BUN ratio \> 20:1

FALSE In pre-renal azotemia (e.g. Hypovolemia), BUN increases more than creatinine and BUN/Crea ratio \> 20:1

T/F GFR decreases with age, but Creatinine remains constant due to decreased muscle mass

TRUE

• ” Water pressure” at the GC. • Promotes GFR. • Increased by vasodilation of afferent arteriole or moderate vasoconstriction of efferent arteriole

GC Hydrostatic Pressure

• “Water pressure” at the BS that opposes GC hydrostatic Pressure and GFR. • Increased by ureteral obstruction

BS Hydrostatic Pressure

* “Proteins attracting water” at the GC. * Opposes GFR. * Increased by plasma protein concentration.

GC Oncotic Pressure

“Usually ignored”. • Normal value: 0 (no protein is normally filtered to BS

BS Oncotic Pressure

• Not a Starling Force. • Hydraulic conductance/filtration coefficient describes capillary permeability. • Promotes GFR. Increased by histamine • (e.g. in burns)

Fraction of renal plasma flow that is filtered

FILTRATION FRACTION (FF) • Normal Filtration Fraction: 20%

T/F ↑ Filtration Fraction → ↑ peritubular capillary protein concentration → ↑ reabsorption in the tubules

true

RENAL Flashcards

(65 cards)