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PhysQ2_Test1
RenalFcn
| Question | Answer |
|---|---|
| What do the kidneys regulate | Inorganic Ion Balance Osmolarity Volume Water |
| What do the kidneys excrete | Metabolic waste(urea,uric acid, creatinine) Foreign Chemicals (drugs) |
| What do the kidneys secrete | Hormones: Renin & Epo -1,25-dihydrocholecalcificol |
| Juxtaglomerular(granular cells) secrete what? | Renin |
| Interstitial cells secrete what? | Epo |
| How much water is inputted per day? | 2300mL |
| How much water is outputted per day? | 1200mL |
| How much water is UNACCOUNTED for each day? | 1100mL (steady state) |
| Pt has urinary flow of >1100ml/day. Dx? | Negative Water Balance |
| Pt has urinary flow of 1100ml/day. Dx? | Steady State |
| Pt has urinary flow of <1100ml/day. Dx? | Positive Water Balance |
| Pt has diarrhea, what do you suspect of their sodium/water balance? | Negative Balance |
| Pt on diuretic, what do you suspect of their sodium/water balance? | Negative Balance |
| Pt has adrenal dysfunction(NOT enough aldosterone), what do you suspect of their sodium/water balance? | Negative Balance |
| Pt on excess steroids, what do you suspect of their sodium/water balance? | Positive Balance |
| Pt has congestive heart failure, what do you suspect of their sodium/water balance? | Positive Balance |
| Pt has salt-retaining renal disease, what do you suspect of their sodium/water balance? | Positive Balance |
| This part of the kidney is striated | Medulla |
| This part of the kidney is granular | cortex |
| Ureter pressure is typically high or low? | Very low |
| This structure has 3 components: tubular, vascular & combined (JGA) | Nephron |
| This contains the glomerulus & Bowman's Capsule | Renal Corpuscle |
| This DRAINS the Bowman's Caspule where 60-80% of filtered solute & water is reabsorbed (isosmotic) | Proximal Tubule |
| These descending and ascending loops generate osmotic gradients in the medulla that allow the kidney to concentrate the urine | Loop of Henle |
| This is where thick ascending limb passes btwn afferent/efferent arteriole | Juxtaglomerula Appartaus (JGA) |
| This has some reabsorption of water/ions. Fluid here is iso OR hyposomtic | Distal Convuluted Tubule |
| This is where the final concentration of urine is adjusted | Collecting Duct |
| In the collecting duct water permeability is controlled by what | Vasopressin |
| These glomeruli in outer cortex have short loops of Henle that do NOT extend into the inner medulla | Cortical Nephrons |
| These glomeruli near corticomedullary border have long loops of Henle and extend deep into the inner medulla. | Juxtamedullary Nephrons |
| The number of juxtamedullary neprhons will control what? | The ability to produce a certain amt of concentration in the urine |
| All nephrons function in what way? | In parallel (collecting ducts shared by many nephrons) |
| Capillary endothelium, basement membrane & capsular epithelial cells all comprise this | Filtration barrier |
| Podocytes separated by slits are present in the capsular epithelial cells. What do they constitute? | The path of filtrate flow from capillary lumen into urinary space |
| This is composed of macula densa, granular cells & extraglomerula mesangial cells | JGA (Juxtaglomerula Apparatus) |
| This helps control glomerula filtration rate & renin secretion (BP & volume) | JGA (Juxtaglomerula Apparatus) |
| These cells found inbetween and within capillary loops of the JGA contract in response to angiotensin 2 | Mesangial cells |
| This part of the peritubular capillary bed follows the loops of Henle of JGA nephrons. Found in medulla | Vasa Recta |
| Cortical aa give off afferent arterioles. How many per glomerulus? | One afferent arteriole per glomerulus |
| Fluid NOT filtered by kidney goes where | Efferent arterioles-->peritubular capillaries |
| There are 2 arterioles (afferent & efferent) and 2 capillary beds (glomerula & peritubular) which do what | Go in series |
| These specialized tubular capillaries of juxtamedullary nephrons are long, hairpin shaped that follow the loops of henle. They supply nutrients to medullary tissue & are impt for water recovery | Vasa Recta |
| Renal nerves are SNS(Adrenergic: dopamine/NE) and use which receptors | Alpha1 on arterioles |
| Are the kidneys PNS or SNS or both? | SNS only (Adrenergic: NE/Dopamine) |
| Only adrenergic stimulation (SNS) will do what to renal blood flow & glomerula filtration rate | Will decrease renal blood flow & glomerula filtration rate |
| Adrenergic stimulation (SNS) with the simultaneous release of PGE2 and PGI2 will do what to renal blood flow & glomerula filtration rate | Will reduce the reduction of renal blood flow and glomerula filtration rate -PGE/PGI will oppose the effect of SNS |
| SNS (adrenergic) stimulation of granular cells(JGA) will lead to what when beta receptors are stimulated? | Renin release |
| What is the rate of glomerula filtration? | 120-125ml/min |
| After glomerula filtration, what is produced? | A protein-free filtrate |
| What occurs from tubular lumen to PTC | Tubular Reabsorption |
| What occurs from PTC to tubuluar lumen | Tubular secretion |
| Kidneys receive how much of cardiac output? | 1/4 -180L Filtrate/day -Plasma filtered 65x/day |
| Dividing the glomerula filtration rate/renal plasma flow gives you what? | Filtration Fraction |
| Vasoconstriction in the renal area is mediated by which receptors | Alpha1 |
| Vasoconstriction by SNS (alpha1) effects RBF & GFR how? | Decreases renal blood flow Decreases glomerula filtration rate |
| AngII, ADH, ATP & Endothelun all do what? | Vasoconstrict-->DEC RBF & GFR |
| AngII constricts both afferent & efferent arterioles. Which are more sensitive to its effects? | Efferent arterioles |
| ANP, Glucocorticoids, NO, Prostaglandins all do what? | Vasodilate--> INC RBF & GFR |
| Constant blood flow and GFR @difft arterial pressures determined by? | Autoregulation: Range 80-180mmHg |
| This can be OVERridden by LARGE increases in sympathetic tone(vasoconstriction by SNS or other constrictors) | Autoregulation |
| When would you expect to see decreased RBF & GFR? | Hypotension during severe blood loss |
| Intrinsic to vascular smooth m cells it contracts in response to stretch of vessels. | Myogenic Mechanism for Autoregulation of RBF & GFR |
| Increasing GFR will INC NaCl delivery to LOH which is sensed by the macula densa. This will cause resistance of the afferent arteriole(Ra) to INC-->DEC RBF&GFR | Tubuloglomerula Feedback("Flow Dependent") Autoregulation of GFR & RBF |
| Signaling that affects RBF & GFR mainly by changing resistance in this arteriole | AFFerent arteriole |
| This maintains constancy of salt load delivered to distal tubule | Tubuloglomerula Feedback |
| What is the suspected tubuloglomerula feedback signal | Adenosine |
| All small-MW solutes NOT protein-bound appear in the filtrate comparitively how w/blood plasma concentrations? | In SAME concentrations |
| The fluid in Bowman's Capsule: | Protein-FREE filtrate of blood plasma |
| Fenestrae-->basal lamina-->slits btwn pedicels of podocytes(bridged by diaphragms) | Route of Filtrate |
| What are the MAIN barriers to proteins during filtration | Basal Lamina & Filtration Slits |
| Why are proteins unable to filter into glomerula | BC slits are coated w/negative charge and cannot pass thru since proteins also negative |
| What is more permeable to filtration: polycation or polyanion? | Polycation (+)charge |
| Mesangial cells (produce AngII) alter filtration rate Kf how? | By decreasing |
| What is the driving force for GFR? | Blood pressure in glomerula capillary (Pgc) |
| What slows down GFR? | Back pressure in Bowman's Capsule (Pbc) |
| What oncotic pressure is caused by proteins unable to cross the barrier, slowing GFR. Will increase as plasma is diverted into BC. | Oncotic pressure of glomerular capillary blood (pi-gc) |
| Glomerula Capillary Pressure Hydrostatic Pressure | 45mmHG |
| Oncotic Pressure of glomerula capillary? | 26mmHg (MEAN VALUE) |
| Pressure of Bowman's Capsule? | 10mmHg |
| Kf for filtration | 14ml/min/mmHg |
| When afferent (Ra) and efferent (Re) BOTH INC what happens to glomerula capillary hydrostatic pressure? | There is NO EFFECT on glomerula capillary pressure if BOTH resistances INC |
| When afferent (Ra) and efferent (Re) BOTH INC what happens to renal blood flow? | There is a DRAMATIC decrease in renal blood flow |
| When afferent (Ra) INC and efferent (Re) stays constant what happens to glomerula capillary hydrostatic pressure? | Glomerula capillary pressure will DEC |
| When afferent (Ra) INC and efferent (Re) stays constant what happens to renal blood flow? | Renal Blood Flow will DEC |
| When afferent (Ra) stays constant and efferent (Re) INC what happens to glomerula capillary hydrostatic pressure? | Glomerula capillary pressure will INC |
| When afferent (Ra) stays constant and efferent (Re) INC what happens to renal blood flow? | Renal blood flow will DEC |
| INC glomerula surface area does what to GFR | Increase GFR |
| INC renal a pressure does what to GFR | Increase GFR |
| DEC afferent-arteriole resistance via afferent dilation does what to GFR | Increase GFR |
| INC efferent-arteriole resistance via efferent constriction does what to GFR | Increase GFR |
| INC intratubuluar pressure bc of an obstruction of tubule or extrarenal urinary system does what to GFR | Decrease GFR |
| INC systemic plasma oncotic pressure does what to GFR | Decrease GFR |
| DEC renal plasma flow causing an INC in osmotic pressure in glomerula capillaries will do what to GFR | Decrease GFR |
| Amount of material in glomerula filtrate | Filtered Load=GFR*Px |
| Amt of material lost in urine | Excretion Rate=Ux * V |
| Amt of material added to (secreted) or removed (reabsorbed) from glomerula filtrate | Transport rate=Tx=FL-ER |
| Positive transport rate | Reabsorption: material was removed from filtrate |
| Negative transport rate | Secretion: material was added to filtrate |
| Fraction of filtered mass represented by excreted mass | Fractional Excretion: FE=ER/FL |
| Fractional excretion <1 | Reabsorption: material was removed from filtrate |
| Fractional excretion >1 | Secretion: material was added to filtrate |
| What is 100% reabsorbed | Glucose |
| Transcellular & paracellular(leaky epithelium) are what | Routes of reabsorption |
| What 2 barriers must you cross for transcellular reabsoption | Apical & basolateral membrane _Diffusion thru IF & capillary wall is fast |
| Perfect GFR marker is freely filtered, not reabsorbed or secreted. What is gold standard but not commonly used? | Inulin |
| What is commonly used to indicate GFR | Creatinine clearance & plasma creatinine |
| Produced by skeletal m @relatively constant rate from breakdown of creatinine phosphate. Freely filtered, not reabsorbed, only slightly secreted. At a steady-state conc in blood. | Creatinine |
| Which levels can provide an estimate of GFR over the preceding hrs | Creatinine |
| a.a. catabolism in liver makes urea which varies w/protein intake & liver function. About 1/2 of filtered urea is reabsorbed. This is NOT a good GFR marker | Blood Urea Nitrogen (BUN) Normal: 9-18 |
| What happens to reabsorption of urea when GFR is low | Reabsorption will increase |
| High BUN:Cr ratio: >15 | Dehydration (DEC GFR) Upper GI Bleeding |
| Normal BUN:Cr ratio: 10-15 | Acute tubular necrosis Loss of nephrons |
| Low BUN:Cr ratio: <10 | Severe skeletal m injury(INC Cr) Liver Dz(DEC BUN) Malnutrition(DEC BUN) |
| What is more sensitive to decreased GFR, BUN or plasma Cr | BUN |
| Volume of plasma that is cleared of solute x per minute | Clearance |
| Injected diuretic that inhibits osmotic water flow from lumen-->basolateral spaces. Causes Na+ back-diffusion into lumen of tubule w/INC Na+ and H20 loss. | Mannitol (in Proximal Tubule) _INC loss of water & electrolytes in urine |
| Cr clearance of 85-125 for females | Normal |
| Cr clearance of 97-140 for males | Normal |
| Clearance of secreted substance, lesser or greater than CCr | Clearance of secreted substance GREATER than clearance of creatine(and thus >GFR) |
| Clearance of reabsorbed substance, lesser or greater than CCr | Clearance of secreted substance lESSER than clearance of creatine(and thus >GFR) _Glucose, complete reasorption, clearance is zero |
| Clearance of substance:Clearance of Inulin=1 | substance being filtered must also be a GFR marker |
| Clearance of substance:Clearance of Inulin<1 | Substance Not Filtered OR Filtered & Reabsorbed |
| Clearance of substance:Clearance of Inulin >1 | Substance Filtered & secreted |
| This can estimate RPF(renal plasma flow) because ALL the blood is cleared of this | Para-aminohippurate(PAH) |
| Glucose uses this process to move during reabsorption | Secondary active transport w/Na+ INFLUX |
| How much Na+ is reabsorbed in the proximal tubule | 67% (2/3) |
| How much water is reabsorbed in the proximal tubule | 65% (2/3) _Solute Linked |
| How is Na transported across basolateral membrane | By Na/K ATPase _H20 will follow passively |
| How does Na enter proximal tubule cells | Organic cotransport & Na/H antiport |
| How does Cl enter proximal tubule cells | Paracellular Routes |
| How does Na leave proximal tubule cells | Na/K ATPase or via cotransport w/bicarbonate |
| Stimulates Na/H exchange across apical membrane(NHE family of transporters) & INC Na reabsorption & H secretion. | Angiotensin II |
| Stimulates Na reabsorption | SNS Activity |
| Inhibits Na/PO4 cotransport. INC urinary excretion of PO4. | Parathyroid Hormone |
| What can the loop of Henle NOT transport more than? | 200 |
| Tubular Fluid/Plasma (TF/P) ratio in Bowman's space for freely filtered solutes | 1 |
| What happens to osmolarity across the proximal tubule? | Osmolarity DOES NOT change |
| Tubular Fluid/Plasma Conc. (TF/P) ratio=1 | Reabsorption of substance has been EXACTLY proportional to reabsorption of water |
| Tubular Fluid/Plasma Conc. (TF/P) ratio <1 | Reabsorption of substance has been GREATER than reabsorption of water _more water in plasma, than tubules _more solute in tubules |
| Tubular Fluid/Plasma Conc. (TF/P) ratio >1 | Reabsorption of substance has been LESS than reabsorption of water OR There's net secretion of the substance _more water in tubules, than plasma _more solute in the filtrate |
| Tubular Fluid/Plasma Inulin (TF/P) used why? | Since ONLY filtered, it's conc in the tube is solely determined by water movement |
| Max rate which renal can transport a certain solute | Tubular Maximum (Tm) _caused by saturation of membrane transport proteins |
| Fluid leaving LOH more or less dilute than other fluids? | MORE dilute. |
| Below Tm | All filtered load is reabsorbed into tubules |
| Above Tm | Extra filtered load is excreted |
| Where are Tm's usually found? | Proximal Tubule |
| Where glucose first appears in the urine. Depends on the GFR | Threshold of plasma |
| What happens to the threshold when you decrease GFR? | Decreasing filtration rate will increase the threshold(not all receptors are full therefore takes longer to saturate) |
| What happens to the threshold when you increase GFR? | Increasing filtration rate will decrease the threshold(easier to saturate all the receptors) |
| Causes back-diffusion into lumen of tubule w/INC Na+ and water loss (diuresis). INC water loss & electrolytes in urine. | Mannitol _Osmotic Diuresis |
| Where is the Na/K pump always present? | Basolateral membrane twds ISF of tubule |
| Furosemide(lasix) a loop diuretic blocks this | Na/K/2Cl- transporter (in Thick Ascending Limb) |
| What stimulates the Na/K/2Cl transporter | ADH _Stimulation can be blocked by Loop diuretic(lasix) |
| Can result in a rapid loss of Na & H20 (polyuria) | Osmotic Diuresis |
| Occurs w/high filtered urea load | Osmotic Diuresis _rapid loss of Na/H20(polyuria) |
| Occurs when gluose load exceeds Tm in DM patients | Osmotic Diuresis _rapid loss of Na/H20(polyuria) |
| Non-reabsorbed carbohydrate that's given IV to induce osmotic diuresis | Mannitol _rapid loss of Na/H20(polyuria) |
| Is tubuluar secretion specific or non-specific? | VERY non-specific |
| Typical cmpds SECRETED | Metabolites, waste products, foreign chemicals tagged by liver |
| Liver will tag things w/glucoronic acid or sulfate. What does this do? | Promotes secretion into filtrate |
| How are organic anions (PAH) secreted? | Via tertiary active transport |
| PAH is taken into filtrate(secreted) in exchange for what? | alpha-KG will go back to blood |
| How does PAH leave on the apical side twds the filtrate for secretion? | PAH-anion transporter |
| The apical side faces which substance: plasma or filtrate | Filtrate |
| If you have INC plasma levels of an ion, how will it effect other anions? | Secretion of anions will be inhibited since compete for same transporter. |
| Infusion of PAH with penicillin is used why? | Extends penicillin's half-life by inhibiting it's secretion into filtrate |
| Stimulates Na+ reabsorption in late distal tubule & collecting duct(principal cells) | Aldosterone |
| Stimulates K+ secretion so that Na+ can be reabsorbed | Aldosterone |
| Angiotensin II stimulates the release of this | Aldosterone |
| K+ plasma stimulates the release of this | Aldosterone |
| Vasoconstrictor which stimulates aldosterone release & Na/H exchange in the proximal tubule | Angiotensin II |
| Functions favor salt retention & elevation of arterial BP | Angiotensin II |
| Levels of this hormone which favors salt retention & elevation of arterial BP is controlled by renin | Angiotensin II |
| Renin release by JGA has 3 components | 1)Intrarenal baroreceptors 2)Macula Densa 3)Renal SNS |
| Granular cells of JGA respond to pressure(stretch) in AFFerent arterioles. Release of renin INVERSELY related to pressure in AFFerent arterioles | Intrarenal baroreceptors |
| Pressure in afferent arterioles rises, what happens to renin release? | Renin release decreases which decreases blood volume to decrease blood pressure |
| Pressure in afferent arterioles drops, what happens to renin release? | Renin release increases which increases blood volume to increase blood pressure |
| Senses flow to distal tubule(GFR) and renin release is INVERSELY related to GFR | Macula Densa |
| GFR increases, what happens to renin release | Renin release decreases which decreases blood volume to decrease blood pressure |
| GFR decreases, what happens to renin release | Renin release increases which increases blood volume to increase blood pressure |
| Stimulation of these increases renin release via b-receptor stimulation | Renal Sympathetic nn |
| A hemorrhage would do what to renin? | Increase renin secretion which increases blood volume to increase blood pressure |
| A hemorrhage would do what to angiotensin 2? | Increase angiotensin 2 which increases blood volume to increase blood pressure |
| A hemorrhage would do what to aldosterone? | Increase aldosterone which increases blood volume to increase blood pressure |
| What is the effect of lowering blood volume? | Lowers blood pressure |
| Released from atria when pressures are high, increases NaCl excretion by INC GFR. | Atrial Natriuretic Peptide(ANP) |
| Dilates the afferent arteriole & INC GFR & the filtered load of NaCl | Atrial Natriuretic Peptide(ANP) |
| Decreases NaCl reabsorption by the collecting duct by directly inhibiting renin/aldosterone secretion AND Na+ uptake by the medullary collecting duct | Atrial Natriuretic Peptide(ANP) |
| MOST important hormone regulating water balance that's released from pituitary when plasma osmolality INC | ADH(Antidiuretic Hormone) |
| MOST important hormone regulating water balance that's released from pituitary when plasma volume DEC | ADH(Antidiuretic Hormone) |
| Causes the movement of aquaporins to control water balance | ADH(Antidiuretic Hormone) |
| Though an impt hormone to regulate water, has little effect on NaCl excretion | ADH(Antidiuretic Hormone) |
| Hypovolemia senses SMALL changes in plasma osmolarity via OSMORECEPTORS. Stimulate this: | ADH(Antidiuretic Hormone) |
| Hypovolemia senses LARGE changes in plasma osmolarity via ARTERIAL & L ATRIAL BARORECEPTORS. Stimulate this: | ADH(Antidiuretic Hormone) |
| INC Na/K/2Cl cotransporters in the LOH increasing the medullary gradient | ADH(Antidiuretic Hormone) |
| INC permeability of the collecting duct to water | ADH(Antidiuretic Hormone) |
| INC permeability of inner medullary collecting duct to urea | ADH(Antidiuretic Hormone) |
| Avg Osmolarity level | 290mOsm/L |
| During a hemorrhage what happens to ADH secretion? | ADH secretion increases in order to raise plasma volumes & thus raise blood pressure. Will lower water excretion & increase its reabsorption |
| During a hemorrhage what happens to too much water that's ingested? | ADH secretion decreases, and water reabsorption decreases and excess water is excreted |
| ml/min of plasma cleared of a given substance | Clearance |
| ml/min of plasma cleared of osmotically active particles | Osmolar Clearance= (Uosm*V)/Posm |
| Positive osmolar balance is a sign of gaining osmoles & water in plasma. Progressing to edema. What's ur Osmolar clearance? | DEC Osmolar Clearance(water gain) |
| Decreased GFR causes edema by causing this | DEC Osmolar Clearance(water gain) |
| Increased aldosterone causes edema by causing this | DEC Osmolar Clearance(water gain) |
| "Dumping" osmolytes leads to a loss of ECF. How does this effect osmolar clearance? | INC Osmolar Clearance(water loss) |
| Diuretic reduce the ability of the kidney to reabsorb normally. How does this effect osmolar clearance? | INC Osmolar Clearance(water loss) |
| Reduced aldosterone reduce the ability of the kidney to reabsorb normally. How does this effect osmolar clearance? | INC Osmolar Clearance(water loss) |
| What would it mean if the osmotic clearance=urine flow | Urine is isotonic |
| Volume is greater than osmotic clearance | Additional solute-free water is being LOST from the body (urine is HYPOtonic) |
| Volume is less than osmotic clearance | Additional solute-free water is being RETURNED to the body (urine is HYPERtonic) |
| If you take the urine flow-osmotic clearance, the difference gives you what? | Amt of solute-free water lost/saved |
| ml/min of solute-free water excreted by the kidneys | Water clearance=Volume-Osmotic Clearance |
| Water Clearance is negative | Solute-free water being conserved by the body |
| Water Clearance is positive | Solute-free water being excreted by the body _Dilute urine |
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