Phys 27 Flashcards

A urine dipstick is normal in a healthy adult because the glomerular capillary barrier normally produces filtrate with which composition?

A) Protein-rich and cell-free

B) Protein-free and cell-free

C) Protein-free with erythrocytes

D) Protein-rich with erythrocytes

Glomerular filtrate is normally essentially devoid of red blood cells because glomerular capillaries are relatively impermeable to which components?

A) Proteins and cellular elements

B) Sodium and chloride ions

C) Water and small solutes

D) Glucose and amino acids

A patient has normal plasma calcium, but not all calcium is freely filterable at the glomerulus. Which calcium fraction is not filtered?

A) Ionized calcium

B) Filtered calcium

C) Protein-bound calcium

D) Tubular calcium

Most plasma fatty acids are not freely filtered across glomerular capillaries because they are primarily:

A) Bound to proteins

B) Stored in erythrocytes

C) Trapped in podocytes

D) Secreted by tubules

Which two variables directly determine glomerular filtration rate?

A) Hematocrit and plasma sodium

B) Kf and net filtration pressure

C) Tubule length and urine flow

D) ADH and bladder pressure

The glomerular capillary filtration coefficient, Kf, is the product of which two capillary properties?

A) Pressure and plasma protein

B) Diameter and blood viscosity

C) Permeability and surface area

D) Osmolality and renal flow

In an average adult, which value best matches normal glomerular filtration rate

A) 13 ml/min

B) 60 ml/min

C) 125 ml/min

D) 1100 ml/min

A normal adult has a GFR of 125 ml/min. Which daily filtration volume does this approximate?

A) 3 L/day

B) 30 L/day

C) 60 L/day

D) 180 L/day

Which equation correctly defines filtration fraction?

A) Renal plasma flow/GFR

B) GFR/renal plasma flow

C) GFR/renal blood flow

D) Urine flow/GFR

A student compares the glomerular capillary membrane with typical systemic capillaries. What structural feature is unique?

A) Three major filtration layers

B) No basement membrane

C) Two endothelial layers

D) Complete cellular occlusion

Which sequence lists the three major layers of the glomerular capillary membrane from blood outward?

A) Podocyte; endothelium; basement membrane

B) Basement membrane; podocyte; endothelium

C) Endothelium; basement membrane; podocyte

D) Endothelium; podocyte; basement membrane

The outer epithelial cell layer of the glomerular filtration barrier is formed by which cells?

A) Mesangial cells

B) Podocytes

C) Macula densa cells

D) Juxtaglomerular cells

The glomerular capillary endothelium contains thousands of small holes. What are these openings called?

A) Slit pores

B) Fenestrae

C) Tight junctions

D) Canaliculi

The glomerular basement membrane is mainly a meshwork of which substances

A) Elastin and fibrinogen

B) Albumin and globulin

C) Collagen and proteoglycans

D) Keratin and myosin

Why can large amounts of water and small solutes pass through the glomerular basement membrane?

A) It has large mesh spaces

B) It lacks negative charge

C) It actively pumps water

D) It contains red cell pores

Podocyte foot processes are separated by filtration gaps called:

A) Fenestrae

B) Slit pores

C) Major calyces

D) Tight junctions

Through which structure does filtrate move between podocyte foot processes?

A) Fenestrated liver pores

B) Macula densa plaques

C) Slit pores

D) Cortical collecting ducts

Which property of glomerular epithelial cells provides additional restriction to plasma protein filtration?

A) Positive electrical charge

B) Negative electrical charge

C) High lipid solubility

D) Smooth muscle contraction

Despite high filtration rate, the glomerular filtration barrier selectively filters molecules mainly according to:

A) Size and electrical charge

B) pH and temperature

C) Sodium and potassium content

D) Hormonal and neural tone

A molecule has filterability of 1.0. What does this mean?

A) Not filtered at all

B) Freely filtered like water

C) Half as filtered as water

D) Secreted after filtration

Albumin is strongly restricted from glomerular filtration primarily because it is large and has which charge?

A) Positive

B) Neutral

C) Negative

D) Variable

Why does the negatively charged glomerular wall repel albumin?

A) Albumin is positively charged

B) Albumin is negatively charged

C) Albumin is lipid soluble

D) Albumin is bound to calcium

Which glomerular wall component contributes negative charge that restricts albumin filtration?

A) Proteoglycans

B) Hemoglobin

C) Creatinine

D) Bicarbonate

For dextrans of equal molecular weight, which type is filtered more readily through the glomerular barrier?

A) Negatively charged dextran

B) Neutral dextran

C) Protein-bound dextran

D) Albumin-bound dextran

The negative charges of the basement membrane and podocytes most strongly restrict which molecules?

A) Small positively charged ions

B) Large negatively charged molecules

C) Small neutral solutes

D) Water molecules

A child develops selective albuminuria despite nearly normal kidney histology. Which early barrier abnormality best explains this?

A) Loss of negative charges

B) Excess slit pore closure

C) Increased erythrocyte filtration

D) Loss of renal blood flow

Loss of negative charges on the glomerular basement membrane before obvious histologic change is characteristic of:

A) Nephrotic obstruction

B) Minimal change nephropathy

C) Acute pyelonephritis

D) Renal papillary necrosis

In minimal change nephropathy, which urinary abnormality occurs because lower molecular weight proteins are filtered?

A) Glycosuria

B) Hematuria

C) Proteinuria or albuminuria

D) Ketouria

Which protein is especially likely to appear in urine when glomerular negative charge is lost?

A) Albumin

B) Fibrinogen

C) Hemoglobin

D) Myosin

The term albuminuria most directly refers to which abnormal finding?

A) Albumin in urine

B) Albumin in plasma

C) Albumin in interstitium

D) Albumin in cells

Which pair correctly identifies the two immediate determinants of GFR in the filtration equation?

A) Kf and net filtration pressure

B) RPF and filtration fraction

C) Hematocrit and renal blood flow

D) Urine pressure and bladder pressure

Which equation correctly describes glomerular filtration rate?

A) GFR = Kf/NFP

B) GFR = NFP/Kf

C) GFR = Kf × NFP

D) GFR = RPF × hematocrit

Net filtration pressure across glomerular capillaries is the sum of which forces?

A) Hydrostatic and colloid osmotic forces

B) Electrical and metabolic forces

C) Tubular and ureteral pressures

D) Neural and hormonal forces

Which force favors filtration across the glomerular capillary membrane?

A) Bowman hydrostatic pressure

B) Glomerular hydrostatic pressure

C) Glomerular oncotic pressure

D) Plasma protein pressure

Which force opposes filtration by pushing fluid back toward glomerular capillaries from Bowman’s capsule?

A) Bowman hydrostatic pressure

B) Bowman oncotic pressure

C) Glomerular hydrostatic pressure

D) Interstitial oncotic pressure

Which force opposes filtration because plasma proteins retain water within glomerular capillaries?

A) Bowman hydrostatic pressure

B) Bowman oncotic pressure

C) Glomerular colloid osmotic pressure

D) Glomerular hydrostatic pressure

Which force would promote filtration if proteins were present in Bowman’s capsule?

A) Bowman colloid osmotic pressure

B) Glomerular colloid osmotic pressure

C) Bowman hydrostatic pressure

D) Peritubular hydrostatic pressure

A patient with ureteral obstruction has increased pressure transmitted backward into Bowman’s capsule. What is the expected direct effect on GFR?

A) GFR increases markedly

B) GFR remains unchanged

C) GFR decreases

D) GFR doubles transiently

A patient with uric acid stones obstructing the ureter develops reduced filtration. Which pressure change best explains the lower GFR?

A) Increased Bowman hydrostatic pressure

B) Decreased plasma oncotic pressure

C) Increased afferent hydrostatic pressure

D) Decreased renal venous pressure

Calcium or uric acid precipitates lodge in the ureter and obstruct urinary outflow. Which downstream complication may occur if obstruction persists?

A) Nephrotic syndrome

B) Hydronephrosis

C) Central diabetes insipidus

D) Minimal change disease

Hydronephrosis from ureteral obstruction is best described as distention and dilation of which structures?

A) Cortex and glomeruli

B) Renal artery and vein

C) Renal pelvis and calyces

D) Tubules and vasa recta

A patient has an obstructing ureteral stone with persistent elevated Bowman’s capsule pressure. What is the major renal risk if the obstruction is not relieved?

A) Increased nephron regeneration

B) Permanent kidney damage

C) Increased renal oxygen delivery

D) Reduced plasma protein filtration

When one-fifth of glomerular capillary fluid filters into Bowman’s capsule, why do remaining plasma proteins become concentrated?

A) Proteins are not filtered

B) Proteins are actively secreted

C) Proteins enter podocyte cytoplasm

D) Proteins bind filtered glucose

If glomerular hydrostatic pressure is held constant, increasing blood flow into the glomerulus tends to have which effect on GFR?

A) Increases GFR

B) Decreases GFR

C) Stops filtration

D) Causes hydronephrosis

If glomerular hydrostatic pressure is constant but blood flow into the glomerulus falls, which effect on GFR is expected?

A) GFR rises sharply

B) GFR decreases

C) GFR becomes pressure-independent

D) GFR equals renal blood flow

Which set contains the three main determinants of glomerular hydrostatic pressure?

A) ADH, aldosterone, renin

B) Albumin, sodium, chloride

C) Arterial pressure, afferent resistance, efferent resistance

D) Tubule length, plasma volume, hematocrit

A drug dilates the afferent arteriole without changing other variables. What happens to glomerular hydrostatic pressure and GFR?

A) Both decrease

B) Pressure decreases; GFR increases

C) Pressure increases; GFR decreases

D) Both increase

Afferent arteriolar dilation increases GFR primarily by producing which hemodynamic change?

A) Increased glomerular hydrostatic pressure

B) Increased Bowman capsule pressure

C) Increased glomerular oncotic pressure

D) Reduced renal artery pressure

Afferent arteriolar constriction would be expected to have which effect on glomerular hydrostatic pressure and GFR?

A) Both increase

B) Both decrease

C) Pressure increases; GFR decreases

D) Pressure decreases; GFR increases

A patient receives a drug that moderately constricts efferent arterioles. Which immediate glomerular pressure change explains the initial GFR effect?

A) Increased Bowman pressure

B) Reduced glomerular pressure

C) Increased glomerular hydrostatic pressure

D) Reduced plasma protein pressure

At moderate levels of efferent arteriolar constriction, what is the usual effect on GFR?

A) Slight increase

B) Severe decrease

C) No possible change

D) Complete filtration arrest

With severe efferent arteriolar constriction, what happens to GFR?

A) Continues increasing indefinitely

B) Decreases

C) Becomes independent of proteins

D) Equals renal plasma flow

Which pattern best describes GFR as efferent arteriolar constriction progresses from moderate to severe?

A) Decrease then increase

B) Increase then decrease

C) No change then increase

D) Continuous linear increase

Why does severe efferent arteriolar constriction eventually decrease GFR despite raising glomerular hydrostatic pressure?

A) Bowman pressure becomes negative

B) Plasma proteins disappear from capillaries

C) Colloid osmotic pressure rises rapidly

D) Afferent arterioles fully dilate

During severe efferent constriction, plasma protein concentration increases markedly. Which effect makes colloid osmotic pressure rise nonlinearly?

A) Donnan effect

B) Starling dilution

C) Ureterorenal reflex

D) Micturition reflex

In severe efferent arteriolar constriction, why does colloid osmotic pressure rise faster at higher protein concentrations?

A) Proteins become freely filtered

B) Protein-bound ions add osmotic force

C) Bowman capsule secretes albumin

D) Vasa recta stop concentrating urine

If renal blood flow and GFR decrease, sodium filtration decreases. What happens to sodium reabsorption and renal oxygen consumption?

A) Both increase

B) Reabsorption increases; oxygen falls

C) Reabsorption falls; oxygen rises

D) Both decrease

Why does reduced GFR lower renal oxygen consumption?

A) Less sodium is reabsorbed

B) More proteins are filtered

C) More glucose is secreted

D) Less blood reaches cortex

Which equation correctly represents renal blood flow?

A) Resistance ÷ pressure gradient

B) Renal vein pressure ÷ resistance

C) Pressure gradient ÷ total resistance

D) GFR ÷ renal plasma flow

Renal blood flow is calculated using which pressure gradient?

A) Bowman minus tubular pressure

B) Renal artery minus renal vein

C) Glomerular minus Bowman pressure

D) Afferent minus efferent pressure

In the renal blood flow equation, the pressure gradient is divided by which variable?

A) Total renal vascular resistance

B) Filtration fraction

C) Plasma colloid osmotic pressure

D) Glomerular filtration coefficient

If renal artery and renal vein pressures remain constant, increased renal vascular resistance has what effect on renal blood flow?

A) Increases flow

B) Decreases flow

C) Stops GFR only

D) Increases filtration fraction only

If renal artery and renal vein pressures remain constant, decreased renal vascular resistance has what effect on renal blood flow?

A) Decreases flow

B) Does not affect flow

C) Increases flow

D) Stops medullary flow

Which kidney region receives most renal blood flow?

A) Renal cortex

B) Renal medulla

C) Renal pelvis

D) Renal papilla

Blood flow to the renal medulla is supplied by which specialized capillary system

A) Glomerular capillaries

B) Cortical veins

C) Vasa recta

D) Afferent arterioles

The vasa recta are best described as a specialized portion of which capillary system?

A) Peritubular capillary system

B) Glomerular capillary system

C) Portal venous system

D) Pulmonary capillary system

A patient with severe hemorrhage has intense renal sympathetic nerve activation. What is the expected effect on renal arterioles, renal blood flow, and GFR?

A) Vasodilation; increased flow; increased GFR

B) Vasoconstriction; decreased flow; decreased GFR

C) Vasodilation; decreased flow; increased GFR

D) Vasoconstriction; increased flow; decreased GFR

Strong activation of renal sympathetic nerves directly causes which renal vascular response?

A) Constriction of renal arterioles

B) Dilation of renal arterioles

C) Relaxation of efferent venules

D) Dilation of vasa recta

A patient has a moderate fall in carotid sinus and cardiopulmonary receptor pressure, causing reflex sympathetic activation. What is the usual effect on renal blood flow and GFR?

A) Marked increase in both

B) Complete loss of autoregulation

C) Little influence on both

D) Severe decrease in both

Which situation is most likely to substantially decrease renal blood flow and GFR through sympathetic effects?

A) Mild baroreceptor unloading

B) Moderate cardiopulmonary unloading

C) Strong renal nerve activation

D) Normal postural adjustment

Which adrenal medullary hormones constrict both afferent and efferent arterioles, reducing renal blood flow and GFR?

A) Aldosterone and cortisol

B) Norepinephrine and epinephrine

C) Renin and angiotensin II

D) ADH and oxytocin

Which paired renal effect best matches norepinephrine and epinephrine release

A) Arteriolar dilation; increased GFR

B) Afferent dilation; reduced filtration

C) Arteriolar constriction; reduced GFR

D) Efferent dilation; increased flow

Endothelin is best described as which type of renal vascular mediator?

A) Vasodilator from podocytes

B) Vasoconstrictor from damaged endothelium

C) Anticoagulant from collecting ducts

D) Natriuretic peptide from macula densa

Which mediator can be released by damaged vascular endothelial cells in the kidneys and other tissues?

A) Endothelin

B) Calcitriol

C) Erythropoietin

D) Albumin

Which mediator is formed both in the kidneys and in the systemic circulation?

A) Angiotensin II

B) Evans blue dye

C) Antipyrine

D) 51Cr-labeled erythrocytes

Nitric oxide and prostaglandins help preserve renal perfusion by counteracting vasoconstrictor effects of which mediator?

A) Erythropoietin

B) Calcitriol

C) Angiotensin II

D) Inulin

Which pair of mediators opposes angiotensin II–mediated vasoconstriction in renal blood vessels?

A) ADH and aldosterone

B) Nitric oxide and prostaglandins

C) Epinephrine and norepinephrine

D) Endothelin and renin

Increased angiotensin II levels have which combined effect on glomerular hydrostatic pressure and renal blood flow?

A) Lower pressure; lower flow

B) Lower pressure; higher flow

C) Raise pressure; lower flow

D) Raise pressure; higher flow

Angiotensin II raises glomerular hydrostatic pressure primarily by constricting which vessel?

A) Afferent arteriole

B) Efferent arteriole

C) Interlobular artery

D) Cortical vein

A patient has elevated angiotensin II during low effective circulating volume. Which effect helps preserve GFR?

A) Prevents fall in glomerular pressure

B) Increases Bowman capsule pressure

C) Dilates efferent arterioles strongly

D) Blocks sodium reabsorption

Elevated angiotensin II helps prevent decreases in GFR by maintaining which pressure?

A) Bowman hydrostatic pressure

B) Renal venous pressure

C) Glomerular hydrostatic pressure

D) Interstitial oncotic pressure

Angiotensin II reduces renal blood flow by efferent constriction. What downstream peritubular effect promotes sodium and water retention?

A) Increased peritubular flow

B) Decreased peritubular flow

C) Increased Bowman pressure

D) Decreased tubular permeability

A drug inhibits nitric oxide formation in the kidney. Which renal hemodynamic pattern is expected?

A) Lower resistance; increased GFR

B) Higher resistance; decreased GFR

C) Lower resistance; decreased sodium excretion

D) Higher resistance; increased GFR

Inhibition of nitric oxide formation eventually causes high blood pressure through which renal effects?

A) Increased GFR and natriuresis

B) Decreased resistance and natriuresis

C) Increased resistance and reduced natriuresis

D) Decreased filtration fraction and pressure

Administration of a nitric oxide synthesis inhibitor decreases urinary sodium excretion because it causes which primary renal vascular change?

A) Increased renal vascular resistance

B) Decreased renal vascular resistance

C) Selective venous dilation

D) Vasa recta rupture

Renal prostaglandins help protect GFR and renal blood flow primarily by opposing vasoconstriction of which vessels?

A) Afferent arterioles

B) Renal veins

C) Collecting ducts

D) Ureters

A patient taking a prostaglandin-inhibiting drug is at risk for reduced renal perfusion during vasoconstrictor states. Which lost protective action explains this?

A) Opposing afferent vasoconstriction

B) Increasing efferent vasoconstriction

C) Blocking macula densa signaling

D) Increasing Bowman capsule pressure

Feedback mechanisms intrinsic to the kidneys maintain relatively constant renal blood flow and GFR despite arterial pressure changes. What is this process called

A) Autoregulation

B) Micturition

C) Osmosis

D) Protein washdown

Renal autoregulation refers to the kidney’s ability to keep which variables relatively constant despite arterial pressure changes?

A) Sodium intake and thirst

B) RBF and GFR

C) Hematocrit and albumin

D) ADH and aldosterone

The major purpose of renal autoregulation is to maintain a relatively constant GFR and allow precise control of what?

A) Water and solute excretion

B) Red cell sedimentation

C) Bladder wall tension

D) Plasma protein synthesis

Why does arterial pressure usually affect urine volume less than expected?

A) GFR cannot be filtered

B) Autoregulation and tubular adaptation

C) Plasma proteins freely enter filtrate

D) Bowman's pressure always decreases

Glomerulotubular balance describes which tubular response when GFR rises?

A) Tubular reabsorption increases

B) Tubular reabsorption decreases

C) Renin release stops completely

D) Afferent resistance always rises

A patient’s GFR rises, but urine volume increases less than predicted. Which tubular phenomenon helps explain this?

A) Proteinuria

B) Glomerulotubular balance

C) Vesicoureteral reflux

D) Minimal change nephropathy

Tubuloglomerular feedback controls GFR through which two arteriolar mechanisms?

A) Afferent and efferent feedback

B) Venous and lymphatic feedback

C) Cortical and medullary feedback

D) Sympathetic and somatic feedback

Which feedback system has afferent and efferent arteriolar components that act together to regulate GFR?

A) Ureterorenal reflex

B) Micturition reflex

C) Tubuloglomerular feedback

D) Baroreceptor reflex

The juxtaglomerular complex consists of which key cell groups?

A) Podocytes and mesangial cells

B) Macula densa and JG cells

C) Principal and intercalated cells

D) Fibroblasts and epithelial cells

Macula densa cells are located in which nephron region?

A) Initial distal tubule

B) Proximal straight tubule

C) Collecting duct tip

D) Thin descending limb

Juxtaglomerular cells are located in the walls of which vessels?

A) Renal veins only

B) Afferent and efferent arterioles

C) Peritubular capillaries only

D) Interlobar and arcuate arteries

A fall in sodium chloride concentration at the macula densa initiates which afferent arteriolar response?

A) Increased afferent resistance

B) Decreased afferent resistance

C) Complete afferent occlusion

D) No change in resistance

When macula densa NaCl delivery decreases, lowering afferent arteriolar resistance helps restore GFR by increasing which pressure?

A) Bowman hydrostatic pressure

B) Glomerular hydrostatic pressure

C) Renal venous pressure

D) Interstitial oncotic pressure

Macula densa detection of decreased sodium chloride increases release of which substance from juxtaglomerular cells?

A) Calcitriol

B) Albumin

C) Renin

D) Endothelin

A low NaCl signal at the macula densa produces which paired response?

A) Afferent resistance falls; renin rises

B) Afferent resistance rises; renin falls

C) Efferent resistance falls; renin falls

D) Bowman pressure rises; renin rises

Which statement best distinguishes renal autoregulation from glomerulotubular balance?

A) Autoregulation stabilizes GFR; GT balance adjusts reabsorption

B) Autoregulation empties bladder; GT balance controls sphincter

C) Autoregulation raises proteins; GT balance lowers GFR

D) Autoregulation secretes EPO; GT balance activates vitamin D

A patient has low renal arterial pressure. Macula densa signaling increases renin release, ultimately helping preserve GFR. Which sequence best explains this response?

A) Renin; angiotensin I; angiotensin II

B) Renin; aldosterone; prostaglandin E

C) Endothelin; renin; nitric oxide

D) ADH; angiotensinogen; calcitriol

Renin released from juxtaglomerular cells functions primarily as which type of molecule?

A) Steroid hormone

B) Plasma protein buffer

C) Enzyme

D) Membrane channel

Angiotensin II helps return GFR toward normal during reduced renal perfusion by primarily constricting which vessel?

A) Afferent arteriole

B) Efferent arteriole

C) Cortical collecting duct

D) Renal vein

A patient with decreased renal perfusion relies on angiotensin II to maintain filtration. Which paired effect best describes angiotensin II at the glomerulus?

A) Efferent dilation; lower PG

B) Afferent dilation; higher PB

C) Efferent constriction; higher PG

D) Afferent constriction; higher πB

A patient with bilateral renal artery stenosis is started on an ACE inhibitor and develops acute kidney injury. What mechanism best explains the fall in GFR?

A) Loss of efferent constriction

B) Increased afferent constriction

C) Increased Bowman pressure

D) Excess podocyte contraction

Why can ACE inhibitors cause larger-than-usual GFR reductions when renal arterial pressure is low?

A) They block angiotensin II formation

B) They increase plasma protein filtration

C) They increase Bowman capsule pressure

D) They activate renal sympathetic nerves

Which drug class can reduce GFR in renal artery stenosis by blocking angiotensin II action?

A) Loop diuretics

B) Beta blockers

C) Angiotensin receptor antagonists

D) Calcium channel blockers

Renal artery stenosis creates hypertension that may depend on angiotensin II–mediated efferent tone. Which treatment complication is especially important?

A) Severe decrease in GFR

B) Increased glomerular bleeding

C) Increased nephron regeneration

D) Severe protein synthesis

A patient with renal artery stenosis develops acute renal failure after RAAS blockade. Which physiologic support was removed?

A) Afferent vasodilation by endothelin

B) Efferent constriction by angiotensin II

C) Bowman pressure by prostaglandins

D) Tubular secretion by aldosterone

A renal arteriole responds to increased arterial pressure by resisting stretch and contracting. What autoregulatory mechanism is this?

A) Glomerulotubular balance

B) Myogenic mechanism

C) Ureterorenal reflex

D) Donnan effect

The myogenic mechanism helps maintain relatively constant renal blood flow and GFR through which vascular property?

A) Resistance to stretching

B) Increased protein filtration

C) Reduced calcium entry

D) Increased tubular secretion

Stretch of renal vascular smooth muscle allows increased entry of which ion, causing contraction?

A) Sodium

B) Potassium

C) Calcium

D) Chloride

Which sequence best describes the renal myogenic response to increased pressure?

A) Stretch; calcium entry; contraction

B) Stretch; sodium exit; relaxation

C) Stretch; renin release; dilation

D) Stretch; protein loss; filtration

A patient begins a high-protein diet. What is the expected effect on renal blood flow and GFR?

A) Both decrease

B) Both increase

C) RBF decreases; GFR increases

D) RBF increases; GFR decreases

A patient develops proximal tubular injury after mercury poisoning. Which tubular transport defect is expected?

A) Increased NaCl reabsorption

B) Decreased NaCl reabsorption

C) Increased albumin filtration

D) Decreased calcium filtration

Large doses of tetracycline damage proximal tubules. Which renal handling change best matches this injury?

A) Decreased sodium chloride reabsorption

B) Increased protein-bound calcium filtration

C) Increased efferent arteriolar resistance

D) Decreased Bowman capsule pressure

Which toxic exposures are specifically associated with proximal tubular damage that decreases NaCl reabsorption?

A) Mercury and tetracyclines

B) Lead and ethanol

C) Arsenic and lithium

D) Cadmium and acetaminophen

The first step in urine production forms a filtrate that is protein-free and lacks red blood cells. What is this fluid called?

A) Peritubular fluid

B) Glomerular filtrate

C) Renal lymph

D) Plasma ultraconcentrate

Which composition best describes normal glomerular filtrate?

A) Protein-rich with erythrocytes

B) Protein-free with salts

C) Fat-rich with leukocytes

D) Albumin-rich with platelets

Which plasma substances are exceptions to free filtration because large portions are protein-bound?

A) Calcium and fatty acids

B) Sodium and chloride

C) Urea and creatinine

D) Glucose and bicarbonate

Minimal change nephropathy causes proteinuria primarily through loss of which barrier property?

A) Negative basement membrane charge

B) Glomerular hydrostatic pressure

C) Bowman capsule pressure

D) Peritubular capillary flow

Minimal change nephropathy is believed to involve abnormal secretion of what factor type?

A) T-cell cytokines

B) B-cell antibodies

C) Platelet thromboxanes

D) Macrophage prostaglandins

Abnormal T-cell cytokines in minimal change nephropathy are thought to reduce which glomerular barrier feature?

A) Anionic charge

B) Hydrostatic pressure

C) Bowman capsule volume

D) Calcium permeability

Why does plasma protein concentration rise across glomerular capillaries?

A) Fluid filters into Bowman capsule

B) Albumin enters Bowman capsule

C) Proteins are secreted by podocytes

D) Sodium leaves through erythrocytes

Which two factors determine glomerular capillary colloid osmotic pressure?

A) Arterial oncotic pressure; filtration fraction

B) Bowman pressure; urine flow

C) ADH level; sodium intake

D) Hematocrit; bladder pressure

Moderate efferent arteriolar constriction raises glomerular hydrostatic pressure. Under what condition can this increase GFR?

A) Bowman pressure rises markedly

B) Renal blood flow is preserved

C) Albumin becomes freely filtered

D) Afferent resistance also rises

Which statement best describes renal medullary perfusion?

A) Medulla receives most renal flow

B) Vasa recta supply medullary flow

C) Glomeruli directly supply medulla

D) Medulla lacks capillary flow

Which disease-state group is associated with increased endothelin release?

A) Pregnancy toxemia; renal failure; uremia

B) Diabetes insipidus; tabes dorsalis; reflux

C) Nephrotic syndrome; cirrhosis; ascites

D) Hypernatremia; burns; diarrhea

Which renal vessels are relatively protected from angiotensin II–mediated vasoconstriction?

A) Preglomerular vessels

B) Efferent arterioles

C) Cortical veins

D) Peritubular capillaries

The afferent arteriole is protected from angiotensin II vasoconstriction partly by increased local release of which vasodilators?

A) Aldosterone and ADH

B) Prostaglandins and nitric oxide

C) Endothelin and norepinephrine

D) Renin and angiotensin I

Which arteriole is especially protected by vasodilators such as prostaglandins and nitric oxide?

A) Afferent arteriole

B) Efferent arteriole

C) Renal vein

D) Ureteral arteriole

A patient has elevated angiotensin II. Which paired renal effect is expected from preferential efferent constriction?

A) Lower GFR; lower reabsorption

B) Higher RBF; lower reabsorption

C) Lower RBF; higher reabsorption

D) Higher RBF; higher GFR

How does angiotensin II increase sodium and water reabsorption?

A) It increases peritubular capillary flow

B) It decreases peritubular capillary flow

C) It blocks proximal sodium transport

D) It raises Bowman capsule pressure

Which set contains renal vasodilators that tend to increase GFR?

A) NO, prostaglandins, bradykinin

B) Endothelin, epinephrine, norepinephrine

C) Angiotensin II, aldosterone, ADH

D) Renin, albumin, creatinine

Tubuloglomerular feedback depends on which two major mechanisms?

A) Afferent and efferent feedback

B) Cortical and medullary reflux

C) Sympathetic and somatic feedback

D) Glomerular and ureteral reflexes

Macula densa cells have Golgi apparatus directed toward arterioles, suggesting which function?

A) Secretion toward arterioles

B) Filtration of plasma proteins

C) Storage of erythropoietin

D) Reabsorption of fatty acids

ACE inhibitors and angiotensin II receptor antagonists can reduce GFR primarily by blocking which support mechanism?

A) Efferent arteriolar constriction

B) Afferent arteriolar dilation

C) Bowman capsule relaxation

D) Medullary osmotic washout

What is the expected GFR effect of ACE inhibitors or angiotensin II receptor blockers, especially when renal perfusion pressure is low?

A) GFR decreases

B) GFR increases

C) GFR becomes unchanged

D) GFR exceeds RPF

The myogenic mechanism of renal autoregulation depends on vascular smooth muscle doing what during increased blood pressure?

A) Resisting stretch by contraction

B) Releasing albumin into filtrate

C) Increasing sodium secretion

D) Relaxing after calcium entry

What is the main protective role of the renal myogenic mechanism during increased blood pressure?

A) Prevents excessive RBF and GFR rise

B) Prevents all sodium filtration

C) Increases bladder emptying

D) Blocks angiotensin II formation

A high-protein meal increases amino acid delivery and renal tubular amino acid reabsorption. What happens to renal blood flow and GFR?

A) Both decrease

B) Both increase

C) RBF increases; GFR decreases

D) RBF decreases; GFR increases

What is the long-term renal adaptation to high protein intake?

A) Kidney growth with higher RBF/GFR

B) Kidney shrinkage with lower RBF/GFR

C) Loss of afferent arteriolar response

D) Complete macula densa suppression

Amino acids are reabsorbed primarily in which nephron segment?

A) Proximal tubule

B) Distal tubule

C) Thin ascending limb

D) Collecting duct

Amino acid reabsorption in the proximal tubule increases sodium reabsorption. How does this affect macula densa NaCl delivery?

A) It decreases NaCl delivery

B) It increases NaCl delivery

C) It has no effect

D) It blocks renin release

Which sequence best explains why high protein intake increases GFR?

A) Amino acid reabsorption; lower macula densa NaCl; afferent dilation

B) Protein filtration; higher Bowman pressure; afferent dilation

C) Amino acid secretion; higher NaCl; efferent dilation

D) Albumin reabsorption; lower renin; GFR increase

Increased blood glucose can increase renal blood flow and GFR through a mechanism similar to amino acids because glucose is reabsorbed where?

A) Proximal tubule

B) Distal tubule

C) Collecting duct

D) Loop thin limb

How does increased glucose reabsorption in the proximal tubule affect macula densa NaCl delivery?

A) Decreases NaCl delivery

B) Increases NaCl delivery

C) Does not affect delivery

D) Completely blocks filtration

A patient with hyperglycemia has increased proximal sodium-glucose reabsorption. Which tubuloglomerular response can follow?

A) Afferent resistance decreases; GFR rises

B) Afferent resistance increases; GFR falls

C) Efferent resistance decreases; GFR falls

D) Bowman pressure increases; GFR falls

Increased blood glucose is expected to have which renal hemodynamic effect?

A) Decreases RBF and GFR

B) Increases RBF and GFR

C) Increases RBF only

D) Decreases GFR only