Urinalysis: Renal Function Flashcards by Dana Powell

What is the functional unit of the kidney?

A. glomerulus
B. renal cortex
C. loop of Henle
D. nephron

D. nephron

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What two types of nephrons do the kidneys contain?

A. renal and cortex
B. medullary and cortical
C. juxtamedullary and cortical
D. none of the above

C. juxtamedullary and cortical

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What type of nephrons make up 85% of nephrons?

A. juxtamedullary
B. cortical
C. renal
D. none of the above

B. cortical

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The type of nephron responsible for renal concentration is the:

A. cortical
B. juxtamedullary

B. juxtamedullary

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The type of nephron responsible for removal of waste products and reabsorption of nutrients is the:

A. cortical
B. juxtamedullary

A. cortical

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What renal functions (s) is/are associated with urine formation?

A. filtration
B. reabsorption and secretion
C. blood flow
D. all of the above

D. all of the above

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Filtration of protein is prevented in the glomerulus by:

A. hydrostatic pressure
B. oncotic pressure
C. renin
D. the glomerular filtration barrier

D. the glomerular filtration barrier

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The _____________ supplies blood to the kidney.

A. peritubular capillaries
B. renal artery
C. renal vein
D. renal pelvis

B. renal artery

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The human kidneys receive approximately _______ of the blood pumped through the heart at all times.

A. 50%
B. 10%
C. 80%
D. 25%

D. 25%

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Blood enters the capillaries of the nephron through the _______________.

A. efferent arteriole
B. renal artery
C. afferent arteriole
D. renal vein

C. afferent arteriole

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After entering the afferent arteriole, blood flows through the ____________ and into the ______________.

A. efferent arteriole; glomerulus
B. glomerulus; renal vein
C. glomerulus; efferent arteriole
D. renal vein; peritubular capillaries

C. glomerulus; efferent arteriole

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The varying sizes of arterioles help to create the ______________ important for glomerular filtration and to maintain consistency of glomerular capillary pressure and renal blood flow within the glomerulus.

A. hydrostatic pressure differential
B. oncotic pressure
C. osmotic gradient
D. renal plasma flow

A. hydrostatic pressure differential

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The smaller size of the efferent arteriole increases the _______________.

A. renal plasma flow
B. glomerular capillary pressure
C. filtration barrier
D. none of the above

B. glomerular capillary pressure

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Before returning to the renal vein, blood from the efferent arteriole enters the ______________ and ___________ and flows slowly through the cortex and medulla of the kidney close to the tubules.

A. glomerulus; afferent arteriole
B. loops of Henle, distal convoluted tubule
C. loops of Henle; vasa recta
D. peritubular capillaries; vasa recta

D. peritubular capillaries; vasa recta

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The peritubular capillaries surround the ______________ and ____________.

A. vasa recta; loops of Henle
B. loops of Henle, distal convoluted tubules
C. proximal and distal convoluted tubules
D. proximal convoluted tubules and collecting ducts

C. proximal and distal convoluted tubules

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The _________________ provides for the immediate reabsorption of essential substances from the fluid in the proximal convoluted tubule and final adjustment of the urinary composition in the distal convoluted tubule.

A. renal artery
B. renal vein
C. loops of Henle
D. peritubular capillaries

D. peritubular capillaries

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The peritubular capillaries provide for the immediate reabsorption of essential substances from the fluid in the ________________and final adjustment of the urinary composition in the ________________.

A. proximal convoluted tubule; distal convoluted tubule
B. renal artery; renal vein
C. proximal convoluted tubule; collecting duct
D. afferent arteriole; efferent arteriole

A. proximal convoluted tubule; distal convoluted tubule

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The function of the peritubular capillaries is:

A. reabsorption
B. filtration
C. secretion
D. Both A and C

D. both A and C

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Blood flows through the nephron in the following order:

A. efferent arteriole, peritubular capillaries, vasa recta, afferent arteriole
B. peritubular capillaries, afferent arteriole, vasa recta, efferent arteriole
C. afferent arteriole, peritubular capillaries, vas recta, efferent arteriole
D. efferent arteriole, vasa recta, peritubular capillaries, afferent arteriole

C. afferent arteriole, peritubular capillaries, vas recta, efferent arteriole

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The ______________ are located adjacent to the ascending and descending loops of Henle in juxtamedullary nephrons.

A. vasa recta
B. efferent arterioles
C. afferent arterioles
D. peritubular capillaries

A. vasa recta

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In what area of the nephron do the major exchanges of water and salts take place between the blood and the medullary interstitium?

A. cortical nephrons
B. juxtamedullary nephrons
C. peritubular capillaries
D. loops of Henle

D. loops of Henle

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The exchange of water and salts in the nephron maintains the _____________ in the medulla, which is necessary for renal concentration.

A. renal plasma flow
B. osmotic gradient
C. oncotic pressure
D. filtration barrier

B. osmotic gradient (salt concentration)

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Based on the average body size of 1.73 m^2 of surface, the total renal blood flow is approximately ______________, and the total renal plasma flow ranges from ________ to _________.

A. 1700 mL/min; 340 to 600 mL/min
B. 1200 mL/min; 900-1200 mL/min
C. 1200 mL/min; 600-700 mL/min
D. 1200 mL/min; 1200-1700 mL/min

C. 1200 mL/min; 600-700 mL/min

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Normal values for renal blood flow and renal function tests depend on _________.

A. age
B. weight
C. body size
D. none of the above

C. body size

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The glomerulus consists of a coil of approximately 8 capillary lobes, the walls of which are referred to as the _________________. A. glomerular filtration barrier B. plasma filtrate C. juxtaglomerular apparatus D. RAAS

A. glomerular filtration barrier

The glomerulus is located within ___________, which forms the beginning of the renal tubule. A. juxtaglomerular apparatus B. Bowman's capsule C. filtration barrier D. renal medulla

B. Bowman's capsule

What is the main function of the glomerulus? A. supply blood flow to the renal artery B. non-selective filter of plasma substances <70,000 MW C. non-selective filter of plasma substances >70,000 MW D. none of the above

B. non-selective filter of plasma substances <70,000 MW

What factors affect the filtration process in the glomerulus? A. the cellular structure of the capillary walls and bowman's capsule B. hydrostatic pressure and oncotic pressure C. feedback mechanism of the RAAS D. all of the above

D. all of the above

Plasma filtrate must pass through three glomerular filtration barrier cellular layers. Name them.

the capillary wall membrane, the basement membrane (basal lamina), and the visceral epithelium of Bowman's capsule

Cellular structure of the glomerulus: The endothelial cells of the capillary wall differ from those in other capillaries by containing ____________. A. pores B. fissures C. arterioles D. none of the above

A. pores

Cellular structure of the glomerulus: Capillaries containing pores are referred to as: A. peritubular capillaries B. fenestrated capillaries C. closed capillaries D. open capillaries

B. fenestrated capillaries

Cellular structure of the glomerulus: Fenestrated capillaries increased ____________ but do not allow passage of ______________ and _______________.

1. capillary permeability 2. large molecules 3. blood cells

Filtration of protein is prevented in the glomerulus by: A. hydrostatic pressure B. oncotic pressure C. renin D. glomerular filtration barrier

D. glomerular filtration barrier

Cellular structure of the glomerulus: Further restriction of large molecules occurs as the filtrate passes through the ________________ and the ____________ covering the filtration slits formed by the intertwining foot processes of the ______________ of the inner layer of Bowman's capsule.

1. basement membrane 2. thin membranes 3. podocytes

Cellular structure of the glomerulus: In addition to the structure of the glomerular filtration barrier that prohibits the filtration of large molecules, the barrier contains a ____________________ that repels molecules with a positive charge even though they are small enough to pass through the 3 layers of the barrier. A. shield of negativity B. shield of positivity C. shield of RAAS D. none of the above

A. shield of negativity

If it were not for the shield of negativity, all routine urines would have positive reagent strip readings for ____________. A. blood B. leukocytes C. protein/albumin D. all of the above

C. protein/albumin Albumin has a positive charge and would easily pass through the barrier

What is the primary protein associated with renal disease? A. microalbumin B. albumin C. all of the above D. none of the above

B. albumin

The presence of _____________ resulting from the smaller size of the efferent arteriole and the glomerular capillaries enhances filtration. A. oncotic pressure B. renin C. hydrostatic pressure D. shield of negativity

C. hydrostatic pressure

By increasing or decreasing the size of the afferent and efferent arterioles, an autoregulatory mechanism with the _________________ maintains the glomerular blood pressure at a relatively constant rate regardless of fluctuations in systemic blood pressure. A. shield of negativity B. glomerulus C. medulla D. juxtaglomerular apparatus

D. juxtaglomerular apparatus

_________ of the afferent arterioles and ________ of the efferent arterioles when blood pressure drops prevents a marked decrease in blood flowing through the kidney, thus preventing an increase in the blood level of toxic waste products. A. dilation; dilation B. dilation; constriction C. constriction; dilation D. constriction; constriction

B. dilation; constriction

An increase in blood pressure results in ___________ of the afferent arterioles to prevent overfiltration or damage to the glomerulus. A. constriction B. dilation

A. constriction

_____________ regulates the flow of blood to and within the glomerulus. A. juxtaglomerular apparatus B. macula densa C. hydrostatic pressure D. renin-angiotensin-aldosterone system

D. renin-angiotensin-aldosterone system

The RAAS responds to changes in ___________ and ______________ that are monitored by the ______________.

1. blood pressure 2. plasma sodium content 3. juxtaglomerular apparatus

The juxtaglomerular apparatus consists of the juxtaglomerular cells in the ______________ and the __________ of the ______________.

1. afferent arteriole 2. macula densa 3. distal convoluted tubule

Low plasma _________ content __________ water retention within the circulatory system, resulting in a _______ overall blood volume and subsequent ________ in blood pressure. What senses these changes?

1. sodium 2. decreases 3. decreased 4. decrease 5. macula densa of the DCT

The renin-angiotensin-aldosterone system is responsible for all of the following except: A. vasoconstriction of the afferent arteriole B. vasoconstriction of the efferent arteriole C. reabsorbing of sodium D. releasing aldosterone

A. vasoconstriction of the afferent arteriole

The primary chemical affected by the renin-angiotensin-aldosterone system is: A. chloride B. sodium C. potassium D. hydrogen

B. sodium

Secretion of renin is stimulated by: A. juxtaglomerular cells B. angiotensin I and II C. macula densa cells D. circulating angiotensin-converting enzyme

C. macula densa cells

When the macula densa senses changes in blood flow to and within the glomerulus, what enzyme is produced by the juxtaglomerular cells? A. aldosterone B. renin C. angiotensin D. all of the above

B. renin

What enzyme reacts with the blood-borne substrate angiotensin to produce angiotensin I? A. aldosterone B. angiotensin C. renin D. none of the above

C. renin

As angiotensin I passes through the alveoli of the lungs, ______________ changes it to the active form angiotensin II. A. aldosterone B. renin C. angiotensin-converting enzyme (ACE) D. none of the above

C. angiotensin-converting enzyme (ACE)

How does angiotensin II correct renal blood flow? A. causes vasodilation of the afferent arterioles B. stimulates reabsorption of sodium and water in the PCT C. triggering the release of the sodium-retaining hormone aldosterone by the adrenal cortex and ADH by the hypothalamus D. all of the above

D. all of the above

As the systemic blood pressure and plasma sodium content increase, the secretion of renin ___________. A. increases B. decreases C. remains the same

B. decreases

Analysis of the fluid as it leaves the glomerulus shows the filtrate to have a specific gravity of ____________. A. 1.010 B. 1.035 C. 1.000 D. 1.024

A. 1.010

As a result of the glomerular mechanisms, every minute approximately 2-3 million glomeruli filter approximately ___________ of water-containing low-molecular-weight substances. A. 300 mL B. 240 mL C. 100 mL D. 120 mL

D. 120 mL

When the plasma ultrafiltrate enters the proximal convoluted tubule, the nephrons, through cellular transport mechanisms, begins ____________ essential substances and water. A. secreting B. reabsorbing C. filtering D. transporting

B. reabsorbing

The cellular mechanisms involved in tubular reabsorption are termed _______________ and ___________.

active transport and passive transport

The hormone aldosterone is responsible for: A. hydrogen ion secretion B. potassium secretion C. chloride retention D. sodium retention

D. sodium retention

The fluid leaving the glomerulus has a specific gravity of: A. 1.005 B. 1.010 C. 1.015 D. 1.020

B. 1.010

For active transport to occur, a chemical: A. must combine with a carrier protein to create electrochemical energy B. must be filtered through the proximal convoluted tubule C. must be in higher concentration in the filtrate than in the blood D. must be in higher concentration in the blood than the filtrate

A. must combine with a carrier protein to create electrochemical energy

What is active transport responsible for the reabsorption of in the proximal convoluted tubule?

glucose, amino acids, and salts

What is active transport responsible for the reabsorption of in the ascending loop of Henle?

chloride

What is active transport responsible for the absorption of in the proximal and distal convoluted tubules?

sodium

____________ is the movement of molecules across a membrane as a result of differences in their concentration or electrical potential on opposite sides of the membrane (gradients). A. active transport B. passive transport C. filtration D. reabsorption

B. passive transport

Passive reabsorption of water takes place in all parts of the nephron except the ______________, the walls of which are impermeable to water. A. proximal convoluted tubule B. collecting duct C. ascending loop of Henle D. descending loop of Henle

C. ascending loop of Henle

Which of the tubules is impermeable to water? A. proximal convoluted tubule B. descending loop of Henle C. ascending loop of Henle D. distal convoluted tubule

C. ascending loop of Henle

Where is urea passively reabsorbed? A. proximal convoluted tubule B. descending loop of Henle C. ascending loop of Henle D. both A and C

D. both A and C

Passive reabsorption of sodium accompanies the active transport of _______________ in the ascending loop of Henle. A. chloride B. water C. urea D. glucose

A. chloride

The plasma concentration at which active transport stops is termed ____________. A. countercurrent mechanism B. renal threshold C. electrochemical energy D. none of the above

B. renal threshold

What is the plasma renal threshold for glucose? A. 200-250 mg/dL B. 50-60 mg/dL C. 100-200 mg/dL D. 160-180 mg/dL

D. 160-180 mg/dL

Where does the passive transport of water occur in the nephron?

1. proximal convoluted tubule 2. descending loop of Henle 3. collecting duct

Where does the passive transport of urea occur in the nephron?

1. proximal convoluted tubule 2. ascending loop of Henle

Where does the passive transport of sodium occur in the neprhon?

ascending loop of Henle

Glucose will appear in the urine when the: A. blood level of glucose is 200 mg/dL B. Tm for glucose is reached C. renal threshold for glucose is exceeded D. all of the above

D. all of the above

Glucose appearing in the urine of a person with a normal blood glucose level is the result of _______________. A. tubular damage B. excess solute filtration

A. tubular damage

Glucose appearing the urine of a person with a high blood glucose level is the result of ______________. A. tubular damage B. excess solute filtration

B. excess solute filtration

Renal concentration begins in the ____________, where the filtrate is exposed to the ____________ of the renal medulla.

1. descending loop of Henle 2. ascending loop of Henle

Tubular concentration: Water is removed by ____________ in the descending loop of Henle, and _____________ are reabsorbed in the ascending loop.

1. osmosis 2. sodium and chloride

Excessive reabsorption of water as the filtrate passes through the highly concentrated medulla is prevented by the water-permeable walls of the ascending loop. The selective reabsorption process is called the __________. A. renal threshold B. maximal reabsorptive capacity C. countercurrent mechanism D. collecting duct

C. countercurrent mechanism

Concentration of the tubular filtrate by the countercurrent mechanism depends on all of the following except: A. high salt concentration in the medulla B. water-impermeable walls of the ascending loop of Henle C. reabsorption of sodium and chloride from the ascending loop of Henle D. reabsorption of water in the descending loop of Henle

D. reabsorption of water in the descending loop of Henle

The countercurrent mechanism serves to maintain the _______________ of the medulla. A. renal threshold B. osmotic gradient C. oncotic pressure D. none of the above

B. osmotic gradient

The _______ and ________ leaving the filtrate in the ascending loop prevent dilution of the medullary interstitium by the water reabsorbed from the descending loop. A. sodium, glucose B. sodium, potassium C. sodium, chloride D. sodium, water

C. sodium, chloride

The actual concentration of the filtrate leaving the ascending loop is quite low owing to the reabsorption of salt and not water in that part of the tubule. Reabsorption of sodium continues in the distal convoluted tubule, but it is now under the control of ____________, which regulates reabsorption in response to the body's need for sodium. A. ADH B. glucose C. renin D. aldosterone

D. aldosterone

The final concentration of the filtrate through the reabsorption of ___________ begins in the ______________ and continues in the ______________.

1. water 2. late distal convoluted tubule 3. collecting duct

ADH regulates the final urine concentration by controlling: A. active reabsorption of sodium B. tubular permeability C. passive reabsorption of urea D. passive reabsorption of chloride

B. tubular permeability

Decreased production of ADH: A. produces a low urine volume B. produces a high urine volume C. increases ammonia excretion D. affects active transport of sodium

B. produces a high urine volume

A high level of ADH _________ permeability, resulting in _________ reabsorption of water, and a ___________ urine.

1. increased 2. increased 3. low-volume concentrated

Absence of ADH renders the walls ____________ to water, resulting in a _________ volume of dilute urine.

1. impermeable 2. large

Just as the production of aldosterone is controlled by the body's sodium concentration, production of ADH is determined by the state of _____________. A. body hydration B. chloride concentration C. glucose concentration D. none of the above

A. body hydration

______________ involves the passage of substances from the blood in the peritubular capillaries to the tubular filtrate. A. tubular reabsorption B. tubular secretion C. renal blood flow D. none of the above

B. tubular secretion

What are the functions of tubular secretion? A. eliminating waste products not filtered by the glomerulus B. regulating the acid base balance in the body through secretion of hydrogen ions C. removes substances from the filtrate and returns them back to the blood D. both A and B

D. both A and B

Why can't many foreign substances (such as medications) be removed by the glomerulus? A. they are too big B. they are too small C. they are bound to plasma proteins D. they are not bound to plasma proteins

C. they are bound to plasma proteins

When protein-bound foreign substances enter the peritubular capillaries, they develop a stronger affinity for the ___________ and dissociate from their carrier proteins, which results in their transport into the filtrate by the tubular cells. A. vasa recta cells B. peritubular cells C. hydrogen ions D. none of the above

B. peritubular cells

What is the major site of removal for nonfiltered foreign substances, such as medications? A. distal convoluted tubule B. collecting duct C. loop of Henle D. proximal convoluted tubule

D. proximal convoluted tubule

The buffering capacity of the blood depends on ___________, which is readily filtered by the glomerulus and must be expediently returned to the blood to maintain the proper pH. A. hydrogen ions B. ammonia C. bicarbonate D. none of the above

C. bicarbonate

Bicarbonate ions filtered by the glomerulus are returned to the blood: A. in the proximal convoluted tubule B. combined with hydrogen ions C. by tubular secretion D. all of the above

D. all of the above

The secretion of ____________ by the renal tubular cells into the filtrate prevents the filtered bicarbonate from being excreted in the urine and causes the return of bicarbonate ion to the plasma. A. hydrogen ions B. ammonia C. chloride D. carbonic anhydrase

A. hydrogen ions

Where is almost 100% of filtered bicarbonate reabsorbed? A. distal convoluted tubule B. collecting duct C. proximal convoluted tubule D. loop of Henle

C. proximal convoluted tubule

As a result of their small molecular size, hydrogen ions are readily filtered and reabsorbed. Therefore, the actual excretion of excess hydrogen ions depends on ______________. A. tubular reabsorption B. tubular secretion C. renal blood flow D. none of the above

B. tubular secretion

What is/are the primary method(s) for hydrogen ion excretion in urine? A. the secreted hydrogen ion combines with a filtered phosphate ion and is excreted rather than reabsorbed B. in the PCT, ammonia is produced from the breakdown of amino acid glutamine; the ammonia reacts with the hydrogen ion to form ammonium ion, which is then excreted in urine C. hydrogen ion combines with bicarbonate and is excreted in the urine D. both A and B

D. both A and B

The inability to produce acid urine

metabolic acidosis or renal tubular acidosis

If ammonia is not produced by the distal convoluted tubule, the urine pH will be: A. acidic B. basic

B. basic

beta2-microglobulin A. exogenous B. endogenous

B. endogenous

creatinine A. exogenous B. endogenous

B. endogenous

A ____________ test measures the rate at which the kidneys are able to remove a filterable substance from the blood. A. cystatin C B. beta2-microglobulin C. clearance D. none of the above

C. clearance

A test that requires an infused substance is termed an __________ procedure. A. exogenous B. endogenous

A. exogenous

A test that uses a substance already present in the body is termed an ____________ procedure. A. exogenous B. endogenous

B. endogenous

cystatin C A. exogenous B. endogenous

A. exogenous

125I-iothalamate A. exogenous B. endogenous

A. exogenous

_____________ is a waste product of muscle metabolism that is produced enzymatically by creatinine phosphokinase from creatine, which links with ATP to produce ADP and energy. A. creatinine B. microglobulin C. cystatin C D. none of the above

A. creatinine

Some creatinine is secreted by the tubules, and secretion _________ as blood levels rise.

increases

__________ present in human plasma react in the chemical analysis (creatinine clearance) and may help counteract the falsely elevated rates cause by tubular secretion.

chromogens

How do medications cause falsely low serum creatinine levels?

by inhibiting tubular secretion of creatinine

What happens to urinary creatinine if specimens are kept at room temperature for extended periods?

bacteria break it down

Why will a diet heavy in meat consumed during collection of a 24 hour urine specimen influence the results if the plasma specimen is drawn before the collection period?

because the increased intake of meat can raise the urine and plasma levels of creatinine during the 24 hour collection period

In what conditions would creatinine clearance be an unreliable indicator? A. muscle-wasting disease B. lupus C. persons involved in heavy exercise D. athletes supplementing with creatine E. A, C, and D

E. A, C, and D

The largest source of error in creatinine clearance tests is: A. secretion of creatinine B. improperly timed urine specimens C. refrigeration of urine D. time of collecting blood sample

B. improperly timed urine specimens

Given the following information, calculate the creatinine clearance: 24-hour urine volume: 1000 mL serum creatinine: 2.0 mg/dL urine creatinine: 200 mg/dL

69 mL/min Calculate volume (V) in mL/min: 24 hours x 60 minutes = 1440 minutes 1000 mL/1440 minutes = 0.69 mL/min Calculate creatinine clearance: C = UV/P C = (200 mg/dL x 0.69 mL/min)/2.0 mg/dL C = 138/2.0 = 69 mL/min

Clearance tests used to determine GFR must measure substances that are: A. not filtered by the glomerulus B. completely reabsorbed by the PCT C. secreted in the DCT D. neither reabsorbed or secreted by the tubules

D. neither reabsorbed or secreted by the tubules

Performing a clearance test using radionucleotides: A. eliminates the need to collect urine B. does not require an infusion C. provides visualization of the filtration D. Both A and C

D. Both A and C

What is the normal reference range of plasma creatinine? A. 1.0-2.0 mg/dL B. 0.5-1.5 mg/dL C. 1.5-2.0 mg/dL D. 0.5-0.9 mg/dL

B. 0.5-1.5 mg/dL

What is the formula for creatinine clearance when body sizes greatly deviate from 1.73 m^2 of surface area, such as with children?

The most frequently used formula for eGFR is called the ____________________ study.

Modification of Diet in Renal Disease (MDRD)

At the present time the formula for eGFR recommended by the NKDEP is called the _____________ formula.

MDRD-IDMS-traceable formula

Variables that are included in the MDRD-IDSM estimated creatinine calculations include all of the following except: A. serum creatinine B. weight C. age D. gender

B. weight

_________ is a small protein produced at a constant rate by all nucleated cells and whose measurement has been shown to provide a good procedure for screening and monitoring GFR. A. beta2-microgobulin B. creatinine C. cystatin C D. none of the above

C. cystatin C

Monitoring levels of cystatin C is recommended for which type of patients? A. pediatric and elderly patients B. persons with diabetes C. critically ill patients D. all of the above

D. all of the above

An advantage of using cystatin C to monitor GFR is that: A. it does not require urine collection B. it is not secreted by the tubules C. it can be measured by immunoassay D. all of the above

D. all of the above

An advantage of cystatin C is that it is independent of ___________.

muscle mass

___________ dissociates from human leukocyte antigens at a constant rate and is rapidly removed from the plasma by glomerular filtration. A. beta2-microglobulin B. radionucleotides C. cystatin C D. none of the above

A. beta2-microglobulin

A rise in plasma level of ______________ has been shown to be a more sensitive indicator of a decrease in GFR than creatinine clearance. A. radionucleotides B. cystatin C C. creatine D. beta2-microglobulin

D. beta2-microglobulin

The beta2-microglobulin test is not reliable in patients who have a history of ____________ or ___________.

1. immunologic disorders 2. malignancy

Although they are exogenous procedures and more labor intensive and costly, injecting radionucleotides such as 125-I-iothalamate provides a method for determining GFR and enables ____________________ of the filtration in one or both kidneys.

visualization

Although the GFR is a frequently requested laboratory procedure, its value does not lie in the detection of early renal disease. What is it used to determine instead? A. extent of nephron damage in known cases of renal disease B. to monitor effectiveness of treatment designed to prevent further nephron damage C. to determine the feasibility of administering medications, which can build up to dangerous blood levels if the GFR is markedly reduced D. all of the above

D. all of the above

What is often the first function affected in renal disease? A. tubular secretion B. GFR C. tubular reabsorption D. all of the above

C. tubular reabsorption

Tests to determine the ability of the tubules to reabsorb the essential salts and water that have been nonselectively filtered by the glomerulus are called ____________.

concentration tests

A urine osmolality reading of ____________ or higher is normal. A. 1200 mOsm B. 2000 mOsm C. 200 mOsm D. 800 mOsm

D. 800 mOsm

A urine to serum ratio of __________ or greater indicates normal tubular reabsorption. A. 2:1 B. 3:1 C. 4:1 D. 1:1

B. 3:1

Neurogenic vs. Nephrogenic diabetes insipidus: A patient has an abnormal urine osmolality, after fluid is further restricted, the urine osmolality is still abnormal. The patient is then injected with ADH. What is indicated if the urine osmolality test is now normal?

indicates the patient is not able to produce ADH (neurogenic diabetes insipidus)

indicates the renal tubules are not responding to ADH (nephrogenic diabetes insipidus)

____________ measures only the number of particles in a solution, whereas ____________ is influenced by the number and density of the particles.

1. osmolality 2. specific gravity

Renal concentration is concerned with small particles, particularly ________ and _______.

sodium and chloride

Solute dissolved in solvent will: A. raise the vapor pressure B. lower the boiling point C. decrease the osmotic pressure D. lower the freezing point

D. lower the freezing point

Substances that may interfere with freezing point measurement of urine and serum osmolality include all of the following except: A. ethanol B. lactic acid C. sodium D. lipids

C. sodium

Reference serum osmolality values are from ______ to ________ mOsm.

275 to 300 mOsm

Under normal random conditions, the ratio of urine to serum osmolality should be at least ______; after fluid intake, it should reach _____.

1. 1:1 2. 3:1

The ratio of urine to serum osmolality, in conjunction with procedures such as controlled fluid intake and injection of ADH, is used to differentiate whether diabetes insipidus is caused by ___________________ or ________________.

1. decreased ADH production (neurogenic) 2. inability of the renal tubules to respond to ADH (nephrogenic)

Clinical osmometers use NaCl as a reference solution because: A. 1 g molecular weight of NaCl will lower the freezing point 1.86*C B. NaCl is readily frozen C. NaCl is partially ionized similar to the composition of urine D. 1 g equivalent weight of NaCl will raise the freezing point 1.86*C

C. NaCl is partially ionized similar to the composition of urine

The normal serum osmolarity is: A. 50 to 100 mOsm B. 275 to 300 mOsm C. 400 to 500 mOsm D. 3 time the urine osmolarity

B. 275 to 300 mOsm

After a controlled fluid intake, the urine-to-serum osmolarity ratio should be at least: A. 1:1 B. 2:1 C. 3:1 D. 4:1

C. 3:1

Formula for free water clearance

First calculate the osmolar clearance: Cosm = (Uosm x V)/Posm and then subtracting the osmolar clearance value from the urine volume in mL/min.

Using a urine osmolality of 600 mOsm (U), a urine volume of 2 mL/min (V), and a plasma osmolality of 300 mOsm (P), calculate the free water clearance.

Cosm = (600 x 2)/(300) = 4.0 mL/min Ch20 = 2 - 4.0 = -2.0 (free water clearance) indicates that less than the necessary amount of water is being excreted, a possible state of dehydration

Calculate the free water clearance from the following results: Urine volume in 6 hours: 720 mL Urine osmolarity: 225 mOsm Plasma osmolarity: 300 mOsm

1. calculate urine volume in mL/min 6 hours x 60 minutes = 360 minutes 720/360 = 2 mL/min 2. Cosm = (225 x 2)/300 = 1.5 mL/min 3. CH20 = 2 - 1.5 = 0.5 (free water clearance) excess water has been secreted

What test is most commonly associated with tubular secretion and renal blood flow? A. creatinine clearance B. freezing point depression C. osmolality D. p- aminohippuric acid (PAH)

D. p- aminohippuric acid (PAH)

To provide an accurate measure of renal blood flow, a test substance should be completely: A. filtered by the glomerulus B. reabsorbed by the tubules C. secreted when it reaches the distal convoluted tubule D. completely removed from the blood each time it comes in contact with functional renal tissue

D. completely removed from the blood each time it comes in contact with functional renal tissue

PAH is A. exogenous B. endogenous

A. exogenous

PAH test formula

Cpah (mL/min) = (U x V)/P U: mg/dL PAH V: mL/min urine P: mg/dL PAH

Given the following data, calculate the effective renal plasma flow: urine volume in 2 hours: 240 mL urine PAH: 150 mg/dL plasma PAH: 0.5 mg/dL

1. calculate the urine volume in mL/min 60 min x 2 hours = 120 minutes 240 mL / 120 minutes = 2 mL/min 2. Cpah (mL/min) = (150 x 2)/0.5 = 600 mL/min

The ability of the kidney to produce an acid urine depends on the tubular secretion of ___________ and the production and secretion of ______________ by the cells of the distal convoluted tubule.

1. hydrogen ions 2. ammonia

The inability to produce an acid urine in the presence of metabolic acidosis is called _______________.

renal tubular acidosis

Renal tubular acidosis can be caused by the: A. production of excessively acidic urine due to increased filtration of hydrogen ions B. production of excessively acidic urine due to increased secretion of hydrogen ions C. inability to produce an acidic urine due to impaired production of ammonia D. inability to produce an acidic urine due to increased production of ammonia

C. inability to produce an acidic urine due to impaired production of ammonia

Tests performed to detect renal tubular acidosis after administering an ammonium chloride load include all of the following except: A. urine ammonia B. arterial pH C. urine pH D. titratable acidity

B. arterial pH

Urinalysis: Renal Function Flashcards

(163 cards)