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WorksheetsKidney Functions Overview
Total questions: 74
Worksheet time: 37mins
Which role best describes how kidneys maintain blood pH homeostasis?
Excreting or conserving hydrogen ions
Secreting glucose into the filtrate
Raising plasma calcium by bone resorption
Increasing bicarbonate production in lungs
Match each kidney function to its description.
Water and electrolyte control
Adjusting body fluid osmolarity
Nutrient conservation
Reabsorbing valuable solutes
Nitrogen waste removal
Excreting urea and creatinine
Hormone production
Making renin and erythropoietin
Which set lists hormones or mediators produced by the kidneys?
Renin, erythropoietin, prostaglandins
Insulin, glucagon, somatostatin
Aldosterone, adrenaline, cortisol
Thyroxine, calcitonin, parathyroid hormone
A patient shows dehydration with hypernatremia. Which kidney function is most directly responsible for correcting this disturbance?
Water and electrolyte balance regulation
Removal of nitrogen end products
Hydrogen ion excretion for pH
Gluconeogenesis during fasting
Which event most directly triggers renin release in the kidney as shown in the diagram?
Decreased renal perfusion at the juxtaglomerular apparatus
Increased sodium delivery to the distal nephron
Rise in circulating aldosterone from the adrenal cortex
Enhanced pulmonary ACE expression in endothelial cells
Elevated plasma osmolarity sensed by hypothalamic osmoreceptors
Where does conversion of angiotensin I to angiotensin II primarily occur according to the pathway shown?
On pulmonary and renal endothelial surfaces expressing ACE
Within hepatocytes during angiotensinogen synthesis
Inside adrenal cortical cells during steroidogenesis
In the posterior pituitary before ADH secretion
In the proximal tubule brush border of the nephron
Match each RAAS component to its direct effect indicated in the diagram.
Angiotensin II
Arteriolar vasoconstriction raising blood pressure
Aldosterone
Tubular Na+ and Cl− reabsorption with K+ secretion
ADH (vasopressin)
Collecting duct water reabsorption
Sympathetic activity
Stimulation of renin release and effector pathways
Which combination of effects increases effective circulating volume in the pathway?
Arteriolar vasoconstriction
Tubular NaCl reabsorption
Collecting duct water retention
Inhibition of renin secretion
Decreased aldosterone release
Which statement best describes aldosterone’s role in the pathway?
It promotes Na+ and Cl− reabsorption while enhancing K+ excretion
It causes generalized vasodilation in peripheral arterioles
It directly converts angiotensinogen to angiotensin I
It suppresses ADH release from the posterior pituitary
It is produced by the lung endothelium alongside ACE
A patient receives an ACE inhibitor. Which immediate pathway change is expected?
Reduced angiotensin II formation from angiotensin I
Increased aldosterone-mediated potassium excretion
Enhanced ADH release from the posterior pituitary
Greater conversion of angiotensinogen in the liver
Stimulated renin suppression by negative feedback
Which arrowed sequence correctly traces the early RAAS steps shown?
Decreased renal perfusion → renin release → angiotensin I
Sympathetic surge → aldosterone secretion → angiotensinogen
Pulmonary ACE → angiotensinogen synthesis → renin release
ADH secretion → arteriolar dilation → increased perfusion
Aldosterone rise → renin inhibition → angiotensin II fall
Which laboratory analyte is a primary chemistry test used to assess kidney function?
Urea nitrogen concentration
Serum amylase activity
Plasma lactate level
C-reactive protein
Serum lipase activity
Match each test with what it primarily helps evaluate in renal assessment.
Urea nitrogen
Nitrogenous waste handling
Creatinine
Muscle metabolite clearance
Glomerular filtration rate assays
Rate and efficiency of filtration
Which combination best represents the core chemistry tests for evaluating renal status?
Urea nitrogen and creatinine
Creatinine and GFR assays
Serum lipase and amylase
Urea nitrogen plus GFR assays
CRP and plasma lactate
Which statement best describes urea in human physiology?
Principal end product of amino acid breakdown
Primary intermediate in fatty acid oxidation pathways
Major storage form of amino acids in muscle tissue
Main nitrogen transporter synthesized by erythrocytes
Under normal renal handling, what happens to filtered urea in the nephron?
All filtered then about half reabsorbed
Mostly unfiltered then fully secreted
Fully retained then minimally excreted
Not filtered then completely reabsorbed
If kidney function is impaired, how do BUN levels typically change and why?
Increase because less urea is removed
Decrease because more urea is synthesized
Stay unchanged because urea is insoluble
Fluctuate due to constant tubular secretion
Which factor can artifactually decrease measured BUN in a collected sample?
Urease-producing bacterial contamination
Hemolysis during venipuncture technique
Lipemia from a recent fatty meal
Exposure to ambient room temperature
Best practice to prevent urease-related BUN errors after collection is to:
Analyze within one hour or refrigerate
Vigorously mix to lyse erythrocytes
Freeze immediately at minus eighty
Add acid to denature bacterial enzymes
Which testing approach is recommended only as a screening method for BUN?
Chromatographic dipstick such as Azostix
Enzymatic photometric rate assay
Kinetic Jaffe spectrophotometric method
Isotope dilution mass spectrometry
Which statement about urea solubility and excretion is accurate?
Urea requires high water volume for excretion
Urea is highly soluble and excreted without water
Urea precipitates in plasma and is dialyzed poorly
Urea is lipid soluble and excreted in bile
Dehydration affects BUN primarily by:
Increasing retention of urea causing azotemia
Enhancing renal perfusion and urea clearance
Reducing tubular reabsorption of filtered urea
Lowering protein catabolism and urea generation
Which scenario most likely elevates BUN via increased amino acid availability?
High-protein diet intake over several days
Strict vegan diet with low protein content
High-carbohydrate diet with low nitrogen load
Ketogenic diet devoid of amino acid catabolism
Strenuous physical activity can raise BUN because it:
Accelerates amino acid breakdown in tissues
Decreases hepatic conversion of ammonia
Eliminates urea through sweat excessively
Increases renal secretion of urea directly
Match each cause with its primary effect on BUN measurement or physiology.
Urease-producing bacteria in sample
Decreases measured BUN artifactually
Dehydration state in the patient
Increases retention leading to azotemia
High-protein dietary intake
Raises BUN from more amino acids
Chromatographic Azostix dipstick
Used only for screening evaluation
Renal dysfunction impairing excretion
Elevates BUN due to poor clearance
Which combination of factors would most likely produce a falsely low BUN result in vitro?
Delay before analysis at room temperature
Contamination with urease-positive bacteria
Immediate refrigeration after collection
Use of Azostix strictly as a screen
Prompt analysis within one hour
Which statements about BUN testing methods are correct?
Photometric assays are widely used in laboratories
Chromatographic dipsticks serve as screening tools
Dipsticks replace confirmatory quantitative methods
Photometry measures color change related to urea
Chromatography eliminates need for sample timing
A patient with elevated BUN is most consistently explained by which mechanism?
Reduced renal excretion of filtered urea
Increased urinary secretion of creatinine
Complete reabsorption of tubular urea
Enhanced biliary elimination of nitrogen
Which situation is least likely to cause an increase in BUN?
Low-protein diet sustained for months
Dehydration during a heatwave
Strenuous marathon training period
Persistent kidney dysfunction
Creatinine in blood is primarily formed from which source in the body?
Skeletal muscle creatine stores
Hepatic glycogen reserves
Adipose triglyceride breakdown
Intestinal bacterial proteins
If a person's activity level remains stable over time, what happens to their creatinine production?
It remains relatively constant
It increases dramatically
It fluctuates unpredictably
It drops to near zero
Which statement best describes the relationship between glomerular filtration rate (GFR) and serum creatinine levels?
Reduced GFR tends to raise creatinine
Reduced GFR tends to lower creatinine
Higher GFR makes creatinine unstable
GFR changes do not affect creatinine
Select all accurate statements about serum creatinine as a kidney function indicator.
It is influenced by GFR changes
It is highly sensitive early on
It derives from creatine in muscle
Levels rise only after major damage
In the absence of inflammatory cells, the presence of protein in urine most strongly suggests which pathophysiologic process?
Glomerular disease with filtration barrier injury
Post-renal obstruction causing dilute urine
Hepatic failure reducing urea formation
Endocrine disease altering tubular transport
Which statement best compares the two testing approaches for assessing proteinuria?
Single-sample UP:UC is accurate and comprehensive
Only 24-hour collection is reliable and accurate
Dipstick alone equals a 24-hour collection
Single-sample testing measures urine volume directly
A clinician plans a UP:UC test in a dog. Which collection and handling protocol is most appropriate?
Collect 5–10 ml by cystocentesis midday, centrifuge, use supernatant
Collect any volume by free catch at night, skip centrifugation
Collect 1 ml by catheter at noon, analyze whole urine unspun
Collect 20 ml morning voided sample, refrigerate pellet only
Match each UP:UC ratio range in dogs with the most likely interpretation.
<1
Healthy dog range
1 to 5
Prerenal or functional proteinuria
>5
Renal disease likely
Which scenario most likely reflects prerenal or functional proteinuria in a dog?
UP:UC ratio of 3 with normal sediment
UP:UC ratio of 0.6 with hematuria
UP:UC ratio of 7 with casts present
UP:UC ratio of 1 with marked pyuria
Why is centrifugation and use of the supernatant recommended before UP:UC analysis?
To remove cells that can confound protein measurements
To concentrate protein by pelleting solutes
To increase creatinine concentration for accuracy
To prevent creatine conversion during storage
Which best defines the UP:UC ratio measured on a single urine sample?
Urine protein concentration divided by urine creatinine
Daily protein excretion divided by serum creatinine
Serum protein divided by urine creatinine concentration
Urine creatinine divided by serum creatinine level
A dog’s UP:UC ratio returns 0.8. How should this result be interpreted?
Within healthy range for dogs
Suggests prerenal functional proteinuria
Strongly indicates renal disease
Indeterminate and always repeat testing
Which statement best describes Iohexol in renal function testing?
Iohexol is a radiographic agent used for clearance
Iohexol is an endogenous protein filtered by glomeruli
Iohexol is secreted mainly by renal tubules for testing
Iohexol binds plasma proteins to slow filtration
When performing Iohexol clearance to estimate GFR, when are serum samples typically collected?
At 2, 3, and 4 hours after administration
At 10, 20, and 30 minutes after dosing
Only once at 24 hours post administration
Hourly for the first eight hours
Which statements about inulin clearance are correct?
Inulin is handled only by glomerular filtration
Inulin undergoes significant tubular secretion
Inulin clearance is considered the best GFR method
Inulin is a radiographic contrast for imaging
Match each test with its primary attribute.
Iohexol clearance
Uses a radiographic agent
Inulin clearance
Measures filtration without tubular handling
Both tests
Estimate glomerular filtration rate
Which clinical scenario most appropriately prompts a water deprivation test?
Persistent polyuria with polydipsia evaluation
Acute kidney failure post contrast exposure
Isolated hematuria after minor trauma
Routine screening in healthy adolescents
Hypertension without urinary symptoms
In a standard water deprivation protocol, what is the intended physiological change?
Induce dehydration to assess ADH response
Expand plasma volume to suppress ADH
Stabilize osmolality with isotonic fluids
Measure renin after salt loading challenge
Promote diuresis with loop diuretic dosing
Select all statements that accurately describe key cautions about the water deprivation test.
Contraindicated in existing dehydration states
May be inappropriate with azotemia present
Generally considered a controversial procedure
Routinely performed without clinician supervision
Primarily measures aldosterone secretion patterns
Which statement best distinguishes the exocrine from the endocrine pancreas?
Exocrine secretes enzymes into ducts, endocrine releases hormones into blood
Exocrine releases hormones into blood, endocrine secretes enzymes into ducts
Both exocrine and endocrine release enzymes into the bloodstream
Both exocrine and endocrine release hormones into the small intestine
Which set lists major digestive enzymes produced by the exocrine pancreas?
Trypsin, amylase, and lipase
Pepsin, lactase, and cellulase
Trypsin, maltase, and sucrase
Amylase, pepsin, and renin
Match each islet cell type to its primary hormone secretion.
Beta (β) cells
Insulin
Alpha (α) cells
Glucagon
Islets of Langerhans
Cell clusters in pancreas
Which statements about the exocrine pancreas are correct?
It constitutes the largest portion of the pancreas
It produces enzyme-rich juice for the small intestine
It primarily secretes insulin into the bloodstream
It delivers digestive enzymes via ducts
Approximately what proportion of islet cells are beta (β) cells that secrete insulin, compared with alpha (α) cells that secrete glucagon?
About 80% beta and 20% alpha
About 50% beta and 50% alpha
About 20% beta and 80% alpha
About 70% beta and 30% alpha
Which test directly measures a pancreatic enzyme that hydrolyzes triglycerides and is widely used to assess acute pancreatitis?
Amylase activity assay in serum
Serum pancreatic lipase immunoreactivity
Trypsinlike immunoreactivity measurement
Fecal elastase concentration test
Match each assessment with what it most specifically detects or infers.
Amylase test
Serum alpha-amylase enzyme activity
Lipase test
Serum pancreatic triglyceride lipase activity
Trypsinlike immunoreactivity
Circulating trypsin or trypsinogen levels
Serum pancreatic lipase immunoreactivity
Antibody-based detection of pancreatic lipase
Which source contributes most to serum amylase under normal physiology?
Pancreas secretion to circulation
Salivary glands into saliva
Small intestine mucosal cells
Hepatic acinar cell leakage
Renal tubular epithelial cells
An increase in serum amylase most strongly supports pancreatic disease when which concurrent finding is present?
Elevated lipase activity as well
Normal lipase with hyperbilirubinemia
High glucose with normal lipase
Low lipase with high trypsin
Elevated ALT but low lipase
Which statement best describes the relation between amylase magnitude and pancreatic disease severity?
Values do not consistently reflect severity
Higher values always indicate worse disease
Low values always exclude pancreatitis
Values correlate linearly with necrosis
Values predict prognosis with high accuracy
What is the principal digestive role of amylase?
Hydrolyzing starch and glycogen to sugars
Emulsifying dietary triglycerides for absorption
Breaking peptides into free amino acids
Neutralizing gastric acid in the duodenum
Activating trypsinogen to trypsin in gut
Which clinical scenarios commonly raise blood amylase concentrations?
Acute pancreatitis episodes
Chronic pancreatitis flare-ups
Obstruction of pancreatic ducts
Uncomplicated viral hepatitis
Primary hyperparathyroidism alone
A patient’s amylase is three times the upper reference limit. What interpretation is most appropriate?
Finding strongly supports pancreatitis
Result rules out pancreatic disease
Suggests salivary gland dysfunction
Indicates severe renal failure only
Implies lab error is very likely
Which preanalytical practice is CONTRAINDICATED for amylase testing?
Using EDTA anticoagulant tubes
Collecting serum without anticoagulant
Using lithium heparin plasma
Promptly separating serum and cells
Refrigerating sample before analysis
Which factor may artifactually lower measured amylase activity?
Lipemia in the sample matrix
Hemolysis during phlebotomy
Mild icterus in the specimen
High ambient lab humidity
Postprandial sampling timing
Regarding species differences, which statement is accurate about amylase reference values?
Dogs and cats have about tenfold higher normals than humans
Humans have about tenfold higher normals than dogs and cats
All mammals share equivalent normal ranges
Birds have similar ranges to dogs and cats
Dogs but not cats exceed human normal ranges
Which statement best describes the primary source of circulating lipase in mammals?
Most serum lipase originates from the pancreas
Most serum lipase comes from the salivary glands
Most serum lipase is produced by adipose tissue
Most serum lipase derives from intestinal mucosa
What is the main biochemical role of pancreatic lipase in digestion?
Hydrolyzing long‑chain fatty acids from lipids
Polymerizing fatty acids into triglycerides
Oxidizing fatty acids to generate ketones
Transporting bile acids into enterocytes
Excess circulating lipase is primarily cleared from the body by which organ system?
Renal filtration through the kidneys
Hepatic metabolism by hepatocytes
Pulmonary exhalation via alveoli
Intestinal excretion without reabsorption
Match each item to its correct description.
Pancreas
Major source of serum lipase
Lipase
Enzyme that breaks down lipid molecules
Kidneys
Filters excess enzyme from circulation
Amylase
Less sensitive marker for pancreatitis
Which statements about immunologic methods for measuring lipase are accurate?
They represent newer testing approaches
They are highly sensitive in dogs and cats
They directly quantify pancreatitis severity
They are less sensitive than amylase assays
Regarding pancreatitis detection, how does lipase compare to amylase?
Lipase is more sensitive but not severity‑proportional
Lipase is less sensitive but severity‑proportional
Both are equally sensitive and severity‑proportional
Amylase is more sensitive and severity‑proportional
A patient has markedly increased serum lipase but only mild clinical signs of pancreatitis. Which interpretation is most appropriate?
Lipase elevation does not scale with severity
Lipase always reflects disease severity precisely
Amylase would necessarily be higher than lipase
Kidney filtration failure is the only explanation
Which combination best characterizes pancreatic lipase physiology?
Pancreatic origin of most circulating lipase
Role in long‑chain lipid hydrolysis
Primary clearance by renal filtration
Direct proportionality to pancreatitis severity
Which statement best describes feline and canine pancreatic lipase immunoreactivity tests in clinical use?
fPLI and cPLI are specific for pancreatitis
fPLI and cPLI are general markers of all inflammation
fPLI is specific but cPLI lacks diagnostic value
fPLI and cPLI primarily assess exocrine insufficiency
Match each species-specific pancreatic lipase immunoreactivity to its abbreviation.
Feline pancreatic lipase immunoreactivity
fPLI
Canine pancreatic lipase immunoreactivity
cPLI
Pancreatitis-specific lipase assay
Both fPLI and cPLI
