Podcast
Questions and Answers
What percentage of cardiac output do the kidneys normally receive in mammals?
What percentage of cardiac output do the kidneys normally receive in mammals?
The glomerulus allows high-molecular-weight proteins to pass into the glomerular filtrate.
The glomerulus allows high-molecular-weight proteins to pass into the glomerular filtrate.
False
What is the primary function of the nephron?
What is the primary function of the nephron?
To filter blood and regulate substances like water, electrolytes, and waste.
The fluid produced by the glomerulus is known as _____ filtrate.
The fluid produced by the glomerulus is known as _____ filtrate.
Signup and view all the answers
Match the following kidney functions with their descriptions:
Match the following kidney functions with their descriptions:
Signup and view all the answers
What is the glomerular filtration rate (GFR) used to measure?
What is the glomerular filtration rate (GFR) used to measure?
Signup and view all the answers
Nephrons serve as the functional unit of the kidney.
Nephrons serve as the functional unit of the kidney.
Signup and view all the answers
Name the structure where blood is filtered in the nephron.
Name the structure where blood is filtered in the nephron.
Signup and view all the answers
What is the approximate daily production of glomerular filtrate for an average-size beagle weighing 10 kg?
What is the approximate daily production of glomerular filtrate for an average-size beagle weighing 10 kg?
Signup and view all the answers
The glomerular capillary wall consists of four layers.
The glomerular capillary wall consists of four layers.
Signup and view all the answers
What is the primary function of the juxtaglomerular apparatus?
What is the primary function of the juxtaglomerular apparatus?
Signup and view all the answers
The ________ is a layer of intricate, interlocking cells in the glomerulus.
The ________ is a layer of intricate, interlocking cells in the glomerulus.
Signup and view all the answers
Match the nephron segments with their primary functions:
Match the nephron segments with their primary functions:
Signup and view all the answers
What structure encases the glomerular tuft?
What structure encases the glomerular tuft?
Signup and view all the answers
Endothelial fenestrae allow for filtration of plasma proteins.
Endothelial fenestrae allow for filtration of plasma proteins.
Signup and view all the answers
Name the two types of nephrons found in avian kidneys.
Name the two types of nephrons found in avian kidneys.
Signup and view all the answers
The comprehensive barrier separating the blood and capsule is made up of the capillary endothelium, basement membrane, and ________.
The comprehensive barrier separating the blood and capsule is made up of the capillary endothelium, basement membrane, and ________.
Signup and view all the answers
What is the primary role of renal arterial blood in relation to the afferent arteriole?
What is the primary role of renal arterial blood in relation to the afferent arteriole?
Signup and view all the answers
Hydrostatic pressure in the glomerular capillaries favors filtration.
Hydrostatic pressure in the glomerular capillaries favors filtration.
Signup and view all the answers
How does the structure of the glomerular capillaries influence the filtration process?
How does the structure of the glomerular capillaries influence the filtration process?
Signup and view all the answers
The components of the glomerular basement membrane include various types of ________.
The components of the glomerular basement membrane include various types of ________.
Signup and view all the answers
Match the following terms with their descriptions:
Match the following terms with their descriptions:
Signup and view all the answers
What is the main force favoring filtration in the glomerulus?
What is the main force favoring filtration in the glomerulus?
Signup and view all the answers
Angiotensin II increases renal blood flow.
Angiotensin II increases renal blood flow.
Signup and view all the answers
What does the myogenic reflex do in renal physiology?
What does the myogenic reflex do in renal physiology?
Signup and view all the answers
In the kidney, _____ is suppressed by increased extracellular volume and increased renal perfusion pressure.
In the kidney, _____ is suppressed by increased extracellular volume and increased renal perfusion pressure.
Signup and view all the answers
Which of the following mechanisms is NOT a part of the autoregulation of glomerular filtration rate?
Which of the following mechanisms is NOT a part of the autoregulation of glomerular filtration rate?
Signup and view all the answers
Negative charges repel negatively charged plasma proteins across the filtration barrier.
Negative charges repel negatively charged plasma proteins across the filtration barrier.
Signup and view all the answers
What effect does angiotensin II have on sodium uptake?
What effect does angiotensin II have on sodium uptake?
Signup and view all the answers
The net filtration rate can be influenced by the _____ and _____ of a substance.
The net filtration rate can be influenced by the _____ and _____ of a substance.
Signup and view all the answers
Match the following pressures with their effects:
Match the following pressures with their effects:
Signup and view all the answers
What happens to the glomerular filtration rate if the afferent arterioles constrict?
What happens to the glomerular filtration rate if the afferent arterioles constrict?
Signup and view all the answers
The shape of a molecule affects its permeability across the glomerular filtration barrier.
The shape of a molecule affects its permeability across the glomerular filtration barrier.
Signup and view all the answers
What role do chemical mediators like nitric oxide play in autonomic regulation of glomerular blood flow?
What role do chemical mediators like nitric oxide play in autonomic regulation of glomerular blood flow?
Signup and view all the answers
The _____ system is an important regulator of GFR and renal blood flow, mediated through hormones.
The _____ system is an important regulator of GFR and renal blood flow, mediated through hormones.
Signup and view all the answers
Which layer of the glomerular basement membrane is relatively dark due to its resistance to electron passage?
Which layer of the glomerular basement membrane is relatively dark due to its resistance to electron passage?
Signup and view all the answers
The main driving force for filtration in the glomerulus is the oncotic pressure in Bowman’s space.
The main driving force for filtration in the glomerulus is the oncotic pressure in Bowman’s space.
Signup and view all the answers
What is the primary function of the glomerular filtration barrier?
What is the primary function of the glomerular filtration barrier?
Signup and view all the answers
In general, substances with a molecular radius of _____ nm or more are not filtered.
In general, substances with a molecular radius of _____ nm or more are not filtered.
Signup and view all the answers
Match the following components of the glomerulus with their roles:
Match the following components of the glomerulus with their roles:
Signup and view all the answers
Which equation represents the relationship of net ultrafiltration pressure at any point along the glomerular capillary?
Which equation represents the relationship of net ultrafiltration pressure at any point along the glomerular capillary?
Signup and view all the answers
The ultrafiltration coefficient is affected by the structural characteristics of the glomerular capillary wall.
The ultrafiltration coefficient is affected by the structural characteristics of the glomerular capillary wall.
Signup and view all the answers
What happens to the plasma oncotic pressure as blood travels through the glomerular capillaries?
What happens to the plasma oncotic pressure as blood travels through the glomerular capillaries?
Signup and view all the answers
The filtration barrier's permselectivity ensures that normally, proteins of the size of _____ are retained in the bloodstream.
The filtration barrier's permselectivity ensures that normally, proteins of the size of _____ are retained in the bloodstream.
Signup and view all the answers
Match components involved in glomerular filtration with their characteristics:
Match components involved in glomerular filtration with their characteristics:
Signup and view all the answers
What causes the decrease in hydrostatic pressure in the capillary along the filtration process?
What causes the decrease in hydrostatic pressure in the capillary along the filtration process?
Signup and view all the answers
Bowman's space is where the glomerular filtrate is formed and collected.
Bowman's space is where the glomerular filtrate is formed and collected.
Signup and view all the answers
What happens to filtration in the distal portions of the glomerular capillaries during increased blood flow?
What happens to filtration in the distal portions of the glomerular capillaries during increased blood flow?
Signup and view all the answers
The mathematical representation of GFR is GFR = Kf × _____ .
The mathematical representation of GFR is GFR = Kf × _____ .
Signup and view all the answers
What type of microscopy shows the three main layers of the glomerular capillary wall?
What type of microscopy shows the three main layers of the glomerular capillary wall?
Signup and view all the answers
What is the primary function of renin in the renin-angiotensin system?
What is the primary function of renin in the renin-angiotensin system?
Signup and view all the answers
Angiotensin-converting enzyme (ACE) is primarily found in the liver.
Angiotensin-converting enzyme (ACE) is primarily found in the liver.
Signup and view all the answers
What substance's release is increased by angiotensin II that affects renal function?
What substance's release is increased by angiotensin II that affects renal function?
Signup and view all the answers
The consequence of increased tubule fluid flow at the macula densa is increased [NaCl] that initiates ______.
The consequence of increased tubule fluid flow at the macula densa is increased [NaCl] that initiates ______.
Signup and view all the answers
Match the following components of the nephron with their functions:
Match the following components of the nephron with their functions:
Signup and view all the answers
Which hormone is responsible for vasoconstriction and can increase blood pressure?
Which hormone is responsible for vasoconstriction and can increase blood pressure?
Signup and view all the answers
The intrarenal renin-angiotensin system operates entirely independently of the systemic renin-angiotensin system.
The intrarenal renin-angiotensin system operates entirely independently of the systemic renin-angiotensin system.
Signup and view all the answers
What does an increase in glomerular filtration rate (GFR) indicate?
What does an increase in glomerular filtration rate (GFR) indicate?
Signup and view all the answers
A decrease in ______ removes NaCl from the tubule fluid due to high tubule fluid flow rate.
A decrease in ______ removes NaCl from the tubule fluid due to high tubule fluid flow rate.
Signup and view all the answers
What role does adenosine play in the kidney?
What role does adenosine play in the kidney?
Signup and view all the answers
Alpha-adrenergic stimulation can cause renal vasodilation.
Alpha-adrenergic stimulation can cause renal vasodilation.
Signup and view all the answers
Name one systemic factor affecting renal perfusion.
Name one systemic factor affecting renal perfusion.
Signup and view all the answers
The contraction of mesangial cells reduces the area available for ______.
The contraction of mesangial cells reduces the area available for ______.
Signup and view all the answers
Which enzyme converts angiotensinogen to angiotensin I?
Which enzyme converts angiotensinogen to angiotensin I?
Signup and view all the answers
What factor can contribute to changes in GFR?
What factor can contribute to changes in GFR?
Signup and view all the answers
Creatinine clearance can be used for determining GFR in birds.
Creatinine clearance can be used for determining GFR in birds.
Signup and view all the answers
What hormone contributes to the regulation of blood volume?
What hormone contributes to the regulation of blood volume?
Signup and view all the answers
A small increase in serum creatinine corresponds to a _____ reduction in GFR.
A small increase in serum creatinine corresponds to a _____ reduction in GFR.
Signup and view all the answers
Match the markers with their characteristics:
Match the markers with their characteristics:
Signup and view all the answers
What is a possible indicator of kidney dysfunction?
What is a possible indicator of kidney dysfunction?
Signup and view all the answers
An abnormally low muscle mass can cause an overestimation of renal clearance.
An abnormally low muscle mass can cause an overestimation of renal clearance.
Signup and view all the answers
What should be assessed to determine GFR accurately?
What should be assessed to determine GFR accurately?
Signup and view all the answers
Cystatin-C is not significantly altered by relative _____ mass.
Cystatin-C is not significantly altered by relative _____ mass.
Signup and view all the answers
What is the primary method of estimating GFR in a clinical setting?
What is the primary method of estimating GFR in a clinical setting?
Signup and view all the answers
Inulin is both reabsorbed and secreted by renal tubule cells.
Inulin is both reabsorbed and secreted by renal tubule cells.
Signup and view all the answers
What does an elevated creatinine level typically indicate?
What does an elevated creatinine level typically indicate?
Signup and view all the answers
In clinical correlation for chronic renal failure, the serum creatinine level was recorded as _____ mg/dL.
In clinical correlation for chronic renal failure, the serum creatinine level was recorded as _____ mg/dL.
Signup and view all the answers
Match the symptoms to chronic renal failure:
Match the symptoms to chronic renal failure:
Signup and view all the answers
What happens to renal blood flow and GFR after a single high-protein meal?
What happens to renal blood flow and GFR after a single high-protein meal?
Signup and view all the answers
Chronic high dietary protein intake leads to sustained increases in renal blood flow and GFR.
Chronic high dietary protein intake leads to sustained increases in renal blood flow and GFR.
Signup and view all the answers
What regulatory mechanism in birds causes a decrease in GFR during dehydration?
What regulatory mechanism in birds causes a decrease in GFR during dehydration?
Signup and view all the answers
The equation for calculating clearance is C = ___ / P, where C is the clearance, U is urine concentration, and P is plasma concentration.
The equation for calculating clearance is C = ___ / P, where C is the clearance, U is urine concentration, and P is plasma concentration.
Signup and view all the answers
What factor primarily reduces GFR in birds during dehydration?
What factor primarily reduces GFR in birds during dehydration?
Signup and view all the answers
The macula densa in avian kidneys is fully developed and regulates GFR effectively.
The macula densa in avian kidneys is fully developed and regulates GFR effectively.
Signup and view all the answers
What causes the vasoconstriction of the afferent arterioles in birds?
What causes the vasoconstriction of the afferent arterioles in birds?
Signup and view all the answers
Increased NaCl delivery to the distal nephron stimulates production of ___________ agents by macula densa cells.
Increased NaCl delivery to the distal nephron stimulates production of ___________ agents by macula densa cells.
Signup and view all the answers
Which of the following are potent vasodilators produced in the kidney?
Which of the following are potent vasodilators produced in the kidney?
Signup and view all the answers
NSAIDs can lead to increased GFR in renal failure patients.
NSAIDs can lead to increased GFR in renal failure patients.
Signup and view all the answers
What is the role of nitric oxide in the kidney?
What is the role of nitric oxide in the kidney?
Signup and view all the answers
The specific role of the connecting tubule-glomerular feedback system is presently __________.
The specific role of the connecting tubule-glomerular feedback system is presently __________.
Signup and view all the answers
Match the following substances with their effects on renal blood flow.
Match the following substances with their effects on renal blood flow.
Signup and view all the answers
Which of the following substances is mainly responsible for renal vasoconstriction?
Which of the following substances is mainly responsible for renal vasoconstriction?
Signup and view all the answers
The relationship between angiotensin II and macula densa COX-2 expression is always inhibitory.
The relationship between angiotensin II and macula densa COX-2 expression is always inhibitory.
Signup and view all the answers
What is the primary treatment to correct electrolyte and acid-base disturbances in the cat?
What is the primary treatment to correct electrolyte and acid-base disturbances in the cat?
Signup and view all the answers
A diet high in total protein is recommended for managing kidney disease in cats.
A diet high in total protein is recommended for managing kidney disease in cats.
Signup and view all the answers
What condition is indicated by the presence of 3+ protein in the urinalysis?
What condition is indicated by the presence of 3+ protein in the urinalysis?
Signup and view all the answers
The presence of _______ in the urine is an indicator of renal injury.
The presence of _______ in the urine is an indicator of renal injury.
Signup and view all the answers
What is the preferred treatment for anemia caused by chronic renal failure in cats?
What is the preferred treatment for anemia caused by chronic renal failure in cats?
Signup and view all the answers
Increased permeability of peripheral capillaries allows for fluid retention in the body's tissues.
Increased permeability of peripheral capillaries allows for fluid retention in the body's tissues.
Signup and view all the answers
What is an effective method for estimating glomerular filtration rate (GFR)?
What is an effective method for estimating glomerular filtration rate (GFR)?
Signup and view all the answers
The major force favoring filtration across the glomerular capillary wall is _______.
The major force favoring filtration across the glomerular capillary wall is _______.
Signup and view all the answers
Which of the following factors does NOT contribute to the production of peripheral edema?
Which of the following factors does NOT contribute to the production of peripheral edema?
Signup and view all the answers
Acute glomerulonephritis only occurs in the presence of renal failure.
Acute glomerulonephritis only occurs in the presence of renal failure.
Signup and view all the answers
What is the main component being addressed in the treatment of acute glomerulonephritis?
What is the main component being addressed in the treatment of acute glomerulonephritis?
Signup and view all the answers
Increased blood pressure and serum creatinine levels are monitored to assess _______.
Increased blood pressure and serum creatinine levels are monitored to assess _______.
Signup and view all the answers
What is a possible cause of acute glomerulonephritis?
What is a possible cause of acute glomerulonephritis?
Signup and view all the answers
What role do podocytes play in the function of the glomerulus?
What role do podocytes play in the function of the glomerulus?
Signup and view all the answers
Mesangial cells play a role in increasing glomerular surface area for filtration.
Mesangial cells play a role in increasing glomerular surface area for filtration.
Signup and view all the answers
What is the function of the negatively charged foot processes of podocytes?
What is the function of the negatively charged foot processes of podocytes?
Signup and view all the answers
The mesh formed by type 4 collagen contributes to the size selectivity of the ________ capillary wall.
The mesh formed by type 4 collagen contributes to the size selectivity of the ________ capillary wall.
Signup and view all the answers
Match the following cell types with their primary functions in the glomerulus:
Match the following cell types with their primary functions in the glomerulus:
Signup and view all the answers
What is the primary component that determines the charge selectivity of the glomerular basement membrane?
What is the primary component that determines the charge selectivity of the glomerular basement membrane?
Signup and view all the answers
Glomerular filtration occurs at a pressure of approximately 120 mmHg.
Glomerular filtration occurs at a pressure of approximately 120 mmHg.
Signup and view all the answers
Blood exits the glomerulus through the ________ arteriole.
Blood exits the glomerulus through the ________ arteriole.
Signup and view all the answers
Match the following components of the filtration barrier to their descriptions:
Match the following components of the filtration barrier to their descriptions:
Signup and view all the answers
Where does the majority of renal blood flow go after passing through the efferent arteriole?
Where does the majority of renal blood flow go after passing through the efferent arteriole?
Signup and view all the answers
The filtration barrier of the glomerulus is impermeable to water.
The filtration barrier of the glomerulus is impermeable to water.
Signup and view all the answers
What pressure is crucial for tubular reabsorption of fluids?
What pressure is crucial for tubular reabsorption of fluids?
Signup and view all the answers
Study Notes
Kidney Physiology Overview
- Kidneys receive 25% of cardiac output in mammals
- Function in several capacities: filtration, reabsorption of needed substances (water, glucose, electrolytes, proteins), and excretion of waste
- Respond to changes in water, electrolyte, and acid-base balance by altering reabsorption/secretion rates
- Produce hormones regulating blood pressure and red blood cell production
- Nephrons are the functional units, composed of glomerulus (filtration) and renal tubule (reabsorption/secretion)
- Nephrons merge into collecting ducts, which empty into renal pelvis
- Knowledge largely based on mouse, rat, and rabbit studies
Glomerular Filtration
- First step in kidney function: blood filtration by glomerulus
- Glomerulus: dense capillary network
- Retains large cellular components and proteins
- Produces glomerular filtrate (plasma-like fluid)
- Glomerular Filtration Rate (GFR): useful clinical measure, expressed in mL/min/kg
- GFR of a 10kg beagle is approximately 37mL/minute or 53.3 liters/day
- Glomerular structure facilitates efficient filtration
Structure of the Glomerulus
- Glomerular tuft composed of a network of capillaries
- Blood flows from afferent arteriole to glomerular capillaries, then to efferent arteriole
- Bowman's capsule surrounds glomerular tuft, lined with parietal epithelium; transitional to proximal tubule cells
- Bowman's space located between glomerular tuft and Bowman's capsule
- Glomerular capillary wall has three layers: endothelium, basement membrane, and visceral epithelium
Glomerular Filtration Rate Determinants
- GFR determined by net filtration pressure, filtration barrier permeability, and available surface area
- Favoring filtration: glomerular capillary hydrostatic pressure, opposing filtration: oncotic pressure in glomerular capillaries, hydrostatic pressure in Bowman's space
- Net ultrafiltration pressure (Puf) = (Pgc - πgc) - Pbs
- Glomerular capillary wall is selectively permeable:
- Molecules < 4 nm radius filter easily
- Molecules > 4 nm radius are typically retained in the capillary
- Plasma proteins remain in bloodstream due to charge and size.
Glomerular Filtration Rate Regulation
- GFR regulated by systemic and intrinsic factors
- Systemic factors: renin-angiotensin-aldosterone system (RAAS). RAAS is activated by reduced renal perfusion pressure. Renin converts angiotensinogen into angiotensin I, which further converts to angiotensin II, causing vasoconstriction.
-
Intrinsic factors:
- Myogenic reflex: automatic response to changes in glomerular perfusion pressure, affects preglomerular arterioles
- Tubuloglomerular feedback (TGF): balances single nephron GFR with tubule transport capacity. Triggered by changes in sodium chloride concentration in distal nephron
Measurement of GFR
- Inulin clearance is the gold standard (freely filtered, not reabsorbed or secreted)
- Endogenous creatinine clearance is commonly used (freely filtered, but potentially secreted)
- Serum creatinine levels indicate GFR
Clinical Correlations
- Chronic renal failure: characterized by elevated serum creatinine, decreased GFR, often seen in geriatric cats
- Glomerulonephritis: characterized by proteinuria, hematuria, possible edema, often acute
- Treatment strategies for both conditions focus on supportive care, managing symptoms, and potentially addressing the underlying cause
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers key concepts of kidney physiology, including the roles of the kidneys in filtration, reabsorption, and waste excretion. It also addresses the structure and function of nephrons and the significance of glomerular filtration rate (GFR) as a clinical measure. Test your understanding of these essential processes in mammalian physiology.
