Podcast
Questions and Answers
Which substance is NOT typically regulated by the urinary system?
Which substance is NOT typically regulated by the urinary system?
- Calcium (Ca++)
- Sodium (Na+)
- Chloride (Cl-)
- Glucose (C6H12O6) (correct)
What is the primary function of the glomerulus in the nephron?
What is the primary function of the glomerulus in the nephron?
- Reabsorption of water
- Concentration of urine
- Filtration of blood (correct)
- Secretion of hormones
Which of the following statements accurately describes glomerular filtration rate (GFR)?
Which of the following statements accurately describes glomerular filtration rate (GFR)?
- GFR is constant and does not change with hydration status.
- GFR indicates the efficiency of the kidneys in filtering blood. (correct)
- GFR measures the amount of water reabsorbed in the nephron.
- GFR is affected only by blood pressure.
Which compound is secreted by the kidneys to help regulate blood pressure?
Which compound is secreted by the kidneys to help regulate blood pressure?
What process is primarily involved in the excretion of metabolic end products by the kidneys?
What process is primarily involved in the excretion of metabolic end products by the kidneys?
What structure is responsible for the initial filtration of blood in the kidney?
What structure is responsible for the initial filtration of blood in the kidney?
Which part of the nephron primarily allows for the reabsorption of essential substances?
Which part of the nephron primarily allows for the reabsorption of essential substances?
What is the correct formula for calculating urinary excretion of a substance?
What is the correct formula for calculating urinary excretion of a substance?
Which type of nephron is primarily involved in concentrating urine?
Which type of nephron is primarily involved in concentrating urine?
What is the average glomerular filtration rate (GFR) in adults?
What is the average glomerular filtration rate (GFR) in adults?
Which region of the kidney contains renal pyramids?
Which region of the kidney contains renal pyramids?
What is the primary role of the peritubular capillaries in the nephron?
What is the primary role of the peritubular capillaries in the nephron?
Which component of the kidney structure converges to form the pelvis?
Which component of the kidney structure converges to form the pelvis?
What components make up the renal corpuscle?
What components make up the renal corpuscle?
What is the nature of the filtrate produced during the renal filtration process?
What is the nature of the filtrate produced during the renal filtration process?
Which pressure is the primary mechanism for physiological regulation of the glomerular filtration rate (GFR)?
Which pressure is the primary mechanism for physiological regulation of the glomerular filtration rate (GFR)?
Which factor would directly reduce the glomerular filtration rate (GFR)?
Which factor would directly reduce the glomerular filtration rate (GFR)?
What is the filter's barrier made of during the renal filtration process?
What is the filter's barrier made of during the renal filtration process?
What happens to GFR when glomerular hydrostatic pressure increases?
What happens to GFR when glomerular hydrostatic pressure increases?
Which of the following influences glomerular capillary hydrostatic pressure (PH)?
Which of the following influences glomerular capillary hydrostatic pressure (PH)?
How is autoregulation of GFR achieved?
How is autoregulation of GFR achieved?
Flashcards
Kidney Function
Kidney Function
The kidneys filter blood, remove waste products, and regulate essential substances in the body.
Urinary System Excretion
Urinary System Excretion
The urinary system removes metabolic wastes, drugs, and other foreign substances from the body.
GFR Regulation
GFR Regulation
Controlling the rate at which substances are filtered from the blood in the kidneys.
Renal Blood Flow
Renal Blood Flow
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Fluid & Electrolyte Balance
Fluid & Electrolyte Balance
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Kidney Structure
Kidney Structure
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Nephron Types
Nephron Types
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Nephron Parts
Nephron Parts
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Filtration Process
Filtration Process
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Reabsorption Process
Reabsorption Process
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Secretion Process
Secretion Process
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GFR: Glomerular Filtration Rate
GFR: Glomerular Filtration Rate
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Urinary Excretion Equation
Urinary Excretion Equation
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Renal Corpuscle
Renal Corpuscle
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Filtration Barrier
Filtration Barrier
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Glomerular Filtration Rate (GFR)
Glomerular Filtration Rate (GFR)
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Glomerular Hydrostatic Pressure (PH)
Glomerular Hydrostatic Pressure (PH)
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Bowman's Capsule Hydrostatic Pressure (PBS)
Bowman's Capsule Hydrostatic Pressure (PBS)
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Colloid Osmotic Force (Ï€)
Colloid Osmotic Force (Ï€)
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Afferent Arteriole Dilation
Afferent Arteriole Dilation
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Efferent Arteriole Constriction
Efferent Arteriole Constriction
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Study Notes
Renal Physiology
- Kidneys are part of the urinary system, responsible for various processes.
- The nephron is the functional unit of the kidney.
- Kidneys excrete metabolic products, drugs, and exogenous compounds (xenobiotics).
- Kidneys regulate essential substances (Na+, K+, H+, Cl−, Ca2+, Mg2+, HCO3−, HPO42−, H2O), osmolarity, and pH.
- Kidneys regulate arterial blood pressure.
- Kidneys secrete renin, erythropoietin, and active vitamin D.
Renal Processes
- Urinary excretion depends on filtration, reabsorption, and secretion.
- Filtration (F): Blood moves from blood to lumen.
- Reabsorption (R): Substances move from lumen to blood.
- Secretion (S): Substances move from blood to lumen.
- Excretion = Filtration - Reabsorption + Secretion
Renal Corpuscle Composition
- Glomerulus: Capillary network
- Bowman's capsule: Beginning of the tubule, composed of parietal and visceral epithelium.
Filtration Barrier
- Fenestrated capillary epithelium
- Basement membrane (also basal lamina)
- Pores formed by Podocytes
Glomerular Filtration Rate (GFR)
- Amount of plasma filtered from glomeruli into Bowman's space per unit time.
- In average adults, GFR is 125 ml/min, or 180 L/day.
Factors Affecting GFR
- Forces favoring filtration include glomerular capillary hydrostatic pressure (glomerular blood pressure).
- Forces opposing filtration include pressure in Bowman's capsule, colloid osmotic pressure (due to plasma proteins). -Net glomerular filtration pressure = glomerular capillary hydrostatic pressure - Bowman's capsule hydrostatic pressure - colloid osmotic pressure.
Glomerular Capillary Hydrostatic Pressure (PH)
- Primary mechanism for physiological regulation of GFR:
- Increase in glomerular hydrostatic pressure results in increased GFR.
- Factors influencing PH:
- Arterial pressure (buffered by autoregulation).
- Afferent arteriolar resistance.
- Efferent arteriolar resistance.
Autoregulation of GFR
- Achieved over a wide range of blood pressures.
- Mechanisms include:
- Myogenic response (blood vessel itself).
- Tubuloglomerular feedback (Juxtaglomerular apparatus).
- Hormones and autonomic neurons.
Tubuloglomerular Feedback
- Paracrine control: Increase in GFR (increased NaCl sensed by macula densa), and resulting constriction in the afferent arteriole.
Juxtaglomerular Apparatus
- Macula densa: Osmoreceptors (modified epithelial cells) in the distal tubule.
- Granular cells (aka. Juxtaglomerular cell): Modified smooth muscle of afferent arteriole, secrete renin.
- Mesangial cells: Regulate glomerular filtration; contractile.
Renin-Angiotensin Mechanisms
- Renin release triggered by decreased blood pressure, sympathetic innervation or reduced osmolarity of the fluid in the macula densa
- Angiotensin II restores blood pressure by causing vasoconstriction in arterioles, and triggering aldosterone secretion, as well as thirst and ADH release by the CNS.
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