Renal Physiology: Glomerular Filtration and Tubular Reabsorption
32 Questions
3 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the formula for urinary excretion rate?

  • Filtration rate - Reabsorption rate + Secretion rate (correct)
  • Filtration rate + Reabsorption rate + Secretion rate
  • Reabsorption rate - Filtration rate + Secretion rate
  • Filtration rate + Secretion rate - Reabsorption rate

    • What is the assumed condition for the filtration calculation of a substance?

  • The substance is only filtered through the glomerulus
  • The substance is freely filtered and not bound to plasma proteins (correct)
  • The substance is not freely filtered
  • The substance is bound to plasma proteins

    • What is the main difference between GFR and tubular reabsorption?

  • One is active and the other is passive
  • One is selective and the other is non-selective (correct)
  • One is complex and the other is simple
  • One is fast and the other is slow

    • What is required for a substance to be reabsorbed?

    <p>It must be transported across the tubular epithelial membranes into the renal interstitial fluid</p> Signup and view all the answers

    What type of transport is involved in reabsorption?

    <p>Both passive and active transport</p> Signup and view all the answers

    What percentage of the filtered load of sodium and water is normally reabsorbed?

    <p>About 65%</p> Signup and view all the answers

    Which substances are reabsorbed in the proximal tubule?

    <p>Glucose, amino acids, sodium, and water</p> Signup and view all the answers

    What is the characteristic of reabsorption in the proximal tubule?

    <p>High capacity for active and passive reabsorption</p> Signup and view all the answers

    What is the main function of the paracellular pathway in the proximal tubule?

    <p>Reabsorption of glucose and amino acid</p> Signup and view all the answers

    What is the purpose of secretion of H+ in the proximal tubule?

    <p>To remove excess hydrogen ions from the blood</p> Signup and view all the answers

    What determines the transport maximum (Tm) for substances in the proximal tubule?

    <p>All of the above</p> Signup and view all the answers

    What is the significance of the threshold for glucose in the proximal tubule?

    <p>It is the amount of glucose above which it starts to appear in the urine</p> Signup and view all the answers

    In which part of the nephron do the epithelial cells have much tighter junctions?

    <p>Distal parts of the nephron</p> Signup and view all the answers

    What is the characteristic of the thin descending segment of the loop of Henle?

    <p>Highly permeable to water and moderately permeable to solutes</p> Signup and view all the answers

    What is the function of the aldosterone hormone in the nephron?

    <p>To increase the transport maximum for sodium reabsorption</p> Signup and view all the answers

    What is the main difference between the transport of glucose and sodium in the proximal tubule?

    <p>Glucose exhibits a transport maximum, while sodium does not</p> Signup and view all the answers

    What is the primary function of reabsorption in the kidney?

    <p>To reabsorb essential nutrients and ions</p> Signup and view all the answers

    What determines the amount of a substance filtered by the kidneys?

    <p>The glomerular filtration rate (GFR)</p> Signup and view all the answers

    What is the main difference between glomerular filtration and tubular reabsorption?

    <p>Filtration is non-selective, while reabsorption is selective</p> Signup and view all the answers

    What is the primary mechanism of reabsorption in the proximal tubule?

    <p>Active transport</p> Signup and view all the answers

    What is the main function of the proximal tubule?

    <p>To reabsorb essential nutrients and ions</p> Signup and view all the answers

    What is the effect of a small change in glomerular filtration or tubular reabsorption?

    <p>A large change in urinary excretion</p> Signup and view all the answers

    What is the significance of the coordinated regulation of glomerular filtration and tubular reabsorption?

    <p>To avoid large fluctuations in urinary excretion</p> Signup and view all the answers

    What is the characteristic of tubular reabsorption in the proximal tubule?

    <p>High capacity for active and passive reabsorption</p> Signup and view all the answers

    What is the primary function of the paracellular pathway in the proximal tubule?

    <p>Reabsorption of sodium and chloride</p> Signup and view all the answers

    Which substances are reabsorbed in the first half of the proximal tubule?

    <p>Glucose and amino acid</p> Signup and view all the answers

    What is the purpose of the secretion of H+ in the proximal tubule?

    <p>To regulate tubular fluid pH</p> Signup and view all the answers

    What determines the transport maximum for substances in the proximal tubule?

    <p>Electrochemical gradient and time</p> Signup and view all the answers

    What is the characteristic of the transport of glucose in the proximal tubule?

    <p>Active transport with a transport maximum</p> Signup and view all the answers

    What is the function of the thin descending segment of the loop of Henle?

    <p>Reabsorption of water and urea</p> Signup and view all the answers

    What is the effect of aldosterone on sodium reabsorption in the distal parts of the nephron?

    <p>Increases sodium reabsorption</p> Signup and view all the answers

    What is the significance of the threshold for glucose in the proximal tubule?

    <p>It is the plasma concentration of glucose below which glucose is not reabsorbed</p> Signup and view all the answers

    Study Notes

    Kidney Function and Reabsorption

    • Urinary excretion rate is calculated as Filtration rate - Reabsorption rate + Secretion rate
    • Filtration of a substance is calculated as GFR × plasma concentration (e.g., Filtration of Glucose = 180 L/day × 1 g/L = 180 gr/day)

    Importance of Reabsorption

    • Small changes in glomerular filtration or tubular reabsorption can cause large changes in urinary excretion
    • Changes in tubular reabsorption and glomerular filtration are closely coordinated to avoid large fluctuations in urinary excretion

    Types of Transport

    • Active transport: primary active, secondary active
    • Passive transport: diffusion (simple, facilitated), osmosis, pinocytosis

    Reabsorption and Secretion in Proximal Tubule (PT)

    • Normally, 65% of filtered load of sodium and water, and a slightly lower percentage of filtered chloride are reabsorbed
    • Reabsorbs all filtered glucose and amino acids
    • High capacity for active and passive reabsorption through transcellular and paracellular pathways
    • Reabsorption of glucose and amino acid especially in the first half of PT
    • Reabsorption of Na in 3 steps
    • Reabsorption of Cl especially in the 2nd half of PT
    • Secretion of organic acids and bases, including bile salts, oxalate, catecholamines, and hydrogen

    Transport Maximum (Tm)

    • Tm for substances that are actively reabsorbed or secreted
    • Example: Glucose transport system in the proximal tubule (GFR × plasma glucose = 125 ml/min × 1 mg/ml = 125 mg/min)
    • Threshold for Glucose: ~ 250 mg/min
    • Tm for glucose: ~ 375 mg/min
    • Substances that are passively transported do not exhibit a Tm
    • Substances that are actively transported but do not exhibit a Tm, such as reabsorption of Na in PT

    Kidney Function and Reabsorption

    • Urinary excretion rate is calculated as Filtration rate - Reabsorption rate + Secretion rate
    • Filtration of a substance is calculated as GFR × plasma concentration (e.g., Filtration of Glucose = 180 L/day × 1 g/L = 180 gr/day)

    Importance of Reabsorption

    • Small changes in glomerular filtration or tubular reabsorption can cause large changes in urinary excretion
    • Changes in tubular reabsorption and glomerular filtration are closely coordinated to avoid large fluctuations in urinary excretion

    Types of Transport

    • Active transport: primary active, secondary active
    • Passive transport: diffusion (simple, facilitated), osmosis, pinocytosis

    Reabsorption and Secretion in Proximal Tubule (PT)

    • Normally, 65% of filtered load of sodium and water, and a slightly lower percentage of filtered chloride are reabsorbed
    • Reabsorbs all filtered glucose and amino acids
    • High capacity for active and passive reabsorption through transcellular and paracellular pathways
    • Reabsorption of glucose and amino acid especially in the first half of PT
    • Reabsorption of Na in 3 steps
    • Reabsorption of Cl especially in the 2nd half of PT
    • Secretion of organic acids and bases, including bile salts, oxalate, catecholamines, and hydrogen

    Transport Maximum (Tm)

    • Tm for substances that are actively reabsorbed or secreted
    • Example: Glucose transport system in the proximal tubule (GFR × plasma glucose = 125 ml/min × 1 mg/ml = 125 mg/min)
    • Threshold for Glucose: ~ 250 mg/min
    • Tm for glucose: ~ 375 mg/min
    • Substances that are passively transported do not exhibit a Tm
    • Substances that are actively transported but do not exhibit a Tm, such as reabsorption of Na in PT

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Learn about the processes of glomerular filtration, tubular reabsorption, and secretion in the kidney, including the importance of reabsorption and how to calculate filtration rates.

    More Like This

    Kidney Physiology Quiz
    24 questions

    Kidney Physiology Quiz

    CongratulatoryIntelligence5915 avatar
    CongratulatoryIntelligence5915
    Renal Physiology Quiz
    8 questions

    Renal Physiology Quiz

    HardyStrontium avatar
    HardyStrontium
    Renal Physiology Quiz
    5 questions

    Renal Physiology Quiz

    TranquilLivermorium avatar
    TranquilLivermorium
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser