Animal Physiology II SC/BIOL 3070 - Iono- & Osmoregulation in Animals Quiz
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Questions and Answers

What is the role of afferent and efferent arterioles in the mammalian kidney?

  • Afferent arteriole removes blood from the glomerulus, while efferent arteriole brings it in
  • Afferent arteriole brings blood to the glomerulus, while efferent arteriole removes it (correct)
  • Both afferent and efferent arterioles bring blood to the glomerulus
  • Both afferent and efferent arterioles remove blood from the glomerulus

    • What is the normal diameter relationship between afferent and efferent arterioles?

  • Their diameters are inversely proportional to each other
  • They have the same diameter
  • The afferent arteriole has a larger diameter (correct)
  • The efferent arteriole has a larger diameter

    • How does the higher resistance in the efferent arteriole affect GFR?

  • It fluctuates filtration
  • It decreases filtration
  • It increases filtration (correct)
  • It has no effect on filtration

    • What are the intrinsic mechanisms used to regulate GFR?

    <p>Mechanisms initiated by the kidneys themselves</p> Signup and view all the answers

    When are intrinsic mechanisms used to regulate GFR?

    <p>During transient changes in blood pressure that accompany daily activities</p> Signup and view all the answers

    How do marine mammals like dolphins obtain their water?

    <p>From metabolic processes</p> Signup and view all the answers

    What is the term used for animals that can adapt to a wide range of salinities?

    <p>Euryhaline animals</p> Signup and view all the answers

    In freshwater, how do teleost fish counteract obligatory solute movement?

    <p>By actively taking up ions from water through their gills</p> Signup and view all the answers

    How do teleost fish in saltwater excrete excess ions?

    <p>Through their gills</p> Signup and view all the answers

    What process yields nitrogenous waste products in animals?

    <p>Amino acid catabolism</p> Signup and view all the answers

    What is the main function of the kidneys in teleost fish osmoregulation?

    <p>Produce large amounts of dilute urine in freshwater</p> Signup and view all the answers

    What is the primary function of aldosterone in the mammalian kidney?

    <p>Regulates Na+ reabsorption and K+ secretion</p> Signup and view all the answers

    Which cells in the distal tubule or collecting duct are affected by aldosterone?

    <p>Principal cells</p> Signup and view all the answers

    What is the net effect of aldosterone activity in the distal tubule or collecting duct?

    <p>Increased Na+ and water reabsorption</p> Signup and view all the answers

    What is the function of atrial mechanoreceptive fibers in the mammalian heart?

    <p>Detect changes in atrial filling and rate</p> Signup and view all the answers

    What is the role of stretch-sensitive secretory cells in the mammalian heart?

    <p>Produce and release atrial natriuretic peptide (ANP)</p> Signup and view all the answers

    What is the effect of atrial natriuretic peptide (ANP) on the kidney?

    <p>Increases renal Na+ excretion</p> Signup and view all the answers

    What is the main function of basolateral Na+/K+ ATPase in proximal tubule cells?

    <p>Pumping Na+ out of the cell into the blood</p> Signup and view all the answers

    What is the function of aquaporins in the descending limb of the loop of Henle?

    <p>Allowing passive movement of water out of the tubule</p> Signup and view all the answers

    What is the significance of the thick ascending limb of the loop of Henle being impermeable to water?

    <p>Allows for reabsorption of NaCl into the interstitium</p> Signup and view all the answers

    What is the function of loop diuretics like Furosemide in the loop of Henle?

    <p>Inhibiting active transport of NaCl</p> Signup and view all the answers

    What is the role of countercurrent exchange in the loop of Henle?

    <p>Preserves concentration gradient in the interstitium</p> Signup and view all the answers

    What distinguishes a juxtamedullary nephron from a cortical nephron?

    <p>Presence of vasa recta</p> Signup and view all the answers

    What is the primary function of the collecting duct in the nephron?

    <p>Reabsorption of Na+ via secretion of K+ and H+</p> Signup and view all the answers

    What triggers the production and secretion of anti-diuretic hormone (ADH) from neurosecretory neurons?

    <p>Increased plasma osmolarity</p> Signup and view all the answers

    How does ADH impact water reabsorption in the distal tubule and collecting duct?

    <p>Promotes aquaporin-2 synthesis</p> Signup and view all the answers

    What is the primary requirement for cell survival?

    <p>Retention of appropriate quantities of water</p> Signup and view all the answers

    What is the difference between Osmoconformers and Osmoregulators?

    <p>Osmoconformers have internal levels of ions and water that fluctuate with levels in the environment, while Osmoregulators maintain the levels of ions and body fluid across changing environmental levels</p> Signup and view all the answers

    Which of the following factors contribute to obligatory osmotic exchanges?

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

    How do small animals differ from large animals in terms of hydration and dehydration?

    <p>Small animals hydrate or dehydrate much faster than larger animals</p> Signup and view all the answers

    Which of the following factors contribute to the permeability of the integument (body covering)?

    <p>Both a and b</p> Signup and view all the answers

    What is the role of metabolic water in osmotic exchanges?

    <p>Both a and c</p> Signup and view all the answers

    What is the primary function of the mammalian kidney?

    <p>Elimination of nitrogenous wastes</p> Signup and view all the answers

    How do teleost fish in seawater maintain hydration?

    <p>By controlling ion levels</p> Signup and view all the answers

    What is the role of active epithelial transport in osmoregulation?

    <p>Controlling water and salt exchange</p> Signup and view all the answers

    What is the difference between obligatory and controlled osmotic exchanges?

    <p>Controlled osmotic exchanges are physiologically regulated, while obligatory osmotic exchanges occur in response to factors over which the animal has little or no physiological control</p> Signup and view all the answers

    Study Notes

    Osmoregulation in Animals

    • Body fluids constitute the immediate environment for cells and molecules
    • The composition of body fluids provides the context in which cells, organelles, and molecules function
    • The major requirement for cell survival is the retention of appropriate quantities of water
      • Water is the most important inorganic constituent in living cells
      • Enzyme activity depends on the degree of hydration
      • Water is a solvent for organic and inorganic substances
      • Water determines the volumes of cells and tissues

    Osmoregulators and Osmoconformers

    • Osmoregulators maintain the levels of ions and body fluid across changing environmental levels
    • Osmoconformers' internal levels of ions and water fluctuate with levels in the environment

    Osmotic Exchanges

    • Osmotic exchanges occur between an animal and its environment through:
      • Transepithelial diffusion
      • Ingestion
      • Defecation
      • Metabolic water production
    • There are two types of osmotic exchanges:
      • Obligatory osmotic exchanges (occur in response to factors over which the animal has little or no physiological control)
      • Controlled osmotic exchanges (physiologically regulated to aid in maintaining homeostasis)

    Factors Contributing to Obligatory Osmotic Exchanges

    • Gradients between external and internal environments
    • Surface area to volume ratios
    • Permeability of the integument (body covering)
    • Feeding, metabolic water, and excretion

    Endocrine Regulation of Mammalian Kidney

    • Aldosterone regulates Na+ reabsorption and K+ secretion by binding to cytosolic receptors in cells of the distal tubule or collecting duct
    • Aldosterone activity:
      • Increases Na+ and K+ channel synthesis and insertion in apical membrane
      • Increases synthesis and number of Na+/K+-ATPases in basolateral membrane
    • Net effect: more Na+ and water reabsorption (smaller urine volume produced)

    Mammalian Kidney

    • Nephron is the functional unit of the kidney
    • Nephron has five major regions:
      1. Bowman's capsule
      2. Proximal tubule
      3. Loop of Henle
      4. Distal tubule
      5. Collecting duct
    • Loop of Henle has three regions:
      1. Descending limb
      2. Thin ascending limb
      3. Thick ascending limb
    • The countercurrent multiplier system multiplies the osmotic gradient between the filtrate and interstitium

    Elimination of Nitrogenous Wastes

    • Amino acid catabolism yields nitrogenous waste products, which are toxic to the animal
    • Nitrogenous wastes are excreted through the kidney

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    Description

    Test your knowledge on iono- & osmoregulation in animals with this quiz. The quiz covers topics such as osmoregulatory challenges on land, mammalian kidney structure and function, endocrine regulation, elimination of nitrogenous wastes, and osmoregulation in aquatic animals.

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