Transport Across Cell Membranes Quiz
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Questions and Answers

What is the primary function of the Na/Glu symporter in epithelial cells?

  • To exclusively transport sodium into the cell
  • To pump glucose out of the cell into the interstitial space
  • To facilitate the absorption of glucose along with sodium (correct)
  • To inhibit the transport of water into the cell

    • Why is oral rehydration therapy considered one of the biggest medical advances of the 20th century?

  • It primarily focuses on the secretion of electrolytes rather than absorption
  • It has saved over 1,000,000 children from dehydration-related deaths annually (correct)
  • It has been shown to reverse symptoms of cystic fibrosis
  • It allows for the rapid absorption of sodium in the bloodstream

    • What role does the Na+ pump play in glucose and water uptake?

  • It maintains the sodium gradient necessary for the Na/Glu symporter (correct)
  • It directly absorbs glucose into the interstitial space
  • It facilitates the secretion of water from epithelial cells
  • It prevents the uptake of sodium in the gut

    • What happens to water during the process of glucose absorption in the intestine?

    <p>Water follows glucose into the epithelial cells via osmosis</p> Signup and view all the answers

    What is the consequence of the secretion of Cl- during sweating?

    <p>It drives water movement out of cells, resulting in salty sweat</p> Signup and view all the answers

    What primary role does the sodium pump have in intestinal glucose absorption?

    <p>It maintains a low intracellular sodium concentration to facilitate glucose transport.</p> Signup and view all the answers

    How does the Na/Glu symporter function in glucose transport?

    <p>It transports glucose against its concentration gradient using energy from sodium.</p> Signup and view all the answers

    Where must the glucose uniporter be located to facilitate the movement of glucose into the interstitial space?

    <p>On the basolateral membrane of epithelial cells.</p> Signup and view all the answers

    What type of transport mechanism is involved when glucose moves from epithelial cells to the interstitial space?

    <p>Facilitated diffusion.</p> Signup and view all the answers

    Why is the position of the sodium pump critical in intestinal absorption?

    <p>It creates a sodium gradient necessary for co-transporters to function properly.</p> Signup and view all the answers

    What is the primary energy source for the Na/Glu symporter?

    <p>Sodium ion gradient.</p> Signup and view all the answers

    Which statement correctly describes the concentration of glucose in the intestinal lumen compared to epithelial cells?

    <p>Glucose concentration is higher in the lumen than in epithelial cells.</p> Signup and view all the answers

    What transport mechanism do amino acids use for absorption in the intestine?

    <p>Na+/amino acid co-transporters.</p> Signup and view all the answers

    Which of the following best describes the relationship between sodium and glucose transport in epithelial cells?

    <p>Sodium helps facilitate glucose transport indirectly through co-transport mechanisms.</p> Signup and view all the answers

    What role does the interstitial space play in glucose absorption?

    <p>It serves as a pathway for glucose moving to the blood circulation.</p> Signup and view all the answers

    What is the role of the Na+/Glucose cotransporter in physiology?

    <p>Regulates bulk uptake of glucose and water.</p> Signup and view all the answers

    Which of the following best describes regulated water uptake as compared to bulk uptake?

    <p>Regulated water uptake is controlled by hormonal signals while bulk uptake is passive.</p> Signup and view all the answers

    What major impact did the understanding of glucose absorption have in the 20th century?

    <p>It saved the lives of millions of children worldwide.</p> Signup and view all the answers

    What is one of the foundations for understanding systems and integrated physiology?

    <p>Transport processes across cell membranes.</p> Signup and view all the answers

    Which physiological process is demonstrated by the bulk uptake of water?

    <p>Osmosis through selectively permeable membranes.</p> Signup and view all the answers

    What aspect of physiology does studying glucose absorption help to illuminate?

    <p>The interactions between different physiological systems.</p> Signup and view all the answers

    Which statement accurately reflects the role of bio-electric potentials in nerve physiology?

    <p>They allow for signal transmission in neurons.</p> Signup and view all the answers

    Which of the following systems is NOT one of the main 11 systems discussed in physiology?

    <p>Thermoregulatory system.</p> Signup and view all the answers

    What process facilitates the movement of Na+ into cells initially?

    <p>Active transport through Na+ pump at the basolateral membrane</p> Signup and view all the answers

    Which of the following correctly describes the role of the Na+/Glucose symporter?

    <p>It allows Na+ to move into the cell along with glucose</p> Signup and view all the answers

    Why is the concentration of Na+ lower inside epithelial cells after the Na+ pump operates?

    <p>Na+ is continuously extruded via the basolateral Na+ pump</p> Signup and view all the answers

    What is the main effect of the Na+ pump on the concentration gradient across the apical membrane?

    <p>It creates a concentration gradient favoring Na+ influx</p> Signup and view all the answers

    What type of junctions are primarily found between epithelial cells that assist in solute transport?

    <p>Tight junctions</p> Signup and view all the answers

    Which of the following correctly describes the transport of water in relation to Na+ movement?

    <p>Water follows Na+ due to osmotic gradients</p> Signup and view all the answers

    In the context of intestinal absorption, how does Na+ transport primarily influence glucose absorption?

    <p>Na+ transport provides the necessary energy for glucose uptake</p> Signup and view all the answers

    What cellular location is primarily responsible for extracting sodium ions from the intracellular fluid?

    <p>Basolateral membrane</p> Signup and view all the answers

    How does a leaky epithelial cell differ from a tight epithelial cell regarding solute transport?

    <p>Leaky cells allow for greater selective permeability</p> Signup and view all the answers

    What is the ultimate purpose of having a Na+ concentration gradient across a cell membrane?

    <p>To promote the uptake of essential nutrients through secondary active transport</p> Signup and view all the answers

    What is the primary mechanism of glucose absorption in the intestines?

    <p>Na+/Glucose cotransporter mechanism</p> Signup and view all the answers

    What distinguishes bulk uptake of water from regulated uptake?

    <p>Bulk uptake primarily involves tight junctions in the small intestine</p> Signup and view all the answers

    What role do tight junctions play in water absorption in the gut?

    <p>They allow some passive movement of water</p> Signup and view all the answers

    What factor is crucial for water absorption from the lumen to interstitial fluid?

    <p>Osmotic gradient between compartments</p> Signup and view all the answers

    In healthy individuals, how is the process of water absorption characterized?

    <p>It is a constitutive process.</p> Signup and view all the answers

    How does the body control the movement of water across cell membranes?

    <p>By maintaining osmotic gradients</p> Signup and view all the answers

    Which statement about bulk water absorption in the kidneys is true?

    <p>It occurs in the presence of an osmotic gradient.</p> Signup and view all the answers

    What is a significant characteristic of the tight junctions in the small intestine?

    <p>They allow for some paracellular movement.</p> Signup and view all the answers

    What is one of the major outcomes when an osmotic gradient is not maintained?

    <p>Reduced water absorption</p> Signup and view all the answers

    Why is the bulk uptake of water considered a constitutive process in healthy individuals?

    <p>It occurs continuously without external triggers.</p> Signup and view all the answers

    Study Notes

    Transport Across Cell Membranes

    • Glucose absorption is a critical physiological process.
    • Na+/Glucose cotransporter is responsible for bulk glucose uptake.
    • Sodium Pump: located on the basolateral membrane, it uses active transport to create a sodium concentration gradient.
    • Na+/Glucose Symporter: located on the apical membrane, it uses the energy from sodium moving down its concentration gradient to drive glucose uptake.
    • Glucose Uniporter: located on the basolateral membrane, it facilitates the movement of glucose from the cell to the interstitial space.

    Water Absorption

    • Bulk absorption of water in the intestines and kidneys is a key process.
    • Tight Junctions: in the small intestine and proximal tubule of the kidney, they are 'leaky' and allow for water movement.
    • Water absorption is driven by an osmotic gradient.

    The Role of The Sodium Pump

    • The sodium pump creates a low internal sodium concentration, enabling the Na+/Glucose symporter to function and draw glucose into the cell.
    • This creates an osmotic gradient, allowing for the movement of water.

    Oral Rehydration Therapy (ORT)

    • ORT is a medical breakthrough that revolutionized the treatment of dehydration.
    • It leverages the Na+/glucose co-transporter to efficiently rehydrate patients, specifically children.
    • Key breakthrough: understanding the coupling of sodium and glucose transport in the small intestine.

    Secretion of Water

    • Sweating: an example of water secretion.
    • Chloride ions are secreted, followed by water and sodium ions.
    • This is why sweat is salty.

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    Lecture 5 Transport II.pptx

    Description

    Test your knowledge on the mechanisms of transport across cell membranes, focusing on glucose and water absorption. Discover how the sodium pump and cotransporters function in physiological processes. This quiz will cover essential topics related to membrane transport in cells.

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