Microcirculation Quiz: Capillary Fluid Exchange G. 16 - 1.5
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Questions and Answers

What is the primary factor that determines osmotic pressure?

  • The size of the dissolved molecules
  • The mass of the dissolved molecules
  • The type of dissolved molecules
  • The number of dissolved molecules (correct)

    • Which protein contributes the most to the total plasma colloid osmotic pressure?

  • Globulins
  • All contribute equally
  • Fibrinogen
  • Albumin (correct)

    • What is the approximate total plasma colloid osmotic pressure (Πp)?

  • 8 mm Hg
  • 28 mm Hg (correct)
  • 41 mm Hg
  • 30 mm Hg

    • What is the approximate contribution of globulins to the total plasma colloid osmotic pressure?

    <p>20% (C)</p> Signup and view all the answers

    What is the approximate contribution of fibrinogen to the total plasma colloid osmotic pressure?

    <p>Negligible (C)</p> Signup and view all the answers

    Which force is responsible for moving fluid outward from the arterial end of the capillary?

    <p>Capillary hydrostatic pressure (D)</p> Signup and view all the answers

    What is the approximate total outward force at the arterial end of the capillary?

    <p>41 mm Hg (D)</p> Signup and view all the answers

    What is the typical range of interstitial fluid pressure in the arterial ends of capillaries?

    <p>30 to 40 mm Hg (D)</p> Signup and view all the answers

    In which tissue does the glomerular capillary have the highest hydrostatic pressure?

    <p>Kidneys (D)</p> Signup and view all the answers

    What is the general rule regarding interstitial fluid pressure compared to the pressure surrounding the tissue?

    <p>Interstitial pressure is usually a few millimeters of mercury lower than surrounding pressure. (D)</p> Signup and view all the answers

    What is the average cerebrospinal fluid pressure in an animal lying on its side?

    <p>10 mm Hg (C)</p> Signup and view all the answers

    What is the average hydrostatic pressure in the peritubular capillaries of the kidneys?

    <p>13 mm Hg (B)</p> Signup and view all the answers

    How does the pressure in the interstitial fluid of most tissues compare to the pressure exerted by their encasements?

    <p>It is always lower. (C)</p> Signup and view all the answers

    What is the primary function of caveolins?

    <p>Transport small molecules across the cell membrane (A)</p> Signup and view all the answers

    Why are there discrepancies in interstitial fluid pressure measurements?

    <p>All of the above. (D)</p> Signup and view all the answers

    What are the small, oval windows present in the endothelial cells of the glomerular capillaries called?

    <p>Fenestrae (C)</p> Signup and view all the answers

    Which of the following processes is NOT directly associated with the function of caveolae?

    <p>Exocytosis (A)</p> Signup and view all the answers

    Which of the following is NOT a method for measuring interstitial fluid hydrostatic pressure?

    <p>Eponychium (B)</p> Signup and view all the answers

    What is the significance of caveolae in the transport of macromolecules?

    <p>Caveolae facilitate the movement of macromolecules across the cell membrane through a process called transcytosis. (D)</p> Signup and view all the answers

    According to the passage, what is the role of caveolae in the transport of plasma proteins?

    <p>Caveolae engulf packets of plasma containing plasma proteins and move them through the endothelial cell. (B)</p> Signup and view all the answers

    How does the intermittent flow of blood through capillaries differ from continuous flow?

    <p>Intermittent flow is characterized by short bursts of blood flow, while continuous flow is a steady and constant flow. (D)</p> Signup and view all the answers

    What is the key difference in the composition of the fluid that can pass through the glomerular capillaries compared to the fluid that passes through other capillaries?

    <p>Glomerular capillaries allow the passage of only small molecules, while other capillaries allow larger molecules as well. (D)</p> Signup and view all the answers

    What can we conclude about the role of the caveolae in the overall transport of substances through the endothelial cell?

    <p>Caveolae work together with other transport mechanisms to facilitate the movement of substances through the endothelial cell. (B)</p> Signup and view all the answers

    What is the primary mechanism that prevents backflow of lymph through the lymphatic capillaries?

    <p>Overlapping edges of endothelial cells acting as valves (D)</p> Signup and view all the answers

    How does fluid pressure within a lymphatic capillary affect the flow of lymph?

    <p>Increased pressure causes the lymphatic capillary endothelial cells to contract, pushing lymph forward. (D)</p> Signup and view all the answers

    What is the role of the lymphatic pump in the movement of lymph?

    <p>The lymphatic pump is the primary driver of lymph flow, pushing lymph towards the venous circulation. (A)</p> Signup and view all the answers

    Which of the following is NOT a factor that contributes to lymph flow?

    <p>Blood pressure in the capillary network. (A)</p> Signup and view all the answers

    What evidence suggests that contraction of the lymphatic capillary endothelial cells contributes to lymph pumping?

    <p>The observation of rhythmic contraction in lymphatic capillaries in certain animal tissues. (A), The presence of actomyosin filaments within the lymphatic capillary endothelial cells. (B)</p> Signup and view all the answers

    What is the primary function of the lymphatic capillaries?

    <p>To collect interstitial fluid and return it to the blood circulation. (C)</p> Signup and view all the answers

    Explain the mechanism of lymph flow through a lymphatic vessel.

    <p>Lymph flows from the interstitial fluid into the lymphatic capillaries, is pushed forward by the lymphatic pump, and returns to the blood circulation through the veins. (C)</p> Signup and view all the answers

    What is the relationship between interstitial fluid pressure and lymph flow?

    <p>Higher interstitial fluid pressure promotes increased lymph flow. (D)</p> Signup and view all the answers

    Which of the following structures is responsible for regulating blood flow into capillary beds?

    <p>Precapillary sphincters (D)</p> Signup and view all the answers

    What is the primary route for the diffusion of water-soluble substances across capillary walls?

    <p>Intercellular clefts (A)</p> Signup and view all the answers

    Which of the following is NOT a component of the microcirculation?

    <p>Aorta (B)</p> Signup and view all the answers

    How does the structure of the venule differ from the arteriole?

    <p>Venules have a thinner muscular coat. (A)</p> Signup and view all the answers

    Which of the following substances are likely to diffuse easily through the intercellular clefts of capillaries?

    <p>Glucose (A)</p> Signup and view all the answers

    What is the primary function of the metarteriole?

    <p>To transport blood directly from arteries to veins (C)</p> Signup and view all the answers

    Which of the following is NOT a factor that influences the rate of diffusion across the capillary wall?

    <p>Presence of a transporter protein (D)</p> Signup and view all the answers

    How do caveolae contribute to the function of capillaries?

    <p>They facilitate the transport of larger molecules. (A)</p> Signup and view all the answers

    What is the primary reason for the high protein concentration in thoracic duct lymph?

    <p>The liver and intestines contribute a significant portion of lymph to the thoracic duct. (A)</p> Signup and view all the answers

    What is the primary function of the anchoring filaments in lymphatic capillaries?

    <p>They help to maintain the integrity of the capillary walls. (A)</p> Signup and view all the answers

    Which of the following mechanisms allows large particles, such as bacteria, to enter the lymphatic capillaries?

    <p>Passage through the flap valves between endothelial cells. (D)</p> Signup and view all the answers

    How do the flap valves in lymphatic capillaries contribute to the unidirectional flow of lymph?

    <p>They prevent backflow of lymph into the surrounding tissues. (C)</p> Signup and view all the answers

    What is the typical protein concentration of thoracic duct lymph?

    <p>3 to 5 g/dl (C)</p> Signup and view all the answers

    Which of the following best describes the role of the lymphatic system in the absorption of fats?

    <p>The lymphatic system is responsible for absorbing nearly all dietary fats. (A)</p> Signup and view all the answers

    How does the lymphatic system contribute to the removal of bacteria from the body?

    <p>As lymph flows through lymph nodes, bacteria are filtered and destroyed. (B)</p> Signup and view all the answers

    What is the significance of the lymphatic system's ability to absorb high molecular weight substances?

    <p>It makes it possible for proteins, which cannot be absorbed by blood capillaries, to re-enter the circulatory system. (B)</p> Signup and view all the answers

    Study Notes

    Microcirculation and Lymphatic System: Capillary Fluid Exchange, Interstitial Fluid, and Lymph Flow

    • The microcirculation's primary roles are nutrient transport to tissues and waste removal
    • Arterioles regulate blood flow to each tissue based on local conditions
    • Capillary walls are thin, permeable endothelial cells enabling quick exchange of water, nutrients, and waste products
    • The human body contains approximately 10 billion capillaries with a combined surface area of 500-700 square meters
    • Cells are typically within 20-30 µm of a capillary

    Structure of the Microcirculation and Capillary System

    • Organ microcirculation is tailored to its specific needs
    • Nutrient arteries branch 6-8 times into arterioles (10-15 µm) before branching again into smaller arterioles (5-9 µm) that supply blood to capillaries
    • Arterioles are highly muscular, controlling diameter
    • Metarterioles, the terminal arterioles, lack a continuous muscular coat, but smooth muscle fibers are present at intervals
    • A precapillary sphincter regulates capillary entrance
    • Venules have weaker muscular walls than arterioles—despite the lower pressure, they can still contract
    • Metarterioles and precapillary sphincters respond directly to local tissue conditions (nutrients, metabolic byproducts, and hydrogen ions) to regulate blood flow

    Structure of the Capillary Wall

    • Capillary walls consist of a single layer of endothelial cells and a thin basement membrane
    • Walls are about 0.5 µm thick
    • Internal diameters range from 4-9 µm, limiting blood cell passage

    Pores in the Capillary Membrane

    • Intercellular clefts are passageways between endothelial cells, allowing passage
    • Width of clefts is 6-7 nanometers, smaller than many molecules
    • The cleft occupies a small fraction of the capillary wall, but allows rapid movement of water and other substances, essential for exchange

    Flow of Blood in the Capillaries-Vasomotion

    • Blood flow is intermittent, not continuous, due to vasomotion (intermittent constriction of metarterioles & precapillary sphincters, sometimes arterioles)
    • Oxygen concentration in tissues is the primary regulator of vasomotion

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    Related Documents

    Guyton Ch 16 PDF: The Microcirculation and Lymphatic System

    Description

    Test your understanding of the microcirculation and lymphatic system, focusing on capillary fluid exchange, interstitial fluid, and lymph flow. This quiz covers the roles of arterioles, the structure of the microcirculation, and the specific needs of various organs in nutrient transport and waste removal.

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