Regulation of Blood Flow in Physiology 2024
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Questions and Answers

What is the role of arterioles in the circulation?

  • Serve as exchange sites
  • Hold more than half of the blood in the circulatory system
  • Direct blood to individual tissues by selectively constricting and dilating (correct)
  • Act as pressure reservoirs
  • Which vessel type serves as blood reservoirs in the circulatory system?

  • Venules
  • Capillaries
  • Arteries
  • Veins (correct)
  • What is the main function of elastic arteries?

  • Act as pressure reservoirs (correct)
  • Direct blood to individual tissues by selectively constricting and dilating
  • Hold more than half of the blood in the circulatory system
  • Serve as exchange sites
  • Which factor is responsible for vasoconstriction and vasodilation?

    <p>Smooth muscle cells in the blood vessel wall</p> Signup and view all the answers

    What is the relationship between pressure and peripheral resistance in the circulation?

    <p>Direct relationship</p> Signup and view all the answers

    What is the main function of capillaries in the circulatory system?

    <p>Serve as exchange sites</p> Signup and view all the answers

    What determines blood flow according to Ohm's law?

    <p>Pressure difference and impediment to blood flow</p> Signup and view all the answers

    What triggers the release of nitric oxide (NO) in the endothelial cells of blood vessels?

    <p>Sudden stretch of small blood vessels</p> Signup and view all the answers

    What causes myogenic contraction in the smooth muscle of blood vessel walls?

    <p>Stretch-induced vascular depolarization</p> Signup and view all the answers

    What is responsible for the long-term control of blood flow in tissues over a period of days, weeks, or even months?

    <p>Increase or decrease in the physical sizes and numbers of blood vessels</p> Signup and view all the answers

    In acute control of local blood flow, what leads to rapid changes in local vasodilation or vasoconstriction of arterioles and precapillary sphincters?

    <p>Markers related to high tissue metabolism</p> Signup and view all the answers

    What is the primary function of vasomotion in blood vessels?

    <p>To adjust blood flow based on tissue metabolic needs</p> Signup and view all the answers

    What greatly influences blood flow and blood pressure?

    <p>Changes in the diameter of arteries</p> Signup and view all the answers

    What pressure is under tonic sympathetic control?

    <p>Arterial pressure</p> Signup and view all the answers

    What happens when factors cause arteriole vasoconstriction?

    <p>Peripheral resistance increases</p> Signup and view all the answers

    What does increased sympathetic activity lead to in veins?

    <p>Vasoconstriction</p> Signup and view all the answers

    At what value does cardiac output no longer keep up, according to the text?

    <p>Approx. 9 L/min</p> Signup and view all the answers

    What does the vascular function curve represent?

    <p>Venous return as a function of right atrial pressure</p> Signup and view all the answers

    What determines the right atrial pressure, end-diastolic volume, and end-diastolic fiber length?

    <p>Venous return</p> Signup and view all the answers

    What point is the unique operating or equilibrium point of the system in the steady state?

    <p>The point where cardiac output and venous return are equal</p> Signup and view all the answers

    What is the relationship between right atrial pressure, venous return, end-diastolic volume, and end-diastolic fiber length?

    <p>As venous return increases, right atrial pressure increases, and end-diastolic volume and end-diastolic fiber length increase.</p> Signup and view all the answers

    What is the value for the right atrial pressure at which venous return is zero and right atrial pressure is at its highest value?

    <p>4 mm Hg</p> Signup and view all the answers

    What occurs when the two curves intersect in the cardiac and vascular function curves?

    <p>Cardiac output is equal to venous return.</p> Signup and view all the answers

    What does increased sympathetic activity lead to in veins?

    <p>Vasoconstriction</p> Signup and view all the answers

    What determines peripheral resistance and how does it affect blood pressure?

    <p>Arteriole vasoconstriction increases peripheral resistance, which decreases blood pressure.</p> Signup and view all the answers

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