The Sympathetic Vasoconstrictor Mediator
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Questions and Answers

Which of the following factors is the main determinant of vascular resistance on a minute-to-minute basis?

  • Length of the blood vessel
  • Viscosity of blood
  • Radius of the vessel (correct)
  • Distribution of Vascular Resistance
  • Which site represents the primary site of vascular resistance maintaining normal blood pressure?

  • Cardiac Output
  • Kidneys
  • Capacitance venules
  • Resistance arterioles (correct)
  • Which of the following hormones is responsible for increasing arterial blood pressure by vasoconstriction?

  • Nitric Oxide
  • Prostaglandins
  • Angiotensin II (correct)
  • Bradykinin
  • Which endothelium-derived factor is responsible for vasodilation?

    <p>Prostacyclin (PGI2)</p> Signup and view all the answers

    Which enzyme catalyzes the conversion of angiotensinogen to angiotensin I?

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

    What is the main function of angiotensin II?

    <p>Sodium conservation</p> Signup and view all the answers

    Which hypothesis of autoregulation suggests that acute pressure-induced stretch of the arterial and arteriolar walls stimulates immediate constriction?

    <p>Myogenic hypothesis</p> Signup and view all the answers

    What is the role of vasopressin (AVP) in regulating vascular resistance?

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

    During exercise, blood flow is redistributed to areas with greater metabolic need. This is an adaptive mechanism that ensures oxygen and nutrients are delivered to active tissues.

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

    Which layer of blood vessels is composed of concentric layers of smooth muscle cells?

    <p>Tunica media</p> Signup and view all the answers

    Which type of blood vessel has the thickest walls and can withstand higher pressures?

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

    Which of the following best describes the primary goal of the pulmonary circulation?

    <p>To carry oxygen from the lungs to the tissues</p> Signup and view all the answers

    What is the main function of the systemic circulation?

    <p>To carry nutrients from the digestive tract to the tissues</p> Signup and view all the answers

    Which of the following statements about blood flow in the pulmonary circulation is true?

    <p>Pressure and vascular resistance are lower compared to the systemic circuit</p> Signup and view all the answers

    What is the purpose of blood flow redistribution in the systemic circulation?

    <p>To direct blood flow to areas with greater metabolic need</p> Signup and view all the answers

    Which mediator is responsible for preventing orthostatic hypotension?

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

    Which mediator is responsible for reducing circulating volume by stimulating natriuresis and diuresis?

    <p>Atrial natriuretic peptide/BNP</p> Signup and view all the answers

    Which mediator is targeted by the heart failure drug sacubitril?

    <p>Atrial natriuretic peptide/BNP</p> Signup and view all the answers

    Which mediator is responsible for inhibiting platelet aggregation and promoting vasodilation?

    <p>Prostacyclin (PGI2)</p> Signup and view all the answers

    According to the Law of Laplace, which of the following occurs when the arterial wall weakens in response to increased pressure, causing a vicious cycle of dilation, increased radius, increased tension, and ultimately a weakened wall?

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

    What is the role of nitric oxide (NO) in maintaining vessel patency and vascular wall health?

    <p>Promoting vasodilation</p> Signup and view all the answers

    What happens to endothelial shear stress in areas of vascular branching and downstream from an atherosclerotic plaque?

    <p>It decreases</p> Signup and view all the answers

    What is the major role played by vascular smooth muscle cells and the sympathetic nervous system in blood pressure regulation?

    <p>Maintaining systemic vascular resistance</p> Signup and view all the answers

    Which of the following is a compensatory response to an acute drop in blood pressure?

    <p>Increased firing of sympathetic fibers to vascular smooth muscle</p> Signup and view all the answers

    What is the most likely cause of the patient's fainting spell?

    <p>Vasovagal Syncope</p> Signup and view all the answers

    Which of the following is a hypothesis of the origin of hypertension?

    <p>Initial defect in sodium and water retention</p> Signup and view all the answers

    Which of the following is a possible cause of secondary hypertension?

    <p>Primary hyperaldosteronism</p> Signup and view all the answers

    What is the main function of angiotensin II?

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

    What is the main function of the systemic circulation?

    <p>Exchange of gases and nutrients with tissues</p> Signup and view all the answers

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