Blood Flow and Blood Pressure Control - Chapter 15
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Questions and Answers

What is the main function of the elastic systemic arteries?

  • To store oxygenated blood
  • To facilitate exchange at capillaries
  • To act as a pressure reservoir (correct)
  • To eliminate carbon dioxide

    • Which vessel type is primarily responsible for returning blood to the heart?

  • Capillaries
  • Veins (correct)
  • Arterioles
  • Arteries

    • What is the primary function of the pulmonary veins?

  • To deliver oxygen-rich blood from the heart to the body
  • To transport deoxygenated blood from the body to the right atrium
  • To carry oxygenated blood from the lungs to the left atrium (correct)
  • To drain blood from the capillaries back to the veins

    • How do arterioles contribute to blood flow control?

    <p>By altering their diameter</p> Signup and view all the answers

    When precapillary sphincters are relaxed, what happens to blood flow?

    <p>Blood flows through all capillaries in the bed</p> Signup and view all the answers

    What does sphygmomanometry measure?

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

    How do the diameters of veins compare to those of arteries?

    <p>Veins have a larger diameter and hold more blood</p> Signup and view all the answers

    What role does cardiac output play in blood pressure?

    <p>It contributes to blood pressure levels</p> Signup and view all the answers

    What occurs to blood pressure as blood travels through the systemic circulation?

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

    What occurs when precapillary sphincters constrict?

    <p>Blood flows through metarterioles, bypassing capillaries</p> Signup and view all the answers

    In the context of the heart's function, how do systems operate in terms of pumps?

    <p>Pumps function jointly, in parallel</p> Signup and view all the answers

    Which statement about veins is true?

    <p>They have thin walls of smooth muscle</p> Signup and view all the answers

    Mean arterial pressure is influenced by which two main factors?

    <p>Cardiac output and peripheral resistance</p> Signup and view all the answers

    What is the primary purpose of precapillary sphincters?

    <p>To regulate blood flow into capillaries</p> Signup and view all the answers

    What characteristic of capillaries facilitates material exchange?

    <p>Single layer of flattened endothelial cells</p> Signup and view all the answers

    Which type of capillaries are found in the bone marrow, liver, and spleen?

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

    How do pericytes affect capillary permeability?

    <p>They decrease permeability</p> Signup and view all the answers

    What mechanism prevents the backflow of blood in veins?

    <p>Presence of one-way valves</p> Signup and view all the answers

    Angiogenesis is necessary for which of the following processes?

    <p>Wound healing</p> Signup and view all the answers

    What influences the growth and differentiation of capillaries?

    <p>Cytokines and growth factors</p> Signup and view all the answers

    How do skeletal muscles assist blood return to the heart?

    <p>By compressing blood vessels</p> Signup and view all the answers

    What is the primary role of sympathetic control in arteriolar resistance?

    <p>To mediate vascular smooth muscle contraction</p> Signup and view all the answers

    Which of the following accurately describes hyperemia?

    <p>A locally mediated increase in blood flow</p> Signup and view all the answers

    What physiological mechanism is most directly involved in myogenic autoregulation of blood flow?

    <p>Increased calcium ion availability</p> Signup and view all the answers

    During sphygmomanometry, what happens at cuff pressure between 80 and 120 mm Hg?

    <p>Korotkoff sounds can be heard</p> Signup and view all the answers

    Which factors influence arteriolar resistance the most?

    <p>Local control, sympathetic reflexes, and hormones</p> Signup and view all the answers

    What role does elastic recoil in the arteries play during ventricular diastole?

    <p>It assists in maintaining driving pressure.</p> Signup and view all the answers

    Which equation represents the Mean Arterial Pressure (MAP)?

    <p>MAP = diastolic P + 1/3(systolic P - diastolic P)</p> Signup and view all the answers

    What happens to the semilunar valve during ventricular contraction?

    <p>It opens to allow blood ejection into the arteries.</p> Signup and view all the answers

    How is blood pressure primarily estimated?

    <p>Using sphygmomanometry.</p> Signup and view all the answers

    In what situation would hypotension occur?

    <p>When MAP is lower than normal.</p> Signup and view all the answers

    What is the relationship between cardiac output and Mean Arterial Pressure (MAP)?

    <p>MAP is proportional to cardiac output times resistance.</p> Signup and view all the answers

    Which of the following best defines pulse pressure?

    <p>The difference between systolic pressure and diastolic pressure.</p> Signup and view all the answers

    What is one of the primary functions of the aorta and elastic arteries?

    <p>To store and expand pressure during ventricular contraction.</p> Signup and view all the answers

    Study Notes

    Blood Vessels

    • Arteries transport blood away from the heart; have elastic walls and thick smooth muscle layers to act as pressure reservoirs.
    • Veins return blood to the heart; possess thin walls of smooth muscle and function as volume reservoirs.
    • Systemic veins contain over half of the blood volume in the circulatory system due to their larger diameters and greater numbers.

    Capillary Function

    • Capillaries are the thinnest blood vessels, with walls only one cell thick, facilitating efficient exchange of materials between blood and tissues.
    • Blood flow can be directed through capillary beds via precapillary sphincters, allowing bypassing of capillaries when constricted.

    Blood Pressure Mechanics

    • Blood pressure is generated when the heart pumps blood through the circulatory system; it changes as blood flows through the system.
    • Sphygmomanometry is used to estimate blood pressure; a cuff inflates and measures arterial blood flow through sounds (Korotkoff sounds).
    • Mean Arterial Pressure (MAP) is calculated using the formula MAP = diastolic pressure + 1/3(systolic pressure - diastolic pressure).

    Arteriolar Resistance

    • Arteriolar resistance affects blood pressure and is influenced by local (myogenic autoregulation, paracrines) and systemic factors (sympathetic reflexes, hormones).
    • Key local factors include active versus reactive hyperemia driven by paracrines like adenosine.

    Regulation of Blood Pressure

    • Cardiac output (CO) and peripheral resistance are crucial in determining blood pressure.
    • Hypotension refers to a MAP lower than normal, while hypertension indicates a MAP above normal.

    Blood Return Mechanisms

    • One-way valves in veins prevent backflow, aided by the skeletal muscle pump that compresses veins to push blood toward the heart.
    • The diaphragm generates pressure changes that aid venous return through smooth muscle contractions in larger veins.

    Angiogenesis

    • Angiogenesis is the formation of new blood vessels, essential for development, healing, and tumor growth, regulated by cytokines like VEGF and FGF.
    • It enhances blood flow during exercise and contributes to collateral circulation in coronary heart disease.

    Exercise and Blood Flow Distribution

    • During exercise, blood flow distribution shifts to meet increased metabolic demands of active tissues, influenced by arteriolar resistance adjustments.

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    Description

    This quiz covers the concepts of blood flow and the mechanisms involved in the regulation of blood pressure, as discussed in Lecture 23 of Chapter 15. Students will explore physiological principles and their implications for pharmaceutical sciences. Prepare to test your knowledge on these critical cardiovascular topics.

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