Vascular Function and Blood Flow Regulation
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Questions and Answers

What happens to pressure in the arterial system when there is an increase in volume?

  • Pressure becomes unpredictable.
  • Pressure decreases significantly.
  • Pressure increases. (correct)
  • Pressure remains unchanged.

    • How does sympathetic stimulation affect peripheral and coronary arteries?

  • There is no effect on either type of artery.
  • Both peripheral and coronary arteries constrict.
  • Peripheral vessels constrict while coronary arteries dilate. (correct)
  • Coronary arteries constrict while peripheral vessels dilate.

    • What is the primary consequence of excess blood in the left ventricle due to aortic regurgitation?

  • Reduction in blood volume in the left atrium
  • Increased oxygen delivery to the body
  • Backflow of blood into the pulmonary circulation (correct)
  • Improved cardiac output to systemic circulation

    • What is the relationship between volume infusion and sympathetic stimulation in both arterial and venous systems?

    <p>Volume infusion leads to sympathetic stimulation, increasing pressure.</p> Signup and view all the answers

    How is compliance of a systemic vein compared to a corresponding artery expressed mathematically?

    <p>Compliance is equal to distensibility times volume</p> Signup and view all the answers

    What is the primary function of the venous system in accommodating large amounts of blood?

    <p>Storing and regulating blood flow when necessary</p> Signup and view all the answers

    What characterizes the relationship between compliance and distensibility in blood vessels?

    <p>Compliance can be high in vessels with lower distensibility</p> Signup and view all the answers

    What does a volume-pressure curve show in the context of the circulatory system?

    <p>The effects of sympathetic and parasympathetic regulation on pressure.</p> Signup and view all the answers

    What is the role of the venous pump in the cardiovascular system?

    <p>It assists in propelling blood forward and regulating cardiac output.</p> Signup and view all the answers

    Which statement is true about the comparison of a common femoral vein to its corresponding artery?

    <p>The vein has about 24 times the compliance of the artery</p> Signup and view all the answers

    What occurs in the systemic arterial and venous systems when 200 ml of volume is added?

    <p>Pressure will increase abruptly.</p> Signup and view all the answers

    How are central venous pressure and right atrial pressure related?

    <p>Central venous pressure equals right atrial pressure.</p> Signup and view all the answers

    What is the primary action of sympathetic activity in the context of blood vessels?

    <p>To constrict peripheral vessels while dilating coronary arteries.</p> Signup and view all the answers

    What volume of blood does a highly distensible vessel typically store per millimeter of mercury rise in pressure?

    <p>Ranges from 0.5 to 1.0 liters</p> Signup and view all the answers

    What factor contributes to low resistance in large distended veins?

    <p>Structural characteristics of the veins</p> Signup and view all the answers

    What is the relationship between vascular compliance, pressure, and volume?

    <p>Vascular compliance combines volume and pressure to determine vessel behavior</p> Signup and view all the answers

    Which statement best describes the importance of volume-pressure curves?

    <p>They provide insights into how to limit volume in arteries or veins.</p> Signup and view all the answers

    What is the expected outcome of sympathetic stimulation in the context of adding volume?

    <p>Pressure will consequently increase due to vascular constriction.</p> Signup and view all the answers

    Which scenario would most likely result in inadequacies related to blood volume?

    <p>Increased blood being returned to the heart too quickly</p> Signup and view all the answers

    What happens to venous tone after severe hemorrhage?

    <p>Venous tone decreases, leading to low venous return.</p> Signup and view all the answers

    What percentage accuracy does the auscultatory method provide compared to direct catheter measurement?

    <p>10%</p> Signup and view all the answers

    What best describes vascular distensibility?

    <p>It refers to the ability to expand in response to pressure changes</p> Signup and view all the answers

    What occurs when the heart pumps with exceptionally vigorous force?

    <p>It results in increased venous return.</p> Signup and view all the answers

    Which physiological characteristic is true regarding large veins when they are distended?

    <p>They accommodate a large volume of blood with low resistance.</p> Signup and view all the answers

    What causes a lesser volume and pressure in the aorta during diastole?

    <p>Blood left in the pulmonary trunk</p> Signup and view all the answers

    In the context of aortic regurgitation, which characteristic is noted?

    <p>Blood flows back to the left ventricle during diastole</p> Signup and view all the answers

    What is a significant difference between patent ductus arteriosus (PDA) and aortic regurgitation?

    <p>PDA has a functional aortic valve</p> Signup and view all the answers

    How does the stiffening of arteries affect pressure during aortic regurgitation in older adults?

    <p>It causes a rise in pressure for a given stroke volume</p> Signup and view all the answers

    What occurs during diastole in cases of aortic regurgitation?

    <p>Abnormal increase in left ventricular volume</p> Signup and view all the answers

    What is a result of non-compliant arteries in older adults?

    <p>Abrupt increase in blood volume and pressure</p> Signup and view all the answers

    Which factor contributes to pulse pressure rising to twice normal in stiff arteries?

    <p>Decreased overall vascular compliance</p> Signup and view all the answers

    During diastole, the presence of incisura is an indication of what?

    <p>Functional aortic valve preventing backflow</p> Signup and view all the answers

    What causes venous pressure in the feet to be approximately +90 mmHg in a standing adult with absent venous valves?

    <p>Gravitational pressure effect</p> Signup and view all the answers

    What occurs when blood leaks from the venous system to the interstitial space?

    <p>Swelling in the lower extremities</p> Signup and view all the answers

    What happens to blood volume within 15 to 30 minutes of standing completely still?

    <p>It can be lost by 10 to 20 percent</p> Signup and view all the answers

    Which muscular activity helps to compress the veins in the lower extremities?

    <p>Calf muscle contraction</p> Signup and view all the answers

    What compensatory mechanism does the heart engage when there is apparent blood loss?

    <p>Increased heart rate and output</p> Signup and view all the answers

    What is the effect of muscle movement on the venous system in the legs?

    <p>Facilitates venous return to the heart</p> Signup and view all the answers

    What happens to the volume of fluid in the venous segment as blood is pushed into the interstitial space?

    <p>It decreases, leading to apparent blood loss</p> Signup and view all the answers

    What pressure gradient is created in the venous system during standing due to the absence of valves?

    <p>High positive pressure gradient in the lower limbs</p> Signup and view all the answers

    Study Notes

    Vascular Function and Blood Flow Regulation

    • Veins can store 0.5 to 1.0 liters of excess blood, serving as reservoirs for redistribution when blood is needed elsewhere in circulation.
    • Aortic regurgitation can lead to left ventricular overload, causing backflow into pulmonary circulation and resulting in congestion.

    Compliance and Distensibility

    • Compliance is different from distensibility; it accounts for volume in relation to pressure changes.
    • Compliance of systemic veins is 24 times higher than corresponding arteries due to veins being more distensible and having larger volumes.
    • Compliance is calculated as distensibility multiplied by volume.

    Volume-Pressure Relationship

    • Increased volume in both arterial and venous systems results in increased pressure due to sympathetic nervous system stimulation.
    • An infusion of 200 ml in a vascular segment causes an abrupt pressure increase.

    Arterial System Characteristics

    • Non-compliant arteries, such as in atherosclerosis, show a significantly higher pressure increase for a given stroke volume.
    • Pulse pressure can double in non-compliant arteries compared to normal conditions.

    Aortic Regurgitation Effects

    • Improper closure of aortic valves during diastole causes backward flow into the left ventricle, reducing aortic diastolic pressure.
    • Similarities to aortic regurgitation include decreased blood volume in the aorta during diastole, but with distinct features like functional aortic valves in patent ductus arteriosus.

    Venous System and Pressure Management

    • Central venous pressure (CVP) equates to right atrial pressure, allowing blood from systemic veins to flow into the heart.
    • Venous compliance allows large veins to accommodate significant changes in blood volume without significantly increasing resistance.

    Gravitational Effects on Venous Pressure

    • In the absence of venous valves, gravitational forces can lead to +90 mmHg of venous pressure in lower extremities of a standing adult.
    • Standing still for extended periods can cause significant fluid leakage from veins to interstitial spaces, leading to swelling and apparent blood loss.

    Role of Leg Muscles in Venous Return

    • Leg movement and muscle contractions facilitate blood flow back to the heart, counteracting the effects of gravity.
    • Calf muscle contraction compresses veins, assisting in forwarding blood to the heart during movement.

    Summary of Venous Dynamics

    • The body can lose 10-20% of blood volume within 15 to 30 minutes of standing still due to venous pooling and subsequent fluid shifts.
    • The circulatory system compensates for perceived blood loss, adjusting heart function accordingly.

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    Description

    This quiz explores key concepts related to vascular function, including the role of veins as blood reservoirs and the impact of aortic regurgitation. It also covers compliance, distensibility, and the volume-pressure relationship in the arterial and venous systems. Test your understanding of these essential principles of hemodynamics.

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