Muscle Blood Flow and Cardiac Output During Exercise
21 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of stents placed in coronary arteries?

  • To increase blood flow through the artery by dilating it.
  • To treat coronary microvascular disease.
  • To stimulate the growth of new blood vessels in the heart.
  • To prevent the artery from closing again after angioplasty. (correct)

    • According to the provided text, what happens to the endothelium of a coronary artery after a stent is placed?

  • It is damaged by the stent and does not regenerate.
  • It grows over the metal surface of the stent, allowing blood flow. (correct)
  • It becomes thicker and less permeable to blood.
  • It is replaced by a layer of scar tissue.

    • What is a possible outcome for patients who undergo coronary artery angioplasty?

  • They may experience complete resolution of coronary ischemic symptoms.
  • They may experience a decrease in blood flow to the heart.
  • They may require coronary bypass surgery in the future. (correct)
  • They may develop a new type of myocardial infarction.

    • What is the most common symptom of coronary ischemic symptoms?

    <p>Chest pain (angina) (B)</p> Signup and view all the answers

    What is the mechanism of hyperemia during exercise?

    <p>Dilation of blood vessels in the exercising muscles. (C)</p> Signup and view all the answers

    What is the approximate percentage of total coronary blood flow that returns to the right atrium via the coronary sinus?

    <p>75% (C)</p> Signup and view all the answers

    Which of the following statements about coronary blood flow is TRUE based on the provided information?

    <p>The coronary sinus receives blood flow primarily from the right ventricle. (C)</p> Signup and view all the answers

    What is the approximate coronary blood flow (ml/min) through the left coronary artery during diastole?

    <p>50 (A)</p> Signup and view all the answers

    What is the approximate coronary blood flow (ml/min) through the aorta?

    <p>300 (A)</p> Signup and view all the answers

    Which of the following statements is TRUE about the equilibrium point in Figure 21-2?

    <p>It is shifted to point B in response to changes in venous return and cardiac output. (D)</p> Signup and view all the answers

    What is the approximate change in right atrial pressure when the equilibrium point shifts from point A to point B?

    <p>1.5 mm Hg (D)</p> Signup and view all the answers

    Which of the following structures receives the majority of coronary venous blood flow?

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

    Based on the information provided, what is the primary route for venous blood flow from the right ventricle back to the heart?

    <p>Anterior cardiac veins (D)</p> Signup and view all the answers

    What is the primary source of nutrition for the heart muscle?

    <p>The coronary arteries (B)</p> Signup and view all the answers

    Which of the following is NOT a factor in the regulation of coronary blood flow?

    <p>The rate of blood flow through the capillaries of the left ventricle (D)</p> Signup and view all the answers

    The coronary blood flow in the left ventricle muscle during systole compared to diastole is:

    <p>Significantly lower during systole (D)</p> Signup and view all the answers

    What percentage of oxygen is typically removed from the coronary arterial blood as it flows through the heart muscle?

    <p>70% (B)</p> Signup and view all the answers

    Which of the following is TRUE regarding the blood supply to the left ventricle?

    <p>The left coronary artery primarily supplies the anterior and left lateral portions. (D)</p> Signup and view all the answers

    What is the role of the subendocardial arterial plexus?

    <p>To provide blood supply to the inner part of the heart muscle (B)</p> Signup and view all the answers

    The statement "Only the inner one-tenth millimeter of the endocardial surface can obtain significant nutrition directly from the blood inside the cardiac chambers" implies that:

    <p>The blood inside the cardiac chambers contributes minimally to heart muscle nutrition. (D)</p> Signup and view all the answers

    What is the relationship between oxygen demand and coronary blood flow?

    <p>Oxygen demand is directly proportional to coronary blood flow. (B)</p> Signup and view all the answers

    Flashcards

    Coronary ischemic symptoms

    Pain or discomfort in the heart due to insufficient blood flow.

    Angioplasty

    A medical procedure to open narrowed or blocked coronary arteries.

    Stent

    A small mesh tube used to keep arteries open after angioplasty.

    Restenosis

    The re-narrowing of an artery after treatment.

    Signup and view all the flashcards

    Collateral circulation

    Alternate pathways for blood flow that develop when primary vessels are blocked.

    Signup and view all the flashcards

    Coronary Blood Flow

    The volume of blood delivered to the heart muscle per minute, measured in ml/min.

    Signup and view all the flashcards

    Aorta Flow Rate

    The aorta has a blood flow of approximately 300 ml/min, supplying most of the body's blood.

    Signup and view all the flashcards

    Pulmonary Artery Flow Rate

    The pulmonary artery carries about 200 ml/min of blood to the lungs for oxygenation.

    Signup and view all the flashcards

    Right Coronary Artery Flow Rate

    The right coronary artery has a blood flow of about 100 ml/min, supplying blood to the right heart.

    Signup and view all the flashcards

    Left Coronary Artery

    Supplies blood to the left side of the heart, which works harder than the right.

    Signup and view all the flashcards

    Coronary Sinus Function

    Most venous blood from the left ventricle returns to the right atrium through the coronary sinus, accounting for 75% of the flow.

    Signup and view all the flashcards

    Right Atrial Pressure

    The pressure in the right atrium, which rises slightly with increased cardiac output.

    Signup and view all the flashcards

    Venous Return of Right Ventricle

    Venous blood from the right ventricle enters the right atrium through small veins, bypassing the coronary sinus.

    Signup and view all the flashcards

    Endocardial nutrition

    Only the inner one-tenth millimeter of the endocardial surface of the heart receives nutrition from cardiac blood.

    Signup and view all the flashcards

    Left coronary artery function

    Supplies mainly the anterior and left lateral portions of the left ventricle.

    Signup and view all the flashcards

    Right coronary artery function

    Supplies the most of the right ventricle and the posterior part of the left ventricle in 80% to 90% of people.

    Signup and view all the flashcards

    Coronary blood flow changes

    Blood flow through coronary arteries varies during systole and diastole phases of the heart cycle.

    Signup and view all the flashcards

    Nutrient capillaries

    Coronary capillary blood flow in the left ventricle muscle is critical for nutrition during cardiac cycles.

    Signup and view all the flashcards

    Oxygen demand and blood flow

    Coronary blood flow is regulated in proportion to the heart muscle's oxygen needs.

    Signup and view all the flashcards

    Coronary oxygen extraction

    Approximately 70% of the oxygen in coronary blood is extracted by the heart muscle.

    Signup and view all the flashcards

    Coronary vasculature layers

    Includes epicardial, intramuscular, and subendocardial arteries supplying blood to the heart.

    Signup and view all the flashcards

    Study Notes

    Muscle Blood Flow and Cardiac Output During Exercise

    • Blood flow to skeletal muscles and the heart's coronary arteries is primarily regulated by local control of vascular resistance, responding to muscle tissue metabolic needs.
    • Strenuous exercise places high demands on the circulatory system due to the large mass of skeletal muscle requiring increased blood flow.
    • Resting skeletal muscle blood flow is 3-4 ml/min/100g of muscle.
    • During intense exercise in well-conditioned athletes, skeletal muscle blood flow can increase 25-50 fold, reaching 100-200 ml/min/100g of muscle. Peak flows can exceed 400 ml/min/100g in endurance-trained athletes.
    • Blood flow during muscle contraction increases and decreases with each contraction. During contractions, blood flow is reduced due to vessel compression by the contracting muscle.
    • During exercise, all muscle capillaries open, increasing capillary surface area for better oxygen and nutrient diffusion.
    • Decreased oxygen in muscle tissue is a primary driver for increased blood flow, causing local arteriolar vasodilation.
    • Chemical factors like potassium, ATP, lactic acid, and carbon dioxide contribute to vasodilation.

    Control of Skeletal Muscle Blood Flow

    • Reduced oxygen levels in muscle tissue stimulate the release of local vasodilators causing arteriolar dilation.
    • This results in a significant increase in muscle blood flow, supporting the metabolic needs of active tissues.

    Coronary Circulation

    • Normal coronary blood flow averages 5% of cardiac output, approximately 225 mL/min.
    • During strenuous exercise, coronary blood flow increases threefold to fourfold to match the increased metabolic needs of the heart.
    • Coronary blood flow is primarily regulated by local muscle metabolism and is proportional to oxygen demand.
    • Coronary blood flow varies throughout the cardiac cycle. Reduction in blood flow occurs during systole due to compression from the contracting muscle but returns quickly during diastole.

    Ischemic Heart Disease

    • Ischemic heart disease, often a result of insufficient coronary blood flow, is a major cause of death in Western countries.
    • Atherosclerosis, a process where cholesterol deposits build up in the coronary arteries, is a common cause of diminished coronary blood flow.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Muscle Blood Flow & Cardiac Output During Exercise PDF

    Description

    This quiz explores the mechanisms of blood flow to skeletal muscles and the heart during exercise. It highlights how exercise intensity affects vascular resistance and blood circulation, emphasizing the needs of well-conditioned athletes. Test your knowledge on how these physiological changes support enhanced performance.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser