lecture 6 Cardiovascular System Overview
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Questions and Answers

What happens to the AV valves when the ventricles are relaxed?

  • AV valves close due to higher pressure in the ventricles
  • AV valves remain closed regardless of pressure
  • AV valves only open when arterial pressure rises
  • AV valves open due to lower pressure in the ventricles (correct)

    • Which blood vessels bring deoxygenated blood to the heart?

  • Pulmonary arteries
  • Aorta
  • Pulmonary veins
  • Vena cava (correct)

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

  • Delivering blood to the heart
  • Site of gas and nutrient exchange (correct)
  • Site of blood collection from tissues
  • Conducting vessels for blood

    • How do the systemic and pulmonary systems differ in terms of pressure and resistance?

    <p>Pulmonary has low pressure, systemic has high pressure</p> Signup and view all the answers

    What is the role of small arteries in the circulatory system?

    <p>Deliver blood locally to arterioles and capillaries</p> Signup and view all the answers

    What is cardiac output?

    <p>The total volume of blood pumped by both sides of the heart per minute</p> Signup and view all the answers

    What is the main reason for the thicker wall of the left ventricle compared to the right ventricle?

    <p>It must deliver blood to the entire body under high pressure</p> Signup and view all the answers

    What characterizes arteries in the circulatory system?

    <p>They receive tremendous pressure from ventricle contractions</p> Signup and view all the answers

    What is the primary function of the atria in the heart?

    <p>To serve as reservoirs and transfer blood to the ventricles</p> Signup and view all the answers

    Which heart chambers are responsible for pumping blood into the systemic and pulmonary circulations?

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

    What role do the semi-lunar valves serve in the heart?

    <p>To prevent backflow of blood into the ventricles</p> Signup and view all the answers

    What is the function of the pericardium surrounding the heart?

    <p>To prevent over-stretching and provide lubrication</p> Signup and view all the answers

    What type of tissue is the myocardium primarily made of?

    <p>Muscle tissue</p> Signup and view all the answers

    How does the cardiac cycle contribute to the cardiovascular system?

    <p>It ensures oxygen delivery to tissues</p> Signup and view all the answers

    What is the role of the cardiac valves during blood flow?

    <p>They ensure blood flows in one direction only</p> Signup and view all the answers

    Which type of blood vessels carry blood away from the heart?

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

    What occurs when the ventricles are contracted?

    <p>Aortic and pulmonary valves open due to pressure</p> Signup and view all the answers

    Which statement correctly describes the pulmonary circulation?

    <p>It involves a low pressure loop between the heart and lungs.</p> Signup and view all the answers

    How do small arteries regulate blood pressure?

    <p>Through the contraction of their smooth muscle</p> Signup and view all the answers

    Which of the following statements about veins is correct?

    <p>Veins receive blood from smaller venules.</p> Signup and view all the answers

    What role do the atrioventricular (AV) valves serve during ventricular relaxation?

    <p>They open to allow blood flow from the atria to ventricles.</p> Signup and view all the answers

    What distinguishes systemic circulation from pulmonary circulation?

    <p>Systemic circulation is characterized by high pressure and high resistance.</p> Signup and view all the answers

    What is the primary function of the chordae tendineae in the heart?

    <p>They anchor the AV valves to the papillary muscles.</p> Signup and view all the answers

    Which factors affect the cardiac output of the heart?

    <p>The rate and force of ventricular contraction</p> Signup and view all the answers

    What is the primary function of the atria in the heart?

    <p>To act as reservoirs for blood</p> Signup and view all the answers

    Which of the following best describes the role of the heart valves?

    <p>They ensure blood flows only in one direction</p> Signup and view all the answers

    What separates the two halves of the heart?

    <p>The muscular septum</p> Signup and view all the answers

    Which layer of the pericardium is attached directly to the heart wall?

    <p>Visceral layer</p> Signup and view all the answers

    How do the pulmonary and systemic circulatory systems primarily differ?

    <p>In the pressure and resistance levels they operate under</p> Signup and view all the answers

    What is the main role of the myocardium?

    <p>To pump blood through the circulatory system</p> Signup and view all the answers

    Which of the following statements about the heart chambers is accurate?

    <p>The atria serve to transfer blood to the ventricles</p> Signup and view all the answers

    What is a key function of the systemic circulatory system?

    <p>Deliver nutrients from the intestine to tissues</p> Signup and view all the answers

    Study Notes

    Cardiovascular System Overview

    • The cardiovascular system (CVS) is comprised of the heart and blood vessels
    • The heart functions as a pump, moving blood throughout the body
    • The heart is divided into four chambers: two atria and two ventricles
    • The atria receive blood from the body and lungs
    • The ventricles pump blood to the lungs and body
    • The heart is separated into two sides (left and right) by a septum: prevents mixing of oxygenated and deoxygenated blood
    • The heart contains four valves: two atrioventricular (AV) valves and two semilunar valves
      • The AV valves regulate blood flow between the atria and ventricles
        • Tricuspid valve: located between the right atrium and right ventricle
        • Bicuspid (mitral) valve: located between the left atrium and left ventricle
      • The semilunar valves regulate blood flow between the ventricles and major arteries
        • Aortic valve: controls blood flow from the left ventricle to the aorta
        • Pulmonary valve: controls blood flow from the right ventricle to the pulmonary artery
    • The heart is covered by the pericardium, which consists of two layers of connective tissue
      • Visceral layer: attached to the heart wall
      • Parietal layer: reinforced, outer layer
      • The fluid-filled cavity between the layers allows for movement of the heart
    • The heart wall is made of myocardial tissue

    Circulatory Systems

    • The CVS consists of two circulatory systems: pulmonary and systemic

    Pulmonary Circulation

    • Moves blood between the heart and lungs
    • Transports deoxygenated blood from the right ventricle to the lungs
    • Transports oxygenated blood from the lungs to the left atrium
    • Lower pressure, lower resistance, highly distensible

    Systemic Circulation

    • Moves blood between the heart and the rest of the body
    • Transports oxygenated blood from the left ventricle to the rest of the body
    • Transports deoxygenated blood from the body to the right atrium
    • High pressure, high resistance
    • The left ventricle works harder than the right ventricle because of the high pressure required to move blood through the systemic circulation

    Functions of the Cardiovascular System

    • Transports oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs
    • Transports nutrients from the digestive system to the body
      • Includes transportation between the liver (metabolic center) and tissues
      • Includes transportation between fat (storage) and tissues
    • Transports waste products from production sites to excretion sites
    • Helps regulate body temperature
    • Transports hormones from endocrine glands to target cells
    • Carries immune cells
    • Helps stabilize the internal environment by buffering pH and ion concentrations

    Heart Valves

    • Are made of fibrous connective tissue

    • Open and close passively based on pressure gradients

    • AV Valves:

      • Open when the ventricles are relaxed
      • Close when the ventricles contract

    • Semilunar Valves:

      • Open when the ventricles contract
      • Close when the ventricles are relaxed

      Blood Vessels

    • Blood vessels form the "pipes" that carry blood throughout the body

    • Arteries

      • Carry blood away from the heart
      • Pulmonary arteries: carry deoxygenated blood from the right ventricle to the lungs
      • Aorta: carry oxygenated blood from the left ventricle to the body

    • Veins

      • Carry blood back to the heart
      • Vena cava: carry deoxygenated blood from the body to the right atrium (superior vena cava - head and arms, inferior vena cava - legs and lower body)
      • Pulmonary veins: carry oxygenated blood from the lungs to the left atrium

    • Arterioles

      • Smaller arteries
      • Control the pressure via the tone of the vessel's smooth muscle

    • Capillaries

      • The smallest blood vessels
      • Site of gas exchange, nutrient delivery, and waste removal

    • Venules

      • Small veins
      • Collect blood from capillaries

    • Veins

      • Receive blood from venules and return it to the heart
      • Venous return is regulated by vein tone

    Cardiac Output

    • The amount of blood pumped by each half of the heart per minute
    • Right heart: pumps blood through the pulmonary system
    • Left heart: pumps blood through the systemic system
    • Increased cardiac output corresponds to increased physical activity
    • Cardiac output is impacted by heart rate and stroke volume
      • Heart rate: number of times the heart beats per minute
      • Stroke volume: volume of blood pumped by the heart per beat

    Cardiovascular System Overview

    • The cardiovascular system (CVS) is made up of the heart and blood vessels.
    • The heart is a four-chambered organ
    • Each chamber is separated by valves that regulate blood flow in one direction.
    • Two sets of valves: atrioventricular (AV) valves and semilunar valves.
    • AV valves: tricuspid (right side) and bicuspid (left side).
    • Semilunar valves: aortic and pulmonary.

    Major Functions of the CVS

    • Transport oxygen and carbon dioxide between the lungs and tissues.
    • Transport nutrients, including those from the intestine to tissues, and between the liver and fat stores.
    • Transport waste products from production sites to excretion sites.
    • Transport heat from the interior of the body to the skin.
    • Transport hormones from endocrine glands to target cells.
    • Carry immune cells.
    • Stabilize the internal environment by buffering pH and ion concentrations.

    Anatomy of the Heart

    • The heart is enclosed within a sac called the pericardium, composed of two layers.
    • The pericardium prevents overstretching and oversizing of the heart.
    • The pericardium contains fluid that allows for some movement of the heart.
    • The two atria serve as reservoirs and help transfer blood to the ventricles.
    • The two ventricles propel blood into the systemic and pulmonary circulations.
    • The heart wall is primarily composed of muscle tissue called myocardium.
    • The heart is divided into two halves by a muscular septum.
    • The endocardium is a layer of epithelium that covers the inner surface of the heart, similar to the endothelium of blood vessels.

    Cardiac Valves

    • Cardiac valves are made of fibrous connective tissue.
    • The valves are attached to a fibrous ring and allow one-way blood flow.
    • Atrioventricular (AV) valves:
      • Bicuspid (mitral) valve is located on the left side of the heart.
      • Tricuspid valve is located on the right side of the heart.
      • The free end of each AV valve is attached to papillary muscles in the ventricles, preventing valve inversion.
    • Semilunar valves:
      • Aortic valve is located between the left ventricle and the aorta.
      • Pulmonary valve is located between the right ventricle and the pulmonary artery.

    Valve Opening and Closing

    • The opening and closing of the heart valves is a passive mechanism controlled by blood pressure and pressure gradients.
    • When ventricles relax, pressure is lower, and AV valves open.
    • When ventricles contract, pressure increases, and AV valves close.
    • When the pressure in the ventricles exceeds arterial pressure, the aortic and pulmonary valves open.
    • When the ventricles are emptied, pressure drops, and all valves close.

    Great Vessels

    • Arteries:
      • Carry blood away from the heart to tissues and organs.
      • Pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs.
      • The aorta carries oxygenated blood from the left ventricle to the rest of the body.
    • Veins:
      • Carry blood from the tissues and organs back to the heart.
      • The vena cava (superior and inferior) carry deoxygenated blood to the right atrium.
      • Pulmonary veins carry oxygenated blood to the left atrium.

    Blood Vessels

    • Arteries branch off the aorta and pulmonary arteries.
      • They require elasticity to handle the pressure from ventricle contractions.
    • Small arteries deliver blood locally to arterioles and capillaries within tissues.
    • Capillaries are the site of gas exchange, nutrient and waste transport, etc.
    • Venules collect blood from capillaries.
    • Veins receive blood from venules and return it to the heart.
    • Alterations in the tone of veins can modify venous return.

    Systemic and Pulmonary Systems

    • Both systems have arteries and veins.
    • Pulmonary system: heart-lungs loop for blood oxygenation.
      • Characterized by low pressure, low resistance, and high distensibility.
    • Systemic system: distributes oxygenated blood and nutrients throughout the body.
      • Characterized by high pressure, high resistance.
    • The left ventricle performs 5-7 times more work than the right ventricle, explaining its thicker wall.

    Cardiac Output

    • Cardiac output is the amount of blood pumped by each half of the heart per minute.
    • The right and left sides of the heart each have their own cardiac output.
    • Cardiac output is a measure of the heart's overall efficiency.

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    Description

    Explore the intricate details of the cardiovascular system, including the heart's anatomy and functions. This overview covers the four chambers of the heart, as well as the roles of valves and blood flow regulation. Perfect for those studying human biology or related health sciences.

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