Cardiovascular System Overview
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Questions and Answers

What is the primary function of the lymphatic system?

  • Transport carbon dioxide to the lungs
  • Defend the body against pathogens (correct)
  • Circulate nutrients to organ systems
  • Remove waste products from blood

    • What is lymph fluid composed of?

  • Only red blood cells
  • Tissue fluid from capillaries (correct)
  • Digested food from the intestines
  • Oxygen and carbon dioxide

    • Which structure is NOT part of the lymphatic system?

  • Thymus
  • Spleen
  • Pulmonary trunk (correct)
  • Lymph nodes

    • How does the systemic circuit primarily function?

    <p>Delivers oxygen and nutrients to the body</p> Signup and view all the answers

    Which component of the circulatory system ejects blood into the aorta?

    <p>Left side of the heart</p> Signup and view all the answers

    What mechanism is utilized by lymphatic capillaries to prevent backflow?

    <p>Valves within the capillaries</p> Signup and view all the answers

    What occurs in the pulmonary capillaries?

    <p>Gas exchange for oxygen-poor blood</p> Signup and view all the answers

    Which of the following describes the return pathway of blood from systemic circulation?

    <p>Systemic venules and veins return blood to the right atrium</p> Signup and view all the answers

    What primarily causes the plateau phase during an action potential in ventricular contractile fibers?

    <p>Ca2+ inflow through slow Ca channels</p> Signup and view all the answers

    Which of the following waves in an ECG represents atrial depolarization?

    <p>P wave</p> Signup and view all the answers

    During which phase does rapid depolarization occur in a ventricular contractile fiber?

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

    What does the depolarization of the atrial contractile fibers produce?

    <p>P wave</p> Signup and view all the answers

    What does the QRS complex on an ECG primarily represent?

    <p>Ventricular depolarization</p> Signup and view all the answers

    What is produced by the depolarization of ventricular contractile fibers?

    <p>QRS complex</p> Signup and view all the answers

    Which interval reflects the time taken for the action potential to travel from the SA node to the AV node?

    <p>P-R interval</p> Signup and view all the answers

    Which heart sound corresponds to the closure of the AV valves?

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

    What occurs during the repolarization phase in a ventricular contractile fiber?

    <p>Closure of Ca2+ channels and K+ outflow</p> Signup and view all the answers

    What happens during atrial systole in the cardiac cycle?

    <p>Atria contract and ventricles are relaxed</p> Signup and view all the answers

    What does the T wave on an ECG signify?

    <p>Ventricular repolarization</p> Signup and view all the answers

    What is the formula for calculating cardiac output (CO)?

    <p>CO = stroke volume x heart rate</p> Signup and view all the answers

    What phase follows depolarization in a ventricular contractile fiber action potential?

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

    What does a normal R–R interval indicate?

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

    What is stroke volume defined as?

    <p>The volume of blood ejected from the ventricles with each contraction</p> Signup and view all the answers

    Which of the following conditions is characterized by no detectable P waves?

    <p>Atrial fibrillation</p> Signup and view all the answers

    What is the main function of the coronary arteries?

    <p>To provide blood to the heart muscle</p> Signup and view all the answers

    Which of the following structures is responsible for initiating the heartbeat?

    <p>Sinoatrial (SA) node</p> Signup and view all the answers

    What is the role of intercalated discs in cardiac muscle?

    <p>To connect muscle fibers for synchronized contractions</p> Signup and view all the answers

    What type of muscle fibers are considered autorhythmic?

    <p>Specialized cardiac muscle fibers</p> Signup and view all the answers

    Which part of the cardiac conduction system transmits impulses after the AV node?

    <p>Bundle of His</p> Signup and view all the answers

    How does the structure of cardiac muscle fibers differ from skeletal muscle fibers?

    <p>Cardiac fibers have intercalated discs</p> Signup and view all the answers

    What is the effect of an artery being partially blocked in coronary circulation?

    <p>It still allows sufficient oxygen to reach heart muscle due to anastomoses</p> Signup and view all the answers

    Which stage of action potential is characterized by a plateau phase?

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

    What is the main function of red blood cells?

    <p>Transport oxygen</p> Signup and view all the answers

    Which component of blood is primarily responsible for clotting?

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

    What is the primary characteristic of arteries?

    <p>Have thick walls</p> Signup and view all the answers

    Which type of white blood cell is primarily involved in the destruction of bacteria and viruses?

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

    What process does hemostasis primarily relate to?

    <p>Stoppage of bleeding</p> Signup and view all the answers

    Which blood component is primarily liquid and makes up 55% of blood?

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

    What is the role of calcium in cardiac muscle contraction?

    <p>It facilitates electrical impulses</p> Signup and view all the answers

    Which type of blood vessel carries blood back to the heart?

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

    What is contained in the plasma of blood that aids in immunity?

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

    What type of white blood cell is primarily responsible for immunity?

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

    What is the effect of epinephrine and norepinephrine on heart rate?

    <p>They increase heart rate and contractility.</p> Signup and view all the answers

    Which ions are crucial for maintaining effective heart pumping?

    <p>K+, Ca2+, and Na+</p> Signup and view all the answers

    What is the Frank–Starling law of the heart's principle?

    <p>Cardiac muscle fibers contract more forcefully when stretched within limits.</p> Signup and view all the answers

    What factors could lead to a decrease in afterload during cardiac cycle?

    <p>Lower blood pressure in the aorta and pulmonary artery.</p> Signup and view all the answers

    How do positive inotropic agents affect cardiac output?

    <p>They increase the force of contraction and cardiac output.</p> Signup and view all the answers

    Which of the following is considered a positive inotropic agent?

    <p>Thyroid hormones</p> Signup and view all the answers

    What role does the cardiovascular center in the medulla oblongata play?

    <p>It receives input from various sensory systems to regulate heart activity.</p> Signup and view all the answers

    What group of individuals might experience increased heart rate under normal conditions?

    <p>Senior citizens and infants.</p> Signup and view all the answers

    Study Notes

    Cardiovascular System (Part I)

    • The cardiovascular system's primary function is transporting blood, regulating various bodily functions, and protecting against diseases.

    Blood Composition

    • Blood is a connective tissue composed of:
      • Plasma (55%): Primarily water with proteins (albumins, globulins, fibrinogen), nutrients, wastes, and gases.
      • Formed elements (45%):
        • Red blood cells (erythrocytes): Biconcave discs containing hemoglobin, transporting oxygen; 4.2-6.2 million per cubic mm.
        • White blood cells (leukocytes): Protecting against disease-causing agents (pathogens). Different types with varying functions: neutrophils, lymphocytes, monocytes, eosinophils, basophils; 5,000-9,000 per cubic mm.
        • Platelets (thrombocytes): Essential for blood clotting; 130,000-360,000 per cubic mm.

    Blood Functions

    • Transportation: Carries oxygen, nutrients, hormones, and waste products.
    • Regulation: Maintains homeostasis, balancing acids/bases and bodily fluids.
    • Protection: Combats disease-causing agents and prevents excessive blood loss.

    Red Blood Cells (RBCs)

    • Transport oxygen throughout the body
    • Biconcave-shaped, small enough for capillary passage
    • Contain hemoglobin:
      • Oxyhemoglobin (bright red) carries oxygen
      • Deoxyhemoglobin (dark red) lacks oxygen.

    White Blood Cells (WBCs)

    • Granulocytes: Neutrophils (55%) - destroy bacteria, viruses, and toxins. Eosinophils (3%) - combat parasitic infections like worms. Basophils (1%) - control inflammation and allergic reactions.
    • Agranulocytes: Monocytes (8%) - Destroy bacteria, viruses, and toxins. Lymphocytes (33%) - play a crucial role in the body's immunity.

    Blood Platelets

    • Fragments of cells that are crucial for blood clotting.
    • About 130,000-360,000 per cubic millimeter of blood.
    • Essential for hemostasis (stopping bleeding).

    Controlling Bleeding (Hemostasis)

    • A complex of three processes:
      • Blood vessel spasm
      • Platelet plug formation
      • Blood coagulation (formation of a clot.)

    Blood Vessels

    • Arteries & Arterioles: Strongest blood vessels, carry blood away from the heart under high pressure, possessing thick walls.
    • Veins & Venules: Blood moves slowly in veins due to low pressure. Valves prevent backflow.
    • Capillaries: Tiny blood vessels connecting arterioles to venules; sites of gas, nutrient, and waste exchange between the blood and body cells.

    Lymphatic System

    • Network of vessels collecting fluids between cells and returning them to the bloodstream, crucial for fluid balance and absorbing lipids.
    • Also critical for defending the body against disease-causing agents (pathogens).
    • Lymph nodes, thymus, and spleen are part of this system.

    Lymph Fluid

    • Tissue fluid that enters lymphatic capillaries
    • Contains Valves preventing backflow of lymph

    Circulation of Blood

    • Blood circulates via two major circuits:
      • Pulmonary circulation: Blood travels from the heart to the lungs for oxygen uptake and release of carbon dioxide.
      • Systemic circulation: Blood travels from the heart to the rest of the body, delivering oxygen and nutrients and removing waste products.

    Systemic and Pulmonary Circulation

    • Systems using separate circuits allowing efficient oxygen and nutrient delivery, accompanied by waste elimination.

    Coronary Circulation

    • Coronary arteries supply the heart muscle with blood, providing oxygen and nutrients.
    • Coronary veins collect used blood, transporting it to the right atrium.

    Heart: A special muscle

    • Specialized muscle with the job of pumping blood throughout the body.

    Cardiac Muscle Characteristics

    • Shorter, less circular than skeletal muscle fibers
    • Branching structure giving a "stair-step" appearance.
    • Typically one nucleus centrally located
    • Ends of fibers connected by intercalated discs (desmosomes and gap junctions)
    • Contains numerous mitochondria (40%).
    • Actin and myosin arrangement is the same as in other muscle tissues.

    Autorhythmic Fibers

    • Specialized heart muscle fibers that self-excite, generating action potentials to trigger heart contractions.
    • Serve as pacemakers regulating rhythmic heartbeats, forming the heart's conduction system.

    Cardiac Conduction System

    • Specialized conductive tissue (SA node, AV node, bundles of His, Purkinje fibers) directs electrical signals rapidly across the heart muscle, coordinating controlled and effective contractions for efficient blood pumping.

    Action Potentials and Contraction

    • Action potentials initiate contraction; depolarization initiates a contraction through the activation of contractile proteins.
    • Depolarization occurs when there is a change in charge across the membrane, and contractile proteins are activated

    ECG (Electrocardiogram)

    • Composite record of action potentials generated by all heart muscle fibers.
    • Wave forms (P, QRS, and T) visually represent the electrical activity during each stage of the cardiac cycle.

    Cardiac Cycle

    • The sequence of events where the heart alternately contracts and relaxes during blood flow; blood flows through each chamber in a rhythmic pattern.
    • Atrial systole: atria contracts, blood enters relaxed ventricles.
    • Ventricular systole: ventricles contract, blood is pumped into arteries.

    Heart Sounds (Auscultation)

    • Sounds caused by blood turbulence when heart valves close ( "lub" - atrioventricular valves, and "dup" - semilunar valves).

    Cardiac Output (CO)

    • Volume of blood pumped by the left ventricle per minute; calculated as heart rate multiplied by stroke volume.

    Stroke Volume (SV)

    • Amount of blood pumped by the left ventricle with each contraction. Regulated by factors in preload, contractility and afterload.

    Factors Affecting Preload

    • How much the heart chamber is stretched before it contracts; directly related to the end-diastolic volume and venous return, impacting the force of contraction.
    • Frank-Starling law of the heart.

    Factors Affecting Contractility

    • The strength of heart contraction relating to a given volume of blood.
    • Influenced by positive and negative inotropic agents (e.g., epinephrine) affecting calcium inflow.

    Factors Affecting Afterload

    • The pressure the ventricles must overcome to pump blood.
    • Increasing afterload lowers stroke volume.

    Exercise and the Heart

    • Exercise significantly impacts cardiac output, Increasing heart rate and stroke volume.

    Regulation of Heart Beat

    • Autonomic nervous system regulates heart rate: sympathetic accelerates and parasympathetic slows it down which is regulated by the cardiovascular center in the medulla oblongata.
    • Hormones (epinephrine/norepinephrine) and blood ionic levels also impact heart rate and contractility.

    Questions addressed.

    • How would increased sympathetic stimulation of the heart affect stroke volume?: Increased sympathetic stimulation leads to increased heart rate and contractility, subsequently increasing stroke volume.

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    CVS Physiology Part 1 PDF

    Description

    This quiz covers the essential components and functions of the cardiovascular system, focusing on blood composition and its roles. Learn about the various blood elements, including red and white blood cells, and platelets. Test your understanding of how blood aids in transportation and regulation within the body.

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