Circulatory and Lymphatic - Part 2
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Questions and Answers

What is the primary function of the sinoatrial node?

  • To set the rhythm of the heart (correct)
  • To control blood pressure
  • To slow down the heart rate
  • To regulate blood volume

    • Which structure in the heart has the slowest intrinsic firing rate?

  • Atrioventricular bundle
  • Atrioventricular node
  • Purkinje fibers (correct)
  • Sinoatrial node

    • Which wave on an electrocardiogram represents ventricular depolarization?

  • T wave
  • P wave
  • U wave
  • QRS wave (correct)

    • What effect does epinephrine have on heart rate?

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

    What is Starling's law of the heart primarily concerned with?

    <p>Stretch and contraction strength</p> Signup and view all the answers

    Which physiological condition can increase heart rate?

    <p>Physical exercise</p> Signup and view all the answers

    Which node serves as the primary pacemaker of the heart?

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

    How does the body typically change cardiac output?

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

    What is the primary function of the white pulp in the spleen?

    <p>Carrying out immune functions</p> Signup and view all the answers

    What changes occur in the thymus with age?

    <p>Fatty infiltrations replace lymphoid tissue</p> Signup and view all the answers

    Where is the spleen primarily located?

    <p>Left hypochondriac region</p> Signup and view all the answers

    What is the function of the red pulp in the spleen?

    <p>Removal and storage of blood cells</p> Signup and view all the answers

    What is the structure and appearance of the thymus gland?

    <p>Bilobed and reddish due to high lymphoid tissue</p> Signup and view all the answers

    What is the main function of adaptive immunity?

    <p>To involve specific recognition of microbes that breach innate immunity</p> Signup and view all the answers

    Which cells are primarily involved in adaptive immunity?

    <p>T lymphocytes and B lymphocytes</p> Signup and view all the answers

    What primarily distinguishes lymph plasma from interstitial fluid?

    <p>Lymph plasma is located in lymphatic vessels</p> Signup and view all the answers

    What is the role of the lymphatic system in the body?

    <p>To drain interstitial fluid and contribute to disease defense</p> Signup and view all the answers

    Where does the right lymphatic duct typically empty lymph plasma?

    <p>At the junction of the internal jugular and subclavian veins</p> Signup and view all the answers

    What distinguishes fetal circulation from postnatal circulation?

    <p>The fetus does not breathe air.</p> Signup and view all the answers

    What is the Cistern Chyli?

    <p>The starting point of the lymphatic system</p> Signup and view all the answers

    Which lymph vessel is the main duct on the left side for returning lymph plasma to blood?

    <p>Thoracic duct</p> Signup and view all the answers

    What is the first line of defense in innate immunity?

    <p>Skin and mucous membranes</p> Signup and view all the answers

    What is the primary function of lymphocytes in lymphoid tissue?

    <p>To provide immune responses against pathogens</p> Signup and view all the answers

    What process occurs immediately after the delivery of a full-term fetus?

    <p>Ductus arteriosus and ductus venosus undergo vasoconstriction.</p> Signup and view all the answers

    What does susceptibility refer to in the context of immunity?

    <p>Vulnerability or lack of resistance.</p> Signup and view all the answers

    What type of connective tissue is lymphoid tissue primarily classified as?

    <p>Reticular connective tissue</p> Signup and view all the answers

    What is the approximate length of the lymphatic duct?

    <p>15-18 cm</p> Signup and view all the answers

    What is the primary function of the placenta during fetal development?

    <p>To allow nutrient and waste exchange with maternal blood.</p> Signup and view all the answers

    Which mechanism is primarily associated with innate immunity?

    <p>Phagocytosis of pathogens.</p> Signup and view all the answers

    When do the lungs begin to function for the fetus?

    <p>Once the fetus is delivered.</p> Signup and view all the answers

    What does innate immunity NOT involve?

    <p>Specific recognition of pathogens.</p> Signup and view all the answers

    What happens to the foramen ovale after birth?

    <p>It closes due to increased pressure in the left atrium.</p> Signup and view all the answers

    What is the role of systemic capillaries?

    <p>Facilitate the exchange of substances between blood and tissues.</p> Signup and view all the answers

    What is the term for the contraction phase of the heart cycle?

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

    What is the average stroke volume for a human?

    <p>75 mL</p> Signup and view all the answers

    Which type of blood vessel is responsible for carrying oxygenated blood away from the heart?

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

    Which phase of the cardiac cycle involves the simultaneous contraction of the atria?

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

    What is the normal resting heart rate for an average human?

    <p>70 bpm</p> Signup and view all the answers

    Which type of blood vessel has the thinnest walls and allows for the exchange of substances?

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

    What does cardiac output (CO) depend on?

    <p>Heart rate and stroke volume</p> Signup and view all the answers

    Which blood vessel type is smaller and branches off from arteries?

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

    What is the primary function of veins?

    <p>Return deoxygenated blood to the heart</p> Signup and view all the answers

    Which type of artery is known for containing more smooth muscle than elastic fibers?

    <p>Muscular arteries</p> Signup and view all the answers

    Study Notes

    Heart as a Pacemaker

    • Sinoatrial (SA) node initiates heartbeats at a rate of 70-80 bpm.
    • Atrioventricular (AV) node serves as a secondary pacemaker at 40-60 bpm.
    • Atrioventricular bundle, bundle branches, and Purkinje fibers can generate impulses at 20-40 bpm.

    Regulation of Heart Rate

    • Starling’s law states that increased heart stretch results in more forceful contractions.
    • Adjusting heart rate is the primary method to influence cardiac output.

    Electrocardiogram (ECG)

    • An ECG measures electrical activity of the myocardium:
      • P wave indicates atrial depolarization.
      • QRS wave indicates ventricular depolarization.
      • T wave indicates ventricular repolarization.

    Heart Rate Control

    • The SA node’s rhythm is modified by physiological factors.
    • Nerve sets influence heart rate: one enhances, the other diminishes it.
    • Hormones like epinephrine increase heart rate.
    • Heart rate rises with body temperature and physical exertion.

    Cardiac Cycle and Output

    • Atria contract simultaneously, followed by ventricular contraction.
    • Systole refers to contraction; diastole refers to relaxation.
    • Cardiac output (CO) formula: CO = heart rate (HR) x stroke volume (SV).
    • Average cardiac output ranges from 5.25 L/min to 35 L/min.

    Blood Vessels

    • Blood vessels facilitate blood transport and nutrient exchange.
    • Types of blood vessels:
      • Arteries: carry oxygenated blood away from the heart.
      • Arterioles: smaller branches of arteries.
      • Capillaries: smallest vessels for nutrient and waste exchange.
      • Venules: small veins that transport blood from capillaries.
      • Veins: carry deoxygenated blood back to the heart.

    Fetal Circulation

    • Unique structures enable material exchange between fetus and mother.
    • Lung, kidney, and digestive systems are inactive before birth.
    • After delivery, the infant’s lungs initiate oxygen intake, ending placental blood flow.

    Immune System: Key Concepts

    • Immunity is the body's ability to resist damage or disease.
    • Susceptibility refers to vulnerability to infections.

    Types of Immunity

    • Innate (nonspecific) immunity:

      • Present at birth; reacts to all microbes similarly.
      • First line includes physical barriers, second line involves immune cells and inflammation.

    • Adaptive (specific) immunity:

      • Involves tailored responses to specific microbes.
      • Relies on lymphocytes (B cells and T cells).

    Lymphatic System

    • Aims to maintain homeostasis through fluid drainage and disease defense.
    • Lymph plasma is a fluid transported by lymphatic vessels, differing from interstitial fluid by its location.
    • Lymphoid tissue contains many lymphocytes.

    Lymphatic Trunks and Ducts

    • Right lymphatic trunks empty into venous junctions; may form the right lymphatic duct.
    • The thoracic duct on the left side is the main route for lymph return to blood circulation.

    Thymus

    • Bilobed organ located mediastinally, crucial for immune function.
    • Lined with lymphoid tissue and has a rich vascular supply, appearing red.
    • Age-related changes include fatty infiltration replacing lymphoid tissue.

    Spleen

    • Largest mass of lymphatic tissue in the body, located in the left hypochondriac region.
    • White pulp supports immune functions (phagocytosis).
    • Red pulp involved in blood cell management:
      • Removal of damaged red blood cells and platelets.
      • Storage of platelets.

    Lymph Nodes

    • Approximately 600 bean-shaped nodes scattered along lymphatic vessels.
    • Act as filters in the lymphatic system, supporting immune responses.

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    Description

    This quiz covers key concepts in cardiovascular physiology, focusing on the heart's pacemaker functions, heart rate regulation, and the interpretation of electrocardiograms (ECG). It highlights the roles of different nodes, hormones, and physiological factors in controlling heart rhythm and cardiac output. Test your knowledge of these essential topics in cardiac health and function.

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