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Anatomy & Physiology: Blood, Heart, and Blood Vessels

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  • Functions of blood

    Transport: oxygen, nutrients, wastes, hormones.
    Regulation: body temperature, pH, fluid balance.
    Protection: prevents blood loss and infection.

  • Composition of whole blood

    Blood consists of plasma (90% water, proteins, solutes) and formed elements (erythrocytes, leukocytes, platelets).

  • Why is blood classified as connective tissue?

    Because it consists of living cells (formed elements) suspended in a nonliving fluid matrix (plasma).

  • Erythrocyte structure and function

    Biconcave, anucleate cells packed with hemoglobin; transport oxygen and carbon dioxide.

  • Hemoglobin composition

    Protein with four globin chains, each bound to a heme group containing iron that binds oxygen.

  • Erythropoiesis regulation

    Controlled by erythropoietin (EPO) from kidneys in response to hypoxia; requires iron, vitamin B12, folic acid.

  • Anemias causes

    Blood loss, decreased RBC production (iron deficiency, pernicious anemia), or increased RBC destruction (sickle-cell anemia).

  • Leukocytes characteristics

    Complete cells critical for defense; can leave bloodstream (diapedesis) and follow chemical signals (chemotaxis).

  • Granulocytes vs Agranulocytes

    Granulocytes have visible granules (neutrophils, eosinophils, basophils); agranulocytes lack granules (lymphocytes, monocytes).

  • Platelet function

    Cell fragments that form platelet plugs and release chemicals to promote clotting.

  • Three steps of hemostasis

    Vascular spasm, platelet plug formation, and coagulation (clotting).

  • Intrinsic vs extrinsic coagulation pathways

    Intrinsic: triggered by factors within blood; extrinsic: triggered by tissue factor from damaged tissue.

  • ABO blood group basics

    Based on presence of A and/or B antigens on RBCs; antibodies in plasma are opposite type.

  • Rh factor and hemolytic disease of the newborn

    Rh- mothers exposed to Rh+ fetal blood produce antibodies causing hemolysis in subsequent Rh+ pregnancies.

  • Heart location and size

    Located in mediastinum, size of a fist, two-thirds left of midline, apex points to left hip.

  • Layers of the heart wall

    Epicardium (outer), myocardium (muscle), endocardium (inner lining).

  • Heart chambers and blood flow

    Right atrium and ventricle pump deoxygenated blood to lungs; left atrium and ventricle pump oxygenated blood to body.

  • Function of heart valves

    Prevent backflow; AV valves between atria and ventricles; semilunar valves at exits of ventricles.

  • Intrinsic conduction system components

    Sinoatrial node, atrioventricular node, AV bundle, bundle branches, and Purkinje fibers coordinate heartbeat.

  • Cardiac muscle differences from skeletal muscle

    Branched cells with intercalated discs, self-excitable, longer refractory period, rely on aerobic respiration.

  • Cardiac cycle phases

    Ventricular filling (diastole), atrial contraction, ventricular systole, isovolumetric relaxation.

  • Cardiac output formula

    Cardiac output = stroke volume × heart rate.

  • Blood vessel layers

    Tunica intima (endothelium), tunica media (smooth muscle), tunica externa (connective tissue).

  • Types of arteries

    Elastic arteries (conducting), muscular arteries (distributing), arterioles (resistance vessels).

  • Capillary types

    Continuous (least permeable), fenestrated (more permeable), sinusoid (most permeable).

  • Vein characteristics

    Thinner walls, larger lumens, contain valves to prevent backflow, act as blood reservoirs.

  • Blood pressure determinants

    Cardiac output, peripheral resistance, and blood volume.

  • Mean arterial pressure (MAP) calculation

    MAP = diastolic pressure + 1/3 (systolic pressure - diastolic pressure).

  • Short-term neural blood pressure regulation

    Baroreceptors and chemoreceptors regulate cardiac output and vessel diameter via medullary centers.

  • Hormonal blood pressure regulation

    Epinephrine, norepinephrine, angiotensin II increase pressure; atrial natriuretic peptide decreases pressure.