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Essentials of Human Anatomy & Physiology - Chapter 10: Blood

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Terms in this set (30)

  • What are the main substances transported by blood?
    Nutrients, wastes, hormones, and body heat are transported by blood through blood vessels.
  • What are the two main components of blood?
    Formed elements (living cells) and plasma (nonliving fluid matrix).
  • What percentage of blood is plasma and what percentage is erythrocytes?
    Plasma is 55% of blood, and erythrocytes (red blood cells) make up 45%, known as the hematocrit.
  • What is the buffy coat in blood?
    A thin, whitish layer between erythrocytes and plasma containing leukocytes (white blood cells) and platelets, less than 1% of blood.
  • Describe the physical characteristics of blood.
    Blood is a sticky, opaque fluid, heavier and thicker than water, with a pH between 7.35 and 7.45, and temperature slightly higher than body temperature.
  • What is the typical blood volume in a healthy adult?
    About 5–6 liters or 6 quarts, making up about 8% of body weight.
  • What is plasma mostly composed of?
    About 90% water with dissolved substances including nutrients, salts, respiratory gases, hormones, plasma proteins, and waste products.
  • Name the main plasma proteins and their functions.
    Albumin (blood buffer, osmotic pressure), clotting proteins (stem blood loss), and antibodies (immune defense).
  • What are erythrocytes and their main function?
    Red blood cells that carry oxygen; they are anucleate, lack mitochondria, and contain hemoglobin.
  • How many hemoglobin molecules does each erythrocyte contain?
    Each erythrocyte contains about 250 million hemoglobin molecules, each binding 4 oxygen molecules.
  • What causes anemia?
    A decrease in oxygen-carrying ability due to low RBC count or abnormal hemoglobin, including sickle cell anemia.
  • What is polycythemia?
    A disorder with an excessive increase in RBCs, caused by bone marrow cancer or living at high altitudes, increasing blood viscosity.
  • What are leukocytes and their key features?
    White blood cells that defend against disease, are complete cells with nuclei, can move in/out of vessels, and respond to chemical signals.
  • What is leukocytosis and leukopenia?
    Leukocytosis is high WBC count (infection response); leukopenia is abnormally low WBC count, often drug-induced.
  • Differentiate granulocytes and agranulocytes.
    Granulocytes have stained cytoplasmic granules and lobed nuclei; agranulocytes lack visible granules and have round or kidney-shaped nuclei.
  • List the five types of white blood cells from most to least abundant.
    Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils.
  • What is the function of neutrophils?
    Most numerous WBCs; multilobed nucleus; act as phagocytes at infection sites; numbers increase during infection.
  • What role do eosinophils play?
    Kill parasitic worms and participate in allergy attacks; have brick-red cytoplasmic granules.
  • What is the function of basophils?
    Rarest WBCs; contain histamine and heparin; involved in inflammatory and anticoagulant responses.
  • What are platelets and their function?
    Fragments of megakaryocytes needed for blood clotting; normal count is about 300,000 per microliter of blood.
  • Where does hematopoiesis occur and what is the common stem cell?
    Occurs in red bone marrow; all blood cells derive from the hemocytoblast stem cell.
  • How is red blood cell production regulated?
    Controlled by the hormone erythropoietin, produced by kidneys in response to low blood oxygen.
  • What are the three phases of hemostasis?
    1. Vascular spasms, 2. Platelet plug formation, 3. Coagulation (blood clotting).
  • Describe the process of platelet plug formation.
    Platelets stick to exposed collagen fibers, release chemicals to attract more platelets, forming a plug to seal breaks.
  • What triggers the coagulation cascade?
    Tissue factor (TF) released by injured tissues interacts with PF3, clotting factors, and calcium to activate prothrombin to thrombin.
  • What is the role of thrombin in clotting?
    Thrombin converts fibrinogen into insoluble fibrin strands that form a mesh to stabilize the clot.
  • What is a thrombus and an embolus?
    A thrombus is a clot in an unbroken vessel; an embolus is a clot that breaks free and can block vessels elsewhere.
  • What causes hemophilia?
    A hereditary bleeding disorder caused by missing clotting factors, leading to prolonged bleeding.
  • What determines human blood groups?
    Presence or absence of specific antigens on RBCs, mainly ABO and Rh antigens.
  • What is the universal donor and universal recipient blood type?
    Type O is the universal donor; Type AB is the universal recipient.