chapter 19-20

• Functions of Blood


  • Transports gases, nutrients, waste products, processed molecules, and regulatory molecules
  • Involved in the regulation of pH, osmosis, and body temperature
  • Protects against disease and initiates tissue repair
• Blood is a type of connective tissue that consists of plasma and formed elements
• Components of Plasma


  • Water (91%)
  • Proteins (albumins, globulins, fibrinogen, hormones, enzymes)
  • Ions
  • Nutrients
  • Waste products
  • Gases
• Platelets are not a component of plasma
• Albumin


  Protein found in plasma that plays an important role in maintaining the osmotic concentration of the blood
• Formed Elements


  • Red blood cells (erythrocytes)
  • White blood cells (leukocytes)
  • Platelets (cell fragments)
• Production of Formed Elements


  1. In embryo and fetus, formed elements produced in a number of locations

  2. After birth, red bone marrow becomes the source of the formed elements

  3. All formed elements derived from hemocytoblasts, which give rise to myeloid stem cells and lymphoid stem cells

  4. Myeloid stem cells give rise to red blood cells, platelets, and most white blood cells

  5. Lymphoid stem cells give rise to lymphocytes
• Red Blood Cells

  • Biconcave discs containing hemoglobin and carbonic anhydrase
  • Hemoglobin molecule consists of four heme and four globin molecules, heme transports oxygen, globin transports carbon dioxide and nitric oxide
  • Iron required for oxygen transport
  • Carbonic anhydrase involved with transport of carbon dioxide
• Erythropoiesis


  1. Stem cells in red bone marrow give rise to late erythroblasts, which lose their nuclei and are released into the blood as reticulocytes

  2. Loss of endoplasmic reticulum by reticulocyte produces a red blood cell

  3. In response to low blood oxygen, kidneys produce erythropoietin which stimulates erythropoiesis
• Fate of Hemoglobin from Ruptured Red Blood Cells


  1. Hemoglobin phagocytized by macrophages

  2. Hemoglobin broken down, heme becomes bilirubin which is secreted in bile
• Red blood cells are the most numerous formed element in the blood, do not have a nucleus, and are produced in the red bone marrow
• Ways of Transporting Carbon Dioxide in the Blood


  • Bicarbonate ions
  • Combined with blood proteins
  • Dissolved in plasma
• Hemoglobin molecule can become associated with four oxygen molecules
• Erythropoietin


  Hormone produced by the kidneys that stimulates the production of red blood cells when blood oxygen decreases
• Initiation of vigorous exercise program

  Increased erythropoietin production, increased concentration of reticulocytes, decreased bilirubin formation
• Fate of Hemoglobin Components After Red Blood Cell Destruction


  • Heme - reused to form new hemoglobin molecule
  • Globin - broken down into amino acids
  • Iron - mostly secreted in bile
• In hereditary hemolytic anemia, there is massive destruction of red blood cells, leading to a reticulocyte count above normal and jaundice as a symptom. Removing the spleen is an effective treatment because it is the site of much of the red blood cell destruction.
• Blood Doping/Boosting


  1. Blood is removed, formed elements separated and frozen, then reinfused before competition

  2. Increases oxygen-carrying capacity and improves performance, but can have negative health effects
• Habitual use of barbiturates causes hypoventilation, which leads to a decreased red blood cell count
• Types of White Blood Cells

  • Neutrophils
  • Eosinophils
  • Basophils
  • Lymphocytes
  • Monocytes
• Eosinophils


  Attack certain worm parasites and modulate inflammation
• Neutrophils


  Small, phagocytic cells that are the most numerous type of white blood cell
• Monocytes


  Leave the blood, enter tissues, and become large, phagocytic cells called macrophages
• Lymphocytes


  Smallest white blood cells, include B cells and T cells, important in immunity and antibody production
• Platelets


  • Cell fragments pinched off from megakaryocytes in red bone marrow
  • Play an important role in clot formation
• Substances Essential for "Good Blood"

  • Iron
  • Vitamin B12
  • Folic acid
• Hemostasis


  1. Vascular spasm - vasoconstriction of damaged blood vessels

  2. Platelet plug formation - platelets bind to collagen, release chemicals, and aggregate

  3. Coagulation - extrinsic and intrinsic pathways lead to thrombin converting fibrinogen to fibrin clot

  4. Control of clot formation - heparin, antithrombin, prostacyclin

  5. Clot retraction and dissolution - platelets contract, plasmin dissolves fibrin
• Fibrinogen


  Plasma protein that forms the network of fibers in a blood clot
• Clot Formation


  1. Activated factor XII

  2. Prothrombinase (factor X, factor V, phospholipids, Ca2+)

  3. Thrombin

  4. Fibrinogen
• The extrinsic pathway of coagulation begins with the release of thromboplastin (tissue factor), leads to the production of activated factor X, and requires Ca2+
• Plasmin


  Chemical involved in the breakdown (fibrinolysis) of a blood clot
• Blood Groups


  • Determined by antigens on red blood cell surface
  • Antibodies can bind to antigens, causing agglutination or hemolysis
• ABO Blood Groups


  • Type A - has A antigens, anti-B antibodies
  • Type B - has B antigens, anti-A antibodies
  • Type AB - has A and B antigens, no anti-A or anti-B antibodies
  • Type O - has neither A nor B antigens, has both anti-A and anti-B antibodies
• Rh Blood Group


  • Rh-positive has D antigen, Rh-negative does not
  • Rh-negative person produces antibodies against D antigen when exposed to Rh-positive blood
  • Rh blood group responsible for hemolytic disease of newborn
• The most common blood type in the US is O positive
• Blood Tests


  • Type and crossmatch - determines ABO and Rh blood groups, tests for agglutination
  • Complete blood count - red blood count, hemoglobin, hematocrit, white blood count, differential
  • Clotting tests - platelet count, prothrombin time
  • Blood chemistry - glucose, urea nitrogen, bilirubin, cholesterol
• Based on the provided blood test results, Ben has iron-deficiency anemia
• Blood tests

  • Red blood count
  • Reticulocyte count
  • White blood count
  • Hemoglobin
  • Hematocrit
  • Prothrombin time
  • Platelets
• Ben has an infected prostate. His physician prescribed several antibiotics before finding one that was effective. Results of the most recent blood tests indicate that Ben is anemic.
• Red blood cells


  • Normocytic, 7.5 mm