M13

• Functions of blood

  • Transport of gases, nutrients and waste products
  • Transport of processed molecules
  • Transport of regulatory molecules such as hormones & enzymes
  • Regulation of pH (normal limits of 7.35 – 7.45) and osmosis
  • Maintenance of body temperature
  • Protection against foreign substances
  • Clot formation
• Blood

  A type of connective tissue; consists of liquid matrix (plasma) containing cells & cell fragments (formed elements)
• Blood makes up about 8% of total body weight
• Total blood volume is about 4-5 L in average adult female & 5-6 L in average adult male
• Plasma accounts for 55% & formed elements for 45% of total blood volume
• Plasma components

  • Albumin
  • Globulin
  • Fibrinogen
• Serum

  Plasma without the clotting factors
• Hematopoiesis

  Process that produces formed elements
• In infant, hematopoiesis occurs in liver, thymus gland, spleen, lymph nodes, and red bone marrow; continuous throughout life
• Hemocytoblast / Stem Cell

  A single population of cells where all the formed elements are derived
• Growth Factor

  Determine the types of formed elements derived from stem cells & how many are produced
• Red Blood Cell (RBC) / Erythrocyte

  • Loses nuclei & most organelles during development
  • Lives for about 120 days in males & 110 days in females
  • 1/3 of its volume is the pigmented protein hemoglobin, which is responsible for red color
• Hemoglobin

  Each consists of four globin chains & four heme groups (1 globin: 1 heme); each heme contains one iron atom necessary to reversibly bind to an oxygen molecule
• Carbon Monoxide can bind more readily than oxygen & does not tend to unbind in iron resulting to dysfunction of hemoglobin; may lead to nausea, headache, unconsciousness, & death
• Ways carbon dioxide is transported in blood

  • Bicarbonate ions, hemoglobin, and plasma
  • Carbonic Anhydrase catalyzes a reaction that converts CO2 & H2O into H+ & HCO3 (approximately 70% of CO2 is transported in this form)
  • 23% of CO2 binds reversibly to globin part of hemoglobin
  • 7% of CO2 is transported dissolved in plasma
• Factors required for production of red blood cells

  • B vitamins (folate & B12) for synthesis of DNA
  • Iron for production of hemoglobin
• Erythropoietin (EPO)

  Produced by the kidney in response to low blood oxygen levels; stimulates the red bone marrow to produce more RBCs
• Bilirubin

  A yellow pigment molecule from conversion of heme molecules in hemoglobin breakdown; normally removed from blood by liver & released into small intestines as bile
• Functions of white blood cells (WBC) / leukocytes

  • To protect the body against invading microorganisms & pathogens
  • To remove dead cells & debris from tissues by phagocytosis
• Types of white blood cells

  • Granulocytes (neutrophil, basophil, & eosinophil)
  • Agranulocytes (leukocyte & monocyte)
• Pus

  Accumulation of dead neutrophils, cell debris, and fluid at sites of infections
• Platelet / Thrombocyte

  Produced in red marrow from large cells, the megakaryocytes
• Three processes in preventing blood loss

  • Vascular Spasm
  • Platelet Plug Formation
  • Blood Clotting / Coagulation
• Vascular Spasm

  Temporary constriction of blood vessels; stimulated by chemicals released by cells of damaged blood vessel wall & by platelets (ex: thromboxanes & endothelin)
• Platelet Plug Formation

  • Platelet Adhesion
  • von Willebrand Factor
  • Platelet Release Reaction
  • Fibrinogen Receptor
  • Platelet Aggregation
• Blood Clotting / Coagulation

  Formation of clot that depends on a number of proteins found within plasma, called clotting factors
• Components of blood clotting

  • Clot: a network of threadlike fibrin that traps blood cells, platelets, & fluid
  • Vitamin K: required in the synthesis of most clotting factors in liver
  • Anticoagulants: prevent clotting factors from forming clots under normal conditions
  • Clot Retraction: process where formed clots begin to condense into more compact structure
  • Fibrinolysis: process of dissolving clot
• Transfusion

  Transfer of blood or blood components from one individual to another
• Infusion

  The introduction of fluid other than blood, such as saline & glucose, into the blood
• Transfusion Reaction

  Characterized by clumping or ruptured blood cells & clotting within blood vessels; caused by interactions between antigens (Ag) and antibodies (Ab)
• Agglutination

  Clumping of cells when antibodies bind to antigens forming molecular bridges
• Hemolysis

  A reaction that causes rupture of RBC in incompatible Ag-Ab binding
• Blood groupings

  • ABO Blood Group
  • Rh Blood Group
• ABO Blood Group

  Two types of antigen appear, Type A & Type B antigens, which are genetically determined
• Rh Blood Group

  Divided to Rh-positive (have Rh antigens on surface of RBC) & Rh-negative (no Rh antigens)
• AB-negative is the rarest combination of blood type
• Hemolytic Disease of the Newborn (HDN) / Erythroblastosis Fetalis

  A disorder of Rh incompatibility that occurs when the mother is Rh-negative & fetus is Rh-positive; no problem in first pregnancy but can be fatal to fetus in later pregnancies
• Rho(D) immune globulin (RhoGAM)

  Antibodies against Rh antigens that is used as prevention of HDN; injection can be given during the pregnancy, before delivery, or immediately after each delivery, miscarriage, or abortion
• Diagnostic blood tests

  • Type and Crossmatch
  • Complete Blood Count
  • Differential White Blood Count
  • Clotting
  • Blood Chemistry
• Type and Crossmatch

  Done to identify the blood group of blood recipient & donor