Anatomy and Physiology Biology 2122K Floyd College

CARDIOVASCULAR SYSTEM BLOOD HEART BLOOD VESSELS

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Hematology - study of blood

BLOOD Liquid connective tissue comprising 8% of body weight 4-5 times more viscous than water, salty Volume liters 8-12 pints

FUNCTIONS Transportation - oxygen, CO 2, nutrients, hormones and wastes Protection - have cells that phagocytize bacteria and produce antibodies; clotting mechanisms that prevent blood loss Regulation - pH, body temperature,water content

Components of Blood PLASMA - is the liquid portion of the blood and consists primarily of water (92%) and plasma proteins (7%) Proteins - albumin, globulins, and fibrinogen FORMED ELEMENTS - solid component of the blood consisting of erythrocytes, leukocytes, and platelets BLOOD = 55% plasma + 45% formed elements

Types of Cells Erythrocytes - Red Blood Cells Carry oxygen Leukocytes - White Blood Cells Immunity Thrombocytes – Platelets Blood Clotting

Erythrocytes Very flexible, biconcave disk lacking a nucleus Most numerous of cells; 5million/mm 3 Transport respiratory gases such as oxygen and carbon dioxide Approximately 120 day life span Hemoglobin - Consists of 4 polypeptide globin chains with a heme molecule in each one Each hemoglobin molecule can carry four oxygen molecules

Each RBC can contain up to 250 million hemoglobin molecules!

Types of Tests Red blood cell count – 4.3 – 5.8 million/mm 3 Hemoglobin – 11.8 – 15.9 g/dl - Females 13.8 – 18.4 g/dl - Males Hematocrit % in Females 41-54% in Males Reticulocyte – measures rate of RBC production

Hematopoiesis Occurs in red marrow Produces 1 oz. (100 billion cells) /day Stem cells called hemocytoblasts produce all types of blood cells. Erythropoiesis: Hemocytoblast (stem cell) Proerythroblast Erythroblast (large numbers of ribosomes produce hemoglobin and store iron) Normoblast - loses nucleus and organelles Reticulocyte - immature (still contain E.R.) Erythrocyte - full process = 5-7 days

Hormonal control of blood production Erythropoietin Produced by kidneys & liver Production due to: Reduced RBC count Reduced oxygen availability Increased tissue demands

Leukocyte - WBC Granulocytes - Neutrophils - phagocytize bacteria (60- 70%); Eosinophils - associated with allergic reactions and parasitic infections (2-4%) Basophils - involved in the inflammatory response as well as allergic reactions; granules contain heparin and histamine (0.5-1%)

Agranulocytes - play a crucial role in immunity Monocytes - phagocytic macrophages (3-8%) Lymphocytes - involved in immunity; B cells and T cells (20-25%)

Thrombocyte - Platelet Cytoplasmic fragments that are essential in blood clotting; help form a platelet plug Platelets have a life span of only 5-9 days Normal platelet count :250, ,00/mm 3

HEMOSTASIS Blood clotting

Stages of blood clotting Vascular spasms - blood vessel constriction Formation of a platelet plug - platelets stick to each other and the collagen exposed in the damaged tissue to form a plug Coagulation - formation of a clot

Coagulation Involves two chemical, enzymatic pathways resulting in the conversion of soluble fibrinogen into insoluble fibrin Extrinsic pathway - cell trauma releases TF Intrinsic pathway - all components in blood Thirteen clotting factors involved; most are produced in the liver Vitamin K dependent - II, VII, IX, X

Stages of blood clotting Formation of prothrombinase (prothrombin activator) Conversion of prothrombin to thrombin Conversion of soluble fibrinogen into insoluble fibrin

Factor (procoagulants) sequence 12 - Hageman (glass) Factor 11 - Plasma thromboplastin antecedent 7 - Serum prothrombin conversion accelerator 4 - Calcium ions 9 - Plasma thromboplastin component 8 - Antihemophilic factor 10 - Stuart Factor (thromboplastin)

Coagulant Factor Sequence (con’t) 10 - Stuart Factor 4 - Calcium Ions 3 - Tissue Factor 5 - Proaccelerin 2 - Prothrombin Thrombin 1 - Fibrinogen Fibrin 13 - Fibrin stabilizing factor Forms prothrombin activator

Coagulation Normal coagulation involves: normal platelets clotting factors vitamin K calcium Clot Retraction - contractile proteins tighten clot Fibrinolysis - clot dissolves

Clotting Disorders Thrombus - stationary clot Embolus - circulating clot Thrombocytopenia - deficient number of platelets Hemophilia - genetic bleeding disorder

Hemophilia 3 types Hemophilia A (classical) - lack of factor VIII. Hemophilia B - lack of factor IX Hemophilia C - lack of factor XI Types A & B are sex-linked recessive.. Appeared in the royal families of Europe, beginning with the children of Queen Victoria

Blood Groups - Typing Blood is typed into groups depending upon the type of agglutinogens (antigens) present on the red blood cell surface The plasma may contain genetically determined agglutinins or antibodies against the blood group antigens that they DO NOT have The ABO and Rh system are based upon antigen-antibody type responses

Blood Typing ABO system - people who posses the A antigen on the RBC surface are type A; if you posses the B antigen you are blood type B; if both A and B are present you are type AB; if neither A or B antigens are present, your blood type is O Type O - universal donor, can give blood to anyone Type AB - universal recipient, can receive blood from any blood type

Rh system - individuals whose red blood cells possess the Rh antigen are Rh+ (Approx 85%) Antibodies against Rh antigens are not present at birth but are stimulated by exposure Hemolytic Disease of the Newborn Only in Rh- mothers and an Rh+ child, after exposure. RhoGam - medication given to prevent sensitization of Rh- mother

Blood Disorders - Erythrocytes Anemia – due to decreased number of red blood cells or a deficiency of hemoglobin RBC deficiency aplastic anemia - destruction of bone marrow hemorrhagic anemia - blood loss hemolytic anemia - rupture of RBC’s Hemoglobin deficiency pernicious anemia - vitamin B 12 deficiency iron deficiency

Blood Disorders - Erythrocytes Thalassemia - faulty hemoglobin Found in people of Mediterranean descent Sickle-cell - faulty hemoglobin Found primarily in Africa and people of African descent. Provides resistance against Malaria Polycythemia - excess RBC’s.

Sickle Cell Anemia

White blood cell disorders Leukopenia / leukocytosis Infectious mononucleosis excess numbers of agranulocytes caused by Epstein-Barr virus Leukemia predominate cell type acute (quick advancing chronic (slow advancing)