Hematology The Study of blood Average adult 810

Hematology The Study of blood

• Average adult = 810 pints of blood • Composition: – PLASMA – liquid portion of blood without cellular components – Serum – plasma after a blood clot is formed – Cellular elements are red cells, white cells and platelets

PLASMA • Straw colored, contains – – Water – Blood proteins – Plasma proteins • FIBRONOGEN – necessary for blood clotting, synthesized in the liver • ALBUMIN – from the liver, helps maintain blood’s osmotic pressure and volume • PROTHROMBIN – a globulin which helps blood coagulate. Vitamin K necessary for prothrombin synthesis.

Plasma – Nutrients – Electrolytes – Hormones, vitamins, enzymes – Metabolic waster products

Erythrocytes-Red Blood Cell • Shape = biconcave discs • RBC • HEMOGLOBIN – gives red color, heme is iron and globin is protein. • Function = transports oxygen to tissues and carbon dioxide away from cells • Normal – men =14 -18 gm, women = 12 -16 gm

Function of Hemoglobin • Red cells travel through the lungs where • O 2 is carried to tissues and released • CO 2 picked up and carried back to lungs for exchange • Arterial blood – lots of oxygen = bright red • Venous blood – lots of CO 2 = dark crimson

ERYTHROPOIESIS • • Manufacture of red blood cells Occurs in bone marrow Red cells live 120 days Old cells broken down by the spleen and liver • HEMOLYSIS – rupture or bursting of erythrocyte, can be from a blood transfusion or disease.

White Blood Cells – LEUKOCYTES • Larger than erythrocytes • 5 types • Normal leukocyte count = 3, 200 – 9, 800 • Types of White Cells • Neutrophils • Eosinophils • Basophils • Lymphocytes • Monocytes

Leukocytes • Basophils produce HEPARIN – an anticoagulant • DIAPEDESIS – when white cells move through capillary wall into neighboring tissue.

• PHAGOCYTOSIS – process when white cells surround, engulf, and digest harmful bacteria.

Inflammation • Body’s reaction to chemical or physical trauma • PATHOGENIC – disease producing microorganisms can cause inflammation • Symptoms – redness, local heat, swelling and pain • Why? Bacterial toxins, increased blood flow, collection of plasma in tissues (edema)

• HISTAMINE increases the blood flow to the injured area • PUS produced – a combination of dead tissue, dead and living bacteria, dead leukocytes and plasma • ABSCESS – pus-filled cavity below the epidermis • PYREXIA – increase in body temperature by the hypothalamus – in response to pathogenic invasion

Abscess

Inflammation • LEUKOCYTOSIS – increase in the number of white cells in response to infection • LEUKOPENIA – decrease in number of white cells due to chemotherapy or radiation

Thrombocytes (Platelets) • Smallest of solid components of blood • Synthesized in red marrow • Not cells – fragments of megakaryocytes • Necessary for the initiation of the blood clotting process

Coagulation (Clotting) • Cut or injury platelets and injured tissue release THROMBOPLASTIN act on PROTHROMBIN in plasma + Calcium ions converts to THROMBIN the thrombin acts as an enzyme and changes FIBRINOGEN FIBRIN creating a mesh that traps red blood cells, platelets and plasma creating a blood clot.

• ANTICOAGULANTS – prevent blood clotting • HEPARIN = antiprothrombin • PROTHROMBIN – dependent on Vitamin K

Blood Facts • There about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there about 40 platelets and one white cell.

Blood Types • Four major types of blood- A, B, AB and O • Inherited from parents • Determined by presence or absence of an ANTIGEN on the surface of the red blood cell

• ANTIBODY – a protein in the plasma that will inactivate a foreign substance that enters the body. – Someone with type A blood has b antibodies – Someone with type B blood has a antibodies – Someone with type AB blood has no antibodies – Someone with type O blood has a and b antibodies

Blood Types • UNIVERSAL DONOR – O • UNIVERSAL RECIPIENT – AB • Red cells also may contain Rh factor • If you have it, you’re Rh + • If you don’t, you’re Rh –

RH Incompatibilties

Disorders of the Blood • ANEMIA • Deficiency in number or % of red cells

IRON-DEFICIENCY ANEMIA • Usually in women, children and adolescents • Deficiency of iron in the diet causing insufficient hemoglobin synthesis • Treat with iron supplements and green, leafy vegetables

APLASTIC ANEMIA • Bone marrow does not produce enough red and white blood cells • Caused by drugs or radiation therapy

SICKLE CELL ANEMIA • Chronic blood disease inherited from both parents • Causes the red cells to form in abnormal sickle shape • Sickle cells break easily and carry less oxygen • Occurs primarily in blacks • Treatment – blood transfusions

POLYCYTHEMIA • Too many red blood cells are formed • May be a temporary condition that occurs at high altitude

EMBOLISM • Air, blood clot, cancer cells, fat, etc. that is carried by the bloodstream until it reaches an artery too small for passage • Also known as a “moving blood clot”

THROMBOSIS • The formation of a blood clot in a blood vessel • The blood clot is a THROMBUS

HEMATOMA • Localized clotted mass of blood found in an organ, tissue or space. • Caused by an injury that can cause a blood vessel to rupture

HEMOPHILIA • Hereditary • Missing clotting factor • Blood clots slow or abnormally • Sex-linked – transmitted genetically from mothers to sons • Treat with missing clotting factor, avoid trauma

THROMBOCYTOPENIA • Not enough platelets • Blood will not clot properly

LEUKEMIA • Malignant condition • Overproduction of immature white blood cells • Hinders synthesis of red cells