Composition of Blood

Erythrocytes Most abundant cell in the body Number of circulating RBCs in peripheral venous blood Derived from erthroblasts Survive 120 days/Bioconcave RBC values vary according to gender and age Women lower, tend to decrease with age Decreased by more than 10% = anemia Primary function: tissue oxygenation

Erythrocyte indices Mean corpuscular volume (MCV) Mean corpuscular hemoglobin (MCH) Mean corpuscular hemoglobin concentration (MCHC)

MCV Mean volume of all the erythrocytes counted in the sample MCV low = microcytic Norm MCV = normocytic MCV high = macrocytic

Normocytic Iron deficiency (detected early) Chronic illness Acute blood loss Aplastic anemia Acquired hemolytic anemia (from a prosthetic cardiac valve)

Microcytic Iron deficiency (detected late) Thalassemia Lead poisoning

Macrocytic Vitamin B 12 or folic acid deficiency Chemotherapy Myeloid leukemia Ethanol toxicity Thyroid dysfunction

MCH Measure of the average amount of weight of hemoglobin within an RBC Macrocytic anemias: the MCHC is increased if the size of the RBC is large Microcytic anemia, hypochromic anemia: the MCH is decreased if the size of the RBC is small of the hemoglobin is diminished

MCHC Mean concentration of hemoglobin in the red cell. Since whole blood is about one-half cells by volume, and all the hemoglobin is confined to the cells, you would correctly expect the MCHC to be roughly twice the value of hemoglobin in whole blood

White Blood Cells (Leukocytes) Granulocytes Neutrophil Eosinophil Basophil Mast cells Agranulocytes Monocyte Lymphocyte

Neutrophil Circulate for about 8 hours before proceeding to the tissues, where they live for about a week Most numerous, 55% Produced as a response to acute body stress Infection Infarction Trauma Emotional distress Phagocytosis invaders Foreign cells Toxins Viruses

Neutrophils.. Found near sites of infection or injury where they will stick to the walls of the blood vessels and engulf any foreign particles that try to enter the bloodstream Found in the pus of wounds Band neutrophils Indicator of acute stress Segmented neutrophils Most mature type

Eosinophil Derived from different stem cells Hallmark = presence of bright orange large granules Ameboid movement = phagocytosis Seen at sites: Invasive parasitic infestations Allergic (immediate hypersensitivity) response (IgE) Critical function: Inactive slow reacting substance of anaphylaxis Neutralize histamine Inhibit mast cell degranulation

Mast Cells Central cell in inflammation Found in vascularized connective tissue

Basophils Large deep purple granules Precise function not understood Contain histamines (causes vasodilation) Heparin (anticoagulant) High number of these cells: Hemolytic anemia Chicken pox

Lymphocytes In the immune/inflammatory response: Neutrophils and monocytes are the brutes Major cells of immune system Lymphocytes are the brains “bubble-boy” T-lymphocytes: Act against virus infected cells and tumor cells AIDS keep a careful watch on their T-cell level, an indicator of the AIDs virus’ activity B-lymphocytes: Produce antibodies

Natural Killer Natural killer (NK) cells Kill tumor cells and virally infected cells Procedure cytokines involved in immune responses

Monocyte Largest of the leukocytes Phagocytic and defend the body against viruses and bacteria Elevated cell count: Malaria Endocarditis Typhoid fever Rocky Mountain spotted fever

Thrombocytes Platelets Disk-shaped cytoplasmic fragments Formed by fragmentation of megakaryocytes Secrete a hormone called serotonin which constricts torn blood vessels Essential for blood coagulation and control of bleeding Live 10 days and then removed by spleen