HEMATOLOGY STRUCTURE

iNTRODUCTION Adult’s body has 8-10 pints of blood on average A loss of more than 2 pints at one time leads to a serious condition How much blood is “taken” when you donate blood? 1 pint which equals approx. 1 pound

COMPOSITION Blood is made of: Plasma Serum Cellular components Liquid portion of blood without its cellular elements Serum Name given to plasma after a blood clot is formed Serum = plasma – (fibrinogen + prothrombin) What are fibrinogen and prothrombin? (clue…look in your book!) Cellular components Erythrocytes, leukocytes, thrombocytes What are each?

Cellular elements of blood (look at figure 12-1 pg 242 also)

Blood plasma Straw-colored Comprising about 55% of the blood volume! Contains 6 substances: Water Plasma proteins (all are formed in the liver) Nutrients Electrolytes Hormones, vitamins, and enzymes Metabolic waste products

Realistic view of blood sample

water Makes up about 92% of the total plasma volume Maintained by the kidneys and by water intake and output

Plasma proteins 3 proteins: Fibrinogen Serum albumin Serum globulin Necessary for blood clotting; without, a small cut or wound would bleed profusely Serum albumin Most abundant of all the plasma proteins Helps to maintain the blood’s osmotic pressure and volume by providing “pulse pressure” needed to hold and pull water from the tissue fluid back into the vessels Serum globulin Also formed in the lymphatic system Gamma globulin: helps in the making of antibodies Prothrombin: helps blood coagulate Vitamin K is necessary in aiding the process of prothrombin synthesis

Nutrients electrolytes Absorbed from the digestive tract Glucose, fatty acids, cholesterol, and amino acids are dissolved in the blood plasma Most abundant are sodium chloride and potassium chloride Come from foods and chemical processes occurring in the body

Hormones, vitamins, enzymes waste products Found in very small amounts in the blood plasma Generally help the body control its chemical reactions All of the body’s cells are actively engaged in chemical reactions to maintain homeostasis Waste products are formed and subsequently carried by the plasma to the various excretory organs What are the excretory organs?

Erythrocytes Shape: biconcave discs, donut-shaped Normal count ranges from 4.5-6.2 for men and 4.2-5.4 for women Erythropoiesis: manufacture of RBCs Vitamin B12 , folic acid, copper, cobalt, iron, and proteins are needed for production Live for 120 days and broken down by the spleen and liver Hemoglobin: breaks down into globin (protein) and heme (iron) Provides the characteristic red color Transports oxygen to the tissues and some carbon dioxide away Normal levels are 14-18 for men and 12-16 for women

leukocytes Larger than RBCs and granular or agranular Normal count averages from 3,200-9,800 Manufactured in bone marrow and lymphatic tissue Body’s natural defense against injury and disease 2 major groups of cells: Granulocytes – live only a few days Agranulocytes – live for a few days to several years

granulocytes Neutrophils Eosinophils Basophils Phagocytize bacteria with lysosomal enzymes Phagocytosis: process where WBCs surround, engulf, and digest harmful bacteria Eosinophils Phagocytize the remains of antibody-antigen reactions Increase in great numbers in allergic conditions, malaria, and in parasite or worm infestations Basophils Activated during an allergic reaction or inflammation Produce histamine and heparin Histamine and heparin do what?

agranulocytes Lymphocytes Monocytes B-lymphocytes: made in bone marrow T-lymphocytes: made in the thymus gland, lymph nodes, and spleen Both help the body by making and releasing antibody molecules and by protecting against the formation of cancer cells Monocytes Formed in the bone marrow and spleen Assist in phagocytosis and are able to leave the bloodstream and attach to tissues (where they become tissue macrophages or histiocytes) Histiocytes help wall off and isolate infected areas

To summarize leukocytes, they help to protect the body from injury and infection by: Phagocytosis and destruction of bacteria Synthesis of antibody molecules “cleaning up” of cellular remnants at the site of inflammation Walling off of the infected area See tables 12-2 and 12-3 pg 245

Thrombocytes (Blood platelets) Smallest of the solid components of the blood Not cells but fragments of the megakaryocytes (see figure 12-1 again) Normal count ranges from 250,000 to 450,000 Function in the initiation of the blood clotting process When a cut or wound occurs, platelets are stimulated to produce sticky projecting structures, that create a “platelet plug” to stop the bleeding