Exercise 34 Blood

Composition of Blood Blood is sticky Color varies from scarlet to dark red The pH of blood is 7.35–7.45 Temperature is 38C Average volume: 5–6 L for males, and 4–5 L for females

Composition of Blood It is composed of liquid plasma and formed elements Formed elements include: Erythrocytes, or red blood cells (RBCs) Leukocytes, or white blood cells (WBCs) Platelets

Blood Plasma - Matrix Blood plasma contains over 100 solutes, including: Water – 90% Proteins – albumin, globulins, clotting proteins, and others Organic nutrients – glucose, carbohydrates, amino acids Electrolytes – sodium, potassium, calcium, chloride, bicarbonate Respiratory gases – oxygen and carbon dioxide

Components of Whole Blood Figure 17.1

Erythrocytes (RBCs) Biconcave discs, anucleate, essentially no organelles Filled with hemoglobin (Hb), a protein that functions in gas transport Red or pink 4.5million to 5.0 million cells/mm3 Life span – 100 to 120 days

Erythrocytes (RBCs) Figure 17.3

Components of Whole Blood Figure 17.2

Leukocytes (WBCs) 4000-11000 cells/mm3 Nucleated Diapedesis Divided into 2 groups: Granulocytes and agranulocytes

Granulocytes Granulocytes – neutrophils, eosinophils, and basophils Contain cytoplasmic granules that stain specifically (acidic, basic, or both) with Wright’s stain Are larger and usually shorter-lived than RBCs Have lobed nuclei

Neutrophils Neutrophils have two types of granules that: Take up both acidic and basic dyes Give the cytoplasm a lilac color Neutrophils are our first body’s defense Increase in bacterial infections 40% - 70% of all WBCs Nucleus with 3 to 7 lobes

Eosinophils Eosinophils account for 1–4% of WBCs Have red-staining, bilobed nuclei connected via a broad band of nuclear material Have red to crimson (acidophilic) large, coarse, lysosome-like granules Lead the body’s counterattack against parasitic worms. Increased in allergic patients Lessen the severity of allergies by phagocytizing immune complexes

Basophils Account for 0.5% of WBCs and: Have U- or S-shaped nuclei with two or three conspicuous constrictions Are functionally similar to mast cells Have large, purplish-black (basophilic) granules that contain histamine. Mediates inflammatory reactions

Agranulocytes Agranulocytes – lymphocytes and monocytes: Lack visible cytoplasmic granules Are similar structurally, but are functionally distinct and unrelated cell types Have spherical (lymphocytes) or kidney-shaped (monocytes) nuclei

Lymphocytes Account for 25% or more of WBCs and: Have large, dark-purple, circular nuclei with a thin rim of blue cytoplasm Responsible for immunologic responses Smallest type of leukocytes There are two types of lymphocytes: T cells and B cells T cells function in the immune response B cells produce antibodies

Monocytes Monocytes account for 4–8% of leukocytes They are the largest leukocytes They have abundant pale-blue cytoplasms They have purple-staining, U- or kidney-shaped nuclei They leave the circulation, enter tissue, and differentiate into macrophages Increases in chronic infections

Leukocytes Figure 17.10

Platelets Platelets are fragments of megakaryocytes with a blue-purple color Irregular shape 250,000 - 500,000/mm3 Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels Thrombocytosis Thrombopenia

Hematologic Tests Total WBCs count Total RBCs count Leukocytosis Leukopenia Leukemia Total RBCs count Polycythemia Anemia

Hematologic Tests Differential WBCs count Hematocrit or packed cell volume (PVC) Obtained by centrifuging the whole blood Normal male: 47 Normal female: 42 Hemoglobin concentration Male normal value: 13-18g/100ml of blood Female normal value: 12-16g/100ml of blood

Hematologic Tests Sedimentation rate It is the speed at which RBCs settle to the bottom of a vertical tube Adult normal value: 0 to 6 mm/hr It is increased in anemia, infections, tissue necrosis, pregnancy It is decreased in polycythemia

Hematologic Tests Bleeding time Coagulation time Measurement of how long a bleeding lasts It tests the health of the platelets Normal rate: 0 to 5 minutes (or 2 to 7) depending on the method used Coagulation time Normal value:2 to 6 minutes It tests the coagulation factors

Hematologic Tests – blood typing RBC membranes have glycoprotein antigens on their external surfaces These antigens are: Unique to the individual Recognized as foreign if transfused into another individual Promoters of agglutination and are referred to as agglutinogens Presence or absence of these antigens is used to classify blood groups

Blood Groups The antigens of the ABO and Rh blood groups cause vigorous transfusion reactions when they are improperly transfused Other blood groups (M, N, Dufy, Kell, and Lewis) are mainly used for legalities Antibodies are also called agglutinins

ABO Blood Groups The ABO blood groups consists of: Type A blood: Has antigens A on the surface of their RBCs Has antibodies anti-B in their plasma Type B blood: Has antigens B on the surface of their RBCs Has antibodies anti-A in their plasma

ABO Blood Groups Type AB blood: Type O blood: Has both A and B antigens on the surface of their RBCs Has no antibodies in their plasma Type O blood: Has no antigens on the surface of their RBCs Has anti-A and anti-B in their plasma

ABO Blood Groups Table 17.4

Rh Blood Groups There are eight different Rh agglutinogens, three of which (C, D, and E) are common Presence of the Rh agglutinogens on RBCs is indicated as Rh+ Anti-Rh antibodies are not spontaneously formed in Rh– individuals However, if an Rh– individual receives Rh+ blood, anti-Rh antibodies form A second exposure to Rh+ blood will result in a typical transfusion reaction

Blood Typing When serum containing anti-A or anti-B agglutinins is added to blood, agglutination will occur between the agglutinin and the corresponding agglutinogens Positive reactions indicate agglutination

Blood type being tested Blood Typing Blood type being tested RBC agglutinogens Serum Reaction Anti-A Anti-B AB A and B + B – A O None