Blood

Blood

• Essential life supportive fluid• Transported in closed system throughout

body through blood vessels

Physical Characteristics

• Viscous• pH 7.35 – 7.45• Temperature: 38 degrees C; 100.4 degrees F• 7% - 8% of total body weight• Males: 5 – 6 liters• Females: 4 – 5 liters

Functions of Blood

• Transportation

• Regulation

• Protection

Formed Elements

• Erythrocytes: (RBCs)

• Leukocytes (WBCs)

• Platelets

General Characteristics of Formed Elements

• Living blood cells• 2 out of 3 are NOT true cells• Most are short lived• Most do not divide• Hematopoiesis occurs in liver, spleen,

thymus, & bone marrow

Plasma

• Liquid portion: 90-92% water with fibrous proteins (fibrin)

• Straw colored, sticky fluid

Plasma

• Proteins• Non-protein nitrogenous substances• Nutrients• Electrolytes• Respiratory gases

Functions of Plasma

• Suspends blood cells & transports blood cells

• Carries metabolic wastes & nutrients• Circulates hormones and maintains water

content and body temperature• Maintains acid-base balance of blood

Erythrocytes

• Shape: biconcave disc• Spectrin (fibrous protein) flexibility to

change shape• Mature anucleate• 4 – 6 million per cubic millimeter• Lifespan: 100 – 120 days• 97% is hemoglobin• Erythropoiesis: 2.4 million per second

Leukocytes (WBC)

Surveillance, Fighters, Protectors

5 Types of WBCs

• Neutrophils: granulocyte• Lymphocyte: agranulocyte• Monocyte: agranulocyte• Eosinophil: granulocyte• Basophil: granulocyte

Neutrophils

• Nuclei: 3-6 lobes; polymorphonuclear leukocytes (polys) or segmented neutrophils (segs)

• Increase in % bacterial or some fungal infections

• Destroy bacteria by phagocytosis• Life span: 0.5 – 9 days

Lymphocytes

• Nucleus: large, dark purple spherical• Increase in % possible viral infection• T & B cells• Produce antibodies• T cells act directly against virus infected

cells & tumor cells• B cells plasma cells antibodies (Ig’s)• Lifespan: a few days to decades

Monocytes

• Nucleus: dark purple kidney or U-shaped with gray blue cytoplasm

• In tissues become macrophages• Increase in % possible chronic infections

i.e. TB & certain viruses & intracellular parasites

• Activate lymphocytic immune response• Lifespan: several months

Eosinophil

• Nucleus: 2 lobes, large red granules• 1 – 4% of all WBCs• Participate in allergic reactions• Increase in % possible parasitic infection

(i.e. flatworms – tapeworms, flukes; roundworms – pinworms, hookworms) or allergic response to antigen-antibody complex

• Lifespan: 0.5 – 9 days

Basophils

• Large coarse purple granules with histamine (inflammatory chemical that acts as vasodilator & attracts other WBCs to the inflamed site)

• Mast cells = similar• Release heparin & histamine• Lifespan: 0.5 – 9 days

Platelets

RBCWBC

Platelet

Platelets

• Thrombocytes • Involved in blood clotting• Small cytoplasmic fragments from

megakaryocyte• 250,000 – 400,000 per microliter• Lifespan: live only 10 days• Aspirin inactivates the platelets

Blood Groups/Types

Blood Group Terms

• Antigens: chemical structures imparting specific properties to the surface of the RBC

• Antibodies: protein substance developed in response to foreign body substances

Blood Group Systems

• Detected on the basis of specific reaction with corresponding antibody (either agglutination, lysis, or hemolysis) as a result of the presence or absence of the blood protein antigens on the RBC surface

• Inherited according to Mendelian laws• Fully formed either at birth or in early postnatal

life & persist throughout life

ABO System

• Discovered by Landsteiner in 1900

• Prior to discovery, blood transfusions were hit or miss

• Type A, Type B, Type AB, & Type O

Type A

• 41% of population

• Has A antigens on the RBC surface

• Has anti-B antibodies in the plasma

• Genotypes AA & AO = Phenotype A

Type B

• 10% of population

• Has B antigens on the RBC surface

• Has anti-A antibodies in the plasma

• Genotype BB & BO = Phenotype B

Type AB

• 4 % of population• Has A & B antigens on the RBC surface• Has NO antibodies in the plasma• Universal Recipient: can receive Type A,

Type B, Type AB, or Type O blood NO antibodies in plasma to react with antigens

• Genotypes: AB = Phenotype AB

Type O

• 45% of population• Has NO antigens on RBC surface• Has anti-A & anti-B antibodies in the

plasma• Universal Donor: can be given to any blood

type no antigens on the RBCs• Genotype OO = Phenotype O

Rh System

• Discovered by Landsteiner & Wiener in 1937

• Discovered in the Rhesus monkey

• Rh is an antigen on the RBC surface

Rh System

• Rh + has the antigens on the RBC (85% of population)

• Rh – does NOT have the Rh antigens• Rh + can accept Rh + or Rh – blood• Rh – can accept ONLY Rh - blood

Rh Incompatibility

• When Rh– person receives Rh+ blood in a transfusion person develops antibodies against the Rh+ factor

• Clinical problem if second transfusion of Rh+ blood given Rh antibodies will clump with the Rh antigens

• S & S of transfusion reaction: chills, fever, rash, itching, SOB, nausea, nephralgia, hematuria, shock & death

Erythroblastosis fetalis• Rh– mother and Rh+ father Rh+ child 1st

pregnancy• Mother develops antibodies to baby’s Rh+

antigens• 2nd pregnancy with Rh+ child mother’s anti-Rh

antibodies attack unborn child’s RBCs• Prevention: shot of Rhogam shortly after birth of

first Rh+ baby to block development of antibodies

Erythroblastosis fetalis

• Antigen-antibody reaction due to mixing of Rh+ blood of fetus with Rh- blood of mother during 2nd Rh+ pregnancy

• Prevented with shot of Rhogam at birth of 1st Rh+ baby