Chapter 10 ObjectivesBlood is the "river of life" that surges within us. It transports everything that must be carried from one place to another within the body-nutrients, wastes (headed for elimination from the body), and body heat-through blood vessels. For centuries, long before modern medicine, people recognized that blood was vital (some believed "magical"), and its loss was always considered to be a possible cause of death. In this chapter, we consider the composition and function of this life-sustaining fluid. The means by which it is propelled throughout the body is discussed in Chapter 11.

Objective Checklist 

Composition and Functions of Blood  Indicate the composition and volume of whole blood. Describe the composition of plasma and discuss its importance in the body. List the cell types making up the formed elements and describe the major

functions of each type. Define anemia, polycythemia, leucopenia, andleukocytosis, and list possible

causes for each condition. Explain the role of the hemocytoblast.

Hemostasis  Describe the blood-clotting process. Name some factors that may inhibit or enhance the blood-clotting process.

Blood Groups and Transfusions  Describe the ABO and Rh blood groups. Explain the basis for a transfusion reaction.

Developmental Aspects of Blood  Explain the basis of physiologic jaundice seen in some newborn babies. Indicate blood disorders that increase in frequency in the aged.

Chapter 10: Blood (add

more space for formed elements objective on notes sheet for students!

Composition and Functions of Blood

Describe the composition and volume of whole blood.

Describe the composition of plasma and discussits importance in the body.

List the cell types making up the formed elements

and describe the major functions of each type.

Define anemia, polycythemia, leukopenia, andleukocytosis, and list the possible causes for each condition.

Explain the role of the hemocytoblast.

Hemostasis Describe the blood-clotting process.

Name some factors that may inhibit

or enhance the blood-clotting process.

Blood Groups and Transfusions

Describe the ABO and Rh blood groups.

Explain the basis for a transfusion reaction.

Developmental Aspects of Blood

Explain the basis of physiological jaundiceseen in some newborn babies.

Indicate blood disorders that increase infrequency in the aged.

Chapter 10: Blood

Composition and Functions of Blood

Describe the composition and volume of whole blood.

Blood is 55% plasma (water, salts, proteins, nutrients, wastes, gases and hormones) and 45% Formed elements (erythrocytes, leukocytes and platelets)Less than 1% is leukocytes and platelets.Hematocrit is the 45% erythrocyte part. Blood is 5 times thicker than water, slightly alkaline (pH between 7.35 and 7.45) and warmer than the body (38°C

or 100.4°F) (pH is restored via respiration and kidneys)Normal blood volume is 5-6 L.

Describe the composition of plasma and discuss its importance in the body.

Plasma is 90% water.Plasma contains proteins (albumen for osmotic pressure, fibrinogen for clotting, and globulins for defense and lipid transport).

These are created mostly in the liver. Various salts are found in plasma including Na+, K+, Ca2+, Mg2+, Cl-, HCO3

-. They help maintain osmotic pressure, pH, and regulate membrane permeability. Other substances are transported by blood: glucose, fatty acids, vitamins, amino acids, wastes (urea, uric acid), oxygen, carbon dioxide, and hormones

List the cell types making up the formed elements and describe the major functions of each type.

Cell types FunctionErythrocytes (RBC’s)

Carry oxygen attached to hemoglobin (12-18g/100ml)About 5 million /mm3

Leukocytes 4-11 thousand/mm3defense against

allergies, foreign matter, infection,immune response, viral attack,

Platelets 250-500 thousand/mm3aid clotting

Specific leukocytesLeukocytes FunctionGranulocytes Neutrophils 3-7

thousand/mm3; phagocytic,

Eosinophils

Basophils

increase with acute infections 100-400/mm3; kill parasites, aid in allergic reactions, reduce inflammation20-50/mm3; contain histamine (vasodilator)

Agranulocytes Lymphocytes

monocytes

1500-3000/mm3; B’s produce antibodies, T’s are involved in graft rejection, fighting tumors and viruses, activate B’s 100-700/mm3; phagocytes turn to macrophages in tissues,

clean-up crew; involved in chronic infections

Define anemia, polycythemia, leukopenia, and leukocytosis, and list the possible causes for each condition.

Anemia is a decrease in oxygen-carrying ability; resulting from low hemoglobin or low RBC count.

Polycythemia is excess RBC’s from cancer, living at high altitude, etc. Leukopenia is low WBC count caused by medicationsLeukocytosis is high WBC count (above 11000/mm3) caused by bacterial or viral infection.

Explain the role of the hemocytoblast.

A hemocytoblast is a blood cell/platelet stem cell in the red bone marrow. It can

form myeloid stem cells which later form RBC’s, platelets, monocytes, neutrophils, eosinophils or basophils or lymphoid stem cells forming lymphocytes. Hemostasis

Describe the blood-clotting process.

Platelets stick to the collagen in the wound; they release chemicals to attract more platelets and form branches, They release serotonin

causing the blood vessels to spasm and constrict, aiding clotting; Thromboplastin is released, reacting with PF3 and other factors and Ca ions to trigger clotting; Prothrombin changes to thrombin, attaching to fibrinogen proteins to form fibrin and mesh that traps RBC’s to form the dark clot. Serum or plasma is released as the clot retracts.

Name some factors that may inhibit or enhance the blood-clotting process.

Factors include anything that roughens the endothelium of vessels. This may be burns, blows, or fatty material. Blood pooling increases clot risks. Excess use of aspirin, heparin, dicumarol, etc. may cause thinning of the blood, decreasing clotting ability.

Blood Groups and Transfusions

Describe the ABO and Rh blood groups.

There are 4 blood types: A, B, AB, OIn addition, each blood type may be Rh+ or Rh-, an antigen traced to Rhesus monkeys. AB is the universal recipient and O is the universal donor.The blood type indicates the antigens present.

Explain the basis for a transfusion reaction.

A transfusion reaction occurs when antibodies attack antigens different from the blood type, causing agglutination, or clotting. For instance, Type A blood contains Anti-B antibodies. If injected in a type B or AB person, the antibodies will attack the B antigens on the recipient blood cells, causing agglutination.

Developmental Aspects of Blood

Explain the basis of physiological jaundice seen in some newborn babies.

Newborns experience jaundice when fetal blood cell counts fall and new RBC’s have not caught up with the demand. The fetal liver cannot keep up with hemoglobin breakdown products in the bile, so the

infant becomes jaundiced, or yellowish.

Indicate blood disorders that increase in frequency in the aged.

Older adults may suffer from the following disorders:

Leukemia – cancer of the blood

Anemia – pernicious anemia caused by stomach mucosa atrophy.

Heart disease, blood vessel problems, and immune

system problems, including atherosclerosis, arteriosclerosis.