Objectives 1. Describe the primary function of blood 2. Describe the characteristics of blood plasma 3. Identify the formed elements of blood and identify the most important function of each 4. Discuss anemia in terms of red blood cell numbers and hemoglobin content 5. List the steps in blood clotting

Blood Function- transportation; carries nutrients and oxygen to all body cells, then eliminates carbon dioxide and other wastes Alkaline – pH Acidosis – alkalinity of blood decreases toward neutral; very sick Note: Blood almost never becomes the least bit acidic

Blood Formation Red bone marrow (myeloid tissue) forms all blood cells EXCEPT some lymphocytes and monocytes, which are formed by lymph tissue in lymph nodes, thymus, and spleen

Blood plasma Blood minus its cells Water containing dissolved substances (foods, salts, hormones, small amount of oxygen) Note: Most oxygen is carried by RBCs as oxyhemoglobin Most abundant type of solute- plasma proteins

Plasma proteins Albumins – help thicken blood, IV administration in cases of hemorrhage, severe burns, or kidney disease can be life- saving Globulins – antibodies that help protect us from infection Fibrinogen – necessary for blood clotting Prothrombin – necessary for blood clotting

Blood serum Plasma minus its blood clotting factors (fibrinogen and prothrombin) Obtained from whole blood by allowing blood to clot in the bottom of a tube and then pouring off the liquid serum Serum contains antibodies so it can be used to treat patients who have a need for a specific antibody

Approximate Normal Counts RBCs – 5 million per mm 3 Anemia – deficiency in number or function of RBCs and the hemoglobin (iron containing protein in RBC) Total WBC – 4,500 to 11,000/mm 3 Platelets – 150,000 to 400,000/mm 3

Questions If you had a red blood cell count of 3 million what does that mean in comparison with what is considered a normal range? With this information, your physician concludes that you are anemic. How did the doctor arrive at this conclusion?

Question Because of a fractured left femur sustained while playing football, an acute infection developed. The doctor ordered a lab test to check your WBC count. Would you expect the WBC count to be 3000, 5000, or 15,000? Explain your answer.

Blood Clotting 1. Release of clotting factors from both injured tissue cells and sticky platelets at the injury site (platelet plug) Clotting factors: prothrombin (a protein in normal blood) prothrombin activator (formed when clotting factors in damaged cells react with plasma) normal amount of blood calcium

2. Formation of thrombin If normal amount of blood calcium is present, prothrombin activator converts prothrombin ( a protein in normal blood) to thrombin ( a protein used for blood clotting)

3. Formation of fibrin and trapping of RBCs to form a clot Thrombin reacts with fibrinogen (a normal plasma protein) to change it to a fibrous gel called fibrin