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 7.35-7.45• 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 mm3

• Anemia – deficiency in number or function of RBCs and the hemoglobin (iron containing protein in RBC)

• Total WBC – 4,500 to 11,000/mm3

• Platelets – 150,000 to 400,000/mm3

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