Blood physiology by prof.Israa F.Jafar Physiology of Blood Components, Characteristics, Functions of Blood Major Components of Blood 1. Formed elements - the actual cellular components of blood (special connective tissue) a.erythrocytes - red blood cells b.leukocytes - white blood cells c.platelets - cell fragments for clotting 2. Blood plasma - complex non-cellular fluid surrounding formed elements; protein & electrolytes. Separation of Components in a Centrifuge VOLUME clear/yellowish PLASMA 55% thin/whitish buffy coat <1% with LEUKOCYTES & PLATELETS reddish mass - ERYTHROCYTES 45% LAYER top middle bottom hematocrit - percentage by VOLUME of erythrocytes when blood is centrifuged (normal = 45%) Whole Blood Plasma CENTRIFUGE Characteristics of Blood Packed Red Cells 1. bright red (oxygenated) 2. dark red/purplish (unoxygenated) 3. much more dense than pure water 4. pH range from 7.35 to 7.45 (slightly alkaline) 5. slightly warmer than body temperature 100.4 F 6. typical volume in adult male 5-6 liters 7. typical volume in adult female 4-5 liters 8. typically 8% of body weight Major Functions of Blood 1. Distribution & Transport a. oxygen from lungs to body cells 1
Blood physiology by prof. Israa F.Jafar b. carbon dioxide from body cells to lungs c. nutrients from GI tract to body cells d. nitrogenous wastes from body cells to kidneys e. hormones from glands to body cells 2. Regulation (maintenance of homeostasis) a. maintenance of normal body pH by blood proteins (albumin) & bicarbonate b. maintenance of circulatory/interstitial fluid by electrolytes that aid blood proteins (albumin) c. maintenance of temperature (blushed skin) 3. Protection a. platelets and proteins "seal" vessel damage b. protection from foreign material & infections byleukocytes, antibodies& complement proteins Plasma (the liquid part of blood) A. General Characteristics 1. plasma makes up 55% of normal blood by volume 2. water is 90% of the plasma by volume 3. many different SOLUTES in the plasma a. albumin - pH buffer & osmotic pressure b. globulins - binding proteins & antibodies c. clotting proteins - prothrombin & fibrinogen d. other proteins - enzymes, hormones, others e. nutrients - glucose, fatty acids, amino acids, cholesterol, vitamins f. electrolytes - Na+, K+, Ca++, Mg ** , Cl-, phosphate, sulfate, bicarbonate, others 2
BONE MARROW Blood physiology by prof.Israa F.Jafar In the adult, red blood cells, many white blood cells, and platelets are formed in the bone marrow. In the fetus, blood cells are also formed in the liver and spleen, and in adults such extramedullary hematopoiesis may occur in diseases in which the bone marrow becomes destroyed or fibrosed. In children, blood cells are actively produced in the marrow cavities of all the bones. By age 20, the marrow in the cavities of the long bones, except for the upper humerus and femur, has become inactive . Active cellular marrow is called red marrow; inactive marrow that is infiltrated with fat is called yellow marrow. The bone marrow is actually one of the largest organs in the body, approaching the size and weight of the liver. It is also one of