Chapter 17 provides knowledge of blood. This chapter presents the following content: Overview: Blood composition and functions, blood plasma, formed elements, hemostasis, transfusion and blood replacement, diagnostic blood tests, developmental aspects of blood. | CHAPTER 17 Blood BLOOD COMPOSITION Blood: a fluid connective tissue composed of Plasma Formed elements Erythrocytes (red blood cells, or RBCs) Leukocytes (white blood cells, or WBCs) Platelets BLOOD COMPOSITION Hematocrit Percent of blood volume that is RBCs 47% ± 5% for males 42% ± 5% for females Consider 45 % as an average Figure 1 Withdraw blood and place in tube. 2 Centrifuge the blood sample. Plasma • 55% of whole blood • Least dense component Buffy coat • Leukocytes and platelets • <1% of whole blood Erythrocytes • 45% of whole blood • Most dense component Formed elements PHYSICAL CHARACTERISTICS AND VOLUME Sticky, opaque fluid Color scarlet to dark red pH – 38 C ~8% of body weight Average volume: 5 L FUNCTIONS OF BLOOD Distribution of O2 and nutrients to body cells Metabolic wastes to the lungs and kidneys for elimination Hormones from endocrine organs to target organs FUNCTIONS OF BLOOD Regulation of Body temperature by absorbing and distributing heat Normal pH using buffers Adequate fluid volume in the circulatory system FUNCTIONS OF BLOOD Protection against Blood loss Plasma proteins and platelets initiate clot formation Infection Antibodies Complement proteins WBCs defend against foreign invaders BLOOD PLASMA 90% water Proteins are mostly produced by the liver 60% albumin 36% globulins 4% fibrinogen BLOOD PLASMA Nitrogenous by-products of metabolism—lactic acid, urea, creatinine Nutrients—glucose, carbohydrates, amino acids Electrolytes—Na+, K+, Ca2+, Cl–, HCO3– Respiratory gases—O2 and CO2 Hormones FORMED ELEMENTS Only WBCs are complete cells RBCs have no nuclei or organelles Platelets are cell fragments Most formed elements survive in the bloodstream for only a few days Most blood cells originate in bone marrow and do not divide Figure Platelets Neutrophils Lymphocyte Erythrocytes Monocyte ERYTHROCYTES Biconcave discs, anucleate, essentially no organelles Filled with hemoglobin (Hb) for gas transport Provide flexibility to change . | CHAPTER 17 Blood BLOOD COMPOSITION Blood: a fluid connective tissue composed of Plasma Formed elements Erythrocytes (red blood cells, or RBCs) Leukocytes (white blood cells, or WBCs) Platelets BLOOD COMPOSITION Hematocrit Percent of blood volume that is RBCs 47% ± 5% for males 42% ± 5% for females Consider 45 % as an average Figure 1 Withdraw blood and place in tube. 2 Centrifuge the blood sample. Plasma • 55% of whole blood • Least dense component Buffy coat • Leukocytes and platelets • <1% of whole blood Erythrocytes • 45% of whole blood • Most dense component Formed elements PHYSICAL CHARACTERISTICS AND VOLUME Sticky, opaque fluid Color scarlet to dark red pH – 38 C ~8% of body weight Average volume: 5 L FUNCTIONS OF BLOOD Distribution of O2 and nutrients to body cells Metabolic wastes to the lungs and kidneys for elimination Hormones from endocrine organs to target organs FUNCTIONS OF BLOOD Regulation of Body temperature by absorbing and distributing heat Normal pH .
