Chapter 18 Vu (McGH) Blood

◦ Oxygen from the lungs and nutrients from the digestive tract ◦ Metabolic wastes from cells to the lungs and kidneys for elimination ◦ Hormones from endocrine glands to target ◦ Body protection Regulation: ◦ Appropriate body temperature by absorbing and distributing heat ◦ Normal pH in body tissues using buffer systems ◦ Adequate fluid volume in the circulatory system Protection: ◦ Blood prevents blood loss by: ◦ Activating plasma proteins and platelets ◦ Initiating clot formation when a vessel is broken ◦ Blood prevents infection by: ◦ Synthesizing and utilizing antibodies ◦ Activating complement proteins ◦ Activating WBCs to defend the body against foreign invaders Blood is the body’s only fluid tissue It is composed of liquid plasma and formed elements Formed elements include: ◦ Erythrocytes, or red blood cells (RBCs) ◦ Leukocytes, or white blood cells (WBCs) ◦ Thrombocytes (Platelets) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Centrifuge Whole blood 1 Withdraw blood into a syringe and place it into a glass centrifuge tube. 3 Components of blood separate during centrifugation to reveal plasma, buffy coat, and erythrocytes. Plasma (55% of whole blood) Water 92% by weight Proteins 7% by weight Albumins 58% Globulins 37% Fibrinogen 4% Regulatory proteins 1% Other solutes 1% by weight Electrolytes Nutrients Respiratory gases Waste products Buffy coat (1% of whole blood) 55% Platelets 150–400 thousand per cubic mm Leukocytes 4.5–11 thousand per cubic mm 1% Neutrophils 50–70% Lymphocytes 20–40% 44% Eosinophils 1–4% Monocytes 2–8% Basophils 0.5–1% Formed elements Hematocrit – the percentage of RBCs out of the total blood volume Male: 42% - 52%; Female: 37% - 47% Erythrocytes (44% of whole blood) Erythrocytes 4.2 –6.2 million per cubic mm Physical Characteristics Blood is a sticky, opaque fluid with a metallic taste Color varies from scarlet (oxygen-rich) to dark red (oxygen-poor) The pH of blood is 7.35–7.45 Temperature is 38C, slightly higher than “normal” body temperature Blood accounts for approximately 8% of body weight Average volume of blood is 5–6 L for males, and 4–5 L for females Blood Plasma Blood plasma contains over 100 solutes, including: ◦ Proteins – albumin, globulins, clotting proteins, and others ◦ Nonprotein nitrogenous substances – lactic acid, urea, creatinine ◦ Organic nutrients – glucose, carbohydrates, amino acids ◦ Electrolytes – sodium, potassium, calcium, chloride, bicarbonate ◦ Respiratory gases – oxygen and carbon dioxide Plasma proteins ◦ Blood considered a colloid