University:
Glendale Community College
Course:
BIO160 | Introduction to Human Anatomy and Physiology
Academic year:

2019
Views:

80

Pages:

10
Author:

unidosenluz0y

The Circulatory System: Blood Chapter 18 • Functions and properties of blood • Plasma • Blood cell production • Erythrocytes • Leukocytes • Blood Types • Hemostasis Functions and Properties of Blood • Functions in respiration, nutrition, waste elimination, thermoregulation, immune defense, water balance, electrolyte and pH balance • Adults have 4-6 L of blood composed of: – plasma, a clear extracellular fluid – formed elements = blood cells and platelets • Properties of blood: – viscosity = resistance to flow – osmolarity = concentration of dissolved particles Hematocrit • Centrifuge separates formed elements from plasma • Hematocrit is the percent of total volume that is cells – Normal hematocrit values Female: 37-48% Male: 45-53% Plasma and Plasma Proteins • Plasma is a mixture of proteins, enzymes, nutrients, wastes, hormones, and gases – if allowed to clot, the liquid that remains is called serum • 3 major categories of plasma proteins: – albumins are the most abundant plasma protein • contributes to viscosity and osmolarity and influences blood pressure, flow and fluid balance – fibrinogen is precursor of fibrin threads that help form blood clots – globulins (antibodies) provide immune system defenses • alpha, beta and gamma globulins • Albumens and fibrinogen plasma proteins are formed by the liver • Globulins are antibodies produced by white blood cells called plasma cells Plasma and Serum Blood to which an anticoagulant has been added will not clot. Blood cells will settle to the bottom of the tube leaving plasma at the top of the tube. Blood to which no anticoagulant has been added will clot. Blood cells get caught in the clot leave serum behind. Non-protein Components of Plasma • Nitrogenous compounds – amino acids from dietary protein or tissue breakdown – nitrogenous wastes (urea and ammonia) are toxic end products of catabolism that are normally removed from the blood by the kidneys • Nutrients (glucose, vitamins, fats, minerals) • Dissolved gases like O2 and CO2 are transported in plasma • Many electrolytes (Na+, Cl+, K+, HCO3-, Ca+2, and others) – sodium makes up 90% of plasma cations accounting for more of the blood’s osmolarity than any other solute Formed Elements of Blood neutrophil eosinophil erythrocyte monocyte lymphocyte platelets basophil • Formed Elements = Erythrocytes, Platelets, Leukocytes (neutrophil, eosinophil, basophil, monocyte, lymphocyte) • Non-formed Elements = Plasma Blood Cell Production (Hematopoiesis/Hemopoiesis) • The following hematopoietic tissues produce blood cells: – yolk sac of vertebrate embryos produce stem cells that colonize fetal bone marrow, liver, spleen lymph nodes and thymus – liver stops producing blood cells at birth and the thymus stops at about age 10, but the other tissues continue to produce WBCs – bone marrow contains stem cells that produce RBCs, WBCs and platelets • Stem cells multiply continually and are pluripotent (capable of differentiating into multiple cell lines) • Red bone marrow is active; yellow bone marrow is inactive and fatty • Stem cells are stimulated by hormones including erythropoietin (EPO) from the kidney and the liver amniotic sac yolk sac placenta Stem Cells of Hematopoiesis