Blood (Plasma, RBCs, Platelets) PDF

BLOOD © 2012 Pearson Education, Inc.  BLOOD  Blood (Fluid connective tissue) Major transport medium of the body Gases (Oxygen and carbon dioxide) Nutrients (Lipids, carbohydrates, amino acids)...

BLOOD © 2012 Pearson Education, Inc.  BLOOD  Blood (Fluid connective tissue) Major transport medium of the body Gases (Oxygen and carbon dioxide) Nutrients (Lipids, carbohydrates, amino acids) Hormones (many examples) Immune system components (WBC and Antibodies) Waste products Minerals and ions Water © 2012 Pearson Education, Inc.  Important Functions of Blood Transportation of dissolved substances Regulation of pH and ions Restriction of fluid losses at injury sites Defense against toxins and pathogens Stabilization of body temperature © 2012 Pearson Education, Inc.  Physical Characteristics of Blood Three General Characteristics of Blood 1. 38C (100.4F) is normal temperature 2. High viscosity 3. Slightly alkaline pH (7.35–7.45) Blood volume (liters) = 7% of body weight (kilograms) Adult male 5 to 6 liters Adult female 4 to 5 liters © 2012 Pearson Education, Inc.  Physical Characteristics of Blood  Whole Blood = Plasma + Formed Elements (cells)  Plasma =matrix of blood connective tissue  Fluid consisting of:  Water  Dissolved plasma proteins  Other solutes  Formed elements = Specialized cells of blood c.t.  All cells and solids Fractionation Process of separating whole blood for clinical analysis Into plasma and formed elements © 2012 Pearson Education, Inc.  Abundance of Red Blood Cells Hematocrit: (packed cell volume, PCV) percentage of RBCs in centrifuged whole blood Male: 40–54 Female: 37–47 © 2012 Pearson Education, Inc.  Functions and Properties of Blood © 2012 Pearson Education, Inc.  Three Types of Formed Elements Red blood cells (RBCs) or erythrocytes Transport oxygen and carbon dioxide White blood cells (WBCs) or leukocytes Part of the immune system Platelets or thrombocytes Cell fragments involved in clotting © 2012 Pearson Education, Inc.  Plasma Composition 50–60% of blood volume More than 90% of plasma is water Extracellular fluids Interstitial fluid (IF) and plasma Materials that plasma and IF exchange across capillary walls Water Ions Small solutes Plasma proteins Albumins (54 - 60%) Globulins (35 - 38%) Fibrinogen (4 - 7%) © 2012 Pearson Education, Inc.  Plasma composition Albumins (54 - 60%) Transport substances such as fatty acids, thyroid hormones, and steroid hormones Globulins (35 - 38%) Antibodies, also called immunoglobulins Transport globulins (small molecules): hormone-binding proteins, metalloproteins, apolipoproteins (lipoproteins), and steroid-binding proteins Fibrinogen (4 - 7%) Molecules that form clots and produce long, insoluble strands of fibrin © 2012 Pearson Education, Inc.  Plasma Composition Other Plasma Proteins 1% of plasma Changing quantities of specialized plasma proteins Peptide hormones normally present in circulating blood Insulin, prolactin (PRL), and the glycoproteins thyroid-stimulating hormone (TSH), follicle- stimulating hormone (FSH), and luteinizing hormone (LH) © 2012 Pearson Education, Inc.  Plasma Origins of Plasma Proteins More than 90% made in liver Antibodies made by plasma cells Peptide hormones made by endocrine organs © 2012 Pearson Education, Inc.  Red Blood Cell Quantity Red blood cells (RBCs) Erythrocytes Make up 99.9% of blood’s formed elements Abundance of RBCs Red blood cell count - the number of RBCs in 1 microliter of whole blood Male: 4.5–6.3 million Female: 4.2–5.5 million © 2012 Pearson Education, Inc.  Red Blood Cell Structure Small and highly specialized discs Thin in middle and thicker at edge biconcave discs Filled with the protein Hemoglobin (eliminated organelles for space) © 2012 Pearson Education, Inc.  Red Blood Cell--Hemoglobin Structure Red pigmented protein molecule that transports respiratory gases. It gives whole blood its color Binds and transports oxygen and carbon dioxide Complex quaternary structure--Four globular protein subunits Each with one molecule of heme Each heme contains one iron ion © 2012 Pearson Education, Inc.  Hemoglobin Structure Iron ions—Bind O2, CO, CO2 Associate easily with oxygen (oxyhemoglobin, HbO2) Dissociate easily from oxygen (deoxyhemoglobin) When low oxygen is detected in peripheral capillaries Hemoglobin releases oxygen Binds carbon dioxide and carries it to lungs Forms carbaminohemoglobin The more hemoglobin in the RBC the more O2 it can carry and the deeper red the blood color. © 2012 Pearson Education, Inc.  Other Hemoglobin Functions Hemoglobin is also involved in regulating blood flow and blood pressure by the release of nitric oxide which causes vasodilation that improves blood flow and enhances oxygen delivery. Red blood cells also contain carbonic anhydrase which catalyzes the conversion of carbon dioxide and water to carbonic acid. This compound transports about 70% of carbon dioxide in the plasma. It is also a buffer. © 2012 Pearson Education, Inc.  Three Effects of RBC Shape on Function 1. High surface-to-volume ratio Quickly absorbs and releases oxygen 2. Discs form stacks called rouleaux Smooth the flow through narrow blood vessels 3. Discs bend and flex entering small capillaries 7.8-µm RBC passes through 4-µm capillary © 2012 Pearson Education, Inc. Figure 19-2d The Anatomy of Red Blood Cells Red blood cell (RBC) Rouleau (stacked RBCs) Nucleus of endothelial cell Blood vessels (viewed in longitudinal section) Sectioned capillaries LM  1430 When traveling through relatively narrow capillaries, RBCs may stack like dinner plates. © 2012 Pearson Education, Inc.  Red Blood Cells—Life span Short—110-120 days Why? © 2012 Pearson Education, Inc.  RBC Formation and Turnover 1% of circulating RBCs wear out per day About 3 million RBCs per second Hemoglobin Conversion and Recycling Macrophages of liver, spleen, and bone marrow Monitor RBCs Engulf RBCs before membranes rupture (hemolyze) © 2012 Pearson Education, Inc.  Hemoglobin Conversion and Recycling Phagocytic cells engulf old, damaged RBCs and break them down into two components: 1. Heme 2. Globin (protein) Heme is converted to biliverdin by removing the iron Iron is released and recycled Globin is broken down to amino acids © 2012 Pearson Education, Inc.  Breakdown of Biliverdin Biliverdin is converted to Bilirubin Is excreted by liver (bile) Jaundice is caused by bilirubin buildup Converted by intestinal bacteria to urobilins and stercobilins Amino acids from globulin breakdown are absorbed by the intestinal tract and used as a nutrient. © 2012 Pearson Education, Inc.  Iron Recycling Iron removed from heme is recycled and conserved To transport proteins (transferrin) To storage proteins (ferritin and hemosiderin) © 2012 Pearson Education, Inc.  Events Occurring in the Red Bone Marrow Events Occurring in Macrophages Macrophages in liver, RBC formation spleen, and bone marrow Fe2+ Fe2+ transported in circulation by transferrin Amino acids Heme Average life span of 90% RBC is 120 days Biliverdin New RBCs Old and released into damaged Bilirubin 10% In the bloodstream, circulation RBCs the rupture of RBCs Bilirubin bound is called hemolysis. to albumin in bloodstream Hemoglobin that is not phagocytized breaks down, and the alpha and beta chains are eliminated in urine. Liver Kidney Bilirubin Hb Absorbed into the circulation Urobilins Excreted in bile Urobilins, Eliminated Bilirubin stercobilins in urine Events Occurring in Events Occurring in the Liver Events Occurring in the Large Intestine Eliminated the Kidney in feces © 2012 Pearson Education, Inc. Events Occurring in Macrophages Macrophages in liver, spleen, and bone marrow Fe2+ Fe2+ transported in circulation by transferrin Amino acids Heme Average life span of 90% RBC is 120 days Biliverdin Old and Bilirubin 10% damaged In the bloodstream, RBCs the rupture of RBCs Bilirubin bound is called hemolysis. to albumin in bloodstream Hemoglobin that is not phagocytized breaks down, and the alpha and beta chains are eliminated in urine. © 2012 Pearson Education, Inc.  Events Occurring in the Red Bone Marrow RBC formation Fe2+ transported in circulation by transferrin Average life span of RBC is 120 days New RBCs released into In the bloodstream, circulation the rupture of RBCs is called hemolysis. Hemoglobin that is not phagocytized breaks down, and the alpha and beta chains are eliminated in urine. © 2012 Pearson Education, Inc. Events Occurring in the Liver Bilirubin bound to albumin in bloodstream Hemoglobin that is not phagocytized breaks down, and the alpha and beta chains are eliminated in urine. Liver Bilirubin Absorbed into the circulation Excreted in bile Urobilins, Bilirubin stercobilins © 2012 Pearson Education, Inc.  Events Occurring in Hemoglobin that is not the Kidney phagocytized breaks down, and the alpha and beta chains are eliminated in urine. Kidney Hb Absorbed into the circulation Urobilins Events Occurring in the Large Intestine Urobilins, Eliminated Bilirubin stercobilins in urine Eliminated in feces © 2012 Pearson Education, Inc.  New Blood cell production Hemopoiesis/hematopoiesis Process of producing formed elements By myeloid and lymphoid stem cells Hemocytoblasts 1. Myeloid stem cells become RBCs, some WBCs 2. Lymphoid stem cells become lymphocytes © 2012 Pearson Education, Inc.  Red bone marrow Hemocytoblasts Myeloid Stem Cells Lymphoid Stem Cells Progenitor Cells Blast Cells Proerythroblast Myeloblast Monoblast Lymphoblast Myelocytes Erythroblast stages Band Cells Ejection of nucleus Megakaryocyte Promonocyte Prolymphocyte Reticulocyte Erythrocyte Platelets Basophil Eosinophil Neutrophil Monocyte Lymphocyte Red Blood Cells Granulocytes Agranulocytes (RBCs) White Blood Cells (WBCs) © 2012 Pearson Education, Inc.  RBC Production Erythropoiesis Occurs only in myeloid tissue (red bone marrow) in adults Stem cells mature to become RBCs Stimulating Hormones Erythropoietin (EPO) Also called erythropoiesis-stimulating hormone Secreted when oxygen in peripheral tissues is low (hypoxia) Due to disease or high altitude or…… © 2012 Pearson Education, Inc.  Stages of RBC Maturation Myeloid stem cell Proerythroblast Erythroblasts Reticulocyte Mature RBC © 2012 Pearson Education, Inc.  Dietary Factors Affecting RBC Production Vitamin B12 and folic acid are necessary They are required for DNA synthesis making them necessary for the growth and division of all cells Iron is also necessary It is required for hemoglobin synthesis 34 © 2012 Pearson Education, Inc.  Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (a) (b) a: © The McGraw-Hill Companies, Inc./Al Telser, photographer :b © Ed Reschke © 2012 Pearson Education, Inc. 35  Platelets Cell fragments involved in human clotting system Nonmammalian vertebrates have thrombocytes (nucleated cells) Circulate for 9–12 days Are removed by spleen 2/3 are reserved for emergencies © 2012 Pearson Education, Inc.  Platelet Production Also called thrombocytopoiesis Occurs in bone marrow Megakaryocytes Giant cells in bone marrow Manufacture platelets from cytoplasm © 2012 Pearson Education, Inc.  Platelet Counts 150,000 to 500,000 per microliter Thrombocytopenia Abnormally low platelet count Thrombocytosis Abnormally high platelet count © 2012 Pearson Education, Inc.  Three Functions of Platelets Important in Hemostasis 1. Release important clotting chemicals 2. Temporarily patch damaged vessel walls 3. Reduce size of a break in vessel wall Continue to Hemostasis © 2012 Pearson Education, Inc.