Lesson 5 Blood part 1 02 16 2016 An Introduction to Blood and the Cardiovascular System The Cardiovascular System consists of o A pump the heart o A conducting system blood vessels o A fluid medium blood Is specialized fluid of connective tissue Contains cells suspended in a fluid matrix Blood o Transports materials to and from cells o Materials include Oxygen O2 and carbon dioxide CO2 Nutrients Hormones Waste products Immune system components 19 1 Physical Characteristics of Blood Important Functions of Blood o Transportation of dissolved substances o Regulation of pH and ions o Restriction of fluid losses at injury sites o Defense against toxins and pathogens o Stabilization of body temperature Whole Blood composed of o Plasma fluid consisting of Water Dissolved plasma proteins Other solutes o Formed elements All cells and solids Red blood cells white blood cells platelets Three Types of Formed Elements o Red blood cells RBCs or erythrocytes Transport oxygen o White blood cells WBCs or leukocytes Part of the immune system o Platelets Cell fragments involved in clotting Hemopoiesis Process of producing formed elements o Formed elements formed from myeloid and lymphoid stem Fractionation Process of separating whole blood for clinical cells analysis o Separation into plasma and formed elements o A thin buffy coat composed of platelets and white blood cells found between RBC pellet and plasma fluid above Three General Characteristics of Blood o 38 C 100 4 F is normal temperature o high viscosity 5x more viscous than water caused by dissolved proteins formed elements in blood o slightly alkaline pH 7 35 7 45 Characteristics of Blood o Blood volume liters 7 of body weight kilograms Adult male 5 6 liters Adult female 4 5 liters Loss of 10 blood volume will cause a significant decrease in blood pressure 19 2 Plasma The Composition of Plasma o Makes up 50 60 of blood volume o More than 90 of plasma is water o Extracellular fluids Interstitial Fluid IF and Plasma What is interstitial fluid Materials in plasma and IF exchange across capillary walls Water Ions Small solutes Plasma Proteins found in blood include o Albumins 60 Transport substances such as fatty acids thyroid hormones and steroid hormones o Globulins 35 Antibodies also called immunoglobulins Transport globulins small molecules hormone binding proteins mealloproteins apolipoproteins lipoproteins and steroid binding proteins Molecules that form clots and produce long insoluble o Fibrinogen 4 strands of fibrin Other Plasma Proteins o 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 Origins of Plasma Proteins o More than 90 made in liver o Antibodies made by plasma cells activated B lymphocytes o Peptide hormones made by endocrine organs Serum Liquid part of a blood sample o Produced when dissolved fibrinogen converts to solid fibrin fibrin is removed from sample o Serum lacks clotting proteins and CA2 used up during the clotting process 19 3 Red Blood Cells Red Blood Cells RBCs body Hemoglobin o Make up 99 9 of blood s formed elements o Average adult has 25 trillion RBCs 1 3 of all cells in human o The red pigment that gives whole blood its color o Binds and transports oxygen and carbon dioxide o Normal hemoglobin adult male 14 18 g dL whole blood o Normal hemoglobin adult female 12 16 g dL whole blood o NOTE 1 dL 100 mL o Red blood cell count the number of RBCs in 1 microliter of whole blood a drop of blood is approx 50 L Abundance of RBCs Male 4 5 5 5 million Female 4 2 5 5 million o Hematocrit packed cell volume PCV percentage of RBCs in centrifuged whole blood RBC volume total volume Male 40 54 Female 37 47 Structure of RBCs o Small and highly specialized discs o Thin in middle and thicker at edge Three important effects of RBC shape on function o High surface to volume ratio Quickly absorbs and releases oxygen o Discs form stacks called rouleaux Smooth the flow through narrow blood vessels o Discs bend and flex entering small capillaries 7 8 m RBC passes through 4 m capillary Sickle Cell Anemia causes by mutation of an amino acid in beta subunit of hemoglobin Low O2 cause mutated Hb to alter RBC shape making it stiff easily damaged Change in shape also causes it to block narrow capillaries Can use the same treatments as thalassemia discussed later Life Span of RBCs o Lack nuclei mitochondria and ribosomes Means no repair and uses anaerobic metabolism to generate ATP Live about 120 days Hemoglobin Hb o Protein molecule that transports respiratory gases o Normal hemoglobin adult male 14 18 g dL whole blood o Normal hemoglobin adult female 12 16 g dL whole blood Hemoglobin Structure o Complex quaternary structure o Four globular protein subunits 2 alpha subunits 2 beta subunits Each with one molecule of heme o Each heme contains one iron ion The iron ion Associate easily with oxygen oxyhemoglobin HbO2 Dissociate easily from oxygen deoxyhemoglobin o Carries oxygen from lungs to peripheral tissues o At tissues with low oxygen peripheral capillaries Hemoglobin releases oxygen Binds picks up carbon dioxide and carries it to lungs When bound to CO2 hemoglobin becomes carbaminohemoglobin Hemoglobin Functions Fetal Hemoglobin o Strong form of hemoglobin found in embryos Has high affinity for O2 o Takes oxygen from mother s hemoglobin Hb problem o Thalassemia inability to produce enough Hb subunits Causes reduction of RBC production and fragile short lived RBCs affecting development and growth If severe may require periodic blood transfusions or treated by converting adult Hb to fetal Hb with hydroxyurea or butyrate RBC Formation and Turnover o 1 of circulating RBCs wear out per day about 3 million new RBCs per second turnover and formation usually matches Hemoglobin Conversion and Recycling o Macrophages of liver spleen and bone marrow Monitor RBCs Engulf RBCs before membranes rupture hemolyze o Phagocytes break hemoglobin into components Globular proteins break down to amino acids Heme to biliverdin organic green colored compound bad bruises look greenish because of biliverdin formation in blood filled tissues Iron recycles Breakdown of Biliverdin o Biliverdin green is converted to bilirubin yellow in the phagocyte Bilirubin is transported by blood to liver for excretion in bile to the intestine Jaundice yellowish skin and
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