Transcript Blood
Chapter 12 Blood Blood Type of connective tissue Functions –Transporting substances to maintain homeostasis Travels through the vessels Blood Volume 8% of body weight Typical adult has 5 liters of blood Blood Composition Formed elements –Erythrocytes –Leukocytes –Thrombocytes Fluid element –Plasma Blood Sample 45% cells by volume Hematocrit –% of blood sample that is packed cells (most of which are the RBC’s) 35% Plasma Erythrocytes RBC Characteristics –Biconcave disks • Thicker on outside and thin on middle • Adaptation for function of gas transport Erythrocytes RBC Characteristics –1/3 hemoglobin by volume • Deoxyhemoglobin –Hemoglobin without O2 • Oxyhemoglobin –Hemoglobin with O2 Erythrocytes RBC Characteristics –Cyanosis • Blue –Only a good color if you are a SMURF! • Abundant deoxyhemoglobin Erythrocytes RBC Characteristics –Develop from proerythroblast –Several intermediate stages –Young stages have nucleus –Mature RBC lacks nucleus Red Blood Cell Counts Males –4.6 – 6.2 million/cc Females –4.2 – 5.4 million/cc • Why are females lower in this count? Red Blood Cell Breakdown Macrophages in liver and spleen phagocytize damaged cells Hgb is broken down to heme and globin Heme is decomposed into Fe and biliverdin Red Blood Cell Breakdown Fe is reused for new Hgb synthesis or stored as ferritin in the liver. Some biliverdin is converted into bilirubin Bilirubin and biliverdin excreted in bile as pigments. Red Blood Cell Production Done in the red bone marrow. Erythropoietin –Hormone produced by kidneys –Lack of cells it is produced to stimulate cell production –Triggered by O2 levels Red Blood Cell Production Life of RBC 120 days. Production is regulated by negative feedback. Red Blood Cell Production Dietary factors – B12 and folic acid significantly influence RBC production – Fe required for RBC synthesis Anemia – Lack of Fe or Hgb. Other types also Leukocytes Function –Protection against disease Two major types –Granulocytes –Agranulocytes Granulocytes Have grainy looking cytoplasm Types –Neutrophils –Nucleus has two – five lobes –Phagocytosis/First on the scene –54% of blood sample Granulocytes Eosinophils –Bilobed nucleus –Prevalent in allergic reactions and parasitic worm infections –1 – 3% of blood sample Granulocytes Basophils –Similar to eosinophils in shape –Release histamine – promotes inflammation –Releases heparin – blood thinner –Less than 1% of blood sample Agranulocytes Lack grains in cytoplasm –Monocytes • Largest of all leukocytes • Phagocytosis • 3 – 9% of blood samples Agranulocytes Lymphocytes –T-cells directly attack anything foreign –B-cells produce antibodies for longer term protection –25 – 33% of blood sample Leukocyte infection fighting Diapedesis –Allows them to leave circulation –Ameboid movement Positive Chemotaxis –Release of chemicals that signal other cells to the area. Pus Contains WBC’s Dead microorganisms Fluid White Blood Cell Counts 5,000 – 10,000 cells per cc. Leukocytosis –More than 10,000 cells per cc Leukopenia –Less than 5,000 cells per cc White Blood Cell Counts Differential blood count –Separates and counts each specific type of white blood cell Plasma 92% water Contains organic and inorganic molecules Plasma Functions –Transporting nutrients, gasses and vitamins –Helps regulate fluid and electrolyte balance –Maintaining a favorable pH. Plasma Proteins Most abundant of dissolved substances. Three major plasma protein –Albumins –Globulins –Fibrinogen Albumins Smallest of plasma proteins Make up 60% of the proteins Synthesized in the liver Function to maintain blood osmotic pressure Globulins Three types – 36% of proteins – Alpha • Made in liver • Transport lipids and fat soluble vitamins – Beta • Same as Alpha Globulins Gamma –Synthesized in lymphatic tissue –Constitutes the antibodies of immunity Fibrinogen Synthesized in liver Makes up 4% of proteins Soluble protein that plays the role in blood coagulation Gasses Oxygen Nitrogen Carbon dioxide Nutrients Amino acids Sugars Lipids Plasma Lipoproteins Chylomicrons –Have a high concentration of triglycerides –Transports dietary fats to muscle and adipose tissue Plasma Lipoproteins Very low-density lipoproteins VLDL –High concentration of triglycerides/ Made in liver –Transports triglycerides from liver to adipose tissue Plasma Lipoproteins Low-density Lipoproteins LDL –High concentration of cholesterol/Made from VLDL molecules –Delivers cholesterol to various cells including liver Plasma Lipoproteins High-density Lipoproteins HDL –Relatively high concentration of protein and low concentrations of lipids. –Transports to the liver chylomicron remnants. Nonprotein Nitrogenous Substances NPN Amino acids Urea Uric acid Creatine Creatinine Plasma Electrolytes Na HCO3 K PO4 Ca SO4 Mg Cl Blood Clotting Hemostasis Three Steps –Blood Vessel Spasm –Platelet Plug Formation –Blood Coagulation Blood Vessel Spasm Damage to a vessel causes a vasospasm Lasts only a few minutes but sets into motion the next two steps Platelet Plug Formation Platelets will stick to anything rough or jagged. Sends out serotonin so smooth muscle will contract again. Plug forms to stop bleeding Blood Coagulation Forms a blood clot Complex and requires clotting factors Major event in blood clot formation is conversion of fibrinogen to fibrin. Blood Coagulation Tissue damage release tissue thromboplastin. This along with Ca+2 produces prothrombin activator Blood Coagulation Prothrombin activator and +2 Ca combine with Prothrombin to form Thrombin Blood Coagulation Thrombin and Ca+2 combine with fibrinogen to form fibrin Fibrinogen is soluble Fibrin is insoluble Blood clotting is positive feedback mechanism Blood Coagulation Thrombus –Stationary blood clot Embolus –Moving blood clot Blood Typing Genetically determined ABO blood grouping used Based on presence or absence of antigens on RBC Blood Typing Antigens –On the RBC membrane –Specific shape like puzzle pieces Antibodies –Found in plasma –Reciprocal shape to antigens Blood Typing A –A antigens –anti-B antibodies B –B antigens • anti-A antibodies Blood Typing AB –Both A and B antigens –No antibodies O –No antigens –Both anti-A & anti-B antibodies Blood Typing O = universal donor AB = universal recipient Transfusion reactions occur due to agglutination – clumping of RBC Rh factor Discovered in Rhesus monkeys Antigen D –Present is Rh positive –Absent in Rh negative Anti-D antibody Erythroblastosis Fetalis If Rh negative mother has Rh positive fetus can develop this with subsequent children Use Rhogam to prevent this.