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Honors A & P Blood Unit Functions of Blood • Distribution – Transporting digestive nutrients, oxygen, wastes, hormones, etc. • Regulation – Fluid balance within the body tissues and maintaining human body temperature. • Protection – Immune system (disease) and blood clotting (loss of blood) What is in Blood? • Blood is a vascular connective tissue • The three formed elements, or cells, in the blood are: erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets). • Plasma is the liquid portion of the blood, which is ~92% water. The other 8% are mainly proteins as well as waste products, gases, and nutrients. Composition of Blood / Hematocrit • From a sample of whole blood: – Plasma makes up 55%. – 45% are red blood cells = hematocrit test – <1% are white blood cells and platelets Blood Composition / Complete Blood Count (CBC) RBC’s = 4 – 6 million cells/mL WBC’s = 5 – 11 thousand cells/mL Platelets = 12 – 300 thousand cells/mL Blood Volume & Characteristics • On average, accounts for 8% of our total body weight – 5 to 6 liters of blood for males – 4 to 5 liters of blood for females • Under normal conditions, one’s complete blood volume circulates completely through the human body every minute. Erythrocytes / Red Blood Cells • Biconcave shape, flexible cells • 7.5 x 2 micrometers • Red Blood Cells transport oxygen on molecules called Hemoglobin. • Oxyhemoglobin vs. Deoxyhemoglobin. • Average lifespan is 120 days. Blood Typing • Researched why some blood transfusions saved patients while some caused death in other patients • Proposed that humans have multiple classifications, or types, of blood A, B, AB, O • Won Nobel Prize in Medicine in 1930 for establishment of blood types. Karl Landsteiner Blood Typing – ABO System • The A, B, O blood group designates the “letter” to one’s blood type. • Blood type is determined by which antigens (on the RBC’s) are present. • Antibodies (in the plasma) against foreign antigens are also present. • Blood type is genetically determined and the ABO antigens and antibodies are present at birth. Blood Typing – Rh System • Rh factor determines the + or – of your blood type. • It is an antigen on RBC’s that may (+) or may not (-) be present at birth. • Rh antibody will only be created upon an exposure to foreign antigen (not present at birth). • Rh+ individual – Has Rh antigen – Will not develop the antibody • Rh- individual – Does not have the Rh antigen – May develop the antibody upon exposure Erythroblastosis Fetalis Agglutination Reaction Test • Agglutination reactions are a clumping of particles / cells due to antigenantibody complexes forming RBC Disorders • Anemia’s – series of disorders of a reduced ability to carry oxygen in the blood (RBC count vs. Hemoglobin level) • Polycythemia – increased RBC count that leads to increased blood viscosity (thickness) Leukocytes / White Blood Cells • Leukocytes are the mobile units of the body’s immune system. • They defend against the invasion of pathogens. • Characteristics: – They can leave the circulation and go to the sites of invasion and tissue damage (Diapedisis) – They chemically trail the presence of foreign antigens to detect disease causing organisms.(Positive chemotaxis) • 5-11 thousand/ml of blood normal. Leukocyte Mobilization Types of Leukocytes / Differential WBC Count Granulocytes (1 day LS) • Neutrophil – Bacterial infections – 60 – 70% • Eosinophil – Parasitic worm infections – 2 – 4% • Basophil – Allergic response (Histimines) – <1% Agranulocytes (1 mo several years LS) • Lymphocytes – Viral infections – Trigger immune response (production of antibodies) – 20 – 25% • Monocytes – Macrophage cells – 3 to 8% Never let monkeys eat bananas!!! Disease Transmission • Pathogen is a disease causing organisms that may be passed from host to host – Direct Contact: kissing, sexual contact, spray from a cough or sneeze – Indirect Contact: shared object conveys the pathogen (clothing, dishes, needles, etc.) – Airborne: inhilation of a pathogen carried by the air (carried in waste, viruses, bacterial spores) – Vectors: an organisms acts as a carrier of the disease (rodents, pests, etc.) usually transmitted through a bite or sting Immune System – Types of Immunity • An immunity is the capability of the body to resist harmful pathogens from invading. 1. Innate immunities are inborn (natural) resistances to disease 2. Acquired immunity that is picked up over the course of one’s lifetime. Immune System: Innate Immunities • Examples: – Nonsuseptability: certain diseases only infect along certain species lines (Pets – Humans) – Physical and Chemical Barriers: skin, enzymes, acidity act to limit disease – Genetic resistance: certain diseases are more / less common based upon genetic racial differences (Tuberculosis) – Nutrition: good nutrition and health leads to a healthy immune system, more resistance (80% of infectious disease is limited to 20% of the human population) – Body temperature: Constant body temperature (100.3 degrees F) prevents invasion from some pathogens Immune System: Acquired (Induced) Immunities • Active vs. Passive: – Active immunities take a while to develop in the body, but last a long time. – Active Immunities develop by an individual generating antibodies for themselves. – Passive immunities are immediate acting, but are short lived. – Passive Immunities are generated elsewhere and acquired by an individual. • Natural vs. Artificial: – Natural forms have the immunity develop in a natural manner. – Artificial forms have the immunity develop in an artificial manner and introduced into the body. Acquired (Induced) Immunity Diagram Examples are listed at the bottom of each of the 4 cells … Immune System – Immune Response • The immune response is how your body recognizes and defends itself from pathogens that have entered the body. 1. The non-specific immune response is a general response of the body upon invasion of a pathogen, regardless of the type of pathogen. 2. The specific immune response is a targeted attack made by the immune system in response to a particular pathogen. Immune System – Non Specific Immune Response • Examples: – Upgrade of chemical barriers: increase of the amount of tears, saliva, acids, mucus, etc. to isolate the pathogen that has entered – Mobilization of Phagocytes: Macrophages and other WBC’s migrate to infection site to engulf pathogen for the purpose of recognition – Fever / Inflammation: WBC’s release pyrogens (trigger an increased body temperature to weaken a pathogen) and histamines (causing swelling and inflammation Immune System - Specific Immune response • T – Lymphocytes trigger the overall activity of the immune system upon recognition – T4 (helper) Cells: increases the activity of the specific immune system – T8 (cytotoxic) Cells: attack and destroy infected cells through apoptosis – Ts (surpressor) Cells: reduce the activity level of the specific immune system upon control of the pathogen Immune System – Specific Immune Response • B – Lymphocytes upon recognition differentiate into plasma cells which are responsible for the production of antibodies. – Antibodies may then agglutinate (cause clumping of cells) or neutralize (surround and immobilize) a pathogen – Macrophage cells then engulf the agglutinated or neutralized pathogens and lyse themselves (and the engulfed pathogens as well). Specific Immune Response B-Lymphocytes T- Lymphocytes Recognition T4 2000 / second T8 WBC Disorders • Leukocytosis (increase WBC count) and Leukopenia (decrease WBC count) are symptoms that other disorders are occurring in the body • Leukemia – cancer of the WBC • HIV – viral invasion of T –lymphocytes • Autoimmune diseases – immune system loses the ability to distinguish foreign from self antigens Platelets • They remain functional for about 10 days. • 1/3 stored in spleen • 200 - 250 thousand/ml of blood • They begin the clotting process upon an injury. Hemostasis • The series of events that stops the flow of blood from an injury. • Release of Tissue Factor – Injury tissue releases tissue factor, exposes collagen fibers – Platelets disintegrate and release tissue factor Hemostasis • Vasoconstriction: arteries leading to the damaged area constrict to limit blood flow / loss Hemostasis • Platelet Plug Formation – tissue factor causes platelets become “sticky”, they cling to one another and the inner lining of a damaged blood vessel. Hemostasis • Coagulation – formation of a blood clot. – – – Formation of Thromboplastin Prothrombin + Thromboplastin Thrombin Fibrinogen + Thrombin Fibrin Hemostasis Platelet Disorders • Thrombus: clot that develops and persists in an unbroken blood vessel – May block circulation, leading to tissue death – Embolus: a thrombus freely floating in the blood stream • Pulmonary emboli impair the ability of the body to obtain oxygen / Cerebral emboli can cause strokes / Cardiac emboli can cause heart attack / Platelet Disorders • Hemophilia- recessive genetic disorder that reduces levels of clotting factors • Prolonged episodes of bleeding hematoma formation Hematopoisis: Formation of Blood Cells (Formed Elements) • Takes place in the red bone marrow • Very active in the skull, ribs, vertebrae, pelvis, femur and humerus. • All formed elements originate from the hemocytoblast (adult blood forming stem cell) • Cells then develop in the marrow as precursor cells – when fully mature, are released into the blood stream. Hematopoisis - Control • RBC’s: Due to oxygen deficiency, the kidneys and liver release Erythropoitin (EPO) which triggers RBC formation. • Platelets: Due to platelet deficiency, the kidneys and liver release Thrombopoitin (TPO), which triggers platelet production • WBC’s: Upon recognition of an invading pathogen, WBC’s secrete Interleukins and Colony Stimulating Factors (CSF’s) to trigger additional WBC production. Red Bone Marrow – Precursor Cells Blood Stream – Mature Formed Elements