Blood and Immune System Lecture Notes - PDF

Blood and Immune system Dr-Muhammad Shenwaz Dr-Hind Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood circulation Copyright © 2006 Pearson Education, Inc.,...

Blood and Immune system Dr-Muhammad Shenwaz Dr-Hind Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood circulation Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Overview of Blood Circulation ▪ Blood leaves the heart via arteries that branch repeatedly until they become capillaries ▪ Oxygen (O2) and nutrients diffuse across capillary walls and enter tissues ▪ Carbon dioxide (CO2) and wastes move from tissues into the blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Overview of Blood Circulation ▪ Oxygen-deficient blood leaves the capillaries and flows in veins to the heart ▪ This blood flows to the lungs where it releases CO2 and picks up O2 ▪ The oxygen-rich blood returns to the heart Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Composition of Blood ▪ Blood is the body’s only fluid tissue ▪ It is composed of liquid plasma and formed elements ▪ Formed elements include: ▪ Erythrocytes, or red blood cells (RBCs) ▪ Leukocytes, or white blood cells (WBCs) ▪ Platelets Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Components of Whole Blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Physical Characteristics and Volume ▪ Blood is a sticky, opaque fluid with a metallic taste ▪ Color varies from scarlet to dark red ▪ The pH of blood is 7.35–7.45 ▪ Temperature is 37C ▪ Blood accounts for approximately 8% of body weight ▪ Average volume: 5–6 L for males, and 4–5 L for females Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Functions of Blood ▪ Blood performs a number of functions dealing with: ▪ Substance distribution ▪ Regulation of blood levels of particular substances ▪ Body protection Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Distribution ▪ Blood transports: ▪ Oxygen from the lungs and nutrients from the digestive tract ▪ Metabolic wastes from cells to the lungs and kidneys for elimination ▪ Hormones from endocrine glands to target organs Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Regulation ▪ Blood maintains: ▪ Appropriate body temperature by absorbing and distributing heat ▪ Normal pH in body tissues using buffer systems ▪ Adequate fluid volume in the circulatory system Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Protection ▪ Blood prevents blood loss by: ▪ Activating plasma proteins and platelets ▪ Initiating clot formation when a vessel is broken ▪ Blood prevents infection by: ▪ Synthesizing and utilizing antibodies ▪ Activating complement proteins ▪ Activating WBCs to defend the body against foreign invaders Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Blood Plasma ▪ Blood plasma contains over 100 solutes, including: ▪ Proteins – albumin, globulins, clotting proteins, and others ▪ Lactic acid, urea, creatinine ▪ Organic nutrients – glucose, carbohydrates, amino acids ▪ Electrolytes – sodium, potassium, calcium, chloride, bicarbonate ▪ Respiratory gases – oxygen and carbon dioxide Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Formed Elements ▪ Erythrocytes, leukocytes, and platelets make up the formed elements ▪ Only WBCs are complete cells ▪ RBCs have no nuclei or organelles, and platelets are just cell fragments ▪ Most formed elements survive in the bloodstream for only a few days ▪ Most blood cells do not divide but are renewed by cells in bone marrow Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Erythrocytes (RBCs) ▪ Biconcave discs, anucleate, essentially no organelles ▪ Filled with hemoglobin (Hb), a protein that functions in gas transport Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Components of Whole Blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.2  Hemoglobin (Hb) ▪ Oxyhemoglobin – Hb bound to oxygen ▪ Oxygen loading takes place in the lungs ▪ Deoxyhemoglobin – Hb after oxygen diffuses into tissues (reduced Hb) ▪ Carbaminohemoglobin – Hb bound to carbon dioxide ▪ Carbon dioxide loading takes place in the tissues PLAY PLAY InterActive Physiology ®: Respiratory System: Gas Transport, pages 3–13 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Erythropoietin Mechanism Start Homeostasis: Normal blood oxygen levels Stimulus: Hypoxia due to decreased RBC count, decreased amount of hemoglobin, or decreased availability of O2 Increases O2-carrying ability of blood Reduces O2 levels in blood Enhanced Kidney (and liver to a smaller erythropoiesis Erythropoietin extent) releases erythropoietin increases stimulates red RBC count bone marrow Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.6  Erythrocyte Disorders ▪ Anemia – blood has abnormally low oxygen- carrying capacity ▪ It is a symptom rather than a disease itself ▪ Blood oxygen levels cannot support normal metabolism ▪ Signs/symptoms include fatigue, paleness, shortness of breath, and chills Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Leukocytes (WBCs) ▪ Leukocytes, the only blood components that are complete cells: ▪ Are less numerous than RBCs ▪ Make up 1% of the total blood volume ▪ Can leave capillaries via diapedesis ▪ Move through tissue spaces ▪ Leukocytosis – WBC count over 11,000 / mm3 ▪ Normal response to bacterial or viral invasion Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Percentages of Leukocytes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.9  Summary of Formed Elements FOR YOUR INFO Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 17.2.1  Summary of Formed Elements FOR YOUR INFO Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 17.2.2 Stem cells Hemocytoblast Myeloid stem cell Lymphoid stem cell Committed Myeloblast Myeloblast Myeloblast Lymphoblast cells Develop- Promyelocyte Promyelocyte Promyelocyte Promonocyte Prolymphocyte mental pathway Eosinophilic Basophilic Neutrophilic myelocyte myelocyte myelocyte FOR YOUR INFO Eosinophilic Basophilic Neutrophilic band cells band cells band cells Eosinophils Basophils Neutrophils Monocytes Lymphocytes (a) (b) (c) (d) (e) Some Agranular leukocytes become Granular leukocytes Some become Macrophages (tissues) Plasma cells Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.11  Leukemia ▪ Leukemia refers to cancerous conditions involving WBCs ▪ Immature WBCs are found in the bloodstream in all leukemias ▪ Bone marrow becomes totally occupied with cancerous leukocytes ▪ The WBCs produced, though numerous, are not functional ▪ Death is caused by internal hemorrhage and overwhelming infections ▪ Treatments include irradiation, antileukemic drugs, and bone marrow transplants Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Platelets ▪ Platelets are fragments of megakaryocytes ▪ Platelets function in the clotting mechanism by forming a temporary plug that helps seal breaks in blood vessels Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Genesis of Platelets FOR YOUR INFO ▪ The sequential developmental pathway is as shown. Stem cell Developmental pathway Hemocytoblast Megakaryoblast Promegakaryocyte Megakaryocyte Platelets Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.12  Hemostasis ▪ A series of reactions for stoppage of bleeding ▪ During hemostasis, three phases occur in rapid sequence ▪ Vascular spasms – immediate vasoconstriction in response to injury ▪ Platelet plug formation ▪ Coagulation (blood clotting) Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Bleeding and Clotting Time Prepared by SARA BAHRAM MIRAN Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Medical Microbiologist  Clotting Time ▪ It is the time taken by blood to coagulate after it has been shed. Coagulation (clotting) of the blood is the most effective defense against bleeding. It is important for the blood to clot quickly when a vessel has been broken, but equally important for it not to clot in the absence of vessel damage. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Clotting Time ▪ The clotting time will be prolonged if the volume of blood per tube or the diameter of the tube is increased, or if the temperature decreased. ▪ The normal range of clotting time is (5-15) minutes. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Clotting Time Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Bleeding Time ▪ More ever it is short timed during cold weather due to capillary construction, and reverse case in hot weather. ▪ A prolonged bleeding time may be a result from decreased number of thrombocytes or impaired blood vessels. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Bleeding Time Bleeding time is a test of platelete function. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Blood Transfusions ▪ Whole blood transfusions are used: ▪ When blood loss is substantial ▪ Packed red cells (cells with plasma removed) are used to treat anemia Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Human Blood Groups ▪ RBC membranes have glycoprotein antigens on their external surfaces ▪ These antigens are: ▪ Unique to the individual ▪ Recognized as foreign if transfused into another individual ▪ Promoters of agglutination and are referred to as agglutinogens ▪ Presence or absence of these antigens is used to classify blood groups Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Blood Groups ▪ Humans have 30 varieties of naturally occurring RBC antigens ▪ The antigens of the ABO and Rh blood groups cause vigorous transfusion reactions when they are improperly transfused Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  ABO Blood Groups ▪ The ABO blood groups consists of: ▪ Two antigens (A and B) on the surface of the RBCs ▪ Two antibodies in the plasma (anti-A and anti-B) ▪ ABO blood groups may have various types of antigens and preformed antibodies ▪ Agglutinogens and their corresponding antibodies cannot be mixed without serious hemolytic reactions Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  ABO Blood Groups Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Table 17.4  Rh Blood Groups ▪ There are eight different Rh agglutinogens, three of which (C, D, and E) are common ▪ Presence of the Rh agglutinogens on RBCs is indicated as Rh+ ▪ Anti-Rh antibodies are not spontaneously formed in Rh– individuals ▪ However, if an Rh– individual receives Rh+ blood, anti-Rh antibodies form ▪ A second exposure to Rh+ blood will result in a typical transfusion reaction Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Hemolytic Disease of the Newborn ▪ Hemolytic disease of the newborn – Rh+ antibodies of a sensitized Rh– mother cross the placenta and attack and destroy the RBCs of an Rh+ baby ▪ Rh– mother becomes sensitized when exposure to Rh+ blood causes her body to synthesize Rh+ antibodies Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Hemolytic Disease of the Newborn ▪ The drug RhoGAM can prevent the Rh– mother from becoming sensitized ▪ Treatment of hemolytic disease of the newborn involves pre-birth transfusions and exchange transfusions after birth Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Transfusion Reactions ▪ Transfusion reactions occur when mismatched blood is infused ▪ Donor’s cells are attacked by the recipient’s plasma agglutinins causing: ▪ Diminished oxygen-carrying capacity ▪ Clumped cells that impede blood flow ▪ Ruptured RBCs that release free hemoglobin into the bloodstream ▪ Circulating hemoglobin precipitates in the kidneys and causes renal failure Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  The Human Immune System Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  What is the immune system? ▪ The body’s defense against disease causing organisms, malfunctioning cells, and foreign particles Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  The First Line of Defense ~Skin~ - The dead, outer layer of skin, known as the epidermis, forms a shield against invaders and secretes chemicals that kill potential invaders - You shed between 40 – 50 thousand skin cells every day! Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The First Line of Defense ~Mucus and Cilia~ - As you breathe in, foreign particles and bacteria bump into mucus throughout your respiratory system and become stuck - Hair-like structures called cilia sweep this mucus into the throat for coughing or swallowing Don’t swallowed bacteria have a Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings good chance of infecting you? The First Line of Defense ~Saliva~ What’s the first thing you do when you cut your finger? - Saliva contains many chemicals that break down bacteria - Thousands of different types of bacteria can survive these chemicals, however Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The First Line of Defense ~Stomach Acid~ - Swallowed bacteria are broken down by incredibly strong acids in the stomach that break down your food - The stomach must produce a coating of special mucus or this acid would eat through the stomach! Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  The Second Line of Defense ~White Blood Cells~ - If invaders actually get within the body, then your white blood cells (WBCs) begin their attack - WBCs normally circulate throughout the blood, but will enter the body’s tissues if invaders are detected Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  White Blood Cells ~Phagocytes~ ▪ These white blood cells are responsible for eating foreign particles by engulfing them ▪ Once engulfed, the phagocyte breaks the foreign particles apart in organelles called ________ Lysosomes Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  The Second Line of Defense ~Interferon~ - Virus-infected body cells release interferon when an invasion occurs - Interferon – chemical that interferes with the ability to viruses to attack other body cells Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  White Blood Cells ~T-Cells~ ▪ T-Cells, often called “natural killer” cells, recognize infected human cells and cancer cells ▪ T-cells will attack these infected cells, quickly kill them, and then continue to search for more cells to kill Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  The Second Line of Defense ~The Inflammatory Response~ - Injured body cells release chemicals called histamines, which begin inflammatory response - Capillaries dilate - Pyrogens released, reach hypothalamus, and temperature rises - Pain receptors activate - WBCs flock to infected area like sharks to blood Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Two Divisions of the Immune System - The efforts of the WBCs known as phagocytes and T-cells is called the cell-mediated immune system. - Protective factor = living cells - Phagocytes – eat invaders - T-cells – kill invaders Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Two Divisions of the Immune System ▪ The other half of the immune system is called antibody-mediated immunity, meaning that is controlled by antibodies ▪ This represents the third line of defense in the immune system Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Third Line of Defense ~Antibodies~ - Most infections never make it past the first and second levels of defense - Those that do trigger the production and release of antibodies - Proteins that latch onto, damage, clump, and slow foreign particles - Each antibody binds only to one specific binding site, known as an antigen Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Antibody Production - WBCs gobble up invading particles and break them up - They show the particle pieces to T-cells, who identify the pieces and find specific B-cells to help - B-cells produce antibodies that are equipped to find that specific piece on a new particle and attach Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Immunity - New particles take longer to identify, and a person remains ill until a new antibody can be crafted - Old particles are quickly recognized, and a person may never become ill from that invader again. This person is now immune. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  What is immunity? - Resistance to a disease causing organism or harmful substance - Two types - Active Immunity - Passive Immunity Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Active Immunity - You produce the antibodies - Your body has been exposed to the antigen in the past either through: - Exposure to the actual disease causing antigen – You fought it, you won, you remember it - Planned exposure to a form of the antigen that has been killed or weakened – You detected it, eliminated it, and remember it What is this second type of exposure called? Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Vaccine ▪ Antigens are deliberately introduced into the immune system to produce immunity ▪ Because the bacteria has been killed or weakened, minimal symptoms occur ▪ Have eradicated or severely limited several diseases from the face of the Earth, such as polio and smallpox Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  How long does active immunity last? ▪ It depends on the antigen ▪ Some disease-causing bacteria multiply into new forms that our body doesn’t recognize, requiring annual vaccinations, like the flu shot ▪ Booster shot - reminds the immune system of the antigen ▪ Others last for a lifetime, such as chicken pox Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Think the flu is no big deal? - Think again… - In 1918, a particularly deadly strain of flu, called the Spanish Influenza, spread across the globe - It infected 20% of the human population and killed 5%, which came out to be about 100 million people Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Passive Immunity ▪ You don’t produce the antibodies ▪ A mother will pass immunities on to her baby during pregnancy - through what organ? ▪ Placenta These antibodies will protect the baby for a short period of time following birth while its immune system develops. What endocrine gland is responsible for this? Why doesn’t the mother just Thymus pass on the WBCs that ▪ Lasts until antibodies die “remember” the antigens? Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Immune Disorders ~Allergies~ - Immune system mistakenly recognizes harmless foreign particles as serious threats - Launches immune response, which causes sneezing, runny nose, and watery eyes - Anti-histamines block effect of histamines and bring relief to allergy sufferers Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Aquired Immune Deficiency Syndrome ▪ Caused by the Human Immunodeficiency Virus ▪ Discovered in 1983 ▪ Specifically targets and kills T- cells ▪ Because normal body cells are unaffected, immune response is not launched Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  AIDS ~The Modern Plague~ - The HIV virus doesn’t kill you – it cripples your immune system - With your immune system shut down, common diseases that your immune system normally could defeat become life-threatening - Can show no effects for several months all the way up to 10 years Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Thank you Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings