Lymphatic System Manuscript PDF

BSMT 1B MCMT 11 - GELI, GUALI, GUIPO, LUTCHE GROUP 5 MANUSCRIPT (CHAPTER 14:LYMPHATIC SYSTEM AND IMMUNITY) PATHOGENS - Microorganisms that cause diseases or damage to the tissues. Fx of Lymphatic System: 1. Maintenance of fluid balance (lymph - fluid that enters the lymphatic capillaries)...

BSMT 1B MCMT 11 - GELI, GUALI, GUIPO, LUTCHE GROUP 5 MANUSCRIPT (CHAPTER 14:LYMPHATIC SYSTEM AND IMMUNITY) PATHOGENS - Microorganisms that cause diseases or damage to the tissues. Fx of Lymphatic System: 1. Maintenance of fluid balance (lymph - fluid that enters the lymphatic capillaries) 2. Lipid Absorption - (lacteals - lymphatic vessel located in the lining of the small intestine. In addition, the lymph passing through these lacteals are called - chyle; where it appears white due to its lipid content.) 3. Defense ANATOMY OF LYMPHATIC SYSTEM: Lymphatic System carries fluid in one direction, from tissues to circulatory system. Lymphatic Capillaries - tiny, closed-ended vessels consisting of simple squamous epithelium. It Is present in most tissues of the body except CNS, Bone Marrow, and tissues lacking blood vessels such as the epidermis and cartilage. Lymphatic Vessels - group of lymphatic capillaries - which resembles small veins. Small Lymphatic Vessels - have a beaded appearance because they have one-way valves that are similar to the valves of veins. Right Lymphatic Duct - right upper limb, and right half of the head,neck, and chest (forms); empties into the right subclavian vein (Fx) Thoracic Duct - rest of the body (forms); empties into the left subclavian vein (Fx) 3 Factors that Contract the Lymphatic Vessels - (1) contraction of surrounding skeletal muscle during activity, (2) periodic contraction of smooth muscle in the lymphatic vessel wall, and (3) pressure changes in the thorax during breathing. Lymphatic Organs - tonsils, lymph nodes, spleen, thymus. Lymphatic Tissues - characterized by housing many lymphocytes (originated from red bone marrow) and other defense cells such as macrophages. TONSILS - lymph nodes in the back of the mouth and top of the throat. They help to filter out bacteria and other germs from the nose and mouth to prevent infection in the body. 3 groups of tonsils - Palatine, Pharyngeal, and Lingual Tonsils  Palatine - Located on each side of the posterior opening of the oral cavity, usually referred as “the tonsils”. Pharyngeal - near the internal opening of the nasal cavity. When enlarged, it is called the adenoid. Lingual - posterior surface of the tongue. Tonsillitis - caused by a viral or bacteria infection Tonsillectomy - removal of an infected palatine tonsils Adenoidectomy - removal of an infected pharyngeal tonsils Lingual tonsils are rarely infected and are usually harder to remove. In adults, tonsils decrease in size and may eventually disappear. LYMPH NODES - Rounded structures, varying the small size of a shelled almond. Distributed along the various lymphatic vessels three superficial aggregations of lymph nodes on each side of the body: (1) inguinal nodes in the groin, (2) the axillary nodes in the axilla (armpit), and (3) the cervical nodes in the neck. PARTS Each lymph node is surrounded dense connective tissue capsule - Trabeculae - subdivide a lymph node into compartments containing lymphatic tissue and sinuses (extensions of the capsule). - The lymphatic tissue consists of lymphocytes and other cells that can form dense aggregations of tissue called lymphatic nodules. (they are not the same with lymph nodes). - Lymphatic Nodules are areas of tissue within lymph nodes and other organs as well. - Lymphatic sinuses are spaces between the lymphatic tissue that contain macrophages on a network of fibers. - Germinal centers are the lymphatic nodules containing the rapidly dividing lymphocytes. These 4 compose the cortex of the lymph node. SPLEEN - is roughly the size of a clenched fist and is located in the left, superior corner of the abdominal cavity - has an outer capsule of dense connective tissue and a small amount of smooth muscle  - Trabeculae from the capsule divide the spleen into small, interconnected compartments containing two specialized types of lymphatic tissue: (1) white pulp and (2) red pulp - White pulp is lymphatic tissue surrounding the arteries within the spleen - Red pulp is associated with the veins. It consists of a fibrous network, filled with macrophages and red blood cells, and enlarged capillaries that connect to the veins. Fx: The spleen filters blood instead of lymph. - Splenectomy - removal of spleen THYMUS - a bilobed gland roughly triangular in shape,located in the superior mediastinum - Each lobe of the thymus is surrounded by a thin connective tissue capsule. - Trabeculae from the capsule divide each lobe into lobules. - near the capsule and trabeculae, lymphocytes are numerous and form dark-staining areas called the cortex. - A lighter-staining, central portion of the lobules, called the medulla, has fewer lymphocytes. - is the site for the maturation of a class of lymphocytes called T cells IMMUNITY The ability to resist damage from foreign substances - such as microorganisms, harmful chemicals, and internal threats INNATE IMMUNITY - nonspecific resistance; the body recognizes and destroys certain foreign substances, but the response to them is the same each time the body is exposed. INNATE IMMUNITY PHYSICAL BARRIERS Prevent microorganisms and chemicals from entering the body in two ways: 1. Skin and mucous membranes form barriers that prevent their entry 2. Tears, saliva, and urine wash these substances from body surfaces CHEMICAL MEDIATORS Are molecules responsible for many aspects of innate immunity COMPLEMENT - group of approximately 20 proteins found in plasma INTERFERONS - are proteins that protect the body against viral infections WHITE BLOOD CELLS Most important cellular components of immunity Important chemicals known to attract WBC: Complement, Leukotrienes, Kinins, Histamine CHEMOTAXIS - movement of WBC toward these chemicals PHAGOCYTIC CELLS PHAGOCYTOSIS - the ingestion and destruction of particles by cells called phagocytes NEUTROPHILS - small phagocytic cells that are usually the first cells to enter infected tissues PUS - accumulation of fluid, dead neutrophils, and other cells at a site of infection MACROPHAGES - monocytes that leave the blood, enter tissues, and enlarge about fivefold MONONUCLEAR PHAGOCYTIC SYSTEM - phagocytes with a single (mono), unlobed nucleus Dust cells - macrophages in the lungs Kupffer cells - liver Microglia - central nervous system CELLS OF INFLAMMATION BASOPHILS - motile WBCs that can leave the blood and enter infected tissues MAST CELLS - nonmotile cells in CT, esp. near capillaries. EOSINOPHILS - produced in red bone marrow; enter the blood, and within a few minutes enter tissues NATURAL KILLER CELLS Type of lymphocyte produced in RBM, account up to 15% of lymphocytes Recognize classes of cells, such as tumor cells or virus-infected cells in general; causes these cells to Lyse INFLAMMATORY RESPONSE LOCAL INFLAMMATION - confined to a specific area of the body SYMPTOMS: redness, heat, swelling, pain, and loss of function SYSTEMIC INFLAMMATION - generally distributed throughout the body > SYMPTOMS: increase in neutrophil numbers, fever, and shock. PYROGENS - stimulate fever production ADAPTIVE IMMUNITY Adaptive immunity - exhibits two defining characteristics: specificity and memory. SPECIFICITY - is the ability to recognize a particular substance MEMORY - is the ability to respond with increasing effectiveness to successive exposures to the antigen. ANTIGENS - are substances that stimulate adaptive immune responses 1. Foreign antigens - are introduced from outside the body. ▪ Allergic Reaction – caused by foreign antigens that produce an overreaction of the immune system. 2. Self-antigens - are molecules of the body produces to stimulate an immune system response. ▪ Autoimmune disease - results when self- antigens stimulate unwanted destruction of normal tissue. - Adaptive immunity can be divided into antibody-mediated immunity and cell-mediated immunity. 1. Antibody - Mediated Immunity – involves proteins called antibodies, which are found in the plasma ▪ B cells – lymphocyte that produces antibodies 2. Cell – Mediated Immunity - involves the actions of a second type of lymphocyte, called T cells.  ▪ Cytotoxic T cells – lyse virus – infected cells, tumor cells, and tissue transplants. Cytokines – promote inflammation and phagocytosis. ▪ Helper T cells - promote or inhibit the activities of both antibody-mediated immunity and cell-mediated immunity. ORIGIN AND DEVELOPMENT OF LYMPHOCYTES Stem Cells – give rise to all the blood cells Clones - Small groups of identical B cells or T cells, form during embryonic development. ACTIVATION AND MULTIPLICATION OF LYMPHOCYTES ANTIGEN RECOGNITION Antigen Receptors – proteins of the lymphocytes. o B - cell receptors – antigen receptors on B cells. o T – cell receptors – antigen receptors on T cells. Major histocompatibility complex (MHC) molecules - are glycoproteins that have binding sites for antigens. o Costimulation - can be achieved by cytokines. ▪ Interleukin-1 - is a cytokine released by macrophages that can stimulate helper T cells. LYMPHOCYTE PROLIFERATION - is an important process that generates the needed defense cells to protect the body. Interleukin-2 - binds to the receptors and stimulates the helper T cell to divide. B-cell proliferation – when helper T cells stimulates B cells to divide and differentiate into cells that produce antibodies. ANTIBODY – MEDIATED IMMUNITY STRUCTURE OF ANTIBODIES Antibodies - are proteins produced in response to an antigen. Variable Region - part of the antibody that combines with the antigen. Constant Region - the rest of the antibody. Gamma Globulins – other name of antibodies Immunoglobulins (Ig) - part of plasma where antibodies found. EFFECT OF ANTIBODIES Direct Effects – occur when a single antibody binds to an antigen and inactivates the antigen, or when many antigens are bound together and are inactivated by many antibodies. Indirect Effects - after an antibody has attached by its variable region to an antigen, the constant region of the antibody can activate other mechanisms that destroy the antigen. ANTIBODY PRODUCTION Primary Response - results from the first exposure of a B cell to an antigen Plasma Cells – produce antibodies Memory B cells - are responsible for the secondary response, or memory response. Secondary Response / Memory Response - occurs when the immune system is exposed to an antigen against which it has already produced a primary response. CELL – MEDIATED IMMUNITY - is a function of cytotoxic T cells and is most effective against microorganisms that live inside body cells. - also involved with some allergic reactions, the control of tumors, and graft rejection. ACQUIRED IMMUNITY There are 2 types of acquired immunity there are ACTIVE & PASSIVE immunity ACTIVE IMMUNITY- result when an individual is exposed to antigen (either naturally or artificially) and the response of the individual’s own system is the cause of immunity. - immunity is provided by the individual’s own immune system. - SELF-PRODUCE PASSIVE IMMUNITY- Occurs when another person or an animal develops immunity and the immunity is transferred to a non-immune individual. - immunity is transferred from another person or an animal. - HAS OTHER RESOURCES OF TRANSFER OF ANTIBODIES Then BOTH active and passive immunity has NATURAL & ARTIFICIAL NATURAL & ARTIFICIAL- refers to the methods of exposure or antibody transfer. NATURAL IS NOT DELIBERATE WHILE ARTIFICIAL IS DELIBERATE Then let’s proceed to the four ways to acquire adaptive immunity 1. ACTIVE NATURAL IMMUNITY - results from natural exposure to an antigen, such as a disease-causing microorganism, that stimulates the immune system to respond against the antigen. Because the individual is not immune during the first exposure, he or she usually develops the symptoms of the disease. -Antigens are introduced through natural exposure. 2. ACTIVE ARTIFICIAL IMMUNITY - an antigen is deliberately introduced into an individual to stimulate the immune system. vaccinations 3. PASSIVE NATURAL IMMUNITY -results when antibodies are transferred from a mother to her child across the placenta before birth. Mother baby - trans placenta (IgG) - breastfeeding (IgA) (6-12months) 4. PASSIVE ARTIFICIAL IMMUNITY - involves the collecting of antibodies from one source and introducing them to an infected individual, usually through injection