Anatomy Exam 2 Study sheet chapter 21.pdf

Anatomy Exam 2 Ch. 21B - - - - - - The immune system is a functional system with two arms that work together to monitor and protect, including the innate or non-specific and adaptive or specific defenses. The innate defenses include intact skin with an intact highly effective physical barrier and in...

Anatomy Exam 2 Ch. 21B - - - - - - The immune system is a functional system with two arms that work together to monitor and protect, including the innate or non-specific and adaptive or specific defenses. The innate defenses include intact skin with an intact highly effective physical barrier and intact mucous membranes acting as a sticky, mucous barrier with various protective components such as nasal hairs, mucus, cilia, gastric juice, acid mantle of the vagina, tears, saliva, and urine, all contributing to immune protection. Neutrophils are a key part of the innate defense, as are eosinophils, basophils, and monocytes, which are referred to as phagocytes and have essential roles in the immune response. Macrophages, which can be free and fixed, and their opsonization phagocytosis are also integral components of the innate defenses. The second line of defense includes antimicrobial proteins like interferons, which can save neighboring cells when defense is being breached by a pathogen. Antimicrobial proteins such as complement and natural killer cells help police the body for any anomalies and turn infected cells into virus factories. Fever is part of the inflammatory response and serves to prevent the spread of harmful agents, dispose of cellular debris, and alert the adaptive immune system, while also setting the stage for repair. The 4 cardinal signs of inflammation are redness, heat, swelling, pain, and potentially the loss of function. The inflammatory response begins with a chemical alarm, or chemokines, released by injured or stressed tissues and immune cells. Vasodilation and increased vascular permeability occur, bringing more blood to the area and allowing exudate to seep into the tissue. Clotting factors, proteins (including antibodies), and immune cells work to wall off the area and provide a scaffold for repair, while phagocytes flood the area, initially in the form of neutrophils and then macrophages to complete the process. Neutrophils are the most abundant type of white blood cell and are essential for fighting off bacterial infections. They are highly mobile and are among the first responders to sites of infection or tissue damage. Neutrophils work by engulfing and destroying bacteria through a process called phagocytosis. Eosinophils are white blood cells that play a role in combating parasitic infections and are also involved in allergic reactions. They release toxic substances to kill parasites and help regulate inflammation in the body. - - - - - Basophils are a type of white blood cell that releases histamine, a compound involved in the body's inflammatory response. They also play a role in allergic reactions and can release substances that attract other immune cells to the site of infection or inflammation. Monocytes are a type of white blood cell that can differentiate into macrophages, which are large phagocytic cells that engulf and digest cellular debris, pathogens, and other foreign substances. Monocytes also play a role in presenting antigens to the adaptive immune system, helping to initiate a more targeted immune response. Phagocytosis is a crucial process in the body's immune response, particularly in the second line of defense. It involves the engulfing and digestion of foreign particles, such as bacteria, by specialized cells called phagocytes. The main types of phagocytes involved in this process are neutrophils and macrophages. When a foreign particle is detected in the body, phagocytes are attracted to the site of infection by chemical signals released by injured or stressed tissues and immune cells. Once they reach the foreign particle, the phagocytes surround and engulf it, forming a vesicle called a phagosome. The phagosome then fuses with a lysosome, a specialized organelle containing digestive enzymes, forming a phagolysosome. Within the phagolysosome, the foreign particle is broken down and destroyed, effectively eliminating the threat to the body. Phagocytosis plays a crucial role in the body's defense against pathogens and is an essential part of the innate immune response. It helps to prevent the spread of harmful agents, dispose of cellular debris and pathogens, and contribute to the overall process of inflammation and tissue repair. Ch. 21C - Two characteristics distinguish immunity from nonspecific resistance Specificity: immunity directed against a particular pathogen Memory: the body reacts quickly when re-exposed to the same pathogen Two types of immunity Cellular (cell-mediated) immunity: T cells directly attack and destroy foreign or diseased host cells inside human cells Humoral (antibody-mediated) immunity: B cells mediated by antibodies that destroy pathogens and work against the extracellular stage of infectious microorganisms Classes of Humoral Immunity - Active vs passive - Active: the body makes its own antibodies; forever - Passive: acquire them from another source; temporary - Natural vs artificial - Natural: exposure to a pathogen - - - - Artificial: introduced for treatment/prevention; via needle Four classes: - Natural active: majority of our immunity; infection; contact with pathogen - Artificial active: vaccine; exposed to pathogen make your own antibodies - Natural passive: mother to fetus via placenta, or milk to infant - Artificial passive: injected with someone else’s antibodies; gamma globulin Antigens - Trigger immune response Epitopes (antigenic determinants) are specific regions that stimulate immune responses Self antigens include MHC proteins (Major Histocompatibility Complex); ABO and Rh blood Cells of the Adaptive System - Lymphocytes B Lymphocytes T Lymphocytes Type of Immune Resp. Humoral Immunity (HI) Cellular Immunity (CI) Antibody Secretion Yes No Primary Targets Extracellular pathogens (bacteria, fungi, parasites) Intracellular pathogens (virus) Site of origin Red bone marrow Red bone marrow Site of Maturation (school) Red bone marrow Thymus Effector cells Plasma cells Cytotoxic T cells (direct hit; true effector of CI) Helper T cells (boss) Regulatory T cells (helps the immune system not overreact) Memory Cells Yes Yes Cells of the Adaptive Systems - APCs - Antigen presenting cells (APCs) that present antigens to T cells - Dendritic cells - starts an immune reaction - Macrophages - eats everything that looks like whatever it ate previously - B cells - very specific; finds an epitope and makes antibodies against it Ch. 21D - - - - - - - - - T Cells have a life history consisting of three stages and three anatomical stations in the body: born in the red bone marrow, go to school in the thymus, and are deployed to the lymphatic organs. In the University of the Thymus, thymosins stimulate maturing T cells to develop surface antigen receptors, making them immunocompetent and capable of recognizing antigens presented to them by antigen-presenting cells. Reticuloendothelial (RE) cells in the thymus test T cells by presenting self-antigens to them, with two ways to fail the test: inability to recognize the RE cells, especially their MHC antigens, or reacting to the self-antigen. Only 2% of T cells that reach the thymus leave as immunocompetent T cells. Naive T cells leave the thymus and colonize lymphatic tissues and organs throughout the body. There are different types of T cells, including cytotoxic T (TC) cells, helper T (TH) cells, regulatory T (TR) cells, and memory T (TM) cells (responsible for memory in cellular immunity), each with specific functions in cellular immunity. Cellular immunity involves T lymphocytes directly attacking and destroying diseased or foreign cells, with the immune system remembering the antigens and preventing future disease. Antigen presentation involves APCs encountering and processing an antigen, migrating to the nearest lymph node to present it to T cells, and T cell activation through binding to MHC displaying an epitope that it recognizes. MHC class I and class II are two types of major histocompatibility complex (MHC) proteins that play a crucial role in the immune system's ability to recognize and respond to foreign antigens. MHC class I molecules are found on the surface of all nucleated cells in the body. They are responsible for presenting endogenous antigens, which are typically derived from intracellular pathogens such as viruses or intracellular bacteria. Cytotoxic T cells (TC cells) recognize these antigens when they are presented on MHC class I molecules. This recognition triggers the TC cells to become activated and to carry out their effector functions, which include killing the infected cells. On the other hand, MHC class II molecules are primarily found on the surface of antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. MHC class II molecules present exogenous antigens, which are derived from extracellular pathogens like bacteria and parasites. Helper T cells (TH cells) recognize these antigens when they are presented on MHC class II molecules. This recognition leads to the - activation of the TH cells, which then promote the immune response by activating other immune cells and enhancing nonspecific resistance. In summary, MHC class I molecules present endogenous antigens to cytotoxic T cells, while MHC class II molecules present exogenous antigens to helper T cells. Both types of MHC molecules play a critical role in initiating and coordinating the immune response against foreign invaders. Ch. 21E - - Humoral immunity is an indirect method of defense utilizing antibodies produced by B cells to tag antigens for destruction by other means. B cells, or B lymphocytes, develop in the bone marrow and undergo selection to ensure self-tolerance and the production of immunocompetent clones. B cell activation leads to the formation of plasma cells, which secrete defensive immunoglobulins (Igs) and memory antibodies. These antibodies are responsible for various immune responses, including providing natural passive immunity to newborns and influencing hypersensitivity and blood group incompatibilities. Overall, the humoral immune response involves a complex process of antibody production and response to antigens in the body. The 5 classes of antibodies are IgA, IgD, IgE, IgG, and IgM. - IgA is found in body fluids and helps protect against infections. - IgD is found on the surface of B cells and helps activate them. - IgE is involved in allergic reactions. - IgG is the most common antibody and provides long-term protection against infections. - IgM is the first antibody produced in response to an infection. Ch. 21F - - - Immune response may be: - Hypersensitivities: Reaction to something that doesn't need to be reacted to; Immune system is being overly sensitive - Autoimmune diseases: Reacting to a self-antigen - Immunodeficiencies: The response is deficient in some way, shape, or form HypersensitivityType I (Acute) - Common allergies, IgE mediated - Basophils/mast cells release histamine, other inflammatory & vasoactive chemicals - Anaphylaxis Type II (Sub-acute) - IgG or IgM mediated - Cytotoxic response: Antibodies bind to specific cells and stimulate phagocytosis and/or complement activation - Blood transfusion reactions - Type III (Sub-acute) - IgG or IgM mediated - Immune complexes cause intense inflammation & tissue destruction - Systemic lupus erythematous - Type IV (Delayed) - No antibodies involved - APCs activate TH cells which secrete cytokines that activate macrophages & cytotoxic T cells - inflammation and tissue damage - Autoimmune Diseases - Inability to distinguish self for non-self - Over 80 AI diseases - Rheumatoid arthritis, myasthenia gravis, multiple sclerosis, Hashimoto’s thyroiditis, Type I diabetes mellitus, systemic lupus erythematosus, glomerulonephritis - Treatment varies depending on affected tissue(s) - Occurs due to weakly self reactive lymphocytes - Immunodeficiency Diseases - Severe combined immunodeficiency disease (SCID) - Recessive alleles cause scarce or absent B & T cells - Must live in protective enclosures - Acquired immunodeficiency syndrome (AIDS) - HIV/AIDS - Viral infection of the immune system, caused by the human immunodeficiency virus - Transmission & Symptoms - Transmission occurs through the transfer of bodily fluids - Early symptoms - First stages there are few if any symptoms - Within 1-2 months after infection, maybe flu-like symptoms - After symptoms will likely disappear for 12 years or more - Late symptoms - Rapid weight loss - Fever - Extreme fatigue - Swelling of the lymph glands - Diarrhea - Sores of the mount, anus, & genitals - - - Rare opportunistic infections - Memory loss, dementia Treatment - Major drug advancements have been made since 1981 - Currently the FDA has 31 approved antiretroviral drugs - These drugs DO NOT CURE people of HIV or AIDS Prevention - The drugs suppress the virus, allowing people to live longer and healthier lives. - People taking these drugs can still transmit the virus and must remain on the drugs for the remainder of their lives. - Abstain from risky behaviors. - Use condoms to reduce the risk of transmission.Get tested regularly, especially during pregnancy. - Have your partner(s) get tested to ensure their status. - Limit your number of sexual partners to reduce the risk of transmission. - Do not share needles to prevent the spread of the virus. - Emphasize the importance of wearing condoms for prevention.