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Chapter 6 Understanding Stress and Disease immune system - has 3 functions: (1) protects the body from invading bacteria and viruses, (2) removes worn or damaged cells, and (3) patrols for "mutant cells." lymph - Fluid, tissue, and specialized cells that make up the lymphatic system. lymphatic system - System that transports lymph throughout the body. lymph nodes - Small nodules of lymphatic tissue spread throughout the lymphatic system. They clean the lymph of bacteria and debris. lymphocytes - White blood cells found in lymph that are involved in the immune function. There are three types: (1) T-cells, (2) B-cells, and (3) natural killer cells. T-cells - Stem cells form in the bone marrow and travel to the thymus where they are differentiated into T-cells (several types). B-cell - Stem cells form in the bone marrow and remain there where they differentiate into B-cells. thymus - An organ located near the heart that secretes thymosin. It converts stem cells to T-cells. tonsils - Masses of lymphatic tissue located in the throat. Like the lymph nodes, they trap and kill invading cells and particles. spleen - A large organ near the stomach where lymphocytes mature and worn out blood cells are disposed of. the "first line of defense" - against invading organisms is the "skin and mucous membranes." phagocytosis (nonspecific immune response) - The first of two "nonspecific immune responses" in which "granulocytes" attack, engulf, and kill, invading organisms. "Macrophages" clean up the debris and initiate "specific responses." inflammation (nonspecific immune response) - The second of the "nonspecific responses." Blood vessels near the injury initially contract and then enlarge, allowing increased blood flow to the area to help restore damaged tissue. Cell-mediated immunity (specific immune response) - is the process in which T-cells become "sensitized" to the invaders and can, thereafter, recognize them. New "cytotoxic T-cells" form and attack the invaders. indirect B-cell attack - Assisted by "helper T-cells," B-cells differentiate into "plasma cells" which secrete antibodies. The antibodies are "invader specific" as are the T-cells. antibodies - Protein substances produced in response to a specific invader or antigen, marking it for destruction and thus creating immunity from that invader. antigens (antibody generators) - Invading substances such as bacteria that provoke antibody manufacture. primary immune response - Specific immune response to the first attack of a particular invader. Full response takes up to "two weeks." Memory B-cells (lymphocytes) are created which will recognize the invader upon future attacks. secondary immune response - Upon a second attack, the memory cells can react more quickly. Full response takes only "a few days." immunity - The rapid response that develops to a specific foreign microorganism upon repeated exposure. The result is resistance to the disease. humoral immunity - Immunity created through the process of exposure to antigens and production of antibodies "in the bloodstream." vaccination - A method of inducing immunity in which a weakened form of a virus or bacterium is introduced (injected) into the body stimulating the production of antibodies. immune deficiency - The immune system is weakened and cannot function correctly. Chemotherapy is a common cause. acquired immune deficiency syndrome (AIDS) - An immune deficiency caused by the human immunodeficiency virus (HIV) which kills T-cells and macrophages. The result is vulnerability to a wide range of bacterial and viral diseases. allergies - An allergic response is an abnormal response to a foreign substance that normally elicits little or no immune reaction (e.g., foods, pollen, dust, etc.). autoimmune diseases - The immune system mistakenly attacks the body's own cells. Examples are Lupus, rheumatoid arthritis, and multiple sclerosis. transplant rejection - A transplanted heart, liver, or kidney will be recognized as invading foreign tissue unless drugs are given to suppress immune system function. Thus, the person's immune system is weakened. immune surveillance theory - Theory that cancer is the result of the body's immune system failing to detect and destroy mutant cells. psychoneuroimmunology - A multidisciplinary field that focuses on the interactions among behavior, the nervous system, the endocrine system, and the immune system. diathesis-stress model - Theory of stress that suggesting that some individuals are vulnerable to particular stress-related diseases because of genetic weaknesses or biochemical imbalances. This would explain why life event scales are inconsistent in predicting disease. Vulnerability and stress interact. tension headaches - Pain is produced by sustained muscle contractions in the neck, shoulders, scalp, and face as well as by the activity in the central nervous system. infectious disease and stress - Duration of a stressor is more important than its severity with regard to making one more vulnerable to infectious disease. Stress may be a bigger risk factor for the "common cold" than poor diet, lack of sleep, or even white cell count. cardiovascular disease and heart attack - Stress contributes to disorders of the circulatory system, including coronary artery disease, stroke and heart attack. hypertension - Abnormally high blood pressure, with either a systolic reading in excess of 160 or a diastolic reading in excess of 105. A simple cause and effect relationship between stress and hypertension has NOT been found. However, stress may lead to sodium retention which may, in turn, lead to hypertension. reactivity - The idea that some people react more strongly to stress than others. Increased reactivity may play a role in the development cardiovascular disease. African Americans show greater reactivity than European Americans who, in turn, show greater reactivity than Asian Americans. ulcers and stress - Stress is NOT the primary cause of ulcers. Barry Marshall demonstrated that a bacterium could cause gastric problems. Specifically, "H. Pylori" infection may make ulcers more likely in those with other risk factors (stress-related?) such as smoking and high caffeine or alcohol intake. Diabetes mellitus - may be related to stress. Type 1 (juvenile diabetes) begins in childhood and requires insulin injection. Stress may contribute via immune system damage in infancy Type 2 (adult onset diabetes) begins in adulthood and can be controlled with diet. Stress may impact by leading to obesity. Asthma - A chronic disease that causes constriction of the bronchial tubes, preventing air from passing freely. Both physical stimuli (e.g., pollen) or stress can bring on attacks. Rheumatoid arthritis - An autoimmune disorder characterized by a dull ache within or around a joint. Depression - Both genetic vulnerability and stress contribute to depression in some people. the "Kindling Hypothesis" - Theory that an initial episode of depression in response to stress "sensitizes" the brain so that even minor future stressors may lead to significant depression. Posttraumatic Stress Disorder (PTST) - An anxiety disorder caused by experience with an extremely traumatic event and characterized by recurrent and intrusive re-experiencing the event (dreams, flashbacks, dissociation) and avoidance of reminders of the event. Contributing factors include lower IQ, absence of social support, and being female. Hispanics seem to be more vulnerable than other groups. Anxiety Disorders - Stress likely also contributes to other anxiety disorders (e.g., panic disorder, OCD) but the relationship is less clear.