Immune+System+HW2+MC

7.2 Lymphatic System For each of the following define their function and include their role in immunity (the ability to combat disease). (p.127-128) Red bone marrow- it produces all types of blood cells. Bone marrow produces the various types of white blood cells: neutrophils, eosinophils, basophils, lymphocytes, and monocytes. B cells mature in the bone marrow, But the T cells mature in the thymus. In a child, most bones have red bone marrow, but in an adult, it is limited to the sternum, vertebrae, ribs, part of the pelvic girdle, and the upper ends of the humerus and femur. thymus gland- it produces thymic hormones, such as thymosin, that are thought to aid in the maturation of T lymphocytes. Immature T lymphocytes migrate from the bone marrow through the bloodstream to the thymus, where they mature. The thymus is absolutely critical to immunity because without mature T cells the body’s response to pathogens is poor or absent. Spleen- it filters blood. It’s the largest lymphatic organ. Here, macrophages are like powerful vacuum cleaners that engulf pathogens and debris, such as worn out blood cells. A person without a spleen is often slightly more susceptible to infections and may have to receive antibiotic therapy indefinitely. Blood entering the spleen must pass through the sinuses before exiting. lymph nodes- it filters the lymph. As lymph courses through the sinuses, is it filtered by macrophages, which engulf pathogens and debris. Lymphocytes, also present in sinuses, fight infections and attack cancer cells. Physicians feel for the presence of swollen, tender lymph nodes in the neck as evidence that the body is fighting an infection. This is a noninvasive, preliminary way to help make such a diagnoses.

7.3 Nonspecific Defenses (p. 128-130)

Describe the barriers to entry and include their role in immunity Skin and mucous membranes- the intact skin is generally a very effective physical barrier that prevents infection. Mucous membranes lining the digestive, reproductive, and urinary tracts are also physical barriers to entry by pathogens. The ciliated cells that line the upper respiratory tract sweep mucous and trapped particles up into the throat, where they can be swallowed or expectorated. Chemical Barriers-Secretions contain chemicals that weaken or kill certain bacteria on the skin. Prespiration, saliva, and tears contain an antibacterial enzyme called lyosome. The acid pH of the stomach inhibits growth or kills many types of bacteria. Resident Bacteria- created by the normal flora, microbes that usually reside in the mouth, intestine, and other areas. By using up available nutrients and releasing their own waste, these resident bacteria prevent potential pathogens from taking up residence.

Define the players in the inflammatory response Histamine- substance, produced by basophils in blood and mast cells in connective tissue, that causes capillaries to dilates. mast cells- cell to which antibodies, formed in response to allergens, attach, causing it to release histamine, thus producing allergic symptoms. Pus- thick, yellowish fluid composed of dead phagocytes, dead tissue, and bacteria. Cytokines- type of protein secreted by a T cell that stimulates cells of the immune system to perform their various functions. Macrophages- large phagocytic cell derived from a monocyte that ingests microbes and debris.

List the four steps in the inflammatory response (figure 7.9) 1) Injured tissue cells and mast cells release histamine, which causes capillaries to dilate and increase blood flow. 2) Macrophages and dendritic cells phagocytize pathogens and release cyokines, which stimulate the inflammatory response. 3) Neutrophils and monocytes (become macrophages) squeeze through the capillary wall and phagocytize pathogens. 4) Blood clotting walls off capillary and prevents blood loss.

Describe the complement system and its role in immunity.- its composed of a umber of blood plasma proteins designated by the letter C and a subscript. The complement proteins complement certain immune responses, which accounts for their name. Describe the membrane attack complex and its role in immunity.- it produces holes in the surface of bacteria and some viruses. Fluids and salts then enter the bacterial cell or virus to the point that they burst. Describe interferon and its role in immunity. – they are proteins produced by virus-infected cells as a warning to non-infected cells in the area. Interferon binds to receptors of noninfected cells, causing them to prepare for possible attack by producing substances that interfere with viral replication. Interferons are used as treatment in certain viral infections, such as Hepatitis C.

7.4 Specific Defenses (pp.130) Define Antigens.- foreign substance, usually a protein or a polysaccharide, that stimulates the immune system to produce antibodies. How does specific defense differ from nonspecific defense?- When nonspecific defenses have failed to prevent an infection, specific defenses come into play. Specific defenses overcome an infection by doing away with the particular disease-causing agent that has entered the body. They also protect us against cancer. It attacks specific things. Which blood cells are mainly responsible for specific defense, and how do they function? (make a table like the one on page 130)

Table 7.1 Immune Type and Function B cells Produce plasma cells and memory cells Plasma Cells Produce specific antibodies Memory cells Ready to produce antibodies in the future T cells Regulate immune response; produce cytotoxic T cells and helper T cells Cytotoxic T cells Kill virus-infected cells and cancer cells Helper T cells Regulate immunity Memory T cells Ready to kill in the future.

7.5 Acquired Immunity (pp.136) What is acquired immunity? immunity that develops with exposure to various antigens. Your immune system builds a defense that is specific to that antigen.

What is active immunity and explain an example? It’s immunity in which the individual alone produces antibodies against an antigen. An example is when its induced when a person is well so that future infection will not take place with the use of immunization vaccines. What is passive immunity and explain an example? Immunity in which the individual is given prepared antibodies via an injection. An example is if the patient receives a gamma globulin injection.

7. 6 Hypersensitivity Reactions (pp.138-139) When is the immune system hypersensitive? – when the immune system responds in a manner that harms the body, as when individuals develop allergies, receive an incompatible blood type, suffer tissue rejection, or have an autoimmune disease. Explain how an allergy is an example of hypersensitivity.- The response to these antigens, called allergens, usually includes come degree of tissue damage. Explain how tissue rejection is an example of hypersensitivity.-the recipients immune system recognizes that the transplanted tissue is not “self”. Define autoimmune disease.- it’s a disease that will arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body attacks its own cells. Define the following autoimmune diseases. multiple sclerosis (MS)- is an autoimmune condition in which the immune system attacks the central nervous system, affecting the ability of nerve cells in the brain and spinal cord to communicate with each other. Lupus- a systemic autoimmune/connective tissue disease characterized by skin rashes, joint pain and swelling, inflammation of the kidneys, inflammation of the fibrous tissue surrounding the heart (ie, the pericardium), rheumatoid arthritis- a chronic, systemic autoimmune disorder that most commonly causes inflammation and tissue damage in joints (arthritis) and tendon sheaths, together with anemia.