Chapter 7 Study and Book Flashcards
Describe the role of the macrophage in the immune response.
Following phagocytosis of foreign material, macrophages process the antigen for use by the lymphocytes, thus initiating an immune response. Macrophages also stimulate proliferation of lymphocytes.
State the origin and purpose of lymphocytes.
Lymphocytes originate from the stem cells in bone marrow, mature in the thymus or bone marrow, and then migrate to lymphoid tissue, where they are responsible for the immune response
Compare active natural immunity and passive artificial immunity, describing the causative mechanism and giving an example.
Active natural immunity results when a person naturally experiences an infection such as chickenpox (varicella) and develops permanent immunity (memory cells) to the invading virus. Passive artificial immunity is a temporary protection against an infection, such as rabies, gained through forced introduction of antibodies into the body from an external source.
a temporary protection against an infection, such as rabies, gained through forced introduction of antibodies into the body from an external source.
Passive artificial immunity
results when a person naturally experiences an infection such as chickenpox (varicella) and develops permanent immunity (memory cells) to the invading virus
active artifical immunity
What is the purpose of a booster vaccination?
A booster is an additional injection of antigen that serves as a reminder to the memory cells in the immune system and stimulates additional production of antibodies.
Describe the purpose of gamma globulins.
Gamma globulin is given as an injection of antibodies from an external source immediately following exposure to a microbe to minimize the effects of an impending infection (e.g., measles, rubella).
Where is IgA found in the body?
IgA is found in saliva, the secretions and mucous membranes of the respiratory and digestive tracts, and colostrum.
Describe how type III hypersensitivity develops.
Immune deficits may result from dysfunction of the cellular component or antibody production. One or both types of lymphocytes may be deficient because of bone marrow problems or damage to mature lymphocytes (e.g., from human immunodeficiency virus [HIV] infection). Phagocytic cells also may be defective. The second group of immunodeficiencies arises from an abnormality of the immunoglobulins, which may result from a protein deficit, genetic abnormalities, or B cell dysfunction. Immune deficits for both these groups may be classified as primary or secondary disorders.
Explain the process by which an attack of hay fever follows exposure to pollen.
On first exposure to the pollen, IgE antibodies form and attach to mast cells in the nasal mucosa. On subsequent exposure to the same pollen, the allergen reacts with the antibodies on the mast cell, causing release of histamine and other chemical mediators from the mast cells and resulting in inflammation of the nasal mucosa. Inflammation causes swelling of the nasal mucosa, sneezing, and increased watery secretions (hay fever).
Explain why anaphylaxis is considered life threatening.
Anaphylaxis results in severe hypoxia very quickly because of combined respiratory (airway obstructions) and cardiovascular (shock) impairment, leading to loss of consciousness and potential cardiac or respiratory arrest. Immediate treatment is essential.
Describe the pathophysiology of a type III hypersensitivity reaction.
An antigen-antibody complex forms and is deposited in tissue, activating complement and causing inflammation.
Define an autoimmune disease, and explain how the causative mechanism differs from a normal defense.
In an autoimmune disorder, the immune system identifies a component of the individual’s tissues as foreign (self antigens) and develops autoantibodies to it. The ensuing antigen-antibody reaction causes inflammation and, eventually, necrosis in various organs and tissues. In a normal immune response, the body does not identify its own tissues as foreign, and antibodies are formed as a defense against external foreign material.
Describe two factors that promote a successful organ transplant
A successful organ transplantation is promoted by a close tissue match, using blood type and HLA antigens on the lymphocytes, good circulation, and maintenance of antirejection drugs.
Differentiate between a diagnosis of being HIV+ and a diagnosis of having AIDS.
When someone is HIV-positive, the virus and antibodies are present in body fluids, but there are no obvious signs, and the T lymphocyte count is normal. With AIDS, active infection is present, the T lymphocyte count is reduced, and acute opportunistic infections and cancers occur.
