Immune System

B cell

antibody-producing cell that is present in all lymphatic tissues

saliva, tears, and nasal secretions defense

contain enzyme lysozyme that breaks down bacterial cell walls, killing these pathogens

immunization

deliberate exposure of the body to an antigen so that a primary response and immune memory will develop

lymph nodes

filter the lymph and remove foreign materials from the lymph

Tonsils

form protective ring between nasal and oral cavities, protecting against pathogens in nose and mouth

Thymus Gland

helps activate T cells, which are produced in bone marrow but mature in the thymus gland

stomach acid defense

hydrochloric acid in the stomach kills many microorganisms found in food

Skin defense

layer of dead skin cells forms barrier against invasion; bacteria living symbiotically on the skin produce acids that inhibit pathogens

memory cell

long-living cell that is exposed to an antigen during the primary immune response and will respond rapidly if the body encounters the same pathogen later

helper T cell

lymphocyte that activates antibody secretion in B cells and another type of T cell that aids in killing microorganisms

cytotoxic T cell

lymphocyte that destroys pathogens and releases cytokines

Phagocytosis defense

phagocytes surround and internalize foreign microorganisms, and then release digestive enzymes that destroy the microorganisms

antibody

protein produced by B lymphocytes that specifically reacts to a foreign pathogen

interferon

protein secreted by virus-infected cells that binds to neighboring cells and stimulates these cells to produce antiviral proteins

complement protein

protein that enhances phagocytosis by helping the phagocytic cells bind better to pathogens, activating the phagocytes, and enhancing the destruction of the pathogen's membrane

Spleen

stores blood and destroys damaged red blood cells; contains lymphatic tissue that responds to foreign substances in blood

exposure of immune system to disease antigens either through having an infectious disease or immunization

Active Immunity

nonspecific—complement proteins and interferons; specific—B and T cells

Compare specific and nonspecific immune responses.

B lymphocytes are important for producing antibodies—specific chemicals that attach to antigens and increase phagocytosis. T lymphocytes include cytotoxic T cells, which can destroy foreign cells and release cytokines to stimulate the immune response. Helper T cells enhance the response of both B lymphocytes and cytotoxic T cells.

the role that lymphocytes play in immunity.

The phagocyte internalizes and processes an antigen, places a piece of the antigen on its surface, and presents it to helper T cells. Helper T cells present a processed antigen to B cells to activate them so they begin producing antibodies.

Describethestepsinvolvedinactivatinganantibodyresponsetoanantigen

organs and cells that include thymus, tonsils, lymph nodes, lymphocytes; filter lymph and blood and destroy foreign microorganisms; absorb fat

Describethestructureandfunctionofthelymphaticsystem.

The child only will have an active nonspecific immunity and little or no specific immunity.

Evaluate the effects of severe combined immune deficiency on a child born without T cell immunity.

More people who are infected with HIV will develop AIDS.

HypothesizewhathappenswhenanHIVstrainmutatessuchthatviral-replicationdrugs are no longer effective.

Passive: antibodies are produced in one organism, given to another. Active: antibodies are produced in organism with the disease or immunization.

Identifywayspassiveandactiveimmunitycanbeacquired.

When helper T cells decrease, both B- and T-cell immune responses are impaired

Infer why the destruction of helper T cells in HIV infection is so devastating to specific immunity.

Passive Immunity antibodies made by other people or animals are transferred into the body, such as by injection or through a mother's placenta or breast milk to her child

Passive Immunity

reduce the likelihood of developing a disease

Passive and Active Immunity

lymphocyte

type of white blood cell that is produced in red bone marrow and plays a role in specific immunity

Interferon defense

virus-infected cells secrete interferon, which binds to neighboring cells and stimulates these cells to produce antiviral proteins

1. a macrophage digests a pathogen 2. A processed antigen is displayed on the membrane of the macrophage 3. the macrophage binds with a helper T cell 4. The activated helper T cell reproduces and attaches to a B cell or cytotoxic T cell. 5. The B cell begins to make antibodies and the cytotoxic T cell releases cytokines.

Sequence B cell and T cell responses