The Immune system T cell attacking cancer cell Virus with anti- Bodies attached virus bacteria virus

Purpose To fight infection by producing cells that inactivate foreign substances. Nonspecific defenses: act like a fortress wall Specific defenses: act like security guards

Nonspecific defenses: 1 st line of defense Skin: the first line of defense. Layers of dead cells make a barrier. Oil and sweat glands: make an acid environment that kills bacteria. Mouth, nose, eyes: mucus, saliva and tears have enzymes that destroy bacteria entering. Nose hairs trap bacteria.

2 nd line of defense: Inflammatory response A non-specific reaction to tissue damage or infection. Increased white blood cells- engulf bacteria. Fever: higher body temp. slows growth of pathogens. Interferon: proteins that disrupt viral replication. Phagocyte eating a parasite Hepatitis C and interferon fever

Specific defenses: the immune response Triggered by an antigen (viruses, bacteria, etc.) Plasma cells release antibodies: proteins shaped like a ‘Y that bind to the antigen and prevent it from infecting cells. B cells provide immunity against invaders in the bodily fluids. Memory B cells prevent a future infection: Humoral immunity

Cell mediated immunity A body can defend itself against its own cells if they become infected or cancerous. T cells  killer T cells The killer T cells will destroy the infected cells. Memory T cells will respond if the antigen returns. Killer T cells attacking a cancer cell

Organ transplants Our cells recognize another person’s cells as foreign, and attack them. Organ recipients must take drugs that suppress their I.S. to avoid organ rejection for the rest of their lives.

Active immunity Vaccinations introduce a weakened or dead pathogen into the body. Without getting sick, the body makes antibodies, arming the immune system. If you are exposed later, you will not get sick. Flu shot

Passive immunity A mother’s antibodies transfer to her child in utero and with her breast milk, giving her baby protection against diseases.

Immune system disorders 40-3 Pollen, rheumatoid arthritis, dust mite, HIV, asthma

Allergies Allergies An overreaction of the immune systemAn overreaction of the immune system Allergens (pollen, dust, mold) attach to mast cells, which release histamines.Allergens (pollen, dust, mold) attach to mast cells, which release histamines. Body response: sneezing, excess mucus, itchingBody response: sneezing, excess mucus, itching Meds: antihistaminesMeds: antihistamines

Asthma An allergic reaction that causes a chronic respiratory disease.An allergic reaction that causes a chronic respiratory disease. Smooth muscles that line the airways contract, thick mucus clogs the smaller passagewaysSmooth muscles that line the airways contract, thick mucus clogs the smaller passageways #1 cause of serious illness in children.#1 cause of serious illness in children. No cure, but treatments are available.No cure, but treatments are available.

Autoimmune diseases Happens when the I.S. attacks a body’s own cells by mistake.Happens when the I.S. attacks a body’s own cells by mistake. Type I diabetes: antibodies attack insulin- producing cells of the pancreas.Type I diabetes: antibodies attack insulin- producing cells of the pancreas. Multiple sclerosis: antibodies destroy the myelin sheath of neurons in the brain and spine.Multiple sclerosis: antibodies destroy the myelin sheath of neurons in the brain and spine.

AIDS, an immunodeficiency disease Caused by Human Immunodeficiency Virus.Caused by Human Immunodeficiency Virus. It attacks and destroys cells of the immune system itself (helper T cells).It attacks and destroys cells of the immune system itself (helper T cells). The body’s defenses against any disease are eventually destroyed, and the person will die from AIDS.The body’s defenses against any disease are eventually destroyed, and the person will die from AIDS. T cell (green) with HIV viruses HIV

HIV virus is capable of mutating.HIV virus is capable of mutating. Multiple drug resistant strains develop as the virusMultiple drug resistant strains develop as the virus evolves.

Maintaining health Eat a healthful diet.Eat a healthful diet. Get regular exercise and enough rest.Get regular exercise and enough rest. Abstain from harmful activities.Abstain from harmful activities. Get regular medical and dental check- ups.Get regular medical and dental check- ups.

Review 1.The purpose of the immune system is….. 2. Some diseases of the immune system are………….. 3.We can prevent disease by………