the immune system 40-1 40-2 t cell attacking cancer cell virus with anti- bodies attached virus...
TRANSCRIPT
The Immune system 40-1
40-2T 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: 1st 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.
2nd 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
• An overreaction of the immune system
• Allergens (pollen, dust, mold) attach to mast cells, which release histamines.
• Body response: sneezing, excess mucus, itching
• Meds: antihistamines
Asthma
• An allergic reaction that causes a chronic respiratory disease.
• Smooth muscles that line the airways contract, thick mucus clogs the smaller passageways
• #1 cause of serious illness in children.• No cure, but treatments are available.
Autoimmune diseases• Happens when the I.S.
attacks a body’s own cells by mistake.
• 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.
AIDS, an immunodeficiency disease
• Caused by Human Immunodeficiency Virus.• 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.
T cell (green) with HIV viruses
HIV
• HIV virus is capable of mutating. • Multiple drug resistant strains develop as the
virus evolves.
Maintaining health
• Eat a healthful diet.• Get regular exercise
and enough rest.• Abstain from harmful
activities.• 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………