Transcript Immune system - Sonoma Valley High School

The Immune system 40-1
Virus with antiBodies attached
T cell attacking cancer cell
40-2
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
•
fever
A non-specific reaction
to tissue damage or
infection.
• Increased white blood
cells- engulf bacteria.
Phagocyte eating a parasite • Fever: higher body
temp. slows growth of
pathogens.
• Interferon: proteins that
disrupt viral replication.
Hepatitis C and interferon
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 insulinproducing 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 checkups.
Review
1. The purpose of the immune system is…..
2. Some diseases of the immune system
are…………..
3. We can prevent disease by………