Transcript Immune System - Mercer Island School District

Immune System
Period 3
Ethan T, Joshua G, Sydney E, Bryan E
Main function
The main function of the immune system is to fight off infection and pathogens that enter the
body.
Your skin is the first line of defense as part of the innate immune system.
In our bloodstream there are a number of types of white blood cells that destroy foreign
invaders as part of either the innate immune system or the acquired immune system.
Innate vs Acquired Immunity
Innate immunity- Functions as soon as a foreign entity enters the body. Phagocytes, mucous
membranes, and skin all function to destroy or prevent infections from pathogens as soon as
they enter the body.
Acquired immunity- The part of the immune system that fights off localized infections that
the innate system cannot destroy completely. T cells and B cells recognize and destroy specific
pathogens, and remember certain infections for a lifetime. Vaccinations teach the acquired
immune system.
Vaccines
A vaccine is a biological injection designed to provide acquired immunity against viruses.
They contain weakened or dead microbes and viruses, so that the body’s immune system can
recognize and destroy the intruders in the case of a real future infection. Though vaccines
have garnered controversy over health concerns, vaccines are generally accepted as a safe
method of immunization with only rare adverse effects.
Cell types
A phagocyte is a cell that destroys pathogens by surrounding and engulfing them. T cells
destroy body cells that are infected with pathogens. B cells produce proteins that inactivate
pathogens that have not yet infected a body cell.
Proteins
Antibody
Antibodies are proteins made by B cells.
Antibodes can 1) bind to the surface of a
pathogen, preventing it from entering a cell, 2)
complement other immune proteins (sometimes
called complement proteins) to destroy the
pathogens, or 3) mark the pathogen for
destruction by a white blood cell.
Interferons are proteins produced by body cells
that are infected by a virus.
The infected cells release interferons, which
stimulate uninfected body cells to produce
enzymes that will prevent viruses from entering
and infecting them.
A 3D model of
a human
interferon
protein
Organs in the Immune System
Tonsils- Trap pathogens on the surface of the tonsils so T cells and B cells can attack
Lymph nodes- Contain and circulate lymphocytes
Organs in the Immune System
Bone Marrow- Produces red blood cells and lymphocytes that are part of the lymph system.
Thymus- The thymus is located beneath the sternum and is a specialized organ that is only
active when a person is young. Believed to be helpful when a person is still developing an
immune system.
Skin- First line of defense, keeps out any pathogens or viruses that would otherwise easily
enter the body without the protection of skin.
Homeostasis
Homeostasis is the maintenance of a stable
equilibrium between internal processes
and elements.
The immune system aids in homeostasis
by combating pathogens within the
system so as to prevent disruption of
the body’s normal function.
Relation with Other Systems
The immune system works closely with the
circulatory system by transporting white blood
cells.
The digestive system works with the immune
system to decipher which foreign objects are food
or pathogen.
The lymph system helps regulate immune
response to a virus by controlling body fluids.
Diseases that affect this system
Acquired
immunodeficiency
syndrome (AIDS),
caused by the human
immunodeficiency virus
(HIV)
Type 1 Diabetes
Rheumatoid Arthritis
Lupus
HIV/AIDS
HIV attacks the T Helper immune cells (CD4+ T
cells)
T cells, that would normally regulate immune
function, can no longer perform this task
With the body unable to recognize pathogenic
threats, the immune system is compromised, and
infections become unfightable
This is called Acquired Immunodeficiency Syndrome
Type 1 Diabetes
It is believed that the primary cause of
type 1 diabetes is that the immune
cells attack healthy body tissue
The cells in the pancreas which create
insulin are broken down by white
blood cells
Blood sugar cannot be processed
because of the lack of insulin
The result of the disease is that blood
sugar can reach harmful
concentrations if left unchecked or
without treatment