The Immune System

What is the Immune System?

• A group of defenses that protects the body against disease-causing organisms.

• Pathogen- Any disease causing organism.

First Line of Defense

• Skin- The skin keeps most pathogens from entering into the body. • If the skin is cut or torn, pathogens can get in.

• Respiratory System- Mucous and cilia in your windpipe trap pathogens.• Sneezing and coughing gets rid of these trapped

pathogens.

First Line of Defense

• Digestive System- Saliva and acids work to kill pathogens.• HydroChloric Acid- Digests your food

and many pathogens you eat.

• Circulatory System- White blood cells attack and kill pathogens. • Increasing your body temperature

(fever) kills pathogens too.

Inflammation

• When an area is infected with pathogens, it becomes inflamed.

• Inflamed areas become red, swollen and painful. • White Blood Cells go to inflamed areas to fight

off the pathogen. • Puss- Dead white blood cells that have died fighting

off the infection.

Active Immunity• 1. A pathogen (bacteria, virus) enters your

body, and you get sick.

• 2. White Blood Cells produce Antibodies- Specific proteins that attack the pathogen.

• 3. The pathogen dies, and you get better.

• 4. That Antibody stays in your blood incase the pathogen comes back later.

• 5. If the pathogen comes back, white blood cells make more Antibodies to fight off the attack, keeping you from getting sick.

Pathogenenters your

body.

Antibodies aremade.

Pathogendies.

Antibodiesstays in

your blood.

If pathogen returns,

antibodiesbuild up again

ActiveImmunity

Vaccination

• Process of giving a vaccine to help give active immunity.

• Vaccine- Preparation of dead or damaged pathogens.

-After you get the vaccine, your body will begin making antibodies to fight off the pathogen. -If you ever get the real pathogen, your body will know how to kill it quickly with antibodies. -Your body REMEMBERS which antibodies attack which pathogens!

• When antibodies are made in another person or animal, and then given to you.

• Newborn babies have Passive Immunity from antibodies in their mother’s blood.

• This Passive Immunity only last for a few months, so the baby will need vaccines to build up their own Active Immunity.

Passive Immunity

Disease-Causing Organisms

• Bacteria- Tetanus, strep throat, and pneumonia.

• Virus- A small piece of DNA surrounded by a protein coat.

• A virus “Tricks” your cells into making more viruses.• Can cause the flu, AIDS, measles, mumps and

chickenpox.

Disease-Causing Organisms

• Protist – Malaria is spread by mosquitoes and African Sleeping Sickness is spread by Tsetse fly.

• Fungi – Ringworm and Athletes foot.

Infectious Disease

• Any disease that is caused by a virus, bacterium, protist or fungus and is easily spread.

• Infectious Disease can be spread by contact, water, air or food.

• Biological Vector- Any organism that is carrying the disease.

InfectiousDisease

VirusesBacteria

ProtistsFungi

AIDS ChickenpoxStrep Throat

Pneumonia

Malaria Sleeping SicknessRingworm Athletes

Foot