Immunity and Disease

• The Immune System• Infectious Diseases• Noninfectious Diseases

First-Line Defenses

First-Line Defenses

• Work against harmful substances and disease-causing organisms called pathogens.

• Your skin (keeps pathogens out) and respiratory (cilia-traps pathogens; mucus-releases enzymes that weaken pathogens), digestive (enzymes, acids, and mucus), and circulatory systems (white blood cells) are first-line defenses.

Why Do We Get a Fever When We’re Sick?

• White blood cells (WBC) constantly patrol your body looking for invaders. If the WBCs can’t destroy the invaders fast enough, you might get a fever. Many pathogens are sensitive to temperature. A fever slows their growth but speeds up your body’s defenses.

Antigens and Antibodies

• Molecules that are foreign to your body are called antigens.

• When your body detects antigens, killer T cells are formed and they release enzymes that target antigens. Helper T cells are also released to stimulate antibody production.

• Antibodies attack specific antigens. Some antigens have a memory and stay in the blood to attack antigens should they return later (ex-chicken pox).

Active Immunity, Passive Immunity, and Vaccinations• In active immunity, your body makes it’s

own antibodies to fight off an antigen.• In passive immunity, antibodies that have

been produced in another animal are injected into you.

• Vaccinations are used to ward off childhood diseases (measles, mumps, whooping cough). Parts of a virus are injected into you and you develop antibodies specific to certain diseases.

Cases of Disease Before and After Vaccine Availability in the U.S.

DISEASE CASES/YEAR PRE-VACCINE POST-VACCINE 1998

Measles 503, 282 89

Diptheria 175, 885 1

Mumps 152, 209 606

Whooping Cough 147, 271 6,279

Why Get Tetanus Shots?

• Tetanus is caused by bacteria found in soil that paralyzes muscles. We were given a vaccine when younger that gave us passive immunity, but it only lasts 7-10 years. When we get a puncture wound, we get a booster shot (also containing diptheria vaccine) that lasts long enough to keep us from getting the disease. Usually, the antibodies in the vaccine come from humans, but sometimes it comes from horses or cattle.

Infectious Diseases

• Until the advent of the microscope, we had no idea that diseases could be passed from one person to another. We also had no clue that these diseases are caused by living organisms. Louis Pasteur discovered that microorganisms could spoil milk and wine and realized that they could attack humans in the same way.

Disease Organisms

Bacteria (strept throat, pneumonia, plague)

2. Protists (malaria, sleeping sickness)

3. Fungi (athlete’s foot, ringworm)

4. Viruses (colds, flu, AIDS, smallpox)

Smallpox

Mumps

How Diseases Spread

• Infectious diseases are spread by:

a. Direct contact with infected organism.

b. Through water and air.

c. On food.

d. Contact with contaminated objects.

e. Biological vectors (rats, cats, dogs, birds, mosquitoes, fleas, flies).

Disease Prevention

• Most diseases can be prevented by cleanliness. In the 1800’s, Joseph Lister figured out that washing his hands and surgical instruments before and after surgery resulted in fewer patient deaths.

• Wash hands.

• Brush and floss teeth.

• Exercise, eat right, get plenty of rest.

Noninfectious Diseases

Diseases that are not spread from one person to another.

• Chronic Diseases

• Allergies

• Diabetes

• Chemicals and Disease

• Cancer

Chronic Diseases

• Diseases that seem to linger, or last a long time. Some can be cured, others cannot.

Allergies – overly strong reactions of the immune system to a foreign substance.

• Things that cause allergic reactions are call allergens. They can be foods, dust, pollen, molds, antibiotics.

• When you come in contact your body forms antibodies and releases histamines.

Diabetes

• A chronic disease associated with levels of insulin produced by the pancreas.

• Insulin is needed for glucose to pass from blood into your cells.

• Symptoms: fatigue, excessive thirst, frequent urination, tingling in hands/feet.

• Can lead to blurred vision, kidney failure, heart attack, stroke, poor circulation to feet, coma, death.

Chemicals and Disease

• Toxic chemicals can cause birth defects, cell mutations, cancers, tissue damage, chronic disease, and death.

• Asbestos → lung disease

• Lead-based paints → CNS damage

• Alcohol → birth defects

• Pollution → variety of negative affects

CancerCharacteristics of Cancer Cells

1) Cell Growth is uncontrolled.2) These cells do not function as part of

your body.3) These cells take up space and

interfere with normal bodily functions.4) The cells travel throughout your body.5) The cells produce tumors or abnormal

growths anywhere in your body.

Various Tumors

Cancer Treatments

• Surgery.• Radiation treatments with x-rays.• Chemotherapy – the use of chemicals

to destroy cancer cells.

While there has been success with the above treatments, the key is early detection and treatment.

Early Warning Signs

• Changes in bowel or bladder habits.• A sore that does not heal.• Unusual bleeding or discharge.• Thickening or lump in the breast or

elsewhere.• Indigestion or difficulty swallowing.• Obvious change in a wart or mole.• Nagging cough or hoarseness.

The Key to Good Health?

Eat right.

Get plenty of rest.

Minimize stress in your life.

Don’t abuse your body.

See your doctor regularly.

Don’t ignore your body!