Infectious Diseases

•Disease caused by the living pathogens within the body •pathogens (organisms that cause diseases)•Pathogens damage cell

Four Major Pathogen Groups:

Bacteria:Viruses:Fungi:

◦includes molds and yeastProtists:

◦Infects the blood

How Pathogens Spread

Infected PeopleSoil:Food WaterContaminated ObjectsInfected Animals

Body’s Defenses (Barriers)

The following barriers trap and kill most pathogens:◦Skin: Contains destructive chemicals in the oil and sweat.

◦Breathing Passages: Mucus and Cilia trap pathogens

◦Mouth & Stomach: Saliva and Stomach acids

When pathogens Survive BarriersInflammatory Response

◦Fluid and White blood cells begin to fight the pathogen.

◦Causes Inflammation of blood vessels and Fever

◦White blood cells released from blood vessels

◦White blood cell involved is the phagocyte. Phagocyte: engulf pathogens and

break them down.

Immune System

Third Line of Defense against pathogens

Targets each kind of pathogen with white blood cells called lymphocytes. ◦Two types of Lymphocytes: T-Cells – Identifies pathogen using antigens markers designed to recognize the pathogen

B-Cells – produce proteins called antibodies that destroy pathogens.

ACTIVITY

1. DRAW HOW A T-CELL RECOGNIZES AN INVADING VIRUS.

2. Make sure to label all steps. ◦ Hint use figure 7◦ Add color◦ Page 501

Preventing Infectious Disease

Through Active and Passive Immunity

Immunity: is the ability of an organism to destroy pathogens before they can cause disease.

Active Immunity

When an affective person own immune system produces antibodies in response to a pathogen.◦Long lasting

Antibodies are produced through vaccination/immunization.◦Vaccination: is the process by which

harmless antigens are deliberately introduced into an organism.

◦Vaccine: substance used in the vaccination and consist of weakened pathogens.

PASSIVE IMMUNITY

Results when antibodies are given to a person.

The antibodies that fight a pathogen come from a source other than the organisms body.

The antibodies only last a few months.

When you do get sick

A Bacterial infection can be treated by antibiotic.◦Antibiotic: is a chemical that kills

bacteria or slows their growth.

There is no treatment for viral illness but rest.

Summarize

Summarize infectious Diseases and how organisms fight against them.

Noninfectious Disease

Noninfectious Disease: are diseases not caused by pathogens in the body.

They are not transmitted from person to person.

What are the three top noninfectious diseases?

1. Allergies2. Diabetes3. Cancer

Allergies:

Allergy: is a disorder in which the immune system is overly sensitive to a foreign substance.

An allergy develops in response to various foreign substances that set off a series of reactions in the body.◦Allergen: any substance that causes an allergy.

Allergies continued:

Histamine: is a chemical that is responsible for the symptoms of an allergy.

Some allergic reactions can create a condition called asthma.◦Asthma is a disorder in which the respiratory passages narrow.

What is Diabetes?

Diabetes: is when either the pancreas fails to produce enough insulin or the body’s cells fail to properly use insulin.◦Insulin: enables body cells to take in

glucose from the blood and use it for energy.

A person with diabetes has a high level of glucose in the blood, but not enough in their cells.

What are the effects of diabetes?

◦Lose weight◦Feel weak◦Hungry all the time◦Frequent urination◦Blindness ◦Kidney failure◦Heart disease

What are the types of Diabetes?

Type 1◦Usually begins in childhood/early

adulthood◦Pancreas produces little or no insulin◦Requires insulin injections

Type 2◦Develops during adulthood◦Pancreas does not make enough insulin◦Control through diet, weight control and

exercise

What is Cancer?

Cancer: is a disease in which cells multiply uncontrollably, destroying healthy tissue.

Cancer develops from tumors.◦Tumor: an abnormal tissue mass

Cancer is caused by carcinogens.◦Carcinogens: substances or factors in

the environment that cause cancer (cigarette smoke, UV rays)