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.

ACTIVITY1. 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 ImmunityWhen 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 sickA 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 DiseaseNoninfectious 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)