Diseases

INTRODUCTION TO DISEASESChapter 17.1

Disease

• 2 Types– Communicable Disease – a disease that can be

passed to a person from another person, animal, or object.

– Non-Communicable Disease – a disease that is not transmitted by pathogens.

Causes of Communicable Diseases

• Pathogens – tiny organisms that cause communicable diseases.

• Infections – a condition that occurs when pathogens enter the body, multiply, and damage cells.

• Bacteria – tiny one-celled organisms that live nearly everywhere.

• Virus – the smallest disease-causing organism.

Other types of Pathogens

• Fungi – primitive life-forms that feed on organic materials.

• Protozoa – Single-celled organisms that re usually harmless but that can cause certain diseases.

• Rickettsias – disease-causing organisms that resemble bacteria but multiply like viruses.

How are Pathogens Spread?

• Direct contact with the infected person. • Indirect contact with an infected person.• Contact with a vector. – A vector is an organism, such as an insect, that

transmits a pathogen.

THE BODY’S DEFENSES AGAINST INFECTION

Chapter 17.2

In Immune System

• Considered the main line of defense• Nonspecific response – This is a general response such as inflammation or

increased blood flow to the specific area. • Specific response– This is specific more specialized response. – This would be antibodies that help you resist

specific disease such as smallpox.

The Lymphatic System

• A secondary circulatory system that helps the body fight pathogens and maintain its fluid balance.

• Produces lymphocytes– B-Cells– T-Cells

Immunity

• 2 Types– Natural Immunity is present at birth. • Are present on your skin and in mucous membranes.

– Acquired Immunity develops over a person’s lifetime. • Sometimes acquired through a vaccine. • A Vaccine is a preparation of dead or weakened

pathogens that is injected into the body to cause the immune system to produce antibodies.

Typical Vaccinations

NON-COMMUNICABLE DISEASESChapter 17.3

What are Non-Communicable Diseases

• Diseases that are not transmitted by pathogens.

• Chronic Diseases– Diseases that are present either continuously or

off and on over a long time.• Degenerative Diseases– Diseases that cause further breakdown in the

body cells, tissues, and organs as they progress.

Common Non-Communicable Diseases

• Allergies• Alzheimer’s disease• Arthritis• Asthma• Cancer• Cardiovascular disease• Cerebral palsy• Cystic fibrosis