Chapter 5 Fighting Disease Section 1 Infectious Disease
Understanding Infectious Disease When you have an infectious disease, pathogens have gotten inside your body and caused harm. Pathogen: Organisms that cause disease. Infectious Disease: Disease caused by the presence of a living thing within the body.
Understanding Infectious Disease Famous People 1860’s – 1880’s Joseph Lister: British Surgeon hypothesized that microorganisms caused infections. (washed his hands and equipment, what a brilliant man) Louis Pasteur: Showed that microorganisms cause certain kinds of diseases. Killing microorganisms can prevent disease. Robert Koch: demonstrated that each infectious disease is caused by a specific kind of pathogen.
Kinds of Pathogens There are 4 major groups of human pathogens. Bacteria Viruses Fungi Protists
Kinds of Pathogens Bacteria: one-celled microorganisms, damage Body cells directly, and indirectly through toxins. Toxin: Poison, that attacks kills or damages cells.
Kinds of Pathogens Viruses: tiny particles, much smaller than bacteria. Cannot reproduce unless they are inside a living cell. Colds and Flu are caused by viruses. Over 200 kinds. Meds don’t work, body must kill with immune system.
Kinds of Pathogens Fungi: molds and yeast grows in warm, dark, and moist areas. Examples: athlete’s foot and ringworm.
Kinds of Pathogens Protists: eukaryotic organisms unicellular, and multicellular organisms, such as the protozoans, slime molds, brown algae, and red algae. Examples: Malaria African Sleeping Sickness Amebic Dysentery
How Pathogens Are Spread Pathogens can spread through contact with: Infected person Soil Food Water Contaminated object Infected animal
Chapter 5 Fighting Disease Section 2 The Body’s Defenses
Barriers That Keep Pathogens Out First line of Defense: Surfaces of Skin Breathing Passages Mouth Stomach These barriers trap and kill most all pathogens that try to enter the body.
Barriers That Keep Pathogens Out Skin: Chemicals in oil and sweat Fall off with dead skin Tightly lined skin cells Normally enters through skin cuts
Barriers That Keep Pathogens Out Breathing Passages: Contain mucus and cilia Sneeze and Cough
Barriers That Keep Pathogens Out Mouth & Stomach: Saliva contains destructive chemicals Acid in stomach
The Inflammatory Response In the inflammatory response, fluid and white blood cells leak from blood vessels into nearby tissues. The white blood cells then fight the pathogens.
The Inflammatory Response White Blood Cells Phagocyte: white blood cell that engulfs pathogens and destroys them by breaking them down.
The Inflammatory Response Inflammation Blood vessels widen Bigger area faster response Extra fluid, creates a swollen area
The Inflammatory Response Fever Chemicals produce fever Increased temp restricts infections ability to spread reproduce & grow.
The Immune System The cells of the immune system can distinguish between different kinds of pathogens. The immune system cells React to each kind of pathogen with a defense targeted specifically at that pathogen.
The Immune System T Cell To identify pathogens and distinguish one kind of pathogen form another.
The Immune System B Cell Produces proteins that help destroy pathogens. Antibodies: are made for specific antigens, marks them for death.
AIDS Disease caused by the virus, HIV. HIV is the only kind of virus known to attack the human immune system directly and destroy T cells.
Chapter 5 Fighting Disease Section 3 Preventing Infectious Disease
Active Immunity Immunity: The body’s ability to Destroy pathogens before they can cause disease.
Active Immunity Active Immunity: Your own immune system produces antibodies in response to the presence of a pathogen.
Active Immunity The Immune Response T cells and B cells keep the “memory” of how to destroy pathogens that have all ready entered the body. This response can last for life.
Active Immunity Vaccination The process by which harmless antigens are deliberately introduced into a person’s body to produce active immunity. Vaccine: consists of pathogens that have been weakened or killed but can still trigger the immune system.
Active Immunity When You Do Get Sick Antibiotic: chemical that kills bacteria or slows their growth with out harming body cells. Nothing you can take for a viral infection.
Passive Immunity Passive Immunity A person acquires passive immunity when the antibodies that fight the pathogen come from a source other than the person’s body.
Chapter 5 Fighting Disease Section 4 Noninfectious Disease
Noninfectious Disease Diseases that are not caused by pathogens in the body. Can not be transmitted from person to person.
Allergies An allergy develops in response to various foreign substances that set off a series of reactions in the body. Allergens: A substance that causes an allergy. Histamine: a chemical that is responsible For the symptoms of an allergy, such as Sneezing and watery eyes.