CHAPTER 14: IMMUNITY AND INFECTION
Endemic – The habitual presence of a disease in a specified area
_Epidemic__ – Occurrence of disease in excess of normal expectancy
Pandemic – A global epidemic
The Spread of Disease
– Phase 1: _Incubation__
– Symptoms may or may not appear
– Can be contagious
– Phase 2 & 3: “feel a cold coming on”
– Symptoms appear
Defenses against infection: The immune system and vaccines
– Immune system: body’s collective set of defenses against infection and diseases
– Physical and chemical barriers are _the first line of defense__
– Skin
– Mucous membranes
– Respiratory tract
The inflammatory response
– One 2nd line of defense
– Non-specific
– Localized infections
The cell-mediated immune response
– 3rd line of defense
– Specific
– __Lymphocytes___: a type of white blood cell involved in the immune response
– Viruses, fungi, parasites, and some bacteria
Allergies
– Result of a __hypersensitive__ and overactive immune system
– Reacts to a harmless substance as if it’s a harmful pathogen
– Allergens
– __Pollen__
– Animal dander
– Dust mites and cockroaches
– Molds and mildew
– Foods
– Insect stings
Vaccinations/Immunizations
– Helps the body to remember an encounter with a specific antigen
– Types of immunity
– __Active immunity___: a person produces his or her own antibodies to the
microorganism
– Passive immunity: injection of antibodies produced by other human beings
or animals who have recovered from a disease
Pathogens- Disease-causing agents
Bacteria
– Simple, single-celled microscopic organisms
– Produce toxins that cause disease
– _Normal flora___ – harmless or helpful bacteria that naturally inhibit a person
Viruses
– Smallest known pathogens
– Consists of __protein structure__ with RNA or DNA
– Needs a host cell to reproduce
Fungi
– Single- or multicellular organisms
– Transmit: physical contact
Protozoans
– Single-celled microscopic organisms
Prevention and treatment
– Know your controllable risk factors!
– Symptom relief
– __viruses___
– Antibiotics
– ___bacteria___
– Rest and fluids
A microorganism that causes disease is a(n)…
a) Pathogen
b) Antigen
c) Toxin
d) Antibody
Sexually Transmitted Infections
– There are more than 20 known types of STIs.
