a disease that is not caused by pathogens and is not contagious (Alzheimer's, cancer)

beginning suddenly and lasting for a short time (colds, flu)

a pathological condition of a part, organ, or system of an organism characterized by an identifiable group of signs or symptoms

microorganisms which are typically one-celled, have no chlorophyll, multiply by simple division, and can be seen only with a microscope

lasting for a long time and/or recurring frequently (cancer, arthritis, diabetes)

a substance that provokes allergies (pollen, mold, dust, certain foods)

components of the immune and lymphatic systems

a tiny, nonliving particle that can infect cells and cause diseases and cannot be killed with antibiotics

the type of immunity in which the immune system produces antibodies in response to the presence of a pathogen. It can last a few years or up to a lifetime

the body's ability to protect itself from pathogens before they cause disease

body systems that work together to defend the body against disease.

an abnormal reaction to a foreign substance

a contagious disease caused by pathogens (flu, measles, chickenpox, malaria)