s
any abnormal condition that causes illness in a living organism
disease
happening suddenly and lasting for a short time
acute
an abnormal reaction to a normally harmless substance
allergy
the reaction of the immune system that takes place when foreign substances enter the body
immune response
an organism or particle that causes disease
pathogen
continuing or occurring over a long period of time
chronic
substances that produce allergic reactions
allergens
the body’s ability to protect itself from pathogens and other disease-causing agents
immunity
a contagious disease caused by pathogens
infectious disease
a tiny nonliving particle that can infect cells and cause disease
virus
a major component of the immune system that produces, stores, and carries white blood cells
lymphatic system
a type of immunity in which the immune system produces antibodies after exposure to a pathogen or vaccine
active immunity
a disease that is not caused by pathogen s and is not contagious
noninfectious disease
a disease or condition caused by a faulty inherited gene
genetic disorder
a small oval structure that filters fluids and traps pathogens
lymph nodes