Preventing and Treating Diseases

What non-specific systems does the body use to prevent pathogens from getting into it?

Skin; cilia and mucus in the nose, trachea, and bronchi; stomach acid.

What three functions do white blood cells have?

Phagocytosis, producing antibodies, producing antitoxins.

What happens during phagocytosis?

A phagocyte is attracted to the area of infection, engulfs a pathogen, and releases enzymes to digest the pathogen.

What are antigens?

Proteins on the surface of a pathogen.

Why are antibodies a specific defense?

Antibodies have to be the right shape for a pathogen's unique antigens, so they target a specific pathogen.

What is the function of an antitoxin?

Neutralize toxins produced by pathogens by binding to them.

What does a vaccine contain?

Small quantities of a dead or inactive form of a pathogen.

How does vaccination protect against a specific pathogen?

Vaccination stimulates the body to produce antibodies against a specific pathogen - if the same pathogen re-enters the body, white blood cells rapidly produce the correct antibodies.

What is herd immunity?

When most of a population is vaccinated against a disease, meaning it is less likely to spread.

What is an antibiotic?

Drugs that kill bacteria but not viruses.

What do painkillers do?

Treat some symptoms of diseases and relieve pain.

What properties of new drugs are clinical trials designed to test?

Toxicity, efficacy, and optimum dose.

What happens in the pre-clinical stage of a drug trial?

The drug is tested on cells, tissues, and live animals.

What is a placebo?

Medicine with no effect that is given to patients instead of the real drug in a trial.

What is a double-blind trial?

A trial where neither patients nor doctors know who receives the real drug and who receives the placebo.