Human Biology – Infectious Diseases Revision

These vocabulary flashcards cover key terms related to infectious diseases, types of pathogens, transmission methods, body defenses, immunity, and relevant medical treatments.

Infectious Disease

Illness that occurs when pathogens invade and multiply inside the body.

Pathogen

A microorganism (bacteria, virus, fungus, protozoan, or parasite) that causes disease.

Bacteria

Some species release toxins or damage tissues to cause disease.

Virus

Tiny infectious agent that enters host cells, hijacks them to replicate, and often destroys them.

Fungi

Eukaryotic organisms (yeasts, molds) that can infect skin, mucous membranes, or lungs.

Direct Contact Transmission

Spread via skin-to-skin or bodily fluid contact with an infected person.

Indirect Contact Transmission

Spread through touching contaminated objects or surfaces.

Airborne Transmission

Infection acquired by inhaling pathogen-laden droplets in the air.

Foodborne Transmission

Disease contracted from eating contaminated food.

Waterborne Transmission

Disease contracted from drinking or contacting contaminated water.

Vector Transmission

Spread of pathogens via animals such as mosquitoes or fleas.

First Line of Defense

Physical and chemical barriers (skin, mucus, tears, stomach acid) preventing pathogen entry.

Second Line of Defense

Non-specific responses (phagocytes, inflammation, fever) that attack invaders.

Phagocyte

White blood cell that engulfs and digests pathogens.

Neutrophil

Type of phagocyte that rapidly responds to bacterial infections.

Macrophage

Large phagocyte that engulfs pathogens and dead cells; also activates immunity.

Inflammation

Local response with redness, heat, swelling, and pain that attracts immune cells.

Passive Immunity

Short-term protection gained from external antibodies (e.g., breast milk, antiserum).

Active Immunity

Long-term protection produced by the body after infection or vaccination.

Antibiotic

Drug that kills or inhibits bacteria but not viruses.

Antiviral

Medication that slows viral replication to help the body fight infection.

Antibiotic Resistance

Ability of bacteria to survive antibiotics due to genetic mutations and misuse of drugs.