immune system

non infectious diseases

can't be spread e.g cancer, anemia

infectious diseases

contagious and caused by a pathogen

pathogen

organism that causes disease

cellular pathogens

animals, fungi, protozoa, bacteria

non cellular pathogens

viruses, prions

modes of transmission

direct contact, airborne droplets, vectors, contaminated water, contaminated objects

vectors

organisms that carry pathogens without being affected themselves

methods for preventing disease spread

personal hygiene, quarantine laws, animal and pest control, clean water, vaccination, waste disposal, food safety, treatment

microbiome

beneficial bacteria inside person's body

parasite

organism that lives off a host

endoparasite

lives inside body

ectoparasite

lives outside body

Primary hosts

main host during adult stage

secondary hosts

host during larval stage

prion

infectious protein

virus

A tiny, nonliving particle that invades and then reproduces inside a living cell.

bacteria

single celled pathogens

protozoans

single celled organisms found within hosts body

fungi

kingdom of organisms including toadstools and moulds

larger parasites

tapeworms, roundworms, liver flukes, ticks, fleas and lice

antigen

foreign substance that triggers an immune reaction

first line of defence

physical and chemical barriers e.g skin, saliva, nasal hairs and stomach acid

second line of defense

inflammation, caused by increased blood flow, nonspecific

Phagocytosis

phagocytes (type of white blood cell) engulf and destroy pathogens

lymphatic system

contains lymph vessels, lymph nodes, lymph and white blood cells

third line of defence

specific and has ability to remember pathogens

B lymphocytes

produce antibodies which link to antigens, cause pathogens to clump together, allows phagocytes to engulf them

T lymphocytes

destroy foreign cells and your own infected cells by secreting cytokines

killer T cells

produce chemicals to kill pathogens and infected cells

helper T cells

stimulate B cells to make antibodies, activate T cells

memory cells

remembers antigen to speed up and strengthen immune response

active immunity

resistance to a particular pathogen, from being able to create specific antibodies

passive immunity

receiving antibodies from outside source, no memory cells

vaccine

trains immune response to fight pathogen without being exposed to pathogen itself

herd immunity

protection from large % of population being immunised

plagues

contagious disease spreads quickly through population

pandemics

worldwide disease

epidemic

many people in particular area infected in short time

influenza

constantly evolves, gains new surface proteins

tetanus vaccine

safe part of tetanus toxin used as antigen, when infected antibodies from vaccine bind to toxin