the defence system Flashcards
immunity
the ability of the body to resist infection
pathogen
a disease causing organism
general defence system
acts as a barrier to all pathogens attempting to gain entry to the human body
specific defence system
attacks particular pathogens by producing antibodies or killing infected cells
skin
provides structural barrier to infection
clotting
prevents entry of further pathogens
lysozyme
enzyme that attacks and dissolves the cell walls of many bacteria
sebaceous glands
produce sebum which contains chemicals that kill bacteria
mucus
traps pathogens and prevents them from entering the body
cilia
creates a current which moves mucus back up the respiratory system so its swallowed into stomach
acid
hydrochloric acid kills many pathogens
beneficial bacteria
bacteria in the vagina produces lactic acid which prevents growth of pathogens
phagocytes
are attracted by a chemical released by cells when invaded. the phagocytes then engulf and digest the bacteria
macrophages
larger phagocytes that can remain in the spleen, lymph nodes etc or can scavenge for pathogens
complement
set of 20 proteins found in blood plasma that are activated by infection and destroy viruses and micro organisms
interferons
set of defence proteins that limit the spread of viruses and bacteria etc.
inflammation
when cells are infected they secrete a chemical which widens capillaries making them more porous. This causes localised swelling, pain, redness, fever etc.
antigen
a foreign molecule that stimulates the production of antibodies
antibody
a protein produced by white blood cells in response to a specific antigen
induced immunity
ability to resist disease caused by specific pathogens by the production of antibodies
active immunity
involved production of a persons own antibodies in response to foreign antigens that enter the body
natural active immunity
occur when a pathogen enters the body in the normal way for example an infection
passive immunity
when individual are given antibodies that were formed by another organism
natural passive immunity
occurs when a child gets antibodies from its mother
artificial passive immunity
when a person is given an injection containing antibodies made by another organism
vaccination
the administration of a non disease causing dose of a pathogen to stimulate the production of antibodies
immunisation
when we produce or are injected with antibodies against a pathogen
plasma b cells
produce antibodies
memory b cells
survive for years after the infection is eliminated and can make the specific antibody if the same infection later enters the body
helper t cells
stimulate b cells and killer t cells
killer t cells
destroy abnormal cells
memory t cells
if the same pathogen re enters body these stimulate the memory b cells and killer t cells
suppressor t cells
these inhibit the immune system after infection is over i.e. killer t ,plasma b etc
