Disease and Immunity Flashcards
pathogen
a disease-causing organism. each pathogen has its own antigens,
which have specific shapes
transmissible disease
a disease in which the pathogen can be passed from one host
to another
how can a pathogen be transmitted?
(a) by direct contact, including through blood and other body fluids
(b) indirectly, including from contaminated surfaces, food, animals and air
body defences
skin: the surface of our skin is protected by a cornified layer of cells that prevents the entry of pathogens into our bodies
hairs in the nose: help to filter off dust particles and bacteria to keep them from entering our respiratory tract
mucus: moves up dust in the air so it doesn’t enter our lungs
stomach acid: kills bacteria
white blood cells: phagocytes engulf pathogens
importance of controlling disease
(a) clean water: drink water that has been boiled. clean water is free of pathogens and bacteria that could potentially harm our body
(b) proper waste disposal: overflowing dustbins and rubbish can be breeding grounds for bacteria. animals that visit such waste may be contaminated with bacteria and can deposit the bacteria onto our food.
(c) hygienic food preparation: meat should be cooked properly. food handlers must wash hands and clean surfaces + equipment so it is not contaminated with bacteria. food should be covered so flies don’t surround it
(c) personal hygiene: wash hands before and after handling food, and after using the toilet.
(d) proper sewage treatment: to prevent contamination. in rural areas, there should be well-constructed latrines to prevent flies and all from reaching
active immunity
defence against a pathogen by antibody production in the body. active immunity is gained after an
infection by a pathogen or by vaccination
antibodies
proteins that bind to antigens leading to direct destruction
of pathogens. specific antibodies have complementary shapes which fit specific antigens
process of vaccination
(a) weakened pathogens or their antigens are put into the body
(b) the antigens stimulate an immune response by lymphocytes which produce antibodies
(c) memory cells are produced that give long-term immunity
passive immunity
a short-term defence against a pathogen by antibodies acquired from another individual, including
across the placenta and in breast milk.
memory cells are not produced in
passive immunity
importance of breast-feeding
a baby will get antibodies from the mother’s milk. this is important as the baby’s immune system is not fully developed at this time. the antibodies from the mother provides temporary protection against pathogens. this is passive natural immunity