diseases and immunity Flashcards
what is a pathogen
disease causing organism
what are transmissible diseases
1.passed from one individual to another,caused by pathogens
4.pathogen infects host
5 examples of micro-organisms
bacteria,fungi,virus,protozoa,algae
what is a host
a organism which a pathogen lives and reproduces
types of pathogens of virus
influenza,rubella,aids
types of pathogens of bacteria
tuberculosis,typhoid fever,cholera
types of pathogens of protists
african sleeping, sickness,malaria,amoebic dysentery
types of pathogens of fungi
athlete’s foot,thrush
how pathogen damages cell
pathogen enters cell produces wastes called toxin,spreads around host body and causes symptoms
How do pathogens spread
direct contact-passed directly from one host to another through blood and other fluids like semen
indirect contact-
breathing in droplets-influenza,covid-19.
touching a contaminated surface-athlete’s foot,salmonella.
eating or drinking water containing pathogens-cholera,typhoid,dysentry,salmonella
contact with animals that are carrying pathogen-malaria,dengue fever,leishmaniasis
mechanical,chemical,cell defense against pathogens
mechanical-skin,hair in nose
chemical-mucus,stomach acid
cells-phagocytosis,producing antibodies
how do white blood cells attack pathogens
phagocytosis-phagocytes engulfs and surrounds pathogen.
product antibodies(lymphocytes)-antibodies attack and destroy pathogen
how white blood cells reject tissue
lymphocytes and phagocytes respond to any foreign cells in body even if it isnt a pathogen
immune cells released in response to transplant of organ cause organ to be rejected,called tissue rejection
good hygiene practices to control spread of disease
1.keep body clean to reduce risk of getting or passing on transmissible diseases
2.wash hands after toilet,reduces transmission of fecal pathogens
3.cover nose and mouth when coughing or sneezing
food hygiene
1.keep bacteria,virus,hair away from food
2.keep animals away from food
3.dont keep food at room temp
3.seperate raw and cooked food
waste disposal reduce risk
place waste food in covered container,disposing into landfill away from human habitation,burnt or composting in sealed containers
good sewage treatment
sewage treated and safe before release into environment,sewage system must be separated from drinking water supply
cholera spread
bacteria attach to walls of small intestine,producing a toxin that makes cell lining in intestines to release chloride ions from inside the cells into lumen of intestine,chloride ions accumulate in lumen of small intestine and lower water potential ,once water potential is lower than cell lining in the intestine,water starts to move out of capillary into the intestine,large quantity of water lost from body in water faeces,blood lacks chlroide ions and water
what are antigens
chemical that is recognised by body as being foreign,and stimulates production of antibodies
what are antibodies
protein molecule with a particular shape,complementary to antigen found on the outisde of a pathogen.to destroy a pathogen,antibody molecules must be made which are complementary to the antigens on the pathogen,so specific antibody for specific antigen
what are lymphocytes(memory cells)
remain in blood even after pathogen is destroyed,if met with same pathogen again,memory cells will respond quickly,causing a increase in antibody production,cant fall ill again with same pathogen you have immunity to
what is active immunity
when body met with same pathogen and lymphocytes produce antibodies to fight off infection.
what is passive immunity
body doesnt produce antibodies
immune system doesn’t respond
no memory cells produced so only short term protection
e.g. antibodies in mothers blood pass from placenta to fetus before birth
antibodies passed through breast milk,helps fight infection until older and stronger
disease caused by immune system
type 1 diabetes.immune system normally doesnt respond to own cells,however mechanism can go wrong and illicit a response
