chapter 10 Flashcards
(18 cards)
Describe what is a pathogen and a transmittable disease
Pathogen: a disease-causing organism
Transmittable disease : a disease in which the pathogen can be passed from one host to another
How are pathogens transmitted ?
by direct contact ( by bodily fluids like blood or semen )
by indirect contact ( carried in some other way , uninfected individual like surfaces, food animals )
Describe the body defences against pathogens
- Mechanical / physical barrier
- Skin ( blood cloting, forming scab )
- Hairs in nose ( trap, filter dust )
- Cilia in trachea ( filter pathogen from alveoli )
- Chemical barriers
- Mucus ( pathogens get trapped and then removed )
- stomach acid ( contains Hydrochloric acid which kills pathogens )
- Cells
- Phagocytosis ( engulf and digest pathogenic cells, using enzyme )
- Producing antibodies
What is active immunity?
The defence against a pathogen by antibody production in the body
What are the 2 places that antigens are found?
Self antigen: found on own cells
Non self antigen : found in foreign cells like pathogen or transplanted tissue
What are antibodies?
Proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytes
describe the relationship between antibodies and antigens and the process involved
Specific antibodies have complementary shapes which fit specific antigens
- Lymphocyte can read the antigens on the surfaces of cells and recognise the foreign ones.
- then, they make antibodies which are complementary shape to the foreign antigens.
- Antibodies attach to antigens and cause agglutination ( clumping ). They also release chemicals to signal to phagocytes to destroy pathogen
- Phagocytosis occurs
Describe the responses of active immunity
- body infected with pathogen so lymphocytes produce more antibodies
- vaccination
Describe the process of vaccination
- introduce dead or altered pathogen which contains specific antigens into the body
- Pathogen is weakened so cannot cause illness but can provoke immune response
- Lymphocytes produce complementary antibodies
- antibodies target foreign antigen to create memory cells
- memory cells remain in blood and will quickly respond to the antigen if encountered by live pathogen
- memory cells produced so long lasting immunity
state the properties of active immunity
- long term protection
- slow acting
- memory cells produced
- antibodies produced
Explain the role of vaccination in controlling the spread of disease
Herd immunity : Large percentage of population vaccinated, which provides enough protection for the entire population.
: Prevents epidemics and pandemics from occuring
Define passive immunity
Short term defence against pathogens by obtaining antibodies from another individual
Examples of passive immunity
- From mother to infant via breast milk and placenta
- Injecting antibiotics
- Does not produce antibodies and memory cells
Properties of passive immunity
short term protection
fast acting
Difference between active immunity and passive immunity
- memory cell produced or not
antibodies produced or not
fast acting or slow acting
short term or long term
Describe what is cholera
A disease caused by bacteria which is transmitted in contaminated water
What does cholera cause and explain the process
Cholera causes diarrhoea
How?
1. ingested via infected food or water
2. enters small intestine where bacteria attaches to wall
3. bacteria produces toxin that stimulates cell lining of intestine to release chloride ions from inside the cells into lumen of intestine
4.Water potential lowers until it is lower then that of cell lining so water moves out of cells into intestine by osmosis
5. water is lost in watery faeces
State ways to control the spread of diseases
Hygienic food preparations
good personal hygiene
effective waste disposal and sewage treatment
