biology chapter 10 Flashcards
(27 cards)
what are pathogens
organisms that cause diseases are called pathogens. pathogens may be bacteria, viruses and fungi
what is a transmissible disease
a transmissible disease is a disease in which the pathogen can be passes from one host to another
what are the 3 main body defence systems
mechanical barriers, chemical barriers and cells
describe the mechanical barriers
skin - covers almost all parts of your body to prevent infection from the pathogens. if cut or grazed, it immediately heals itself often forming a scab
hairs in the nose- these make it difficult fro pathogens to get past them further up the nose so they are not inhaled into the lungs
describe the chemical barriers
mucus- made un various places in the body, pathogens get trapped in the mucus and can be removed from the body from coughing
stomach acid- contains hydrochloric acid which is strong enough to kill any pathogens that have been caught from the mucus
describe the cell barriers
by phagocytosis - engulfing and digesting pathogenic cells
by producing antibodies - which clump pathogenic cells together so they cannot move as easily
how do pathogens get into our bodies
direct contact - diseases can be transmitted through direct person to person contact. the transmission involves direct contact with the blood or body fluids with the host
indirect contact - diseases can also be transmitted indirectly. indirect transmission can occur through contaminated surfaces, air or water
what are the different ways of how pathogens get into our bodies due to contaminated surfaces
- airborne infection
- by animals
- unhygienic food preparation
- contaminated food and water
how do animals cause the pathogens to get into the bodies
animals such as insects are vectors. vectors are organisms that transmit pathogens from one host to another
how can the spread of waterborne and food borne diseases be controlled or prevented
- having clean water supply
- having proper waste disposal
- having a proper sewage transmit
- preparing food in a hygienic manner
- practising good personal hygiene
what is cholera
cholera is a disease caused by bacterium that is transmitted through contaminated food or water
what can cholera cause to a human
cholera disease causes watery faeces or severe diarrhoea and vomiting
what causes the patient to have a watery faeces or diarrhoea
a bacterium called vibrio cholerae produces toxin in the small intestine. this toxin binds to the cells in the intestines. it causes the cells to reduce absorption of sodium and increases the secretion of chloride ions into the intestines
how can we treat cholera
drink water containing some sugar and ions, this will replace water and ions lost in the faeces
define immunity
immunity is the protection provided by the bodys defence system against a disease
what is an immune system
the bodys defence system is called the immune system. the immune system maybe specific or non specific
what are antibodies
when pathogens enter the bloodstream, they are destroyed by the antibodies. antibodies are proteins produced by lymphocytes to destroy a particular type of pathogen
what are the two types of immunity
active and passive
what is active immunity
active immunity occurs when our bodies produce antibodies in response to antigens or pathogens through out own immune system
what is passive immunity
passive immunity acquired when we are given antibodies
what is vaccination
vaccination involves receiving a vaccine to product active immunity. a vaccine may contain a weakened form of pathogen, harmless form of toxin and dead microorganisms
how does a vaccine work
a vaccine is a preparation containing antigenic materials. it is injected into the body or is taken orally. when the vaccine enters the body, the bodys immune system is activated. the lymphocytes will recognise the antigens or pathogens in the vaccines particles, and will produce appropriate antibodies that will bind to antigens or pathogens and destroy them
define drug
a drug is any chemical substance that can modify or affect chemical reactions of the body
how do antibodies work
antibodies are drugs used to treat bacterial and some fungal infections. antibiotics are made by microorganisms. they kill the growth of bacteria or fungi
