Defences and blood clotting Flashcards
describe primary defences
these are the first line of protection against pathogens
what is the aim of primary defences?
to prevent the pathogen from entering the body
what happens if the primary defences fail?
there are other non specific defences that carry out the same process for any pathogen/foreign body
describe blood clotting
if the skin is damaged/cut, blood clotting occurs to form a scab- this prevents pathogen entry and blood loss
describe the process of blood clotting
- the skin is cut and starts to bleed- blood leaks out of the body
- platelets change the blood protein fibrinogen into fibrin, this forms a network of fibres in the cut
- red blood cells are trapped in the fibres, this forms a blood clot
- the clot hardens to form a scab, this keeps the skin clean and gives it time to heal, in time the scab falls off
what is the next form of defense if the primary and non-specific defenses fail?
if a pathogen is able to enter the body, then the immune system is the next form of defense
what are the different defenses that make up the immune system?
-enzymes in saliva
-tears
-nasal hairs
-stomach acid
-skin
-acid in vaginas
-cilia & mucus in airways
what are the physical methods of defense in the body?
-coughing
-sneezing
how do tears protect the body from pathogens?
they contain lysozymes which are enzymes that destroy bacteria
how do nasal hairs protect the body from pathogens?
they keep out dust and larger microorganisms
how does stomach acid protect the body from pathogens?
it kills pathogens present in contaminated food or drink
how does the skin protect the body from pathogens?
it’s a physical barrier, dead outer cells are difficult for pathogens to penetrate, the sweat glands produce oils that help to kill microorganisms
how does cilia and mucus in the airways protect the body from pathogens?
sticky mucus traps microorganisms, the cilia then moves the mucus up the throat, where it is swallowed
what system carries substances around the boyd?
circulatory system
what cell swallows up invading microorganisms?
white blood cells
what allows the microorganisms to be digested?
enzymes
what is the name for redness, warmth and swelling?
inflamation
what is the name for a harmful microorganism?
pathogen
what does the first line of defence in the body consist of?
chemical and physical barriers
what are some examples of chemical defences?
acid in the stomach and chemicals in the tears
