Defence Against Pathogens Flashcards
What does the skin acts as?
> It acts as a physical barrier, blocking pathogens from entering the body
It acts as a chemical barrier by producing chemicals that are antimicrobial ( which destroy or slow the growth of microorganisms) and can lower the pH, inhibiting the growth of pathogens
What do skin cells do acid wise?
They secrete fatty acids, such as oleic acid, that can kill some bacteria. Fatty acids also lower the pH of the skin, creating an acidic environment that is difficult for pathogens to colonise.
What do skin cells do lysozyme wise?
Skin cells secrete lysozyme, an enzyme which catalyses the breakdown
What does the mucous membrane?
These protect body openings that are exposed to the environment (such as the mouth, nostrils, ears, genitals and anus). Some membranes secrete mucus - a sticky substance that traps pathogens and contain antimicrobial enzymes.
What happens if you breath in air that contains pathogens
Most of the pathogens will be trapped in mucus lining the lung epithelium (the outer layer of cells in the passages to the lungs) which also have cilia that beat and move the mucus up the trachea to the treat and mouth, where its removed.
What is a blood clot?
its a mesh of protein fibres.
What do blood clots do?
They plug wounds to prevent pathogen entry and blood loss.
How are blood clot formed?
By a series of chemical reactions that take place when platelets (fragment of cells in the blood) are exposed to damage blood vessels
What do the signs of inflammation include?
Swelling, pain, heat and redness
How can inflammation be triggered?
Can be triggered by tissue damage - the damage tissue release molecules which increase the permeability of the blood vessels, so they start to leak fluid into the surrounding area which causes swelling and geek’s to isolate any pathogens that may have entered the damaged tissue. The molecules also cause vasodilation (widening of the blood vessels)
What does vasodilation cause?
It increases the blood flow to the affected area which makes the area hot and brings white blood cells to the area to fight off any pathogens that may be present
How is the skin repaired?
The surface is repaired by the outer layer of skin cells dividing and migrating to the edges of the wound. The tissue below the wound then contracts to bring the edges of the wound closer together. it is repaired using collagen fibres - too many collagen fibres and you’ll end up with a scar
When does a sneeze happen?
When the mucous membranes in the nostrils are irritated by things such as dust or dirt
How does a cough happen?
A cough stems from irritation in the respiratory tract
What are coughing and sneezing an attempt of?
To expel foreign objects, including pathogens, from the body
