View source for Human Defences Against Micro-Organism

==Key Stage 4==
===Meaning===
'''Human defences against micro-organisms''' are all the ways the [[human]] body can prevent [[infection]] by a [[pathogen]].

===About Human Defences against Micro-organisms===
'''Defences against micro-organisms''' can be broken down into two main groups: Chemical Defences and Physical Barriers.

===The Skin===
: The [[human]] body is covered in [[skin]] which acts as a physical barrier to prevent [[micro-organism]]s from getting into the [[blood]] or [[organ]]s.
: The [[skin]] has [[Sweat Gland|sweat glands]] which produce [[sweat]] which contains [[antimicrobial]]  [[chemical]]s which can kill [[pathogen]]s.
: When the [[skin]] is cut the [[blood]] can [[Blood Clot|clot]] to produce another physical barrier to stop [[pathogen]]s getting into the body.

===The Nose===
: The [[nose]] has hairs which act as a physical barrier as they can trap [[micro-organism]]s before they enter the [[lung]]s.
: The [[nose]] is full of [[mucus]] which acts as a physical barrier since it is a sticky substance which [[micro-organism]]s can get stuck in. This [[mucus]] is then swallowed into the harsh environment of the [[stomach]] which kills [[micro-organism]]s.

===The Trachea===
: The [[trachea]] is full of [[mucus]] which acts as a physical barrier since it is a sticky substance which [[micro-organism]]s can get stuck in. This [[mucus]] is then swept up away from the [[lung]]s by [[Ciliated Epithelial Cell]]s into the throat where it is then swallowed into the harsh environment of the [[stomach]] which kills [[micro-organism]]s.

===The Eyes===
: The eyelids sweep [[micro-organism]]s from the surface of the [[eye]]s.
: The eyelashes prevent some [[micro-organism]]s getting into the [[eye]]s.
: The tear ducts produce 'Lysosomes' which are [[antimicrobial]].

===The Stomach===
: The [[stomach]] is kept at a very low [[pH]] with [[Hydrochloric Acid]] which kills most [[micro-organism]] which enter the [[stomach]].