Innate immunity is:
The characteristics of innate immunity are that the response:
Innate immunity includes the fundamental mechanisms that facilitate resistance to infection, which include:
Innate immunity can be divided into:
Innate defences include basic mechanisms resisting infections; predominantly including:
Anatomical barriers include the epithelia of skin and mucous membranes, and also in the respiratory tract, cilia (Figure 1).
Skin has the following properties:
Mucoase have the following properties:
Physiological barriers include pH (eg stomach acidity), oxygen tension, temperature and various soluble factors.
Protective reflexes include:
Hence, anatomical and physiological barriers together with the protective reflexes try to block all the entrance gates for microbes: such as ingestion, inhalation, skin contact, sexual contact and exchange of body fluids.
Cells of the innate immune system are either present in the connective tissue of epithelia, for example tissue macrophages which are also known as histiocytes (histo=ιστός=tissue in Greek), including hepatic Kupffer cells, alveolar macrophages, giant cells of granulomas, osteoclasts and dermal Langerhans cells) or migrate to the epithelia to fight invaders (eg polymorphonuclear neutrophils (PMNs).
