Depolarizationof the axon hillock to threshold results in the generationand propagation of an action potential. The action poten-tial is a transient change in the membrane potential charac-terized by a gradual depolarization to threshold, a rapid ris-ing phase, an overshoot, and a repolarization phase.
Ecology. Staphylococcus aureus is a normal inhabitant of the skin and mucous membranes in the nose of a healthy human, while S. epidermidis inhabits only the skin of healthy humans. S. aureus is infectious to both animals and humans.he Staphylococcus aureus genome, which is the most common species amoung the genome projects, is about 2.8 Mega-base pairs long with approximately 2,600 open reading frames, comprising 84.5% of the genome.
Natural habitat. The human body is the normal ecological habitat of S. aureus. It is not plentiful in the inanimate environment except transiently after contact with people. It can be isolated in culture from the skin of all people intermittently and has a predilection for colonizing the anterior nares.he S. aureus strains isolated from infections are very often the same strains that the infected individual is colonized with i.e. one does not often âcatchâ S. aureus infections from another person. Rather their âownâ S. aureus makes them unwell when there is a reduction in immunologic function.