Energist UltraPlus VPL™ System
User Manual
SD1-43 Issue 3 (CCF 296)
41
The walls of the follicle form the outer root sheath of the hair and the lower
part of the follicle widens out to form the hair bulb that contains the germinal
matrix, the source of hair growth. Dermal tissue projects into the follicle base
to form the dermal papilla, and this has a network of capillary blood vessels to
supply oxygen, energy and the amino acids needed for growth. Melanocytes
are present in the upper part of the papilla, producing pigment granules that
are distributed throughout the cortex.
The dermal papilla has always been accepted as the central growth area for
each hair, and its removal has frequently been the sole aim of hair removal
systems. However, more recently a second structure, the bulge, has been
identified as a further source of growth cells, which can restart growth from a
follicle even after the destruction of the papilla.
In the follicle the hair is surrounded by an inner root sheath that has three
layers. Henley’s layer is one cell thick and lies to the outer root sheath.
Huxley’s layer is two or three cells thick and is in the middle of the sheath.
The cuticle of this inner root sheath interlocks with the cuticle of the hair. Both
the hair and the inner root sheath grow at the same rate, but the inner root
sheath breaks down about two-thirds of the way up the follicle, so only the
hair emerges past the skin surface. Uncut hairs have a pointed tip.
6.3 Hair Growth Cycle
Hair growth varies greatly between individuals and the specific area of the
body. Scalp hair, as example, grows an average of 2.5mm weekly. Leg hair,
by contrast, grows at about half that rate.
The life cycle of hair follicles, that is, the repeating cycle of growth and rest
phases, affects overall hair production. No new hair follicles are produced
after birth with the appearance (and disappearance) of hair being the result of
changing ratios in the growth/rest cycle. This life cycle is distinguished as
three separate stages:
The cycle of life for each follicle begins with the anagen phase, which is the
reawakening of the follicle’s growth stage where a newly formed hair begins to
