Answers 2024
What are the layers of the skin?
hypodermis, dermis, epidermis
What are the two classifications of hair?
vellus and terminal
What is the follicle and its structure?
Dermis
External Root Sheath
Inner Root Sheath:
Henle Layer
Huxle Layer
Cuticle
Structure of hair:
Cuticle
Cortex (melanin)
Medulla
Papilla
Blood vessels
What pulse duration and fluence should be used for skin type I, II, III (Lighter
skin)?
Use higher fluences.
Use a shorter pulse duration.
Use a smaller spot size (optional)
What pulse duration and fluence should be used for skin type IV, V, VI (darker
skin) ?
Use a lower fluence.
Use a longer pulse duration.
Use a larger spot size (especially for dense and coarse hair).
List normal systemic changes
puberty, pregnancy, menopause
List factors that activate hair growth:
Increased blood supply to the area (topical stimulation)-accelerates.
Hormone stimulation-initiates and accelerates.
What is the chromophore for laser hair removal?
melanin
Name examples of medical laser wavelengths
Ruby: 694 nm (RED light. We don't use anymore)
Alexandrite: 755nm (Green light. Skin type I, II, III)
Diode: 800-810 nm (INVISIBLE light. Skin type I, II, III, IV)
, Nd: YAG: (neodymium: yttrium-aluminum-garnet): 1064 nm (INVISIBLE light. All skin
types. NOT the best but SAFEST for skin type V and VI)
What are the three phases of hair growth?
anagen, catagen, telogen
Describe the anagen phase:
Active hair growth is occurring.
Describe Early Anagen
The follicle is growing and starting to deepen. The hair is beginning to grow, but has
not yet reached the surface of the skin.
Describe Mid-Late Anagen
The follicle is at its maximum depth. The hair is fully visible terminal hair on the
surface of the skin.
The hair shaft bulb is dark or black pigmented and very moist.
Derma papilla is directing and supporting hair growth (nourishment), enclosing the
hair.
Describe the catagen phase:
Brief transitional stage.
Lasts only a few days to a few weeks.
Approx. only 1-2% of the hairs involved.
Hair follicle separates from papilla.
The hair shaft bulb is lighter or brown pigmented and drier.
Hair follicle shortens to 1/3 of its former length.
Describe the late catagen stage
the thin cord of epidermal cells attaching the dermal papilla to the shrunken hair
follicle retracts upwards, followed by the underlying dermal hair papilla, which also
moves upwards.
Describe the telogen phase:
Resting or dormant period.
Pigment cells are also dormant.
The papilla has detached from the follicle.
A 'Club" hair is a terminal hair separated from the papilla that has risen to the middle
of the follicle- it eventually falls out at the end of cycle.
The hair bulb is shrunken, white and consisting of keratinized hair matrix cells.
Length of telogen time varies widely according to type of hair, the area of the body
and nature of the individual.
Only hair germ cells from the outer root sheath and dormant dermal papilla cells
remain at the lower part of the follicle.
Slower growth.
(In some case a follicle doesn't go through telogen. Sometimes a new anagen hair
can emerge before "club" hair has shed.)
Explain why grey hair does not absorb laser technology
Grey hair lack pigment, or they do not have enough pigment granules, so they
cannot absorb enough energy from the laser, even with high fluence. The hair and
their follicles are not destroyed.