The skin contains the following
appendages.
• Each hair is composed of a
medulla, cortex and outer cuticle.
• The hair follicle consists of an
inner root sheath, derived from the epidermis, and
an outer root sheath, derived
from the dermis.
• Several sebaceous glands drain
into each follicle. Discharge from these glands is
aided by the contraction of
erector pili muscles.
• Velus hairs are fine and downy.
• Terminal hairs are coarse.
• Hairs are in either the telogen
or the anogen phase.
• 75% of hairs are in the anogen
(growth) phase at any one time.
• The remaining 25% of hairs are in
the telogen (resting) phase.
• These sweat glands secrete an
odourless hypotonic fluid.
• They are present in all sites of
the body.
• Eccrine glands occur more
frequently in the eyelids, palms, feet and axilla.
• These are located in the axilla
and groin.
• They emit a thicker secretion
than eccrine glands.
• They are responsible for body
odour.
• Hidradenitis suppurativa is an
infection of the apocrine glands.
• These are holocrine glands that
usually drain into the pilosebaceous unit.
1• They drain directly onto the
skin in the labia, penis and tarsus (meibomian
glands).
• They occur more frequently on the
forehead, nose and cheek.
• Sebaceous glands are not the
sole cause of so-called sebaceous cysts. These cysts
are in fact of epidermal origin
and contain all of the substances secreted by the skin
(predominantly keratin).
• Some authorities maintain that
they should therefore be called epidermoid
cysts.
• Eccrine or merocrine glands
secrete opened vesicles via exocytosis.
• Apocrine glands secrete
unbroken vesicles which later discharge.
• Holocrine glands secrete whole cells which then
disintegrate.
• Acanthosisahyperplasia of the
epithelium.
• Papillomatosisaan increase in the
depth of the corrugations at the junction
between epidermis and dermis.
• Hyperkeratosisaan increase in the
thickness of the keratin layer.
• Parakeratosisathe presence of nucleated cells at the
skin surface.
