Hair is embedded. Bulb supplies blood and nutrients. Contracts -
stand up when cold. 1 falls out, 1 is replaced.
Nails
Composed of hardened, dead epithelial cells that are keratinised and flattened. Consists
of nail body, free edge, nail root, lunula (half moon), hyponychium (nail bed), eponychuim
(cuticle), nail matrix - nail growth rate = 1mm per week.
Muscles
Nerves
Glands = Epithelial cells that secrete a
substance. There are several types present in
skin: sebaceous glands, sudoriferous (sweat)
glands, eucrine sweat glands, apocrine sweat
glands and ceruminous glands.
Structure of the Skin
3 parts of the skin:
Hypo - dermis = (subcutaneous layer) Below dermis
Dermis = Deep, thicker layer. Comprised of connective tissue
With connective tissue with blood vessels, nerves, glands and
hair follicles embedded.
Epidermis = Superficial, thinner
layer. Comprised of epithelial cells.
Epidermis Cell: Keratinocytes = Produce keratin and
lamellar granules. Melanocytes = Produces melanin.
Langerhans cells = Participate in immune responses.
Markel cells = Helps to detect touch.
Cells form in basale and get slowly pushed up becoming
keratinised as they near the the surface. Process takes 4
weeks on average.
Functions of the I'System
Absorption, Protection, Sense organ, Temperature, Communication,
Vitamin production, Excretion. ( A PALE SKIN TURNS CRIMSON VERY
EASILY).
Role of the I'System plays in maintaining homeostasis
> Protecting the body and helping to regulate body
temperature. > Allows sensation of pleasurable, painful and
other stimuli in external environment.
Maintaining homeostasis - Wound healing
Wound healing is the body's way of repairing any damage that occurs to the skin in
order to return it to normal structure and function. > Different mechanisms for wound
healing exist which vary depending on the depth of the wound. Epidermal or deep
Epidermal wound healing: > A wound that primarily affects the
epidermis only: > The central deeper part of wounds may extend to the
dermis but edges have minor damage the most superficial epidermal
cells eg abrasions and minor wounds
Deep wound healing: > Injury extends into the dermis and even deeper into the
subcutaneous tissue. > Process to heal such wounds is therefore more complex due
to the different layers affected. Results in scar formation - can affect function of the
skin: decreased elasticity, fewer blood vessels, fewer hairs, glands or nerve endings.
4 Stages of deep wound healing: > Inflammatory phase >
Mitigatory phase > Proliferative phase > Maturation phase