The Integumentary System

The Integumentary System

1. Components of the I'System

   • Hair
     • 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.

2. 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.

3. Functions of the I'System

   • Absorption, Protection, Sense organ, Temperature, Communication, Vitamin production, Excretion. ( A PALE SKIN TURNS CRIMSON VERY EASILY).

4. 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