Ageing+and+Homeostatic+Imbalances

Adolescent to Adult
 * Ageing: **
 * Skin and hair become oilier and acne may appear.
 * Skin shows the effects of cumulative environmental assaults around age 30.
 * Scaling and dermatitis become more common[[image:ucanaandp/flickr-6916288702-hd.jpg width="240" height="155" align="right"]]
 * Epidermal replacement of cells slows and skin becomes thinner. Skin becomes dry and itchy. Subcutaneous fat layer diminishes, leading to intolerance of cold. Decreased elasticity and loss of subcutaneous tissue leads to wrinkles.
 * Decreased numbers of melanocytes and Langerhans’ cells increase the risk of skin cancer
 * Most age related changes occur in dermis
 * Skin becomes thinner and more easily damaged
 * Wrinkling - Collagen fibres decrease in number, stiffen, break apart, and form shapeless tangles
 * Skin sag - due to a reduction in elasticity of elastic fibres and there is a reduction in Fibroblasts (produce collagen and elastin)
 * Reduced ability of skin to heal itself and reduced immunity: Langerhans cells reduce in number and Macrophages become less efficient

Three types of skin cancer
 * Homeostatic Imbalance **
 * Skin Cancer **
 * Basal cell carcinoma,
 * squamous cell carcinoma
 * Melanoma
 * Basal cell carcinoma‍‍[[image:ucanaandp/1236px-Basal_cell_carcinoma3.jpg width="168" height="155" align="right"]]‍‍**
 * Least malignant and most common skin cancer
 * Stratum basale cells proliferate and invade the dermis and hypodermis
 * Slow growing and do not often metastasize
 * Can be cured by surgical excision in 99% of the cases
 * Squamous cell carcinoma**
 * Arises from keratinocytes of stratum spinosum
 * Arise most often on scalp, ears, and lower lip
 * Grows rapidly and metastasizes if not removed
 * Prognosis is good if treated by radiation therapy or removed surgically
 * Melanoma**
 * Cancer of melanocytes is the most dangerous type of skin cancer because it is:
 * Highly metastatic[[image:ucanaandp/1280px-Melanoma.jpg width="174" height="147" align="right"]]
 * Resistant to chemotherapy
 * World Map
 * __Signs and Symptoms__
 * Change in size, shape, or color of an existing mole.
 * Texture of the mole can change – can become hard, lumpy, or scaly.
 * Can also appear as a new, abnormal, or "ugly-looking" mole.
 * Although a melanoma may feel different and may itch, ooze, or bleed, it usually does not cause pain
 * A: Asymmetry; the two sides of the pigmented area do not match
 * B: Border is irregular and exhibits indentations
 * C: Color (pigmented area) is black, brown, tan, and sometimes red or blue
 * D: Diameter is larger than 6 mm (size of a pencil eraser)
 * Treated by wide surgical excision accompanied by immunotherapy
 * Chance of survival is poor if the lesion is over 4 mm thick

Estimates the severity of burns a) – only the epidermis is damaged b)  – epidermis and upper regions of dermis are damaged c) Third-degree – entire thickness of the skin is damaged
 * Burns **
 * Burns considered critical if:Over 25% of the body has second-degree burns
 * Over 10% of the body has third-degree burns
 * There are third-degree burns on face, hands, or feet
 * Symptoms include localized redness, swelling, and pain
 * Symptoms mimic first degree burns, but blisters also appear
 * Burned area appears gray-white, cherry red, or black; there is no initial edema or pain (since nerve endings are destroyed)

Appendages of the Skin Home Review Questions ASSESSMENT: Moodle