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Chapter 5

Chapter 5 notes

Health Studies
Course Code
Anna Walsh

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-The skin provides covering for the body and is the first line of defence against bacteria,
viruses and other types of environmental damage
-The musculoskeletal system provide shape and support for the body, make movement and
adjustments in position possible, protect the internal vital organs from external trauma
-Skin and musculosketlal system (MS) provide the most obvious external signs of aging
Basic anatomy and physiology
-Skin is critical in temperature maintenance
-Skin aids in homeostasis
-Sensory nerves allow us to monitor the environment and warn us through pain
-Aging of skin is most obvious clue to an individuals age
-Skin is largest organ of body
-Outermost layer of skin is called epidermis
-Second layer is called the dermis, a layer of subcutaneous fat
-Epidermis consists most of keratinocyte cell
oProtect the skin and help heal it if its injured
oKeratinocytes are necessary for the synthesis of vitamin D
oKeratinocytes are found deep in the epidermis and rise to the surface (about 30
-Melanoctyes produce melanin for keratinocytes and give color to the skin
oMake up 2% of the cells in the epidermis
oExposure to the sun increases melanin production
-Langerhans cells are an important part of the immune system
oRespond to toxic allergic stimuli
-Dermis consists largely of collagen and elastin tissue
oBlood vessels, pymphatic tissue, nerves, sweat glands and hair follicles
oCells in this layer include mast cells responsible for the skins ability to respond to
toxic allergic stimuli
-Under the dermis is the subcutaneous fat, consisting of adipocytes (fat cells)
oGive shape and form to the body and provides protection and insulation
Age-related changes
-Changes in hair follicles result in graying and loss of hair
-Wrinkles are due to decrease in subcutaneous fat layer and collegen & elastin
-Decrease in the size and number of keratinocytes limits skins production of vitamin D
-Turnover rate of keratinocytes in 50%
-Decrease in melanocytes = disability to protect from the sun
-Langerhans cells decrease by 40%
-Dermis is 20% thinner
-More likely to suffer from hypo/hyperthermia
-Decreased sensitivity to touch, heat, cold, injury
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