Skin Flashcards
The skin is the body’s largest organ. What are the dimensions?
16% body weight, 1.8m(2) surface area
Name the 7 functions of the skin
Protection Thermoregulation Sensation Endocrine Psychosocial Secretion Homeostasis
Explain the skins function: protection
- skin is a barrier
- protection of deeper tissue from injury, bacteria, chemicals and sunlight
- immune function
- inflammation and repair
Explain the skins function: thermoregulation
- balance between heat production and loss
- body temp maintained between 35.8-38.2 degrees C
- mechanisms of heat transfer (4)
- when hot: cooling effect of sweat evaporation from the skin surface, dermal blood vessels dilate to help body cool down
- when cold: dermal blood vessels construct. insulation that retains body heat and keeps the body warm. arrector pili muscles to trap air
What are the four mechanisms of heat?
radiation, conduction, evaporation, convection
Explain the skins function: sensation
- sensory perception, link with external environment
- 4 main sense: pain, touch, pressure, temperature
Explain the skins function: endocrine
- hormone control
- vitamin D regulates calcium and phosphorous levels
- liver and kidneys convert chemical into vitamin D since people in UK do not get adequate
Explain the skins function: psychosocial
- sexual expression
- display/body image
- bonding
- communication - embarrassed flushed face
- touch
- body imagine - attraction, self esteem
- sexual function - changes in puberty, changes due to arousal
Explain the skins function: homeostasis
control of temperature and fluid in the body
Explain the skins function: secretion
hormones
What INtrinsic factors can change skin?
biological processes, genetic predisposition, hormone/endocrine factors, illness
What are biological processes that can change skin?
microcirculation - blood flow
What are genetic predispositions that can change skin?
premature ageing syndrome
What are hormonal/endocrine factors that can change skin?
menopause-reduced hormones, oestrogen and progesterone affecting the collagen content of skin
What illnesses could cause change to the skin?
diabetes
Name some EXtrinsic factors that could change skin?
photo damage, smoking, pollutants, irritants, allergen, heat, over washing, therapeutic treatments (radiotherapy), nutrition (vitamins, minerals etc)
Name some common skin disorders
acne, warts, eczema, cutis laxa, vitiligo
What is the main change to the skin that occurs during pregnancy?
Increased pigmentation
Explain the body areas that get increased pigmentation in pregnancy and why?
- nipples and areole - breastfeeding
- external genitalia - increased blood supply
- abdomen - linea nigra
- face - chloasma (blotchy pigmentation around eyes and forehead
Define ‘striae gravidarum’
stretch marks - red/purple marks that fade to striae albican which are silver/white
Why do striae gravidarum/stretch marks occur?
- elevated cortisol prevents fibroblasts producing collagen and elastin fibres - lack of support for the dermis
- growing tissue creating a lack of underlying physical support for the skin structure - results in dermal and epidermal tearing
What is cortisol and what does it do in pregnancy?
hormone of stress.
- prevents collagen and elastin fibres, lack of support for dermis
- cortisol levels increase 2-4 times during preg, this play a role in baby’s growth and development
What percentage of women experience striae gravidarum?
52-90%
Risk factors of striae gravidarum?
- high weight gain in preg
- higher birth weight baby
- family history
- personal history of striae (i.e. breast or thigh increase in puberty)
- young maternal age
What happens to skin temp during pregnancy?
it becomes warm as well as vascularised and there may be increased sweating
What happens to breast skin during pregnancy?
superficial veins may dilate and pigmentation increase
What happens to skin on hands during pregnancy?
vascular ‘spiders’ and redness
What happens to skin on legs during pregnancy?
ankle oedema (fluid swelling) and potentially varicose veins
define ‘pruritis gravidarum’
itching and often a rash localised to abdomen
What percentage of women experience pruritis gravidarum?
20%
