Function Of The Skin Flashcards
List the 6 main functions of the skin
• Barrier function
• Metabolism & detoxification
• Thermoregulation
• Immune defence
• Communication
• Sensory functions
What is the skin a barrier to
- Physical - friction, mechanical trauma, UV radiation
- Chemical - irritants, allergens, toxins
- Pathogens - bacteria, viruses, fungi
Name a key vitamin metabolised in the skin
Vitamin D3 (cholecalciferol/colecalciferol)
How is vitamin D metabolised in the skin
The action of sunlight (mostly UVB) on a cholesterol-derived compound (7-dehydrocholesterol), produces vitamin D3
What happens to the vitamin D3 produced in the skin
Vitamin D3 stored as hydroxycholecalciferol in liver (storage)
Is converted to 1,25-dihydroxycholecalciferol in kidney (activation)
What are the main roles of Vitamin D
- Promotes Ca & phosphorus absorption in intestine
- Promotes Ca reabsorption in the kidneys
- Enables bone mineralisation
What is the role of the skin in thyroid metabolism
20% of T4 → T3 conversion occurs in the thyroid gland,
the rest occurs in peripheral tissues including the skin
What is the role of the skin in thermoregulation
- contains warm/cold-sensitive thermoreceptors
- controls sweating/shivering/peripheral blood supply
What are sensory functions of the skin
Sense touch, pressure & vibration
Sense/control pain & itch
Detect heat & cold
What are requirements for appropriate skin function
- Intact physical barrier (hydrated & not broken/infected)
- Functioning immune system
- Functioning blood & drainage supply (O2, nutrition etc)
- Means of temperature regulation (sweat glands etc)
- Functioning sensory nerve supply (detect pain etc)
What are some consequences of comprised skin function
- Poor barrier & Fluid loss → dehydration
- Poor barrier & Protein loss → hypoalbuminaemia
- Poor barrier/ immune defence → Infection
- Poor thermoregulation & Heat loss → hypothermia
- Metabolic defect → disordered thyroxine/ vitamin D metabolism
