Effects of the environment on the skin Flashcards
What are the adaptations of the skin?
- Sweating and vasodilation in heat; vasoconstriction in cold
- Hyperkeratosis is the thickening of stratum corneum with rubbing or pressure
- Melanocytes tanning after UV exposure
What are AV shunts?
AV shunts are anastomoses between arterioles and venules
What do AV shunts respond to?
Respond to thermoreceptors in skin
What do AV shunts do?
AV shunts open and close to increase or decrease blood flow to the superficial vascular plexus in the papillary dermis
What do AV shunts in the face respond to?
Respond to emotion
What happens if the AV shunts shunt off for too long?
If the AV shunts shut off for too long there’s danger of frostbite
What is the colour of skin mainly due to?
Mainly due to melanin and haemoglobin
What does melanin protect against?
Melanin protects against DNA damage and thus skin cancer
What happens to melanocyte activity in tanning?
Melanocytes increase activity-make and transmit more melanin
Steps involved in the basics of suntanning?
- UV light shines on the keratinocyte and damage DNA if there isn’t enough melanin
- This results in the production of MSH by keratinocyte
- MSH binds to MC1R on melanocyte causing cAMP signalling resulting in:
- Increased melanin synthesis and transfer
- Increased cell division
What is lichenification?
More extreme form of hyperkeratosis
What is lichenification a reaction to?
A reaction to excessive rubbing or scratching
What is a sunburn?
Is a radiation burn
What are basal cell carcinomas?
Rodent ulcers
usually curable by surgery
What is UV needed for and used for?
- Needed for vitamin D3 production in skin
- UV radiotherapy for skin conditions
