Skin Flashcards
(51 cards)
Functions of the skin (6)
- protection for underlying tissues against abrasions, impact, fluid loss and chemicals; keratin - abrasion, water repellant, Melanin - UV rays
- Vitamin D synthesis
- Excretion of salts, sebum, water
- Thermoregulation
- Sensation
- Storage of fats
What kind of cells is the epidermis made up of
Stratified squamous epithelium of keratinocytes (cells that contain keratin)
Does the epidermis have a blood supply
No
where does the epidermis get its nutrients from
the vasculature of the dermis
What are the 5 layers of the epidermis
Corneum, leusedum, granulosum, spinosum, basale
What does the stratum basale do
it is columnar cells which divide and daughter cells migrate up to replenish the layer above. Where the Melanocytes are found
what does the Stratum spinosum do
Linked together by desmosomes, the cells become increasingly spiky/flattened as they move upwards
What does the stratum granulosome do
dehydrates cells further, keratin fibres cross link, waxy material is secreted into the ECM
What does the stratum lucidum do
Is in thick skin which is palms of feet and hands, Is an extra leyer
What does the stratum corneum do
it is dead cells with no nuclei. layer can be easily removed with tape
why is the epidermis wavy
to increase surface area so it can get resources from dermis blood supply
What do desmosomes do?
Anchor neighbouring cells in the epidermis
what do hemidesmosomes do
anchors the stratum basale to the dermis
what are the two layers of the dermis
Papillary layer - consists of highly vascularised tissues (for nourishment)
Reticular layer - mesh like structure os collagen and elastin fibres
Both layers contain blood vessels, lymphatics, sensory nerve fibres and accessory structures.
What are the two plexus of the skin
The cutaneous plexus which is between the hypodermis and the dermis and supplies the lower dermis and hypodermis with blood
The sub papillary plexus which branches off the cutaneous plexus located deep to the papillary layer supplying blood to the upper dermis and epidermis
Hypodermis purpose
The main function is thermoregulation as it contains fat to act as insulation
Also where injections go to.
Mainly consists of adipocytes
First degree burn
Superficial - only involve the epidermis
Red, pink, dry, painful
skin remains intact
heals 3-10 days
Second degree burn
Normal: Epidermis and some dermis
Painful, moist, red, blistered
usually 1-2 weeks to heal; needs good dressing to avoid infection
Deeper: Epidermis and entire dermis
whiteish waxy looking areas
may lose sensation and get scarring
1 month to heal
Third degree burn
Full thickness burn ie. all layers of skina dn may involve some muscle and bone
waxy white to deep red or black
Hard, dry and leathery
no pain due to sensory nerve endings being destroyed
may require skin grafting and weeks to regenerate + scarring
Accessory structures of the skin
Hair, sweat glands, receptors, nails
What is Hair made of
dead, keratinised cells
Anatomy of hair follicle
hair shaft projects from follicle
Also has arector pilli muscles which when contract cause hair follicle to stand up and goose bumbs
And root hair plexus - a collection of nerves at the base for sensation
Sebaceous glands - produce sebum
Sebum
Oily secretion from sebaceous glands
Nourishes hair shaft and naturally moisturises skin
water repellant
Sweat glands
Eccrine - found in most areas of the skin
Apocrine - founs in armpit, nipples and groin
