Skin Flashcards
functions of skin?
- barrier
- prevent dehydration
- largest sensory organ
- thermoregulation
- metabolic functions
- immune functions
- communications.
what are the layers of skin?
epidermis, dermis, subcutaneous layer (hypodermis)
Features of epidermis?
avascualar.
Features of dermis?
blood vessels, nerves, hair follicles, sweat glands.
features of hypodermis?
fatty layer, adipose tissue, energy reserve, thermoregulation.
how thick is skin?
0.5mm –> 5mm
What is the thinnest skin?
eyelid (0.5mm)
what is the most sensitive skin?
lips.
what are the thickest skin?
soles, palms.
how is skin innervated?
- dermamyotome.
- derma cells become the dermis and drag nerve supply with them so cutaneous nerves are segmental.
what is a dermatome?
area of skin innervated by fibres from a single root.
What are angiosomes?
regions of skin, superficial fascia, deep fascia and possibly even underlying muscle that share common blood supply.
What is the histology of epidermis? from most deep to superficial.
- stratum basale.
- stratum spinosum.
- stratum granulosum
- stratum lucidum
- stratus corneum.
features of stratum spinosum?
-spiny looking cells as they have shrunked a little bit and have a border around them still have nuclei, come from stratum basale.
features of stratum granulosum?
- develop granules inside them called keratohyalin granules.
- start laying down of keratin and other proteins that make the skin water resistant.
- have nuclei.
features of stratum lucidum?
- no nuclei, almost dead, fill up with protein (mostly keratin)
- only found in thick skin.
features of stratum corneum?
-dead, forms protective layer mainly consisting of keratin.
how do the cells in the deepest level of the epidermis function?
extremely active and divide constantly to make more and more new cells.
What happens to the new cells made in the deepest level of the epidermis?
they are pushed upward through the other levels of the epidermis and toward the surface of the skin.
What is the blood supply for epidermis?
no direct blood supply, all nutrient that feed these cells come from the dermis
What are cell types in epidermis?
- keratinocytes
- malanocytes
- langerhan cells
- merkel cells
what is the primary function of keratinocytes.
-responsible for forming tight junctions with the nerves of the skin.
what does the epidermis primarily consist of?
keratinocytes.