The epidermis is the outer most layer of skin.
It is built up of 5 layers (from the outside in)
- stratum corneum
is made of dead flat skin cells
- stratum licidum
- stratum granulosum
- stratum spinosum
- stratum basale
Where cells divide and push previously formed cells into the upper layers. As the cells travel into the higher layers, they flatten and die, eventually. Specialized Epidermal Cells
- melanocyte - produces pigment (melanin)
- Langerhans' cell - frontline defense of the skin’s immune system - Merkel's cell's - not clearly known
The dermis is made of two layers
- papillary layer ( upper)
made of a thin array of collagen fibers
- reticular layer (lower)
made of thick collagen fibers that are set parallel to the surface of the skin. 3 types of tissue that exist throughout - not in layers.
The types of tissue are:
- elastic tissue
- reticular fibers
Special Dermal Cells
- The hair follicles – attached by the erector pili muscle. - Sebaceous (oil) glands (with the hair follicle)
- Apocrine (scent) glands (with the hair follicle)
- eccrine (sweat) glands (not with hair follicle)
- Blood vessels
- Nerves - transmit sensations of pain, itch, and temperature. - specialized nerve cells called Meissner's and Vater-Pacini corpuscles - transmit the sensations of touch and pressure. 3. Subcutaneous Tissue
- layer of fat and connective tissue that stores larger blood vessels and nerves -. regulates temperature of the skin and the body.
Sunburn healing process
-When skin is exposed to the sun for extended periods of time, ultraviolet rays kill and dry out the skin cells on the outer layer of skin. -UVA rays deeply penetrate the dermis and damage tissue, more long term (like skin cancer) / UVB rays more likely to cause more immediate burns -skin starts to quickly repair itself.
- while rebuilding, the dead skin cells on top of the skin guards the deeper layers of...