Two major tissue layers of skin
Epidermis (outer) and dermis (inner)
Epidermal layers (outer to inner)
Epidermis cell type
Stratifiedvis squamous epithelial cells; keratinized
Where does epidermis get nourishment and innervation?
Epidermal layer is avascular, so it needs its nutrients and innervation from dermal layer
Dermis cell type
Dense, irregular CT filled w/ collagen and fibroblasts
Dermis contains these things that help provide it with nutrients and innervation
Blood vessels (nutrients) Nerve endings (innervation)
Hypodermis cell type
Adipose (FAT)
Skin functions
Describe stratum corneum
Most superficial epidermal layer
Dead keratinized cells constantly being sloughed off and replaced by cells that gradually move outward from stratum basale
2 types of stratum corneum
Thin skin and thick skin
Thin skin is part of which epidermal layer? Give example of thin skin.
Stratum corneum
Anterior abdominal wall, eyelids
Thick skin is part of which epidermal layer? Give example of thick skin.
Stratum corneum
Palm of hands, soles of feet
Describe the intermediate basal layers of epidermis
Cells from stratum basale come to these basal layers to transform into keratinized cells
Describe stratum basale
Deepest layer of epidermis
Constant mitotic activity (cells always being made)
Name the specialized cells of epidermis
Stratum basale
Function of melanocytes
Located in stratum basale.
Produce melanin pigments that protect deeper tissue layers from UV rays
Function of Langerhan cells
Located in intermediate basal layer (stratum spinosum).
Macrophages that eat antigens and activate immune system.
Function of Merkel cells
Located in stratum basale.
Type of sensory receptor for touch. Transmits info to sensory nerve endings in underlying dermis.
What do keratinocytes do?
They make up most of epidermis and responsible for:
How does dermis give nutrients to epidermis?
Diffusion
2 dermal layers
2. Reticular layer
Where and what is the significance of papillary layer?
Located in dermis.
Where and what is the significance of reticular layer?
Located in dermis.
Significance of cleavage lines/tension lines/Langer’s lines?
The lines correspond to natural orientation of collage fibers and are generally parallel to orientation of underlying muscle fibers.
Useful for when doctor’s need to cut through skin. They wanna cut according to the lines to help healing go faster.