Epidermis Flashcards
Avascular layer
Epidermis
Lies superficial to dermis
Location of stratum basale
How does the stratum basale connect to the dermis?
It’s wavy borderline
Thick bundles of intermediate filaments
Stratum spinosum
Deepest layer of epidermis
Stratum basale
The dermis is made of what kind of tissue?
Dense connective tissue
How thick is the stratum corneum
20-30 layers thick 3/4 of epidermal thickness
Flattened layer of the epidermis
Stratum granulosum
Most cells are keratinocytes
Epidermis
The epidermis is made out of what tissue?
Stratified squamous epithelium
Cytoplasm is full of granules
Stratum granulosum
What is the Hypodermis tissue made of?
Adipose tissue
A tissue that isn’t technically part of the skin
Subcutaneous tissue
Hypodermis
How does the stratum lucidum form?
Formed from dead cells of the deeper strata
Cells undergo mitosis
Actively dividing
Daughter cells are pushed to become the more superficial layers
Stratum basale
Cornified or keratinized to prevent water loss
Characteristic of epidermis
Anchors skin to underlying organs
Function of Hypodermis
Clear layer of epidermis
Stratum lucidum
Superficial to stratum basale
Stratum spinosum
Where is the stratum granulosum located
Superficial to stratum spinosum
Where is stratum lucidum located
Thick hairless skin of the palms and soles
Outermost layer of the epidermis
Stratum corneum
Organelles are deteriorating
Stratum granulosum
What are the shingle like dead cells in the stratum corneum filled with?
Keratin
The stratum corneum rubs and flakes off slowly and steadily as?
Dandruff
How often does a new epidermis form
25 to 45 days
Outer layer of the skin
Epidermis
Produces melanin
Melanocytes
As melanin is produced it accumulates in these membrane bound granules
Melanosomes
Spider shaped cells
Melanosomes
Taken up by keratinocytes
Melanin
Melanocytes are most common where?
Stratum basale
What determines the amount of melanin produced?
Genetics
Exposure to sunlight
Where melanin is concentrated in one spot
Freckles and moles
Melanin forms a pigment umbrella over superficial nuclei to shield from what?
UV
How does overexposed to uv rays lead to cancer?
Alters the DNA of skin cells
Many people infected with what are more likely to have an eruption
Herpes simplex (cold sore)
Alert the immune system to threats such as bacterial or viral invasion
Epidermal dendritic cells
Associated with sensory nerve endings, serve as touch receptors
Merkel cells
Skin functions
Protects deeper tissue from Mechanical damage Bacterial damage Chemical damage Thermal radiation Ultraviolet radiation Dessication Synthesizes vitamin d AIDS in excretion of urea AIDS in body heat loss or retention
Drying out
Dessication