Epidermis Flashcards
Epidermis is made of (epithelium)
Stratified squamous Epithelium
Nutrients and oxygen
Diffuse from capillaries in the dermis
Keratinocytes are the body’s
Most abundant epithelial cells
Keratinocytes contain
Large amounts of keratin
Thin skin
Covers most of the body
Has 4 layers of keratinocytes
Thick skin
Covers the palms of the hands and the soles of the feet
Has 5 layers of keratinocytes
Stratum basal (germinativum)
Attached to basement membrane by Hemidesmosomes
Forms a strong bond between epidermis and dermis
Contains epidermal ridges
Has many basal cells
Epidermal ridges lie next to
Dermal papillae
Basal cells , replace
Stem cells that replace superficial keratinocytes
Structures of stratum basal
Tactile discs
Melanocytes
Tactile discs
Tactile (merkel) cells with sensory nerve endings
Found in hairless skin
Respond to touch
Melanocytes
Contain the pigment melanin
Stratum spinosum has (number of layers)
8-10 layers of keratinocytes bound by desmosomes
Stratum spinosom cells (appear)
Appear spiny
Stratum spinosum is produced by
Division of cells in stratum basale some continue dividing
Stratum spinosum contains
Dendritic(langerhans)cells which are active in immune response
Stratum granulosum has (layers)
3-5 layers of keratinocytes
Stratum granulosum is produced from
Cells of stratum spindsum
Most cells stop dividing and produce
Keratin
Keratonyalin
Keratohyalin (forms) (promotes)
Forms dense granules
Promotes cellular dehydration and cross-linking of keratin fibers
After production of proteins cells
Die
Stratum lucidum is only found
In thick skin
Stratum corneum
Exposed surface of skin
Water resistant
Keratinization
The formation of protective layers of cells filled with keratin
Water is lost in skin in two way
Insensible perspiration
Sensible perspiration
Insensible perspiration
Water diffuses and evaporates from top layer of skin
Rate increases if stratum corneum is damaged
Sensible perspiration
Water excreted by sweat glands
The layer of the epidermis that contains abundant desmosomesis the stratum
Spinosum
Cells that are in the epidermis that are part of the immune system
Dendritic cells
Melanin is produced by melanocytes within the stratum
Basale
Vitamin D3 is important for proper
Bone development
