The Integumentary System Flashcards
Skin
The body’s largest organ and is the main barrier between you and the outside world.
Layers of the skin
epidermis and dermis
The epidermis
composed of epithelial cells and is the outermost protective layer of the body; non-viable
the epithelial layer
thick, keratinized stratified squamous epithelium
The dermis
the bulk of the skin and is a tough, leathery layer composed mostly of dense connective tissue; vascularized
Epidermal cells
Keratinocytes, Melanocytes, Dendritic cells, Tactile epithelial cells
Keratinocytes function
main cell type; produces keratin
Keratin
protein; strength, sturdiness, and waterproofing of the cell
Epidermal growth factor
a hormone that stimulates mitotic activity in the deepest layer of the epidermis (producing new keratinocytes)
Callus
forms when persistent friction occurs causing a thickening of the epidermis.
Melanocytes function
spider-shaped epithelial cells; synthesize the pigment melanin which is found in the deepest layer of the epidermis
Melanosomes
melanin is made in these membrane-bound granules and is transferred through branching processes to adjacent keratinocytes
Melanin function
provide pigment to the skin and protection from UV rays when out in the sun
Dendritic cell function
star-shaped; ingest foreign substances (macrophages- taking up cellular debris/waste and breaking it down) and activate the immune system
Tactile epithelial cell function
touch receptors; Intimately associated with a disc-like sensory nerve ending
Subcutaneous tissue
tissue found immediately under the skin (deep to the skin)
Subcutaneous tissue function
Anchors skin to underlying structures with the ability to slide, an insulator that reduces heat loss, and a shock absorber
Adipose tissue
absorbs physical damage/ shock & stores fat
Layers of the epidermis in thin skin (deep to superficial)
stratum basale, stratum spinosum, stratum granulosum, and stratum corneum
Layers of the epidermis in thick skin (deep to superficial)
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
Stratum basale
The basal layer; consists of a single row of stem cells, continually renewing cells, 10-25% of the cells are melanocytes and dendritic cells are seen as well
Stratum Spinosum
The prickly layer; Several cell layers of keratinocytes thick, Dendritic cells are the most abundant in this epidermal layer, contains bundles of intermediate filaments made of pre-keratin
Stratum Granulosum
The granular layer; Thin layer- consists of 1 to 5 layers, Keratinization (cell is filled with keratin) begins here
Keratohyaline granules
help to form keratin in upper layers
Lamellar granules
contain a water-resistant glycolipid that is secreted into the extracellular space; retains water in epidermis
Stratum lucidum
The clear layer; extra layer only found in thick skin, just 2-3 rows of clear, flat, dead keratinocytes
Stratum Corneum
The horny layer; Outermost epidermal layer, mostly dead cells, protect skin, cells shed regularly
Layers of the dermis
The papillary and reticular layer