exercise 7
Terms
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copy deck
- dermal papillae
- fingerlike projections from its superior surface
- dermis
- made up of dense irregular connective tissue * papillary layer and reticular layer
- epidermis
- avscular, keratinized stratified squamous epithelium consisting of 4 distinct cell types and 4 or 5 layers
- eponychium
- the thick proximal nail fold commonly called the cuticle
- free edge
- the portion of the nail that grows out away from the body
- hair
- consists of a medulla, surrounded by the cortex and then by a protective cuticle
- hypodermis/superficial fascia
- primarily adipose tissue * not considered part of the skin
- Keratinocytes
- *most abundant epidermal cells *produce keratin (fibrous proein that gives the epidermis its durability and protective capabilites)- connected by desmosomes
- Langerhan's cells
- epidermal dendritic cells- immunity
- Layers of epiderms
- stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale
- lunula
- the proximal region of the thickened nail matrix, which appears as a white crescent
- Meissner's corpuscles
- pain and touch receptors found in the papillary layer
- melanocytes
- spidery black cells that produce brown pigment when exposed to sun. protects DNA
- Merkel cells
- spiky hemispheres that, in conjunction w/ nsensory nerve endings, form sensitive touch receptrs call markel discs located at the epiderma-dermal junction
- nail bed
- exension of the stratum basale beneath the nail
- nail body
- the visible attached portion
- nail folds:
- skin folds that overlap the borders of he nail
- nail matrix
- the thickened proximal part of the nail containing germinal cells responsible or nail growth
- papillary layer
- * superficial dermal layer * uneven, dermal papillae on top of dermal rideges ( produce fingerprints abudndnt capillar networks * Meisner's corpuscles found here
- Pascinian corpuscles
- pressure receptors found in reticular layer
- Reticular layer
- deepest skin layer * composed of dense irregular connective issue and contains many arteries and veins, sweat and sebaceous glands, and Pacinian corpuscles
- root
- he part that is embedded in the skin and adheres to an epithelial nail bed
- stratum basale
- single row of cells immediately adjacent to the dermis * always producing more cells * melanocytes
- stratum corneum
- consists of 20-30 cell layers an accounts for bulk of epidermal thickness * dead cells that are constantly rubbing off
- stratum granulosum
- contains: lamellated granules (waterporofing glycolipid) keratohyaline grandules *cells beginning to die at top
- stratum ludcidum
- very thin translucent band of flattened dead keratinocytes w/ indistinct boundaries
- stratum spinosum
- *several cell layers * cells contain thick weblike bundles of intermediate prekeratin filaments