Skin Flashcards
Components of the integumentary system
Skin Hair Nails Some nerves Some glands
Functions of the integumentary system
Fluid retention
Thermo regulation
Tactical sensitivity - merkel cells
Protects against disease and infection
Shield to external environment
Excretion of waste products - sweat glands
Structure of the skin
Epidermis
Dermis
Subcutaneous adipose layer
Epidermis
Outermost layer
Made up of epithelial tissue
Contains specialised epithelial cells organised in layered structure
Made up of different layers - granular layer, basal layer, squamous, cornified cell layer
Epidermis has no vascular system – all nutrients, passed through epidermis by diffusion from vasculature of the dermis
Granular cell layer
Stratum granulosum
Keratinocytes in granular layer, contain lots of keratohyline granules in cytoplasm.
Contain granules of melanin and other protective products to increase skins, barrier function and protect from UV
Basal cell layer
Stratum basale
Keratinocytes start their journey and proliferate – they appear columns shite an attached to basement membrane. They have elongated nuclei and support squamous cells.
Squamous cell layer
Stratum spinosum
Keratinocytes take on flattened, shape and become flatter as they travel to top of Layer
They contain lamellar granules containing hydrolytic enzymes
Keratin fibres are formed around nuclei
Cornified cell layer
Stratum corneum
Keratinocytes terminally differentiate to corneocytes and provide a barrier to external environment and stop excessive water loss
Coenocytes are filled with keratin
Keratinised layer stops water loss from inside and penetration of water from outside
Melanocytes
They are pigment, synthesising cells found in epidermis
Responsible for production of melanin, and it’s transportation to keratinocytes via melanosome
Melanocyte/keratinocyte interaction
Pigment globules released from melanocytes Dendrites into extracellular Space
They are then captured by microvilli of keratinocyte
Then transported in via a protease activated receptor 2 dependant machine
Membrane of pigment globule is degraded
single melanosomes are released into a keratinocyte cystol and to go to perinuclear area
UV protection is offered to cells nucleus by melanosomes
Merkel cells
Responsible for touch responses
When local keratinocytes deform they stimulate Merkel cells
They contact cell-neurite complexes found in basal layer
Langerhans cells
An immune Cell involved in T cell responses
Found most abundantly in the squamous and granular layers of the epidermis
During skin infection, these cells help to act as first responders to invading pathogens
Dermis
Thickest layer and provides underlying structural properties
Contains fibrous, filamentous and amorphous connective tissue
Divided into two layers, the papillary, and the reticular layers
Contains extracellular matrix, which contains collagen
Layers of the dermis
Papillary dermis – open most layer contains loosely, arranged. Collagen fibres
Reticular dermis – lower layer consists of dense, connective tissue, densely, packed, collagen, and elastic fibres
The dermal fibroblasts
Responsible for production of important matrix proteins
Heavily involved in the wound healing and generating connective tissue which supports the adhesion of the epidermis
