Skin Flashcards
Why is skin an organ
combination of 4 primary tissues- epithelium, connective, muscle, nerve. has its own pathological conditions eg sunburn, acne, melanoma. Reflects underlying systemic conditions eg liver disease
functions of skin
barrier between internal and external environment. needs to be sensitive and protect. thermoregulation
3 layers of skin
epidermis (outer layer) , dermis, hypodermis
4 cell types in epidermis
keratinocytes (waterproofing, self generating), melanocytes (pigment formation), langerhans (immune surveillance), Merkel cells (touch receptors)
layers of the epidermis
stratum basale (where melanocytes are found), stratum spinosum, stratum granulosum, stratum cornium (thickness)
Dermis layers
papillary layer (loose connective tissue), reticular layer (dense irregular tissue)
what muscle is associated with hair follicles
arrector pili muscles. at an angle, attached to follicle root, hair straightens when muscle contacts. next to sebaceous gland
2 types of sweat glands
eccrine, apocrine
sensory nerves in skin
meissner’s corpuscles (light touch fingertips), paccinian corspuscles (vibration and pressure), pain receptors, thermoreceptors
keratinisation
keratin is deposited in cells and these become horny as in dead skin, nails, hair
what is the main type of connective tissue found in hypodermis
adipose
sweat glands in the axilla have which type of secretion
apocrine
which specific stratum of the epidermis does squamous refer
stratum spinosum
which layer of dermis gives most elasticity to skin
reticular layer
which epidermal layer determines thickness
stratum corneum
what connects the epidermis to the dermis
hemidesmosomes by connecting cells of the stratum basale to the dermis via basal lamina
What is the function of the numerous myoepithelial cells (in sweat glands)?
Myoepithelial cells are what propel the secretory contents of the glands to the surface of the body.
What is the function of the epidermal ridges and dermal papillae?
Epidermal ridges and dermal papillae provide increased surface area for the epidermis and dermis to connect.
Where do the ducts empty?
Ducts of eccrine sweat glands empty onto the surface of the skin. Apocrine glands, however, empty into hair follicles in the axillary, areolar and perianal regions.
How does sweat get to the surface?
Eccrine sweat glands have ducts that lead to the surface of the skin. Eccrine sweat glands are a type of merocrine gland (a gland that releases its product by exocytosis). The secretory cells of the eccrine gland are surrounded by myoepithelial cells which can contract to propel its secretions to the surface. Apocrine sweat glands (apocrine being a misnomer, they are truly a merocrine gland, not an apocrine gland) function in the same way, however, their ducts lead to hair follicles, not directly to the skin surface.
tonofibrils
keratin filaments that help provide the cell with strength and support and insert into the desmosomes
