H12 - Skin Flashcards
what are the functions of the skin?
- protection
- sensation
- thermoregulation
- metabolic functions
what are the layer of the skin?
epidermis > dermis > hypodermis
what are the 4 layers of the epidermis
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum corneum
what is the single layer of cells sitting on the basal lamina which serve as stem cells for the epidermis and produce most of the cells of the epidermis ?
stratum basale
what are the features of the stratum spinosum ?
division in the basal layer displaces cells upward into this layer and is about 5 cells think and contains desmosomes
what is the layer of the epidermis which contains large numbers keratohyalin granules, keratin and acts as a ‘waterproof’ barrier?
stratum granulosum
what is the protein in the granules that promotes the aggegration of cytokeratin intermediate filaments (keratin)
profilaggrin
what gives the stratum granulosum layer waterproof features?
lamellar bodies are produced by cells and contain a hydrophobic glycophospholipid that acts as glue and waterproofing agent
what are the cells called that produces keratin?
keratinocytes
what layer is composed of dead squamous cells packed with keratin in a specialised matrix ?
stratum corneum
what is sometimes classed as a 5th layer of the epidermis?
thin layer between s.granulosum and s.corneum consisting of dead cells with abundant keratin
What cells are responsible for producing melanin in the stratum basale layer of the epidermis?
melanocytes
what is the function of Langerhans’ Cells?
resident macrophages in the epidermis that act as antigen presenting cells
What cells are touch receptors associated with a nerve ending, found in the stratum basale of the epidermis?
Merkel Cells
what layer of the epidermis shows the greatest difference between think and think skin>
s. corneum
what is the dense irregular connective tissue with think bundles of collagen fibres and elastic fibres embedded in relatively small amounts of other extracellular matrix material of the dermis
reticular dermis
what is the layer of skin mostly composed of adipose tissue but has occasional bands of irregular connective tissue?
hypodermis
What is the most superficial layer of the dermis, consisting of bundles of collagen and elastic tissue?
Papillary dermis
What is formed in the Papillary Dermis that project upwards and interdigitate with downward projections of the epidermis?
dermal papillae
Where are hair follicles derived from?
epithelium of epidermis
what is the concave reagion at the end of a hair follicle called>
dermal hair papilla
What type of secretion do sebaceous glands exibit?
holocrine
what are Arrector Pili Muscles?
smooth muscle band that is attatched to a hair follicle to make it ‘stand on end’
what type of glands are Eccrine glands?
glands that are found everywhere in the skin and release watery sweat from the gland onto the surface of the skin
