Skin Flashcards
What are the 6 main functions of skin?
Protection
Sensation
Thermoregulation
Metabolism
Immunologic
Sexual attractant
Why is the basal layer of the epidermis folded?
To increase the surface area and therefore the strength of attachment of the dermo/epidermo-junction
Where are the stem cells of the epidermis located?
Basal layer
What are the ridges of the basal layer called?
Epidermal rete ridges
What is the structure that links basement membrane and cells in the basal layer of the epithelium?
Hemidesmosomes
What are the four layers of the Epidermis?
Basal layer Stratum spinosum Stratum Granulosum Stratum Corneum
What features characterise the stratum spinosum?
Spinous processes - these processes are intercellular bridges or desmosomal junctions that hold cells together. Common feature of stratified squamous epithelium
What are the features that characterise the stratum granulosum?
Granules join with tonofibrils to make keratin. There are also granules that secrete water resistant material into the inter-cellular junctions
What is the Stratum corneum?
the keratinised layer of the epithelium
Where are Melanocytes found and what do they do?
1 melanocyte: 8-10 Basal epithelial cells Synthesise melanin
What is the difference between darker pigmented skin and lighter pigmented skin?
Darker skin has more melanin produced by their melanocytes. The number of melanocytes is the same.
Where is melanin found?
Often found in a cluster over the top of nuclei of squamous keratinocytes. Protect DNA from UV damage.
Where are Langerhans cells found?
In all layers of the epidermis, but are most concentrated in the stratum spinosum.
Which muscle makes hairs ‘stand on end’?
Erector pilli
Where are sebaceous glands located?
In the dermis, around hair follicles, into which they secrete lipid-rich solution. Some empty directly onto the skin.
