SKIN function Flashcards
What are skins function
Thermoregulation
Protection/ Barrier
Sensation
What are the 3 skin structures
Epidermis
Dermis
Hypodermis
Describe Epidermis
top layer
barrier/ continued renewal
no structural strength
Kerintocyte
Statification is important for?
barrier function and continued renewal of the epidermis
What are the 4 layers of Statum within the epidermis
Top to bottom
Stratum corneum Stratum- lucidum (only present in thick skin) Stratum granulosm Stratuum spinosum Stratum basal
Describe the Stratum Corneum
25-30 layers deep/ barrier to keep moisture in and outside world out
Describe the Stratum Lucidum
only present in thick skin
fingertips palms soles
Describe the Stratum granulosm
Flattened keratinocyte undergoing apoptosis (death)
Lamellar granules + plasma membrane= lipid rich secretion= barrier
Keratohyalin - dark granules =keratin intermediate filaments into keratin
Describe the Stratum spinosum
8-10 layers
keratinocyte starts to flatten
Keratin intermediate filament and desmosomes hold cells together
Describe the Stratum Basale
Keratinocyte stems cells are the reservoirs of cells for a lifetime of renewal
Transit amplifying keratinocytes a lot to provide top layers
Basement Membrane
Important for attachment between epidermal and dermis
Collagen, perlecan, nidogen, laminin
mutation in BM proteins= epidermolysis bullosa
Rete Ridges function (BETWEEN DERMIS AND EPIDERMIS
Contour provides resistance to shear forces
Pigmentation
Melanocytes reside in the BM on the epidermal side
Describe Melanocytes
Make melanosomes which contain melanin
melanosome are transferred to ketinocytes
Keratinocyte= 36
Melanin’s structure
Nuclear cap protects keratinocyte DNA
Pheomelanin- yellow-red
Eumelanin is brown- black
What cells within the Epidermis protect the cell
Langerhans cells protect against foreign organisms
Dermis Layers
Papillary dermis
Recticular dermis
Papillary dermis
high cell density, loose CT
Reticular dermis
low cell density dense CT
Dermis nutrients
supply the nutrients and remove waSte for both dermis and epidermis
What are the type of wound healing stages
Superficial
partial thickness
full thickness
Superficial wounds
Damage to the epidermis
healing: migration of keratinocyte from edges and dermal appendages
once keratinocytes are together stratification can reform epidermis
What are dermal appendages
sweat gland, Hair follicles, sebaceous glands
Partial thickness wound
All epidemis and some dermis is destroyed
Partial thickness phases of healing
FOurs stages inflammatory migratory proliferation (multiplication) maturation
Full thickness wounds
All epi and dermis is destroyed
hypodermis can be destroyed exposing bone and muscles
Describe wound healing for full thickness
very difficult as all epidermal stem cells have been destroyed
Heals as scar tissue
Intervention is needed
Describe skin graft in full thickness
Split thickness skin graft covers wound
- includes all of the epidermis and part of the dermis