Chapter 18 - Plastics Flashcards
What are the main types of cells in the epidermis
Keratinocytes.
-Originate from basal layer; provide mechanical barrier
Where do the melanocytes originate from?
Neuro ectodermal origin; in basal layer of epidermis.
-Have dendritic processes that transfer melanin to neighboring keratinocytes via melanosomes
What are langerhan cells, and where are they?
in the dermis. Act as antigen presenting cells. They originate from bone marrow. They have a role in contact hypersensitivity reactions (type IV)
These are pressure sensory nerves
Pacinian corpuscles
What are the warmth sensory nerves
Ruffini’s endings
What are the cold sensory nerves?
Krause’s and bulbs
What are the tactile sensation sensory nerves?
Meissner’s corpuscles
What Eccrine sweat glands
Produce aqueous sweat
Used for thermal regulation, usually hypotonic sweat
What are apocrine sweat glands
Produce milky sweat
Highest concentration of glands in palms and soles; most sweat is the result of sympathetic nervous system via acetylcholine
What is the most predominant type of collagen in the dermis?
Type one collagen. 70% of the weight of dermis; gives tensile strength
What are Cushing’s striae caused by?
Loss of tensile strength and elasticity
What is the donor site of a split thickness skin graft regenerated from?
Hair follicles and skin edges
How is a split thickness skin graft supported for the first three days
imbibition, osmotic blood supply
When does neovascularization of a split thickness skin graft begin?
Starts at day three. Tendon, bone without periosteum, XRT areas are unlikely to support graft
What is the most common cause of pedicled or free flap necrosis?
Venous thrombosis
What are the complications of a tram flap?
Flap necrosis, ventral hernia, bleeding, infection, abdominal wall weakness
How does UV radiation cause damage?
Damages DNA and repair mechanisms
- It is both a promoter and an initiator
- Melanin is the single best factor for protecting skin from UV radiation
- UVB is responsible for chronic sun damage
What percentage of skin cancers melanoma?
3 to 5% of skin cancer but accounts for 65% of deaths
What are the risk factors for melanoma?
Dysplastic, atypical, or large congenital nevi-10% lifetime risk for melanoma
- Familial BK mole syndrome-almost 100% risk of melanoma
- Xeroderma pigmentosum
What percentage of melanomas are familial?
10%
What is the most common melanoma site on skin?
Back in men, legs in women
What are signs of poor prognosis in melanoma
Color change, angulation, indentation/notching, enlargement, darkening, bleeding, ulceration
How do you go about diagnosing suspicious lesions for melanoma?
- Less than 2 cm lesion-excisional biopsy unless cosmetically sensitive area. Need resection with margins if Pathology comes back Melanoma
- greater than 2 cm lesions or cosmetically sensitive areas-incisional biopsy, will need Resection with margins if pathology shows melanoma
What is lentigo maligna?
Least aggressive, minimal invasion, radial growth first. Elevated nodules