what are some other structres associated with the skin?
glands, hair, nails, sensory structures
what are the 3 layers of skin?
- epidermis
- dermis
- subcutaneous tissue
what is the function of subcutaneous tissue & what does it contain?
- fat energy store
- insulation
- contains blood vessels & nerves
what is the function of the dermis?
- a matrix of collagen & elastin fibres, surrounded by an extracellular gel-like substance
- these fibres give skin its stregnth & elasticity
what is the epidermis made up of?
- straified squamous epithelium
- 3 cell types, but keratinocytes are main cell type, others are melanocytes & langerhans cells
- 5 layers
where are keratinocytes formed and where do they migrate to?
originate in stratum basale and differentiate as they migrate out towards the surface, where they are shed
what are the 5 layers of the epidermis?
- stratum basale
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
what is the function of melanocytes?
synthesise melanin, which is then transferred to keratinocytes to give protection against UV rays
what is the function of Langerhans cells?
process antigens & migrate to Lymph nodes to induce an immune response
does skin have ability to regenerate? if so, how come?
yes, because of stem cells found throughout hair follicles
detail nail anatomy
losing what part of nail anatomy is more likely to lead to infection?
cuticle
Describe the hair cycle
- Anagen
- 80-80% of hair
- Catagen
- 2-3week phase growth stops/follicle shrinks
- 1-3% of hair
- Telogen
- resting phase for 1-4months
What are the most important functions of skin? (6)
- Thermoregulation
–Insulation, Heat transfer (sweat)
•Skin immune system
–Innate (ie skin, macrophages & complement)
•Barrier
–Protects against Mechanical, Chemical, microorganisms, Ultraviolet light
–Keeps in water and Electrolytes, Macromolecules
•Sensation
–Temperature, touch and pain
- Vitamin D synthesis
- Interpersonal Communication
–Physical appearance, smell, self -identity
What are the main 2 categories of skin disease and give examples of them
- External - temperature, UV, chemical, infection
- Internal - systemic disease, genetics, drugs, infection
What category is this an example of, and what is it called?
- external cause- temperature (cold)
- COLD URTICARIA
When describing skin lesions, small refers to what size?
<5mm
When describing skin lesions, what is a macule?
small circumscribed area
When describing skin lesions, what is a patch?
a larger circumscribed area
When describing skin lesions, what is a papule?
small raised area
When describing skin lesions, what is a plaque?
larger raised area
When describing skin lesions, what is a vesicle?
small fluid filled
When describing skin lesions, what is a bulla?
large fluid filled
When describing skin lesions, what is a pustule?
pustule = small pus filled
