Intro to Derm (complete) Flashcards
Describe the general structure of the skin
- Epidermis (keratinocytes, melanocytes, merkel cells, Langerhans cells [aka DCs])
- Dermis (sebaceous glands, sweat glands, hair follicles)
- Hypodermis
What are the functions of the skin?
1) Barrier
2) Vit D synthesis
3) Water homeostasis
4) Thermoreg
5) Insulation/calorie reservoir
6) Touch/sensation
7) Decoration/beauty
What are the Fitzpatrick Skin Types?
I: Never tans, always burns II: tans w/ difficulty, usually burns III: Average tanning, sometimes burns IV: Easily tans, rarely burns V: Very easy to tan, very rarely burns VI: Never burns
Describe melanocytes and their types
Pigment cells => produce melanin packaged granules called melanosomes (protect from UV)
- Eumelanin: brown to black pigment
- Phemelanin: yellow to red-brown pigment (found in red heads, blondes)
What are the differences in melanin in dark and light skin?
Light skin: melanosomes smaller — distributed in clusters above nucleus in keratinocyte
Dark skin: melanosomes larger and distributed individually throughout the cytoplasm of keratinocyte
Describe Vitiligo
Incidence: 0.5-2%
- Absence of melanocytes
- Acquired depigmentation
- Commonly seen in periorificial and acral areas
Which UV ray helps produce Vit D?
UV B
Not UV A, which are found in tanning beds
Describe the epidermis and its components
Top layer of skin
Components:
- Keratohyalin granules
- Keratinocytes
- Langerhans Cells
- Melanocytes
What are the different layers of the epidermis?
In order from top to bottom:
- Stratum corneum
- Stratum granulosum
- Stratum spinosum
- Stratum basalis
Describe the basal cell layer
the lowermost layer of the epidermis
Has the melanocytes!!
What are hemidesmosomes?
- Attachment point of basal cells to basal lamina of dermal epidermal junction
They connect the epidermis and dermis!!
What is bullous pemphigoid?
Autoimmune => Abs to the hemidesmosomes
Describe the stratum spinosum
- Appears spiny
- B/c cells are held together w/ spiny projections (aka desmosomes)
- Thickest layer of epidermis (above basal layer)
What are desmosomes?
Attachments between keratinocytes
Describe pemphigus vulgaris
AutoAbs to desmosomes
Intraepidermal blisters
Describe keratinocytes
Form skin barrier => protects from microbial, physical, chemical assaults
Also prevents H20 loss
Describe the stratum granulosum
Granular cell layer
- Cells here to loose their nuclei
- Prominent keratohyalin granules contain filaggrin
Describe the stratum corneum
- Made up of dead and desquamating keratinocytes
- Breakdown of filaggrin => forms natural moisturizing factor (binds to water and keeps skin moist)
- NMF levels decline with age
Describe the stratum lucidem
- Extra layer found in thick skin (palm, foot)
- Reduces friction and shear forces between stratum corneum and granulosum
Go look at the histo slide in ppt!!!
What is the clinical word for hair loss?
Alopecia areata
Alopecia universalis (if total hair loss)
What is the clinical word for excess sweating?
Hyper hydrosis
What is a macule?
Flat area of color change
Less than 1cm
What is a patch?
Flat area of color change
More than 1cm
What is a papule?
- Discrete, solid, elevated body
- <1cm in diameter
- May be further classified as scale or crust
