Introduction to General Dermatology Flashcards
Describe the structure of normal skin (from superficial to deep).
Epidermis;
- Outer layer
- 3 cell types: keratinocytes, melanocytes, Langerhans cells
Dermis;
- Collagen and elastin matrix with mucopolysaccharide gel
- Cell types: fibroblasts, dermal dendritic cells, macrophages
Subcutaneous tissue;
- Function: fat energy store, insulation
- Fibrous bands anchor skin to fascia
Describe the function of melanocytes.
- Makes melanosomes (collections of melanin)
- Phagocytoses into keratinocytes where they sit above the nucleus
Describe the function of Langerhans cells.
- Process antigens
- Migrate to lymph nodes induce an immune response
Name and describe the first layer of the epidermis (the most superficial).
- Stratum corneum
- Dead cells with a hard protein envelope
- Cells contain keratin
- Surrounded by lipids
Name and describe the second layer of the epidermis (the second most superficial).
- Stratum lucidum
- Dead cell with dispersed keratohyalin
Name and describe the third layer of the epidermis (the third most superficial).
- Stratum granulosum
- Keratohyalin and a hard protein envelope form
- Lamellar bodies release lipids
Name and describe the fourth layer of the epidermis (the second most deep).
- Stratum spinosum
- Keratin fibres and lamellar bodies accumulate
Name and describe the fifth layer of the epidermis (the most deep).
- Stratum basale
- Cells divide by mitosis
- Some newly formed cells become thee cells of the more superficial strata
What is a lunula?
The white area at the base of a fingernail.
Describe the three stages of the skin’s hair cycle.
Anagen;
- Active growingphase
- 80-90% of hair
Catagen;
- 2–3 week phase growth stops/follicle shrinks
- 1–3% of hairs
Telogen;
- Resting phase for 1-4 months
- Up to 10% of hairs in a normal scalp
List the functions of the skin.
- Thermoregulation
- Skin immune system
- Barrier: mechanical, chemical biological, UV
- Sensation: temperature, touch, pain
- Vitamin D synthesis
- Interpersonal communication
List the five D’s of why skin disease is important
- Disfigurement
- Discomfort
- Disability
- Depression
- Death
Describe the internal causes of skin disease.
- Systemic disease
- Genetics
- Drugs
Describe the external causes of skin disease.
- Photosensitivity: commonly caused by medications
- Cold injury e.g. frostbite, chilblains
- Chemical
- Trauma
- Infection
Define ‘macule’.
Small (less than 5mm) circumscribed area.
Define ‘patch’.
Larger circumscribed area.
Define ‘papule’.
Small raised area.
Define ‘plaque’.
Larger raised area.
Define ‘vesicle’.
Small, fluid-filled.
Define ‘bulla’.
Large, fluid-filled.
Define ‘pustule’.
Small, pus-filled.
Define ‘abscess’.
Large, pus-filled.
Define ‘erosion’.
Loss of epidermis.
Define ‘ulcer.’
Loss of epidermis and dermis.
