Intro to Derm Flashcards
Name the layers of the skin
Epidermis - keratinocytes, melasmasomes and langerhans cells. Dermis - bvs, nerves, sebum glands, hair follicles, pilar erectae muscles. Subcutis - insulation and fat.
How many layers does the Epidermis have? Name them (Stratum), as well as cell types seen in Epidermal layer?
5 Stratum layers (top to bottom/mature to immature): - Stratum Corneum (Mature/Dead Keratinocytes) - Stratum Lucidum - Stratum Granulosum - Stratum Spinosum - Stratum Basale (Immature Keratinocytes + Melanocytes) Remember Keratinocytes differentiate as they move to top. Cell types in Epidermis: - Keratinocytes - Melanocytes (Melasmasomes) - Langerhans Cells (Antigen presenting cells)
How often is the epidermis replaced? What condition speeds this up?
Every 25-30 days In Psoriasis every 2-3 days.
What do Melanocytes do? What do Langerhans cells do?
Melanocytes make melasmasomes aka melanin which sits over Keratinocyte nuclei to protect from UV damage. No of melanocytes doesnt vary between pale and tanned people - it is the number of melasmosomes which differs. LCs - antigen presenting cells, take antigen via lymphatic system.
Name 3 hair types?
ACT A - ANAGEN C - CATAGEN T - TELOGEN
Describe ACT hair stages
A - growth phase, lasts for few years, 90% of hairs are anagen at any one time. In chemo its the anagen hairs which are lost because cell cycle is stopped. C - lasts for 2-3 weeks after anagen phase, growth of hair stops and hair follicle shrinks. T - resting phase of hair, 10% of hairs are T phase at any one time. Last 1-4 months in this phase and then hairs fall out and are replaced by new Anagen hairs. In stress, illness and pregnancy, T hairs are lost.
How is majority of skin disease handled?
OTC drugs, or in primary care with GP. Rarely progresses to secondary or specialist care.
Causes of skin disease?
EXTERNAL - Temperature - UV rays - Medicines Eg cold stress and frostbite INTERNAL - Systemic Illness - Genetics eg AI Bullous Pemphigoid - Systemic Medicines
Complications of Skin Disease? (5 Ds)
- Disfigurement - Depression - Discomfort eg itch - Disability eg can’t work - Death eg extreme cases like TEN
Skin Functions
- Barrier - water electrolyte balance - Sensation - touch, pain etc - Vit D Synthesis - Interpersonal presentation - appearance, smell etc - Thermoregulation - Immune Response eg APCs (Langerhans) - first line of defence
Skin Lesions (MPPP)
FLAT - Small = Macule - Large = Patch RAISED - Small = Papule - Large = Plaque Then remember the extras: FLUID FILLED - Small = Vesicle - Large = Bulla PUS FILLED - Small = Pustule - Large = Abscess Nodule = longer than it is wide
Epidermis loss is called? Epidermis AND Dermis loss is called?
Erosion Ulceration
Common Skin Diseases?
Eczema Acne Vulgaris and Rosacea Psoriasis Bacterial - Impetigo - Cellulitis - Oedema Blisters - Lipdermatosclerosis Viral - Viral Warts - Herpes Simplex and Zoster - DNA Pox Virus Fungal - Tinea - Candidiasis Urticaria = Hives
Name Biopsy types?
Incisional (remove bit of lesion) Excisional (remove whole lesion + border) Punch (takes ED, D and SC layers)
How do you take Bacterial samples?
Swab of lesion and do MCS (Microscopy, Cultures and Sensitivities).
