Session 6 Flashcards
Learning outcomes
- Ability to describe the functions of the skin
- Ability to describe the structure of normal skin
• Ability to describe the functions of the skin LO
Functions of the skin?
- Protective barrier against environmental insults
- Temperature regulation
- Sensation
- Vitamin D synthesis
- Immunosurveillance
- Cosmesis
What is Erythroderma?
Intense and usually widespread reddening of the skin due to inflammatory skin disease. It often precedes or is associated with exfoliation (skin peeling off in scales or layers), when it may also be known as exfoliative dermatitis (ED).
Erythroderma complications (6)
- ‘Total skin failure’
- Hypothermia (loss of thermoregulation)
- Infection (loss of protective barrier)
- Renal failure (insensible losses)
- High output cardiac failure (dilated skin vessels)
- Protein malnutrition (high turnover of skin)
Erythroderma
- >90% of body surface area affected, erythematous (?) and exfoliatitive
- Causes:
- Symptoms:
- Signs:
- Reddening of the skin,
- psoriasis, eczema, drugs, cutaneous T cell lymphoma
- pruritus, fatigue, anorexia, feeling cold
- erythematous, thickened, inflamed, scaly, no sparing
Epidermis
4 major cell types each with individual function
- Keratinocytes - protective barrier
- Langerhan cells- antigen presenting cells
- Melanocytes- produce melanin which provides pigment to the skin and protects cell nuclei from UV DNA damage
- Merkel Cells - contain specialised nerve endings for sensation
Epidermis
- 4 layers of the epidermis
- Each layer represents a different stage of maturation of the keratinocyte
- Average epidermal turnover time is about ?
- The 4 layers of the epidermis include: ?
30 days
stratum corneum (horny layer- most superficial)
stratum granulosum,
stratum spinosum (prickle layer),
stratum basale (basal layer),
• Stratum lucidum found in areas of thicker skin such as palms and soles
Epidermis
Pathology of the epidermis may cause:
a) Change in epidermal turnover
b) Change in surface of the skin
c) Changes in pigmentation of the skin
What are these two images showing
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Dermis
- Composed of ?
- Provides ?
- Also contains ?
- collagen, elastin and glycosaminoglycans
- Strength and elasticity
- immune cells, nerve cells, skin appendages, lymphatics and blood vessels
What are these images showing
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- Produce sebum through?
- Secrete sebum on to skin which?
- Active after puberty
- Stimulated by conversion of ?
- Increased sebum production and bacterial colonisation in conditions such as ?
- hair follicles (pilosebaceous unit)
- Lubricates skin
3.
- Androgen to dihydrotestosterone
- acne vulagris
Eccrine and Apocrine glands
- Function
- Innervated by ?
- Two types: ?
- Regulate body temperature
- sympathetic system
- Eccrine - widespread
Apocrine - active following puberty and are found in axillae, areolae, genitalia and
anus.
Eccrine glands
- Function
- Location
- Innervation
- Sweat - thermoregulation
- highest density in palms and soles, then on the head, but much less on the trunk and the extremities
- Cholinergic sympathetic nerve
An apocrine sweat gland
- Structure
- Location
- Modified apocrine glands include ?
- Innervation
- Coiled secretory portion located at the junction of the dermis and subcutaneous fat, from which a straight portion inserts and secretes into the infundibular portion of the hair follicle.
- The axillae(armpits), areola and nipples of the breast, ear canal, eyelids, wings of the nostril, perianal region, and some parts of the external genitalia.
- the ciliary glands in the eyelids; the ceruminous glands, which produce ear wax; and the mammary glands, which produce milk.
- Adrenergic nerves
Hair
- Each hair consists of modified keratin and is divided into ?
- 3 main types of hair:
- Each hair follicle enters a growth cycle which has 3 main phases:
- hair shaft and hair bulb
- lanugo hair, vellum hair (short hair all over body), terminal hair (coarse long hair)
- anagen, catagen, telogen
What is this image showing?
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