Basic Skin Biology Flashcards
What are the functions of the skin?
Protective barrier against environmental insults
Temperature regulation
Sensation
Vitamin D Synthesis
Immunosurveillance
Cosmesis
What are the complications of erythroderma?
‘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 skin)
What is erythroderma?
Erythroderma is the term used to describe intense and usually widespread reddening of the skin due to inflammatory skin disease. It often precedes or is associated with exfoliation.
What are the causes of erythroderma?
Psoriasis
Eczema
Drugs
Cutaneous T cell lymphoma
What are the signs and symptoms of erythroderma?
Symptoms: Pruritus, fatigue, anorexia, feeling cold.
Signs: erythematous, thickened, inflamed, scaly, no sparing
What are the three main layers of the skin?
Epidermis
Dermis
Hypodermis
What are the four major cell types in the epidermis and what are their individual functions?
Keratinocytes - protective barrier
Langerhan cells - antigen presenting cells
Melanocytes - produce melanin which provides pigment to the skin and protects cell nuclei from UV and DNA damage.
Merkel cells - contain specialised nerve endings for sensation.
What is the average epidermal turnover time?
30 days
What are the four layers of the epidermis?
Stratum basale (basal layer) -deepest
Stratum spinous
Stratum granulosum
Stratum corneum (horny layer) - most superficial
The stratum lucidum is found in areas of thicker skin such as palms and soles.
What could happen to the skin as a result of pathology of the epidermis?
Changes in epidermal turnover
Changes in surface of the skin
Changes in pigmentation of the skin
What is the dermis made from?
Collagen, elastin and glycosaminoglycans
Also contains (in smaller quantities): immune cells, nerve cells, skin appendages, lymphatics and blood vessels.
What is the role of the dermis?
Provides strength and elasticity.
What do sebaceous glands do?
Produce sebum through hair follicles (pilosebatious unit)
Secrete sebum into the skin which lubricates it
Active after puberty
Stimulated by conversion of androgen to dihydrotestosterone
Increase sebum production and bacterial colonisation in conditions such a acne vulgaris
What are the roles of eccrine and apocrine glands?
Regulate body temperature
Innervated by sympathetic system
Eccrine are widespread
Apocrine are active following puberty and are found in axillae, areolae, genitalia and anus
What does a hair consist of?
Each hair consists of modified keratin and is divided into hair shaft and hair bulb.
