Dermatology

Question 1

What are the functions of the skin?

Answer 1

Barrier against environmental insults
Temperature regulation
Sensation
Vitamin D synthesis
Immunosurveillance

Question 2

What is erythroderma?

Answer 2

Intensereddening of the skin due toinflammatoryskin disease, affecting >90% of surface area. It is erythematous and exfoliative.

Question 3

What are the complications of erythroderma?

Answer 3

Hypothermia (thermoregulation lost)
Infection (barrier lost)
Renal failure (insensible losses)
High output cardiac failure (dilated skin vessels)
Protein malnutrition (high skin cell turnover)

Question 4

What are the signs of erythroderma?

Answer 4

Skin is erythematous, thickened, inflamed, and scaly, with no sparing

Question 5

What are the symptoms of erythroderma?

Answer 5

Pruritis, fatigue, anorexia, feeling cold.

Question 6

What are the causes of erythroderma?

Answer 6

Pruritis, eczema, drugs, cutaneous T cell lymphoma

Question 7

What are the four major cell types of the epidermis?

Answer 7

Keratinocytes
Langerhan cells
Melanocytes
Merkel cells

Question 8

What is the function of keratinocytes?

Answer 8

To form a protective barrier

Question 9

What is the function of Langerhan cells?

Answer 9

Antigen presenting cells

Question 10

What is the purpose of melanocytes?

Answer 10

Produce melanin, which pigments the skin and protects cell nuclei from UV DNA damage

Question 11

What is the function of Merkel cells?

Answer 11

Contain specialised nerve endings, for sensation.

Question 12

What are the layers of the epidermis?

Answer 12

Stratum basale (basal layer)
Stratum spinosum
Stratum granulosum
(Stratum lucidum in areas of thicker skin (palm, sole))
Stratum corneum (horny layer, superficial)

Question 13

What does each layer of the epidermis represent?

Answer 13

A different stage of keratinocyte maturation

Total turnover time ~30 days

Question 14

What is the dermis composed of?

Answer 14

Collagen, elastin, glycosaminoglycans (strength, elasticity)

Immune cells, nerve cells, skin appendages, lymphatics, blood vessels

Question 15

What are sebaceous glands?

Answer 15

Glands producing sebum through hair follicles (pilosebaceous unit) onto the skin.
They become active after puberty, stimulated by the conversion of androgen to dihydrotestosterone.

Question 16

When is sebum production increased?

Answer 16

With associated bacterial colonisation, in conditions such as acne vulgaris.

Question 17

What are the functions of eccrine and apocrine glands?

Answer 17

Regulate bodily temperature

Question 18

Where are eccrine and apocrine glands found?

Answer 18

Eccrine are widespread

Apocrine are active following puberty, and are found in axillae, areolae, genitalia, and anus

Question 19

How are eccrine and apocrine glands innervated?

Answer 19

By the sympathetic nervous system

Question 20

What are the three main types of hair?

Answer 20

Lanugo hair (downy hair on foetus/newborn)
Vellum hair (short bodily hair)
Terminal hair (coarse long hair)

Question 21

What are the three growth phases of a hair follicle?

Answer 21

Anagen (active growth, rapid hair root division and shaft elongation)
Catagen (resting stage)
Telogen (regression stage)

Question 22

What are nails comprised of?

Answer 22

A nail plate arising from the nail matrix at the posterior nail fold. It rests on the nail bed, which contains blood capillaries.