Anatomy and Function of the Skin

Question 1

What are the three main functions of the skin?

Answer 1

Protection
Regulation
Sensation

Question 2

How does the skin act as protection?

Answer 2

Skin acts as a physical and immunological barrier against mechanical impacts, microorganisms, radiation and chemicals

Question 3

What are the regulatory functions of the skin?

Answer 3

Regulating body temperature via sweat, hair and changes in peripheral circulation
Regulating fluid balance via sweat and insensible loss
Synthesising vitamin D

Question 4

What are the layers of the epidermis in order from most superficial to most deep?

Answer 4

Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale

Question 5

From which germ layer is the epidermis derived from?

Answer 5

Ectoderm

Question 6

What is the name of the single squamous layer of skin which forms in 7th weeks of gestation?

Answer 6

Periderm

Question 7

At what point in gestation does hair develop in the skin?

Answer 7

Third month

Question 8

The cells of the epithelial root sheath proliferates during embryogenesis to form what structures?

Answer 8

Sebaceous gland bud

Sweat glands

Question 9

What processes is the skin immune system involved in?

Answer 9

Antimicrobial immunity
Skin immunosurveillance
Induction hypersensitivity
Pathogenesis of chronic inflammatory diseases of the skin

Question 10

Describe the function of the langerhans cells in the skin?

Answer 10

Langerhans cells reside in the basal layers and specialise in antigen presentation and acquire antigens in peripheral tissues, transport them to regional lymph nodes and present to naive T cells to initiate an adaptive immune response

Question 11

How long does initial sensitisation to allergen exposure take in the skin?

Answer 11

10-14 days

Question 12

What are the direct effects of UV right on the skin?

Answer 12

Photoageing
DNA damage
Carcinogenesis

Question 13

What changes in the skin will result from chronic UV exposure?

Answer 13

Loss of skin elasticity, fragility, abnormal pigmentation and haemorrhaging of blood vessels

Question 14

What type of photons are absorbed in the skin to synthesise DNA?

Answer 14

UVB photons

Question 15

What are the risks associated with vitamin D deficiency?

Answer 15

Increased risk of common cancers
Autoimmune disease
Infectious diseases
Cardiovascular disease

Question 16

Describe the position and function of Merkel cells in the skin

Answer 16

These lie at the base of the epidermis

Respmd to sustained gentle and localised pressure to assess shapes and edges

Question 17

Describe the position and function of Meissner corpuscles in the skin

Answer 17

Situated immediately below the epidermis

Sensitive to light touch

Question 18

Describe the position and function of Ruffini’s corpuscles in the skin

Answer 18

Situated in the dermis

Sensitive to deep pressure and stretching

Question 19

Describe the position and function of Pacinian corpuscles in the skin

Answer 19

Deep dermis

Sensitive to deep touch, rapid deformation of the skin surface around the joints for position and proprioception

Question 20

What is a macule?

Answer 20

Non-elevated area of skin discolouration

Question 21

What is a papule?

Answer 21

Circumscribed, solicited raised area of skin <1cm

Question 22

What is a pustule?

Answer 22

Small bump containing fluid or pus

Question 23

What is a plaque (on the skin)?

Answer 23

Circumscribed, solid palpable lesion >1cm

Question 24

What is a vesicle?

Answer 24

Circumscribed elevation in skin containing fluid <0.5cm

Question 25

What is a bulla?

Answer 25

Circumscribed elevation in skin containing fluid >0.5cm