Skin structure and function 4

Question 1

name 6 functions of the skin

Answer 1

barrier
metabolism/detoxification
thermoregulation
immune defence
communication
sensory function

Question 2

what is acute skin failure?

Answer 2

loss of cohesion between epidermis and dermis (usually due to a drug)

Question 3

what are the negative consequences of acute skin failure?

Answer 3

loss of moisture/fluid through the skin
loss of heat causing hypothermia
loss of proteins and electrolytes (e.g - low albumin causing swelling, jaundice, illness etc)

Question 4

what is erythroderma?

Answer 4

not a diagnosis, just a term for red skin

Question 5

what are the consequences of erythroderma?

Answer 5

loss of heat and proteins

loss of infection barrier leading to higher infection risk

Question 6

consequence of loss of barrier function?

Answer 6

fluid loss = dehydration
protein loss = hypoalbuminaeia
infection

Question 7

consequence of loss of thermoregulation function?

Answer 7

heat loss = hypothermia

Question 8

consequence of loss of immune defence function?

Answer 8

spread of infection

Question 9

consequence of loss of metabolic function?

Answer 9

disordered thyroxine metabolism

Question 10

consequence of loss of communication function?

Answer 10

inability to display healthy skin > stigma

Question 11

consequence of loss of sensation function?

Answer 11

pain sensation

Question 12

the epidermis acts as a two way barrier against what 3 categories?

Answer 12

physical (trauma)
chemical (irritants, allergens etc)
pathogens (bacteria etc)

Question 13

what is steroid - sulphatase deficiency X-linked ichthyosis?

Answer 13

don’t have normal lipids in keratin resulting in dry scaley skin

Question 14

how does cumulative irritant hand dermatitis occur?

Answer 14

exposure to irritant over time (can vary to days to weeks) results in dermatitis (skin inflammation etc)
E.g - washing dishes every day

Question 15

which wavelength of light has deeper penetration in the skin?

Answer 15

longer wavelengths

Question 16

which wavelengths of light cause quicker damage (e.g sunburn)?

Answer 16

shorter wavelengths (UV rays)
longer wavelengths require repeated exposure for longer time to cause damage

Question 17

ratio of melanocytes to basal cells?

Answer 17

1:10

Question 18

how does melanin protect against skin cancer?

Answer 18

creates a cap on top of basal cells and absorbs UV rays to protect DNA in the cell nuclei

Question 19

what type of metabolism occurs in the skin?

Answer 19

Vit D metabolism
thyroid hormone metabolism
defence against chemicals, drugs etc

Question 20

how is Vitamin D synthesised in the skin?

Answer 20

UV rays convert cholecalciferol (vit D precursor) to Vitamin D3
occurs in epidermis

Question 21

what happens to vitamin D once synthesised?

Answer 21

stored as hydroxycholecalcefirol in liver

converted to 1,25 hydroxycholecalcefirol in kidney which increases calcium absorption and promotes bone mineralization

Question 22

how is thyroid hormone metabolised in the skin?

Answer 22

thyroxine (T4) converted to triiodothyronine
only 20% occurs in liver
80% in other tissues like skin

Question 23

how does skin control temperature?

Answer 23

vasoconstriction/dilation
sweating
hair

Question 24

what are the parts of the skins immune defence function?

Answer 24

Langerhans cells
T cells
epidermis and dermis interact

Question 25

what is the skins immune function used for?

Answer 25

protect against infection, sunlight and allergens

Question 26

what are the 2 types of immune response in the skin?

Answer 26

non-specific

specific (to antigens which have been encountered before and established immunity)

Question 27

give examples of diseases which can occur if the non-specific response in the skin fails?

Answer 27

crusted scabies
tuberculoid leprosy (hansens disease
eczema herpeticum?
lupus?

Question 28

what are the social and communication effects of skin conditions?

Answer 28

visual changes
odour
influence on sociosexual behaviour

Question 29

do skin conditions actually affect life opportunities?

Answer 29

yes - acne is associated with unemployment

due to employer prejudice and effects of acne on feelings of self worth

Question 30

give 4 sensory functions of the skin

Answer 30

touch, pressure, vibration
pain and itch
temperature
nerve endings/receptors on skin