skin and wound healing

Question 1

list function of skin

Answer 1

protection, regulation of body temperature, formation of vitamin D, cutaneous sensation, excretion, absorption

Question 2

describe protection

Answer 2

non-specific defence mechanism
so a barrier against microorganisms
physical agents: melanocytes secrete melanin protect from ultraviolet
chemicals
dehydration

Question 3

describe regulation of body temperature

Answer 3

heat production
heat loss: evaporation
conduction

Question 4

describe formation of vitamin D

Answer 4

liquid based substance converted to vitamin d by sunlight

Question 5

describe cutaneous sensation

Answer 5

sensory receptors, e.g. pacinian sensitive to touch, pain, temperature

Question 6

describe excretion

Answer 6

NaCl in sweat
urea

Question 7

explain changes to skin when ageing

Answer 7

skin becomes thin and fragile
fewer capillaries and cell proliferation decreases so slower wound healing
sensory receptors decline so increased susceptibility to injury and bruising appears frequently
skin appears dry and wrinkled as elastic fibres are reduced and collagen fibres become less flexible
melanocytes decrease causing greying of hair and skin

Question 8

explain changes to skin developing foetus

Answer 8

epidermis develops from single layer of ectoderm
end of 4 weeks a thin outer layer of flattened cells covers embryo
adipose tissue develops from 17-20
>18 weeks fetus covered in protective layer called vernix caseosa
9-12th hair develops
fingernails and toenails 10-18 weeks

Question 9

describe the mechanism of wound healing

Answer 9

inflammation of wound surfaces and blood clot and cell debris fill the gaps
clot becomes scab
proliferation: formation of granulation tissue (phagocytes, fibroblasts) restores blood supply to wound
maturation: fibrosis scar tissue replaces granulation tissue until full thickness restored