The Ageing Integument (Skin)

Question 1

What is the most obvious sign of ageing

Answer 1

the most obvious
indicator of ageing because the appearance of skin is affected
by internal (glycation & ↓elasticity) and external factors (UV)

Hair also changes colour and falls out

Question 2

how does the skin provide a first line of defence?

Answer 2

~ it is continually abraded, burned, scalded and injured
~ it is continually attacked by microorganisms
~ it is irradiated by sunlight, particularly U-V light
~ it is exposed to environmental chemicals

Question 3

What is the main of the integument system?

Answer 3

The cutaneous membrane (skin) composed of:
~ the epidermis (superficial epidermis)
~ the dermis (underlying layer of connective tissue)

Question 4

What the accessory structures of the integument system?

Answer 4

~ hair follicles and nails (keratin based)
~ multicellular exocrine glands (sebaceous & sweat)

Teeth are also part of the integument system

Question 5

Wha is the name and location of the part of the integurent system that is shed?

Answer 5

Epidermal keratinocytes in the stratified squamous epithelium

Question 6

How many layers does the skin have in thin skin?

Answer 6

4 epidermal layers

Question 7

What and where is EGF?

Answer 7

Epidermal Growth Factor (EGF) is a peptide growth factor

produced by salivary glands and glands in the duodenum

Question 8

What are the functions of EGF?

Answer 8

To accelerate:
~ division of basal cells in the stratum basale & spinosum
~ production of keratin in differentiating keratinocytes
~ development of the epidermis and its repair after injury
~ stimulating synthetic activity / secretion by epithelial glands

Question 9

At what age may EGF levels rise?

Answer 9

50+

Question 10

What effects the colour, thickness and density of hair?

Answer 10

Testosterone, genes and age

Question 11

What is intrinsic ageing?

Answer 11

Involves genetically determined structural

changes that occur as a natural consequence of ageing

Question 12

What occurs during intrinsic ageing?

Answer 12

diploid cells (eg fibroblasts) appear to undergo cellular
senesence with finite life-spans in culture (Hayflick limit)
~ hormone changes, particularly decrease oestrogen, and
thyroid hormone promote intrinsic ageing changes
~ generation of reactive oxygen species and free radicals
~ the non-enzymatic Maillard ‘browning’ reaction glycates
amino groups of amino acids and tissue proteins (skin
collagen), forming Amadori Glycation End products (AGE)

Question 13

What does AGE stand for?

Answer 13

Amadori Glycation End (products)

Question 14

What do AGEs cause?

Answer 14

An increase cross-linking in collagen and other proteins

adversely affecting their functions

Question 15

What is skin turgor?

Answer 15

water content of the skin

Question 16

What is present in young skin and is effected by ageing

Answer 16

• Young skin contains healthy fibrillar
collagen bundles and elastin fibres
(formed by fibroblasts) giving the
dermis strength, stretching resistance
and elasticity (proteoglycans)
• Intrinsic ageing promotes significant
collagen cross
-linking and atrophy of
dermis collagen & elastin through
Maillard, Amadori and Advanced
Glycation End product reactions

Question 17

What is extrinsic ageing?

Answer 17

ageing due to environmental or lifestyle factors

Question 18

What factors can cause extrinsic ageing?

Answer 18

~ exposure to UV light, particularly in the fair-skinned, due to
living in sunny countries and sun bathing
~ cigarette smoking ages skin in both sexes causing abnormal
elasin (elasosis) and red skin spots (telangiectasia)
~ smoking mainly causes skin damage by decreasing blood
flow in capillaries which causes O2 and nutrient deficiency
~ smoking reduces collagen and elastin in the dermis and
increases wrinkling even more than UV exposure
~ desquamation (skin peeling) can be caused by sunburn and
some hypocholesteremic drugs
~ steroid use can adversely affect skin thickness

Question 19

What percentage of visible ageing is caused by sunlight?

Answer 19

90%

Question 20

What type of UV causes genetic mutations and cancer?

Answer 20

UVB and UVA

Question 21

What is the primary mechanism that UVA causes genetic damage?

Answer 21

Via the generation of free radicals or reactive oxygen features

Question 22

What reaction does UVA establish?

Answer 22

~ up-regulate matrix metalloproteinases such as collagenase,
gelatinase and stromelysin which destroy collagen, elastin
and other extracellular matrix components
~ impairs repair of collagen, elastin and other components

Question 23

What is the result of UVA damage over time

Answer 23

~ fibroblasts are damaged impairing dermis maintenance

~ leads to permanent wrinkles, furrows and yellowing

Question 24

What percentage of skin cancer is caused by chronic UV exposure?

Answer 24

60-90%

Question 25

How does melanin production change when exposed to chronic UV?

Answer 25

Raised UV light exposure promotes
melanin release from the pineal
gland which increases melanin
production
• Melanin containing melanosomes in
keratinocytes cluster around the
nucleus to protect it from UV light

Question 26

What are 6 facts regarding Melanin and melanocytes?

Answer 26

• Brown tones in the integument
result from synthetic activity of
pigment melanocyte cells
• Melanocytes sit on the basement
membrane in the stratum basale
• Their cellular processes extend
into the superficial layers
• All races have similar numbers of
melanocytes (1000 / mm
2
) but
their melanin content varies
• Melanin is made from the amino
acid tyrosine to absorb U
-V light
• Carotine, a vitamin A precursor,
also accumulates in the skin

Question 27

Why are small amounts of UV benifical?

Answer 27

Small amounts of U-V light are
beneficial because it stimulates
epidermal production of vitamin
D3
from a 7-dehydrocholesteral
~ only occurs in summer
sunlight in the UK
• Active vitamin D (1,25(OH)2D3)
is a hormone that regulates GI
calcium absorption but it also
has immunological functions
• Vitamin D deficiency causes
osteomalacia in adults and
rickets in children

Question 28

What are cleavage lines?

Answer 28

the pattern of collagen and elastic fibres in the skin

Question 29

Why are cleavage lines clinically significant?

Answer 29

~ a parallel cut will remain closed
and heal with little scaring
~ a right
-angle cut will pull open
by retracting elastic fibres leading
to greater scaring
• Surgeons cut parallel to cleavage lines

Question 30

Questions

Answer 30

Q) Describe the ageing related changes in skin and explain how they occur.
Q) How does the skin and other parts of the integument change as a person
ages and what factors can influence the rate of the age-related changes?
Q) Compare the effects of intrinsic (biologically determined) and extrinsic
(environmental or lifestyle) factors that promote ageing of the skin and
special senses, particularly hearing and vision (Summer 2014)

Question 31

What is the result of vitamin D deficiency?

Answer 31

• Vitamin D deficiency in children,
mainly due to lack of sun-light
exposure and lack of dietary
calcium cause rickets
• Bones don’t calcify correctly and
bow due to the weight of the body
• In older people vitamin D
deficiency caused osteopenia

Question 32

What happens to secretary activity as ageing occurs?

Answer 32

Ageing reduces the secretary activity of the sebaceous glands

Question 33

Why does skin thin and lose elasticity?

Answer 33

~ collagen fibres give the dermis strength and resist stretch
~ elastic fibres give the dermis elasticity
~ leads to structural damage and permanent wrinkling