Lecture 1: ANATOMY OF THE SKIN - Part 1

Question 1

Skin is the…

Answer 1

largest and most (only) visible organ of the body

Question 2

What portion of body weight is skin?

Answer 2

16%

Question 3

What surface area is skin?

Answer 3

1.5-2 square metres

Question 4

What makes humans unique?

Answer 4

Our bare (not much hair), sweaty (lots of sweat glands) skin

Question 5

What are the functions of skin?

Answer 5

Protect, excrete, maintain, produce, synthesise, store and detect

Question 6

What does the skin protect?

Answer 6

Underlying tissues and organs against impact, abrasion, fluid loss and chemical attack

Question 7

What does the skin excrete?

Answer 7

Salts, water and organic wastes by integumentary glands

Question 8

What does the skin maintain?

Answer 8

Normal body temperature through either insulation or evaporative cooling as needed (thermoregulation)

Question 9

What does the skin produce?

Answer 9

Melanin and keratin

Question 10

What does melanin do?

Answer 10

Protect underlying tissue from ultraviolet radiation

Question 11

What does keratin do?

Answer 11

Protect against abrasion and serves as a water repellent (hair and nails)

Question 12

What does the skin synthesise?

Answer 12

Vitamin D3, a steroid that is subsequently converted into calcitriol, which is a hormone important to normal calcium metabolism

Question 13

What does the skin store?

Answer 13

Lipids in adipocytes in the dermis and in adipose tissue in the subcutaneous layer

Question 14

What does the skin detect?

Answer 14

Touch, pressure, pain, and temperature stimuli, and relay that information to the nervous system

Question 15

What happens at the chemical level?

Answer 15

Atoms combine to form molecules

Question 16

What happens at the cellular level?

Answer 16

Molecules interact to form cells that secrete and regulate extracellular materials and fluids

Question 17

What happens at the tissue level?

Answer 17

Cells and extracellular materials and fluids combine to form tissues

Question 18

What does epithelial tissue do?

Answer 18

Cover exposed surfaces, line internal passageways and chambers and form secretory glands

Question 19

What does connective tissue do?

Answer 19

Fill internal spaces, provide structural support and store energy

Question 20

What does muscle tissue do?

Answer 20

Contract to produce movement. Includes skeletal, cardiac and smooth muscle

Question 21

What does nervous tissue do?

Answer 21

Conduct electrical impulses and carry information

Question 22

What tissue is skin made of?

Answer 22

Epithelial, connective, muscle and nervous

Question 23

What are the 3 layers of the skin?

Answer 23

Epidermis, dermis and hypodermis

Question 24

What is in the cutaneous layer?

Answer 24

Epidermis and dermis

Question 25

What is in the subcutaneous layer?

Answer 25

Hypodermis

Question 26

What is the epidermis?

Answer 26

Stratified barrier, mostly keratinocytes ( cells with large amounts of keratin), no circulation (avascular)

Question 27

What happens id a cut doesn’t go beyond the epidermis?

Answer 27

No bleeding

Question 28

What is the dermis?

Answer 28

Protein fibres for strength and vascular (nourishes epidermis)

Question 29

What is the hypodermis?

Answer 29

Adipose tissue- insulation

Question 30

What is within the dermis?

Answer 30

Papillary layer and reticular layer

Question 31

Describe the border between the epidermis and dermis

Answer 31

Has papule which increase surface area for nourishment

Question 32

What are the layers of the epidermis?

Answer 32

Stratum corneum, Stratum lucid (in thick skin), stratum granulosum, stratum spinosum, stratum basale

Question 33

What are the cells of the stratum corneum?

Answer 33

Dead dried out hard cells without nuclei which can be completely removed by strip-taping

Question 34

What are the cells of the stratum granulosum?

Answer 34

Contain granules that promote dehydration of the cell, cross linking of keratin fibres. Waxy material is secreted into the intercellular spaces

Question 35

What are the cells of the stratum spinosum?

Answer 35

Intercellular bridges called desmosomes link the cells together. The cells become increasingly flattened as they move upward

Question 36

What are the cells of the stratum basal?

Answer 36

Columnar (tall) regenerative cells. As the basal cell divides and differentiates, a daughter cell migrates upwards to replenish layers above

Question 37

What are simple epithelia?

Answer 37

Single layers of cells

Question 38

What are the types of epithelia?

Answer 38

Squamous, cuboidal and columnar

Question 39

What are stratified epithelia?

Answer 39

Multiple layers of cells

Question 40

What type of epithelial cell is the epidermis?

Answer 40

Stratified squamous

Question 41

What skin layers shed?

Answer 41

The epidermis and not the dermis

Question 42

What protein fibres are in the dermis?

Answer 42

Collagen and elastin

Question 43

Where is thick skin found?

Answer 43

Palms of hands and soles of feet

Question 44

What are the characteristics of thick skin?

Answer 44

No hair, extra epidermal layer (stratum lucidum) for extra rigidity, stratum corneum much thicker but other layers the same

Question 45

What happens to the epidermis in ageing?

Answer 45

Thinner and drier (less sebum and fewer active follicles)

Question 46

What happens to the dermis in ageing?

Answer 46

Thinner (sagging and wrinkling), reduced collagen

Question 47

What happens to skin repair in ageing?

Answer 47

Slower

Question 48

What happens to cooling in ageing?

Answer 48

Impaired (less sweat/sweat glands)

Question 49

What happens to pigmentation in ageing?

Answer 49

Less. Pale skin, grey hair

Question 50

What is the relationship between smoking and skin ageing?

Answer 50

Smoking increases skin ageing

Question 51

What does smoking do?

Answer 51

“reactive oxygen” damages collagen and elastin. vasoconstriction - nicotine increases vasopressin