Structure and function of Skin

Question 1

What does integument or integumentary system refer to?

Answer 1

Refers to the skin, hair and nails

Question 2

What is the largest and heaviest organ of the body?

Answer 2

Skin is the largest and heaviest organ of the body

Question 3

What are the main function of skin?

Answer 3

1) Barrier against:
- Dehydration
- Infection
- Injury
- Solar radiation
2) Thermoregulation
3) Sensation
4) Repair
5) Vitamin D production

Question 4

What are the 3 layers of skin?

Answer 4

• Epidermis
• Dermis
• Hypodermis

Question 5

Where does the thickness of the epidermis vary?

Answer 5

Thickness varies around the body

Question 6

What are the 4 main layers of the epidermis?

Answer 6

• Basal layer
• Stratum spinosum
• Stratum granulosum
• Stratum corneum

Question 7

What does the basal layer contain?

Answer 7

Contain the stem cells of skin that constantly proliferate

Question 8

What does the stratum spinosum have many of?

Answer 8

The cells have many desmosomes visible as spines between cells

Question 9

What is the stratum granulosum?

Answer 9

1-4 layers of cells containing prominent granules

Question 10

What does the stratum granulosum contain?

Answer 10

Contain lamellar bodies containing lipids

Question 11

What do the cell of the stratum granulosum do?

Answer 11

The cells are differentiating to form the stratum corneum

Question 12

What is the stratum corneum?

Answer 12

It is the outer protective layer of the epidermis

Question 13

What is the stratum corneum made up of?

Answer 13

Are squamous cells which have lost their nucleus

Question 14

What does it mean by the stratum corneum being cornified?

Answer 14

Means they’re full of keratin thus tough to injury

Question 15

What are between the cells in the stratum corneum layer?

Answer 15

Non-polar lipids are between the cells

Question 16

What are the other epidermal cell types?

Answer 16

• Melanocytes
• Langerhans cells
• Merkel cells

Question 17

What do melanocytes synthesise?

Answer 17

Synthesise melanosomes and transfer them to basal keratinocytes through long dendrites

Question 18

How do keratinocytes arrange melanin pigments?

Answer 18

Keratinocytes arrange melanin pigments in a cap distal to the nucleus

Question 19

What are langerhans cells involved in?

Answer 19

Involved in the immune system as antigen presenting cells

Question 20

What type of cells are langerhans cells?

Answer 20

Are dendritic cells

Question 21

Where does vitamin D production occur?

Answer 21

Made in the epidermis, mostly in the basal cells and also stratum spinosum

Question 22

What does vitamin D production require?

Answer 22

Requires UV light

Question 23

Where is vitamin D converted into the active form?

Answer 23

Converted to active form in liver and kidney:

-1,25 dihydroxyvitamin D3

Question 24

What is the dermis?

Answer 24

Is dense, irregular connective tissue

Question 25

What does collagen in the dermis provide?

Answer 25

Collagen in the dermis provides tensile strength hence protection against abrasion and impact

Question 26

What does the dermis contain giving its elasticity?

Answer 26

Contains elastin

Question 27

What does the dermis carry?

Answer 27

Carries blood and nerve supply for the epidermis

Question 28

Properties of the dermal epidermal border?

Answer 28

Dermal epidermal border is often wavy to resist shear forces - Can have finger like dermal papillae - The epidermis can have rete ridges

Question 29

What is one effect of UV light on skin?

Answer 29

One effect of UV light on skin is damaged/loss of elastic fibres, resulting in loss of elasticity -Wrinkles

Question 30

What syringe do you use for the hypodermis?

Answer 30

Where you put a hypodermic syringe for a subcutaneous injection

Question 31

What is the hypodermis composed of?

Answer 31

Composed of fat, containing glands, hair follicles, nerves and blood vessels

Question 32

What is the thickest layer of skin?

Answer 32

The hypodermis

Question 33

What is the function of the hypodermis?

Answer 33

Function is to provide insulation, cushioning and energy storage

Question 34

What does the sebaceous gland secrete?

Answer 34

Secretes oily sebum into hair follicles

Question 35

What is the eccrine sweat glands and what does it secrete?

Answer 35

- Normal sweat glands | - Watery secretions onto skin surface and cools body by evaporation

Question 36

What does the apocrine secrete?

Answer 36

Secretes oily fluids into hair follicles

Question 37

Where are apocrine glands found?

Answer 37

Found in armpits and any genital region

Question 38

What sense organs are present in the skin?

Answer 38

``` Thermoreceptors -Senses heat or cold Meissner's corpuscle -Senses touch Nociceptor -Senses pain Pacinian corpuscle -Senses pressure ```