Week 3

Question 1

What does the integumentary system consist of?

Answer 1

The skin as well as accessory organs

Question 2

What connects skin to your body. Is it considered skin itself?

Answer 2

A connective tissue called the hypodermis. It’s part of the integumentary system but not considered skin.

Question 3

What are the layers of the skin?

Answer 3

1) epidermis
2) epithelia
3) dermis
4) eccrine
5) sebaceuos
6) pacinian
7) merkel cells
8) hypodermis
9) fat
10) arrector pili

Question 4

Describe the epidermis: what is it made up of, what are the formation of cells, is it vascular or avascular, where is it found?
What is the deepest layer of the epidermis?

Answer 4

• it is the outer layer of skin
• contains keratin / keratinized
• cells are stratified squamous epithelial cells (stratified = more than one layer, squamous = flat)
• avascular (doesn’t have blood vessels)
• 4 layers = thin skin like on eyelid
• 5 layers = thick skin like on palms of hand and soles of feet
• stratum basale is the deepest layer

Question 5

Where are keratinocytes produced?
What substances do they create and what is the material’s purpose.

Answer 5

In the stratum basale (in the epidermis).
They are cells that produce keratin. They push older layers of kertain layers upwards,
Keratin is a protein that gives hair, nails, skin their hardness/toughness and makes them water-proof

Question 6

Where are merkel cells produced and what is their role? In what body parts are they found?

Answer 6

In the stratum basale (in the epidermis), it’s a receptor that helps with the feeling of touch. It’s found in the feet and hands.

Question 7

What cells does the stratum basale mainly consist of?

Answer 7

It’s a single layer (simple) of columnar or cuboidal basal cells. Some divide and produce keratinocyte cells. There are also merkel cells and melanocyte cells.

Question 8

What is the dermis?
What are the two layers of the dermis? Which is the upper and which is the lower layer?

Answer 8

The dermis is the inner layer of the two main layers of skin, the outer layer being the epidermis.
Papillary (upper layer) and reticular layer (lower layer).

Question 9

What is the role of the dermis?

Answer 9

To support and protect the skin

Question 10

Describe what the papillary layer is made up of.

Answer 10

Made up of:
Made up of loose aerolar connective tissue, and has collagen and elastin fibres forming an airy mesh.
Upper part of dermis projects into stratum basale of epidermis to form finger-like dermal papillae

Question 11

Describe what the reticular layer is made up of

Answer 11

• much thicker than papillary layer
• dense irregular connective tissue
• highly vascularized (has lots of blood vessels) and has lots of nerves
• has elastin: provides elasticity to skin to prevent tears and enable movement
• has collagen, which lets it be stretched, and helps keep skin hydrated by holding onto water

Question 12

What is the hypodermis made up of and what is its job?

Answer 12

It is made up of loose connective tissue, areolar connective tissue, and adipose connective tissue.
It connects our skin to our body, insulates your body, provides cushioning for the skin

Question 13

What causes pigmentation of skin colour? Where are they located? Explain what colour each gives.

Answer 13

Melanin, carotene, and hemaglobin, in the stratum basale.
Melanin makes your skin brownish.
Carotene gives the skin a yellowish colour.
The hemoglobin contributes to the reddish colour.

Question 14

What are the two forms of melanin and what colour do they give off?

Answer 14

Eumelanin (black and brown)
Pheomelanin (reddish colour)

Question 15

Is it true that if you have too much melanin, your body will naturally produce less vitamin D?

Answer 15

Yes

Question 16

How does the production of melanin work?

Answer 16

UV exposure from the sun stimulates keratinocytes (major cells of the epidermis) to signal melanocytes to make melanin. Melanin is produced and keratinocytes carry it to the skin’s surface.

Question 17

What is a benefit of melanin production

Answer 17

UV protection

Question 18

What is the cause of vitiligo and does it have an effect on lifespan?

Answer 18

Melanocytes in certain regions lose ability to produce melanin. It is an autoimmune disorder because the immune system attacks the melanocytes in the skin.
It doesn’t affect lifespan.

Question 19

What is the cause of albinism and what does it make you more susceptible to?

Answer 19

It is a genetic disorder where melanocytes can’t produce melanin, making pale skin, hair or eyes. Can have a complete or partial effect.
You are more prone to UV damage, so you have an increased risk of cancer.

Question 20

What are the accessory structures of the skin (4)?

Answer 20

Hair
Nails
Sweat glands
Sebaceous glands

Question 21

What is the anatomy of hair?

Answer 21

It’s a filament made up of keratin.
The root is found in the hair bulb, in the follicle (pore / opening).
The hair matrix is part of the hair follicle, and it has keratinocytes that multiply to make the hair shaft of growing hair (shaft = hair you can see above skin)

Question 22

What are the medulla and cortex of hair

Answer 22

Medulla = central core of hair
Cortex = outer layer

Question 23

Why does hair become grey/white with age?

Answer 23

Colour of hair is due to melanin production, and with age that decreases, so spaces for melanin are replaced with air

Question 24

Is external hair alive and what is it made up of

Answer 24

Dead and made completely of keratin

Question 25

What are the 3 functions of hair?

Answer 25

1) protection (i.e. protect scalp from sunburn)
2) sensory input - has root hair plexus, which are special nerve fibers that surround the hair bulb and let you feel things. I.e. can feel a bug on your
3) thermoregulation - not as much in humans, but on animals that have fur it keeps them warm

Question 26

What are the 3 phases of hair growth?

Answer 26

1) anagen - cells divide from root
2) catagen - follicle’s active growth
3) telogen - resting stage

Question 27

What are some functions of nails?

Answer 27

1) protection when using hands
2) help with fine motor tasks (picking up small objects, i.e.)

Question 28

What types of glands are sweat glands? What are its two types?

Answer 28

Classified as merocrine glands.
Its two types are eccrine sweat glands (for thermoregulation), which produce water to cool the body down. The second one is apocrine sweat glands (axillary [armpit] and genital regions), which creates a smell.

Question 29

Where are sebaceous glands found? What is their function?

Answer 29

Located all over the body.
They produce sebum (oil) which lubricates and waterproofs the skin.
It is antibacterial and prevents water loss.

Question 30

What are the hair papilla?

Answer 30

Hair papilla are connective tissue containing capillaries and nerve endings and help with hair growth and nourishment. They are located in the hair follicle.