Week 3 Flashcards
What does the integumentary system consist of?
The skin as well as accessory organs
What connects skin to your body. Is it considered skin itself?
A connective tissue called the hypodermis. It’s part of the integumentary system but not considered skin.
What are the layers of the skin?
1) epidermis
2) epithelia
3) dermis
4) eccrine
5) sebaceuos
6) pacinian
7) merkel cells
8) hypodermis
9) fat
10) arrector pili
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?
- 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
Where are keratinocytes produced?
What substances do they create and what is the material’s purpose.
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
Where are merkel cells produced and what is their role? In what body parts are they found?
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.
What cells does the stratum basale mainly consist of?
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.
What is the dermis?
What are the two layers of the dermis? Which is the upper and which is the lower layer?
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).
What is the role of the dermis?
To support and protect the skin
Describe what the papillary layer is made up of.
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
Describe what the reticular layer is made up of
- 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
What is the hypodermis made up of and what is its job?
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
What causes pigmentation of skin colour? Where are they located? Explain what colour each gives.
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.
What are the two forms of melanin and what colour do they give off?
Eumelanin (black and brown)
Pheomelanin (reddish colour)
Is it true that if you have too much melanin, your body will naturally produce less vitamin D?
Yes
How does the production of melanin work?
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.
What is a benefit of melanin production
UV protection
What is the cause of vitiligo and does it have an effect on lifespan?
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.
What is the cause of albinism and what does it make you more susceptible to?
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.
What are the accessory structures of the skin (4)?
Hair
Nails
Sweat glands
Sebaceous glands
What is the anatomy of hair?
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)
What are the medulla and cortex of hair
Medulla = central core of hair
Cortex = outer layer
Why does hair become grey/white with age?
Colour of hair is due to melanin production, and with age that decreases, so spaces for melanin are replaced with air
Is external hair alive and what is it made up of
Dead and made completely of keratin
