Your skin is the largest organ of your body.
It has 3 jobs: Protection, Regulation, Sensation
Natural complexions are being viewed as more beautiful than a "tan".
- Epidermis (above skin) - waterproof, gives you your color, the layer we see
*Dermis-Epidermis junction - a protein layer containing collagen and elastin to give skin flexibility and stretchability
- Dermis - where your glands, hair follicles, and nerves are
- Hypodermis - (below skin) - houses adipose tissue for insulation, and blood vessels
The Epidermis is made up of several separate layers based on what is happening in the cell's lifetime.
The basement membrane sits right on top of the Dermis-Epidermis junction, made up of fibrous proteins to be a solid foundation.
Basal Layer - Keratinocytes (makes Keratin) and Melanocytes (makes Melanin) - stem cells.
Spinous Layer - Cells are actively dividing and getting squished together
Granular Layer - Cells start making the proteins (keratin or melanin) that they are coded to make and it fills up all the intracellular space; the organelles of the cells get crowded out
Lucid Layer (Clear) - Keratinized cells are clear; Melanin-filled cells are colored. Cells are officially dead. Cells become coated in a hydrophobic (afraid of water) oil.
Hard Layer - cells are tightly packed together and dry; the layer we can touch.
These cells are being continuously produced and shed off and replenished because the skin takes a lot of abuse.
UV light from sun or tanning beds (heaven forbid!) stimulates melanocytes to divide faster and create more melanin (because melanin is reflective and keeps UV rays away from the important cells). This is how a tan is created. But during times of huge exposure, like tanning beds, there's not enough melanin to keep all the UV rays out so those rays can wreak havoc on the collagen and elastin proteins. This is why over-tanned skin ages faster.
Hydrating makes sure that the living and dividing cells are plump and as healthy as possible so when they move to the next layer, they are well nourished.
Protection: keeps dirt and bacteria out; protections from UV radiation
Regulation: releases sweat to cool the body's temp; subtly moves blood vessel closer or farther away from the surface to either cool the warm blood (like after exercise) or keep it warm (like in the winter).
Sensations: allows you to feel things that touch you or come close to you.
I can't seem to find any free footage of the original episode (Season 1, Episode 3) without having to sign up for a free streaming service. Netflix it, if you can. Here is the link to the "revisited" clip I found on YouTube. GoldFinger
Alopecia - hair falls out in the same area all at one time. Kind of like crop circles.
3 Stages of the Hair Follicle life cycle
- Anagen phase - active phase, cells are multiplying, hair is growing
- Catagen phase - resting phase, "cat nap"
- Telogen phase - shedding phase
Hair thickness is determined by 2 things: the density of hair follicles (how many follicles in one area) and how large a single hair follicle is (thick vs fine hair).
male patterned baldness - receding hairline from front to back, and the loss of the hair on the crown of the head.
Female patterned baldness - the overall thinning of the hair.
Hirsutism - females get male-patterned balding due to testosterone imbalance
Why does all your hair fall out after you have a baby??
Telogen effluvium - a mass exodus of hair follicles
This can also happen when the body goes through extreme shock or trauma.
There is a condition called post-partum alopecia - this is temporary, and hair grows back afterwards.
Dandruff - caused by the inflammation of the scalp. Inflammation causes skin to be dry and itchy. The topmost skin layer releases in larger amounts, thus the pieces are visible, opposed to when the skin naturally sheds, it's microscopic so you don't usually see the dead skin cells you lose.
Tinea capitis - ringworm on your scalp, aka cradle cap. Usually requires an antifungal to get rid of it.
Hair can actively grow for up to 6 years.
Since hair is dead cells, hair hangs onto the DNA and it can be used to identify people (missing persons) or for paternity tests (who's your daddy)?
Dying and perming affect the proteins that give it color or keep it connected.
If someone has had prolonged exposure to toxin (carbon monoxide, heavy metals, smoking), the hair shows markers of that damage from the toxins. It can also hang on to markers from being exposed to illicit drugs. It's like a timeline of what you've been exposed to.
isclaimer: if you live in a modernized country, the food that you eat will give you more than enough of the vitamins you need, because you have access to a wide variety of fruits and vegetables, plus tons of food products are fortified with vitamins. So rarely is someone deficient in a whole bunch of vitamins all at once.
- Keratin = a fibrous protein that cells make when they are about to die.
- Cornification = the process of a cell filling up with Keratin and becoming hard.
- Follicle = the hole in the skin where they hair grows out
- Melanin = a protein that adds color to cells of the body (most familiar because they help skin tan)
Arrector pili = the muscle that makes your hairs stand up
Fingernails and hair are made out of keratinized cells. Nails are harder to protect the more tender skin below (and are a primitive tool). Hair is tightly stacked but more flexible.
Because hair grows when cells lining the follicles fill up with keratin and die, your hair grows from your scalp, rather than being added to the ends. Your hair and nails are dead cells so they don't absorb nutrients or feel, although hair can absorb and lose moisture (thus conditioner is important).
Cells in the bulb divide every 23-72 hours.
Straight and curly hair is determined by the shape of the follicle. Symmetrical = straight, asymmetrical = curly. Square follicles is a myth.
There are 2 types of melanin - eumelanin = dark colors; pheomelanin = light. Genetics determines what ratio of each type your skin produces thus determines the color of your hair. Gray hair is produced when the cells are absent of all melanin types.