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White matter vs Grey Matter [Show Notes]

October 3, 2016 in Brain / Podcasts tagged axon / brain cells / dendrite / gray / grey matter / myelin / neurons / terminal / white matter by Cynthia Hendrix

Basic Brain Biology

Your brain is made of cells. Those cells are called neurons. Neurons transmit signals in the form of electricity (aka .positive and negative charges). One end of a neuron will build a signal or charge, and once it reaches a certain threshold, then a signal is send down the axons.

Most of the cells in your body touch and transmit signals and pass chemicals through their membranes. Neurons do not touch. The terminals of one will get really really close to the dendrites of another.

They’re really good at the telephone game – mostly because the body tries to minimize the number of neurons involved in passing a signal.

Axons are coated in myelin. Myelin insulates the axon that helps the signal being sent travel faster, and prevents it from getting lost to something else touching it. You want the signal to have to same strength when it reaches its destination as it did when it left its source.

Parts of a neuron

Dendrites: receives signals from previous neuron
Cell body: contains the nucleus and creates and translates signals
Axon: the “wire” that transmits signals
Terminals: sends signals to the next neuron

a hand-drawn sketch of a basic neuron with labeled parts. This makes up white matter and grey matter in the brain.

Grey matter – cell bodies, dendrites, and terminals
White matter – axons wrapped in myelin

Grey matter – information storage and translation
White matter – information transmission

Brain: grey matter is on the outside, white matter is on the inside
Spinal cord: grey matter is on the inside, white matter is on the outside.

PS. Grey? Gray? IDK!!!

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Music Credits: “Radio Martini” Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0/

Hair 101 [Show Notes]

July 6, 2016 in Podcasts tagged 101 / basics / curly / gray / hair / keratin / melanin / straight by Cynthia H.

Key Words

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 the hair grows out
Melanin = a protein that adds color to cells of the body (most familiar because they help skin tan)

Hand-drawn and colored sketch of the layer of skin where hair grows from, with labeled parts.

Hair Basics

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. They are both dead cells so they don’t absorb nutrients or feel.

Because hair grows when cells lining the follicles fill up with keratin and die, it grows from your scalp, rather than being added to the ends.

Cells in the bulb divide every 23-72 hours.

Straight or curly 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. It turns gray because the cells are absent of all melanin types.