keratin: (noun) A tough, fibrous protein that forms the main structural constituent of hair, feathers, hoofs, claws, and horn
Chapter 1

The skin as a living shield

Chapter 2

The science of hair and nails

Chapter 3

The skin as a living ecosystem

YOUR GOAL

Master of The human integumentary system

Ch 2 · The science of hair and nails
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artiteacher The structural power of keratin

Jul 12

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artiteacher Hair and Nails

Hair on your head, nails on your hands, keratin's running the show!

Jul 10

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artiteacher The phases of hair growth

Jul 12

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The truth about nail growth

artiteacher Human fingernails and toenails grow at different rates, influenced by blood flow, age, and even hand dominance.

Jul 10

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The phases of hair growth

artiteacher Every hair on your head grows in a three-stage cycle that determines its length and lifespan.

Jul 10

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Little Layers Lab
BETA

artiteacher Stack skin layers to discover how your skin, hair, and nails protect you.

Jul 10

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Fun Fact

Nail growth: Fingernails grow faster on your dominant hand because increased usage boosts blood circulation to the fingertips.

Jul 10

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Glossary
keratin (noun)
A tough, fibrous protein that forms the main structural constituent of hair, feathers, hoofs, claws, and horns. This protein makes up the dead, visible cells of the human hair shaft and nail plate.

Jul 10

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Gossip

Which hair length do you prefer to rock?

Jul 10

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Quiz

Why do fingernails grow faster during the summer months?

Jul 10

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artiteacher The truth about nail growth

Jul 12

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Quiz

What is the active growth phase of a hair follicle called?

Jul 10

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artiteacher The evolutionary purpose of goosebumps

Jul 12

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Quiz

Apart from human hair and nails, where else is keratin commonly found in nature?

Jul 10

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Quiz

Which tiny muscle contracts to pull hair upright and cause goosebumps?

Jul 10

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Quiz

How much faster do fingernails grow compared to toenails?

Jul 10

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Quiz

On average, how many hairs does a human naturally shed from their head each day?

Jul 10

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Quiz

What is the transitional, non-growth phase of the hair cycle called?

Jul 10

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Quiz

Which tough, fibrous protein makes up the primary structure of human hair and nails?

Jul 10