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Body Lab 3-5 / Week 10 / Monday
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Week 10 · Skin, Touch, Smell and Taste

Monday

The biggest organ
// The senses that touch, sniff and sample the world
⏱ about 15 min

Monday: The Biggest Organ

Rocket rolls in a giant cardboard box. "I built the biggest organ detector ever!" he says.

He points it at a heart poster. Then he points it at a lung poster. Nothing beeps.

Raven taps her own sleeve. "What do you notice that covers us from head to toe?"

Nova floats close to Rocket's hand. "The biggest organ might be hiding in plain sight," she says.

Skin is an organ

An organ is a body part that does a special job.

Your skin is the biggest organ in your whole body.

Skin covers and protects everything inside you. It holds your muscles, bones and organs in.

Skin also helps keep your body at just the right temperature.

And skin lets you feel things. That is your sense of touch.

Three layers

LayerWhere it isWhat is there
EpidermisOn the outsideThe skin you can see. New cells form at its bottom.
DermisUnder the epidermisNerve endings, blood vessels, sweat glands and oil glands
Subcutaneous layerAt the bottomMostly fat. It helps keep you warm.
SKIN JOBS
  • Read the question.
  • Tap your answer.
Which is the biggest organ in the body?
Which layer of skin can you see?
Which layer holds the nerve endings for touch?
StatementTrue or false?
Skin is an organ.?
Skin helps keep your body at the right temperature.?
Skin has only one layer.?
Skin lets you feel things you touch.?
WHY THIS EXERCISESkin is an organ with three layers. It protects you, keeps your temperature right and feels touch.

Always making new skin

New skin cells form at the bottom of the epidermis.

They slowly move up to the top. The trip takes about two weeks to a month.

The cells on top are old and tough. They protect you, then flake off.

Every minute, we lose about 30,000 to 40,000 tiny dead skin cells.

Do not worry! Your epidermis keeps making new cells to take their place.

A SKIN CELL'S TRIP
  • ?The old cell flakes off.
  • ?The cell reaches the top and becomes tough.
  • ?A newer cell takes its place.
  • ?The cell moves up toward the top.
  • ?A new cell forms at the bottom of the epidermis.
WHY THIS EXERCISESkin cells form at the bottom, rise to the top, flake off and are replaced.
The biggest organ is the ____.
The outside layer of skin is the ____.
The bottom layer of skin is mostly ____.
Try it
Look closely at the back of your hand with a magnifying glass.
What lines, bumps or tiny hairs do you notice?

Great exploring, skin scientist! Tomorrow we find out how skin keeps you warm and cool.