# Basic Human Anatomy

How the skin, muscles, bones and organs of the human body layer together, from the heart and lungs to the digestive path and nerves\.

By brave\-wombat\-289d9b21

Topic: Human Body & Medicine

[Open the interactive Jig](https://ask.jig.com/j/maMhMC82SFRX)

## Transcript

### 1. Meet your body

This is a model of a grown\-up human body, standing tall on a museum stand\. Inside you, right now, trillions of tiny living cells are working together\. Let's look under the skin, one layer at a time\.

Drag empty space to turn the model and look at it from any side\.

### 2. Skin: your outer coat

Skin is your body's largest organ\. It keeps germs out, holds water in and helps you feel touch, heat and cold\. It also sweats to cool you down on a hot day\.

An adult's skin covers about 2 square metres, roughly the size of a single bed sheet\.

### 3. Muscles: the movers

Muscles move your bones by pulling on them\. They can only pull, never push, so they work in pairs\. When the biceps on the front of the upper arm tightens, the elbow bends\. Press the button to try it\.

You have more than 600 muscles\. Tough cords called tendons tie them to your bones\.

### 4. Bones: the frame

Under the muscles is the skeleton, the frame that holds you up\. Bones protect soft parts too: the skull guards the brain and the ribs guard the heart and lungs\. Bones are alive, and they grow and mend\.

A baby has around 300 bones\. Many fuse together, so an adult has about 206\.

### 5. Heart: the pump

Your heart is a muscle about the size of your fist\. It squeezes blood through tubes to every part of you: red arteries carry blood away from the heart, and blue veins bring it back\. Slide to see it speed up, like when you run\.

A heart beats about 100,000 times a day and moves around 5 litres of blood every minute at rest\.

### 6. Lungs: the breathers

Your two lungs fill up with air each time you breathe in\. The dome\-shaped muscle beneath them, the diaphragm, pulls down to let air rush in\. Your blood picks up oxygen here and drops off waste gas\.

The left lung is a little smaller than the right, to make room for the heart\.

### 7. Digestion: the food path

Food travels down a tube into the stomach, where it is churned into a mush\. Then it winds through the long, coiled intestines, which soak up the good parts for your body to use\. The big liver above helps out\.

Stretched out, the small intestine would be about 6 to 7 metres long\.

### 8. Brain and nerves: the boss

The brain is the control centre\. Messages race down the spinal cord and out along nerves, shown in yellow, telling muscles when to move\. Other nerves carry back what you see, hear and feel\.

Your brain weighs about 1\.4 kilograms and has around 86 billion nerve cells\.

### 9. One amazing team

Skin, bones, muscles and organs all work together, every second of your life\. Pick a layer to explore it again, and turn the model to look all around\.