The Human Machine

Muscles and Bones

100

Without these, your body would be only a blob. 

Bones

200

These are like strings that connect your muscles and bones.

Tendons

300

When this part of your body bunches up, it pulls on your bones to make you move. 

Muscle

400

If your muscles don't work, you will have trouble _____.

Moving

Light, Eyes, & Vision

100

The "lens" at the front of the eye is called the ____. 

Cornea

200

This colored part of the eye does NOT change the way you see. 

Iris

300

The back of the eye, which works like a movie screen, is called the ______. 

Retina

400

Mr. Charlie has blurry vision. These means his eyes are too ___ or ___ .

Long or short 

Structure and Function of Eyes

100

Light comes into the eye through this part.

Pupil

200

This part of the eye can get bigger if an animal can see at night. 

Pupil

300

Animals that can see in the dark also have this at the back of their eyes. 

Shiny reflective material. 

400

A flash can sometimes makes our eyes look red in photos. This is because of the ____ at the back of our eyes. 

Blood vessels

The Brain

100

This part of the body sends messages to and from the brain. 

Nerves

200

When you touch a hot stove, ____ tells your brain the stove is hot. 

Sensory nerves

300

Now that your brain knows the stove is hot, it tells your hand to get off the stove with _____. 

Movement nerves

400

When a mouse sees an owl, its brain will tell it to ____ or ____. 

Hide or run