What are muscles?

These soft tissue structures when they contract allow you to move your arms and legs.

What are bones?

These rigid organs make up the skeleton.

What are lungs?

These paired organs allow you to breath in air.

What is the heart?

This muscular organ pumps fluid through the circulatory system.

What are the eyes?

These structures are the primary organs of vision.

What are joints?

These structures are the location where two or more bones are fitted together.

What are vertebrae?

These are a series of small bones forming the backbone.

What is oxygen?

This molecule is the most essential inhaled gas.

What is blood?

The heart pumps this fluid throughout the body.

What are eyelids?

These thin folds of skin cover and protect the eyes.

What is flexion?

The bending movement that decreases the angle between body parts.

What is the femur?

This bone is the top most bone in the leg. Also called the thighbone.

What is a stethoscope?

This medical device used to listen to internal sounds of the human body.

What are atria?

These chambers collect blood as it returns to the heart.

What are pupils?

These structures allow light to enter the eyes and strike the retina.

What is extension?

The bending movement that increases the angle between body parts.

What is the humerus?

This bone in the arms runs from the shoulder to the elbow.

What is carbon dioxide?

This molecule is the most exhaled gas by humans.

What are ventricles?

These chambers collect and expel blood out of the heart.

What is the optic nerve?

This nerve transmits visual information to the brain from the eye.

What is a tendon?

This structure attaches a muscle to a bone.

What is calcium?

This is the most abundant mineral in the bones.

What is the trachea?

This hollow tube connects the pharynx to the lungs, allowing the passage of air.

What are valves?

These structures allow blood to flow in only one direction through the heart.

What are the irises?

These structures define the eye color and control how much light enters the eye.