Heart to the lungs to the heart
Lungs to the heart to the other organs
Lungs to the heart to the lungs
Body tissues to the lungs to the heart
Deliver oxygen to body parts
Remove carbon dioxide from the lungs
Deliver vitamins to cells
Promote healing by clotting at wounds
Red blood cells
White blood cells
Make new blood cells
Support the body frame
Supply oxygen to the blood
Can move in only one direction
Allows a small range of sideways movement
Can move up and down and from side to side
Can move in all directions
Pairs of skeletal muscles work in opposition to move bones.
Involuntary muscles work in sets, while voluntary muscles work independently.
Each muscle is responsible for moving several bones.
Muscles from different parts of the body pull together to create movement.
An hour of vigorous activity
An aerobic activity
Exercises to build strength