Know the 5 Major Human Body Systems for the ASVAB

By Rod Powers

You will need to know the five major human body systems for the ASVAB. Your body consists of major systems that work together to keep you alive. (And staying alive is a good thing, so be sure to thank your circulatory system and all the rest!) These systems include the ones listed here.

System Components What the System Does
Central nervous system Brain, spinal cord, and nerves Receives, processes, and responds to all physical stimuli; for
example, if you burn your hand on the stove, this system prompts
you to remove your hand from the stove
Circulatory system Heart, blood, and blood vessels Delivers oxygenated blood from the heart to the rest of the
body and returns the blood to the heart to be oxygenated again
Digestive system Mouth, esophagus, stomach, small and large intestines, rectum,
and anus
Breaks down food into smaller substances that the body can
absorb and process into energy and eliminates the resulting
Musculoskeletal system Bones, joints, voluntary and involuntary muscles Bones support the body’s muscles and organs; joints allow
bones to move; voluntary muscles work in pairs to move joints;
involuntary muscles, which you can’t control, are found in
organs such as the heart
Respiratory system Nose, nasal cavity, trachea, lungs, and blood Inhales air, uses the oxygen in the air to release energy, and
exhales the carbon dioxide that results from this process