The NERVOUS SYSTEM: An AMAZING, COMPLEX ARCHITECTURE

INTRODUCTION to the MOST COMPLEX SYSTEM of ALL in YOUR BODY:
THE NERVOUS SYSTEM

A diagram of the main parts of a neuron

Overview of your SPINAL and CRANIAL nerves. Note the eight CERVICAL nerves, the 12 THORACIC nerves, the 5 LUMBAR nerves, and the 5 SACRAL nerves.
Which nerves innervate your arms?
Which nerves innervate your legs?

Detailed view of the MAJOR NERVES in your body.

The DERMATOMES of your body. If you have a spinal cord injury, for example, by slipping on ice, the corresponding dermatome will become numb or will hurt greatly. For example, if the front of your leg including your knee becomes numb, which vertebrae in your spinal cord has become injured ?

A SAGITTAL view (cut in half) of the brain to show the internal structures. Note in particular the HYPOTHALAMUS and the PITUITARY gland. Among other things, these parts of your brain are critical in changing boys and girls into men and women.

The FOUR LOBES of the Brain: FRONTAL lobe, PARIETAL lobe, OCCIPITAL lobe and TEMPORAL lobe. COMPARE to the bones of the skull. WHAT do each of these lobes do?

REFLEXES are hard wired into your spinal cord, and react even before your brain is notified. Some examples of reflexes are to...

• Help pick up an unexpectedly heavy load
• Drop a disastrously heavy load before your muscles and/or tendons are torn
• Help to balance your body
• Take away your arm or leg from a pan that is too hot or a sharp object on the ground