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Your nervous system, nutrition, and physical activity

Published: December 01, 2017

Your nervous system, your primary internal communication system, senses and interprets changes in external and internal body conditions and relays appropriate instructions to your organs and tissues in response. 

For instance, this communication system senses when you are hungry, thirsty, in pain, or needing oxygen.
It then responds via nerve borne and chemical signals sent to specific glands, organs, involuntary internal muscles, and your digestive, and cardiovascular systems to make changes to alleviate the situation.
What has food got to do with your nervous system?
What has food got to do with your nervous system?
Your nervous system also controls voluntary muscles (leg and arm muscles) in response to sensory stimuli.
There are two parts to your nervous system: your central nervous system (CNS) which consists of your brain and spinal cord, and your peripheral nervous system which consists of 12 pairs of cranial nerves which connect your CNS to the rest of your body tissues.
Two pairs begin in your brain and the remaining ten pairs from your brain stem. In addition to your cranial nerves your spinal cord is the source of 31 pairs of spinal nerves which have both motor and sensory function, and which are identified as:

  • Cervical (C) = 8
  • Thoracic (T) = 12
  • Lumbar (L) = 5
  • Sacral (S) =5
  • Coccygeal = 1

Nerves T2-T12 connect directly to specific muscles and abdominal organs. Click on the Parasympathetic and Sympathetic Nervous System diagram to learn more.

The remaining nerves connect to various muscles via plexuses or networks of nerve branches which consist of nerve fibres from several spinal nerves. Click on the Muscle and Nerve root diagram to learn more.
These nerves are part of 2 systems: your somatic nervous system which connects voluntary muscles to your CNS, and your autonomic nervous system which connects your internal organs and involuntary muscles to your CNS.
Your autonomic system is further divided into your sympathetic nervous system, which restores homeostasis by responding to stress and pain, and your parasympathetic nervous system which controls normal internal body function. 
These two pathways have opposing functions. Messages from your peripheral region are passed as nerve impulses along sensory nerves to your CNS, and messages of response are passed as nerve impulses along motor nerves from your CNS to your peripheral regions...link to the full article to learn more.


Whitney, E. & Rady Rolfes, S. (2005). Understanding Nutrition. Belmont, CA: Thomson Wadsworth
Gropper, S.S., Smith, J.L. & Groff, J.L. (2005). Advanced Nutrition and Human Metabolism (4thEd.). Belmont, CA: Thomson Wadsworth.
American Council on Exercise (1996). Personal Trainer Manual. San Diego, CA: American Council on Exercise
American Council on Exercise (1993) Aerobics Instructor Manual: San Diego, CA: American Council on Exercise