Anatomy and Physiology: Control Systems

The human body has two control systems: the nervous system and the endocrine system.  The nervous system is faster and more complicated.  It sends electrochemical signals which stimulate immediate responses.  When electrochemical signals is being transferred, it goes down the axon of a nerve cell and is transmitted across the synapse (gap between nerve cells) to the next neuron.

The endocrine system works more slowly.  Hormones are released into the bloodstream, which then transports them to their target cells.  The hormones then act on their target cells to regulate their activity.  Unlike the nervous system, which causes a fast, specific response, the one hormone can affect the activity of many cells at the same time.


It is important for the body to have these two control systems because the nervous system is responsible mainly for rapid, immediate movement, such as skeletal muscle movement while the endocrine system is responsible for regulating a lot of the metabolic processes in the body, including cellular respiration.


Sources:
neuron picture from:
http://science.howstuffworks.com/environmental/life/human-biology/brain1.htm
endocrine system picture from: 
http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_mckinley/endocrine%20system.htm
information from:
Elaine N. Marieb's Essentials of Human Anatomy & Physiology, Eighth Edition
https://docs.google.com/viewer?a=v&q=cache:pLygcenOGmsJ:www.angelo.edu/faculty/cadkins/Chp%252011%2520Control%2520Systems%2520of%2520the%2520Body.doc+control+systems+of+the+body&hl=en&gl=us&pid=bl&srcid=ADGEESjnS4rDPRFota_fUK0IVxBfnxaAhxkM67A8zn6hQAvTQanM0JGUS7BZEL72iuxRJ_lkw3cu_lRywmMN0KsoW6dzgfzoiDdKUPzh_6IRXLs7uMUZOfpm0lNiQKajteuzrfxf4jJ4&sig=AHIEtbRkIj6WxLjs0RmupHze3J-lSe08vQ&pli=1