The association cortex processes such mental activities as planning and decision making. The Biology of Behavior 1. The nervous system is a massive network of nerve cells that rapidly relay messages to and from the brain. Neurotransmitters are chemicals which carry information between nerve cells. The endocrine system is a network of glands that manufacture and secrete chemical messengers directly into the bloodstream.
Hormones affect the operation of other glands and organs.
The Nervous System 1. Organization of the Nervous System. The somatic nervous system regulates the actions of the body's skeletal muscles. The autonomic nervous system sustains basic life processes, such as respiration, digestion, and arousal. The sympathetic division responds in emergencies or stressful situations.