Review: Introduction to the Nervous System
Here is what we have learned from this Introduction to the Nervous System:
- The nervous system is the major controlling, regulatory, and communicating system in the body. It is the center of all mental activity including thought, learning, and memory.
- The various activities of the nervous system can be grouped together as three general, overlapping functions: sensory, integrative, and motor.
- Neurons are the nerve cells that transmit impulses. Supporting cells are neuroglia.
- The three components of a neuron are a cell body or soma, one or more afferent processes called dendrites, and a single efferent process called an axon.
- The central nervous system consists of the brain and spinal cord. Cranial nerves, spinal nerves, and ganglia make up the peripheral nervous system.
- The afferent division of the peripheral nervous system carries impulses to the CNS; the efferent division carries impulses away from the CNS.
- There are three layers of meninges around the brain and spinal cord. The outer layer is dura mater, the middle layer is arachnoid, and the innermost layer is pia mater.
- The spinal cord functions as a conduction pathway and as a reflex center. Sensory impulses travel to the brain on ascending tracts in the cord. Motor impulses travel on descending tracts.