Human Nervous System.

Essay by siLver-High School, 10th grade May 2003

download word file, 5 pages 5.0 3 reviews

In the central nervous system, the brain and the spinal cord are the two main parts. The brain and spinal cord are protected by bone. The skull encloses the brain, and the vertebrae of the spinal column surround the spinal cord. The brain and spinal cord are also covered and protected by 3 tough membranes called menings. The cerebrospinal fluid cushions the brain and spinal column. The brain contains four ventricles filled with the fluid; the central canal is filled around spinal column.

The brain has three major parts, cerebellum, cerebrum, and the medulla. Also includes the thalamus, hypothalamus, and pons. The thalamus is the relay center of brain and spinal column (also in pain perception). The hypothalamus controls body temperature, blood pressure, sleep, and emotions (also is involved and controls the endocrine system). Pons is a relay system, which links spinal column and major parts. The cerebrum is the largest part of the brain.

It is divided from front to back into the right and left cerebral hemispheres. Nerve fibers pass from one to another, so the left side of your brain controls the right side of your body, and the right side controls the left side, they intersect somewhere in spinal cord. The outer most layer of the brain is the cerebral cortex consisting of gray matter. The surface of the brain has many folds called convolutions, this increases the surface area. The cerebral cortex performs 3 major functions, sensory, motor, and associative. The sensory receives and interprets impulses from sensory organs. The motors initiate impulses responsible for voluntary movement. Associative is responsible for memory, learning, and thought. Beneath the gray matter is an inner area called white matter. White matter consists of myelinated nerve fibers, and connects each hemisphere and other parts of the nervous system. The...