Central Nervous System Health Article

Definition

The central nervous system (CNS) consists of the brain and spinal cord.

Description

Comprised of the brain and spinal cord, the CNS is central to the body as opposed to peripheral. It is responsible for unconscious and conscious body functions as well as intellectual functions that allow humans to think. The neuron is the basic nerve cell of the nervous system, however, the nervous system contains many types of cells other than nerve cells. The nerve cell consists of a nucleus in a cell body, dendrites, and axons. The CNS is heavily guarded with protective features, however, this does not make it immune to disease and disorder. The CNS is cushioned with cerebrospinal fluid (CFS), protected by three layers of meninges, and protected from the body by the blood-brain barrier. The blood-brain barrier prevents harmful substances and disease-causing organisms from contaminating the bloodstream entering the CNS.

The skull (cranium) encloses the brain. Three main areas of the brain, the cerebrum, cerebellum, and brain-stem, contain myelinated nerve fibers and white matter, in contrast to the cortex of the brain, the layer of gray matter. The cerebrum, the largest part of the brain containing the left and right hemispheres, controls conscious activities like motor functions. The cerebellum, located above the brainstem, communicates with other regions of the brain and spinal cord to control balance and coordination. The brainstem, the lowest part of the brain extending to the spinal cord, controls unconscious activities necessary for survival like breathing and blood pressure. The spinal cord is protected by the vertebral column from the cervical area to the sacrum. The spinal cord nerves relay sensory information to the brain and motor information to the body.

Function

The central nervous system (CNS) is a processing center that integrates sensory and motor activities via the brain and spinal cord. Nerves are like an electrical wire with an insulating sheath, called myelin, that facilitates the smooth, high-speed transmission of messages. Information in the nervous system is carried by brief electrical impulses that are conducted away from the body of the nerve cell along the axons. When impulses reach the tips of axons, information is transmitted to the next nerve cell in line, or to a muscle or organ. At the point of contact, or synapse, the information is carried across the gap between cells by neurotransmitters. The CNS has two-way communication. Nerve fibers either relay messages to the brain to communicate sensory stimuli, or they relay messages away from the brain to the body's tissues and organs. It is through the spinal cord that messages are sent back and forth to the brain. Spinal nerves in the spinal cord connect the message relay system to rest of the body

Role in human health

Many health care providers, neurologists, neurosurgeons, physiatrists, neuropsychologists, nurses, occupational therapists, speech language pathologists, physical

therapists, and vocational rehabilitation counselors play a role on the health care team and share in the responsibility of the neurologic patient. A combination of methods for assessing patients with neurologic diseases and disorders enables health care professionals to make informed treatment recommendations. These include neurologic and physical examination, laboratory tests such as lumbar puncture, brain-imaging scans such as MRI, neuropsychological testing, and nuclear medicine tests. Treating neurologic diseases and disorders requires active patient participation along with education and support from health care professionals. While patient education may be time-consuming, it is extremely important to the process of maintaining health and preventing disease.

Common diseases and disorders

There are hundreds of disabling neurological diseases and disorders that affect every age, race, and ethnicity. A few examples include developmental disorders (cerebral palsy), degenerative diseases (Parkinson's and Alzheimer's disease), metabolic diseases (Tay-Sachs disease), cerebrovascular diseases (stroke), autoimmune diseases (multiple sclerosis), and tumors (glioblastoma).