Neurologic system

OpenStax / CC BY

The neurologic system is the body’s communication network. It coordinates and organizes the functions of all other body systems: There are two divisions of this network:
• The central nervous system (CNS), made up of the brain and spinal cord, is the body’s control center.
• The peripheral nervous system, containing cranial and spinal nerves, provides communication between the CNS and remote body parts.

Central nervous system
• Protects the brain and spinal cord by the skull and vertebrae, cerebrospinal fluid, and three membranes — the dura mater, the arachnoid membrane, and the pia mater.
• Houses the nerve center, called the cerebrum, that controls sensory and motor activities and intelligence.
• Transmits impulses to and from the cerebrum by the thalamus and maintains connections to the brain, spinal cord, autonomic nervous system, and pituitary gland by the hypothalamus.
• Coordinates muscle movements, controls posture, and maintains equilibrium by the cerebellum and the brain stem.
• Relays sensations that are needed for voluntary or reflex motor activity through the spinal cord.

Peripheral nervous system
• Originates in 31 pairs of spinal nerves arranged in segments and attached to the spinal cord.
• Divided into the somatic nervous system, which regulates voluntary motor control, and the autonomic nervous system, which helps to regulate the body’s internal environment through involuntary control of the organ systems.

How neurologic disorders develop
• Alzheimer’s disease — a progressive degenerative disorder of the cerebral cortex.
• Amyotrophic lateral sclerosis — the most common of the motor neuron diseases causing muscular atrophy.
• Epilepsy — a brain condition characterized by recurrent seizures.
• Gullian-Barré syndrome — an acute, rapidly progressive, potentially fatal syndrome that’s associated with segmented demyelination of the peripheral nerves.
• Multiple sclerosis — results from progressive demyelination of the white matter of the brain and spinal cord, leading to widespread neurologic dysfunction.
• Meningitis — a condition that causes inflammation of the brain and spinal cord meninges.
• Myasthenia gravis — a condition that produces sporadic, progressive weakness and abnormal fatigue of the voluntary skeletal muscles.
• Parkinson’s disease — produces progressive muscle rigidity, loss of muscle movement, and involuntary tremors.
• Stroke — a sudden impairment of cerebral circulation in one or more of the blood vessels supplying the brain.