Lesson 6.4 & 6.5: Learning the Key Terms

cranial nerves

12 pairs of nerves that originate in the brain and relay impulses to and from the PNS

craniosacral division

the parasympathetic nervous system, in which nerves originate in the brain stem or sacral region of the spinal cord

dorsal ramus

the division of posterior spinal nerves that transmit motor impulses to the posterior trunk muscles and relay sensory impulses from the skin of the back

endoneurium

a delicate connective tissue that surrounds each nerve fiber

epineurium

the tough outer covering of a nerve

ganglion

a mass of nervous tissue composed mostly of nerve-cell bodies

norepinephrine

a neurotransmitter released by postganglionic neurons in the sympathetic nervous system

paravertebral ganglia

mass of nerve cell bodies close to the spinal cord

perineurium

a protective sheath that surrounds a bundle of nerve fibers

plexuses

complex interconnections of nerves

postganglionic neuron

the second neuron in a series that transmits impulses from the CNS

preganglionic neuron

the first neuron in a series that transmits impulses from the CNS

spinal nerves

neural transmitters that branch from the left and right sides of the spinal cord

thoracolumbar division

the sympathetic system of nerves that lies near the thoracic and lumbar regions of the spine

ventral ramus

the anterior division of spinal nerves that communicate with the muscle and skin of the anterior and lateral trunk

Alzheimer's disease

condition involving a progressive loss of brain function with major consequences for memory, thinking, and behavior

cerebral palsy

a group of nervous system disorders resulting from brain damage before or during birth, or in early infancy

dementia

an organic brain disease involving loss of function in two or more areas of cognition

epilepsy

a group of brain disorders characterized by repeated seizures over time

meningitis

an infection-induced inflammation of the meninges surrounding the brain and spinal cord

multiple sclreosis

a chronic, slowly progressive disease of the central nervous system that destroys the myelin sheath of nerve cell axons

paraplegia

disorder characterized by loss of function in the lower trunk and legs

Parkinson's disease

a chronic nervous system disease characterized by a slowly spreading tremor, muscular weakness, and rigidity

quadriplegia

disorder characterized by loss of function below the neck

traumatic brain injury

mild or severe trauma that can result from a violent impact to the head