1. pertaining to a nerve or nerves.
2. unduly excitable.
- n. acetonemia — in contrast to the more common form of this disease of cattle, the wasting form, this one is manifested by delirious signs of circling, head pushing, leaning, straddling, forceful licking including themselves, salivation and incoordination. There is a strong acetonuria and odor on the breath.
- autonomic n. system — the branch of the nervous system that works without conscious control. The voluntary nervous system governs the striated or skeletal muscles, whereas the autonomic governs the glands, the cardiac muscle, and the smooth muscles, such as those of the digestive system, the respiratory system and the skin. The autonomic nervous system is divided into two subsidiary systems, the sympathetic system and the parasympathetic system. — It is also divided into central and peripheral sections. The core of the central section is the hypothalamus which receives afferent input from many other parts of the brain including the cerebral cortex. Its efferent output goes to many lower centers in the nervous system that have visceral control as their functions, e.g. the respiratory center in the medulla. The peripheral section consists of nonmedullated nerve fibers that leave the central nervous system in the craniosacral outflow (parasympathetic system) or the thoracolumbar outflow (sympathetic) system, and terminate in effector organs after passing through a ganglion, visible paravertebral ganglia in the sympathetic system, or ganglia embedded in the wall of the target organ in the parasympathetic system.
- central n. system — the portion of the nervous system consisting of the brain and spinal cord. See also nervous, brain, cerebral.
- n. dysfunction — can occur in any of four ways: (1) Excitation or irritation, an increase in the number of electrical stimuli or facilitation in their passage. (2) Release phenomena, from the damping, modifying effects of higher centers; includes spasticity, exaggerated tendon jerks. (3) paralysis, due to reduction or cessation of transmission of nerve impulses. (4) Nervous shock, a temporary cessation of activity in the nervous system as a whole in response to an insult applied to a part of it.
- n. excitation — see nervous dysfunction (above).
- n. paralysis — see nervous dysfunction (above).
- peripheral n. system — the portion of the nervous system consisting of the nerves and ganglia outside the brain and spinal cord.
- n. release phenomena — see nervous dysfunction (above).
- n. shock — see nervous dysfunction (above).
- n. system — the organ system that along with the endocrine system, correlates the adjustments and reactions of an organism to internal and environmental conditions, comprising the central, peripheral and autonomic nervous systems.
