a group of physiologically or anatomically related organs or parts

the entire physical structure of an organism (an animal, plant, or human being)

tissue composed of neurons

an encapsulated neural structure consisting of a collection of cell bodies or neurons

a cell that is specialized to conduct nerve impulses

a bundle of fibers (especially nerve fibers)

originates in the thoracic regions of the spinal cord; opposes physiological effects of the parasympathetic: reduces digestive secretions; speeds the heart; contracts blood vessels

originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels

the entire physical structure of an organism (an animal, plant, or human being)

tissue composed of neurons

an encapsulated neural structure consisting of a collection of cell bodies or neurons

a cell that is specialized to conduct nerve impulses

a bundle of fibers (especially nerve fibers)