BIOE 303 Table 9.1 Divisions and Structures of the Nervous System

Brain within the cranium and the spinal cord within the vertebral canal

Responds to nerve impulses (sensations) from sensory nerves; body control center

Central nervous system (CNS)

Composed of sensory, motor, or mixed nerves

Conveys impulses to and from CNS

Peripheral nervous system (PNS)

Composed of specific structures of CNS and nerves of PNS; divided into sympathetic and parasympathetic divisions

Exerts involuntary (autonomic) control of vital body functions, including, heart rate, respiratory rate, blood pressure, digestion, and body temperature

Autonomic nervous system (ANS)

Composed of gray and white matter within the cranium

Serves as control center for nervous system

Brain

Composed of gray and white matter within the vertebral canal of the spinal column

Conveys messages (impulses) to and from brain; reflex center

Spinal cord

Cell within nervous tissue

Responds to stimuli and conveys nerve impulses

Neuron

Transmits impulses from sensory receptor to CNS

Component of a sensory or a mixed nerve within PNS

Sensory (afferent) neuron

Component of a motor or a mixed nerve within PNS

Transmits impulses from CNS to effector organs (muscles or glands)

Motor (efferent) neuron

Cell within nervous tissue

Supports neurons

Neuroglium

Bundle of nerve fibers within PNS

Conveys impulses

Nerve

Bundle of nerve fibers within CNS

Interconnects structures of CNS; conveys impulses

Tract

Cluster of cell bodies of neurons within PNS

Serves as control center for a bundle of neurons

Ganglion

Cluster of cell bodies of neurons within white matter of CNS

Serves as control center fora bundle of neurons

Nucleus

Network of nerves within PNS

Provides overlapping innervation (nerve supply) to certain body regions

Nerve plexus