Anatomy and Physiology-Chapter 6: The Nervous System (Vocabulary 6.1-6.2)

Afferent nerves

Sensory transmitters that send impulses from receptors in the skin, muscles, and joints to the central nervous system.

Autonomic nervous system

Branch of the nervous system that controls involuntary body functions.

Cell body

Part of an axon that contains a nucleus.

Central Nervous System (CNS)

The brain and spinal cord.

Dendrites

Branches of a neuron that collect stimuli and transport them to the cell body.

Efferent nerves

Motor transmitters that carry impulses from the central nervous system out to the muscles and glands.

Myelin sheath

The fatty bands of insulation surrounding axon fibers.

Neurilemma

The thin, membranous sheath enveloping a nerve fiber.

Neuroglia

Non-neural tissue that forms the interstitial or supporting elements of the CNS; also known as glial cells.

Nodes of Ranvier

The uninsulated gaps in the myelin sheath of a nerve fiber where the axon is exposed.

Peripheral Nervous System (PNS)

All parts of the nervous system external to the brain and spinal cord.

Somatic Nervous System

Branch of the nervous system that stimulates the skeletal muscles

Synapse

The intersection between a neuron and another neuron, a muscle, a gland, or a sensory receptor.

Autonomic reflexes

Involuntary stimuli transmitted to cardiac and smooth muscle

Conductivity

The ability of a neuron to transmit a nerve impulse

Depolarized

A condition in which the inside of a cell membrane is more positively charged than the outside

Nerve impulse

Electrical charge that travels along a nerve fiber when stimulated

Polarized

A condition that occurs when the inside of a cell membrane is more negatively charged than the outside

Reflexes

Simple, rapid, involuntary, programmed responses to stimuli

Refractory period

The time between the completion of the action potential and repolarization

Repolarization

The reestablishment of a polarized state in a cell after depolarization

Saltatory conduction

The rapid skipping of an action potential from node to node on myelinated neurons

Somatic reflexes

Involuntary stimuli transmitted to skeletal muscles from neural arcs in the spinal cord

Axon

A long, tail-like projection of a neuron that carries an impulse away from the cell body.

Neuron

A nerve cell that conducts an impulse.