Chapter 7 Nervous System Vocabulary Words #1

human anatomy

Central nervous system

the brain and the spinal cord.

Peripheral nervous system

a system of nerves that connects the outlying parts of the body with the central nervous system.

Afferent nerves

Nerves that carry impulses only toward the CNS

Efferent nerves

Nerves that carry impulses away from the CNS.

Autonomic nervous system

the division of the nervous system that functions involuntarily; also called involuntary nervous system.

Somatic nervous system

a division of the peripheral nervous system; also called the voluntary nervous system.

Neuroglia

the nonneuronal tissue of the central nervous system that performs supportive and other functions; also called glial cells or glia.

Astrocytes

type of CNS supporting cell; assists in exchanges between blood capillaries and neurons.

Microglia

type of CNS supporting cell; phagocytes that ingest debris such as bacteria or dead cells.

Ependymal cells

type of CNS supporting cell; lines the central cavities of the brain and spinal cord and circulates cerebrospinal fluid with their beating cilia.

Oligodendrocytes

type of CNS supporting cell that has many cellular processes, each of which makes up a myelin sheath.

Satellite cells

type of neuroglia in the PNS; protects and cushions peripheral nerve cell bodies.

Schwann cells

type of neuroglia in the PNS; many Schwann cells form the myelin sheath on a single neuron.

Dendrites

the branching extensions of neurons that carry electrical signals to the cell body; the receptive portion of a nerve cell.

Axon

neuron process that carries impulses away from the nerve cell body

Nodes of ranvier

Gaps or indentations between schwann cells.

Bipolar neurons

Neurons with two processes —> one axon and one dendrite

Unipolar neurons

structural class of neuron with one process extending from the cell body.

Multipolar neurons

structural class of neuron with more than two processes extending from the cell body.

Neurotransmitters

chemical released by neurons that may, upon binding to receptors of neurons or effector cells, stimulate or inhibit them.

Synapse

the region of communication between neurons, or a neuromuscular junction between a neuron and a muscle cell.

Myelin sheath

Encloses the axon and acts as an insulating layer.

Neurilemma

The outer layers of the schwann cells.

Multiple sclerosis (MS)

autoimmune disorder of the CNS where the myelin sheaths are converted into hardened scleroses in the brain and spinal cord; results in loss of control.

Ganglia

Small collections of cell bodies found in a few sites outside the CNS in the PNS.

Gray matter

area that contains unmyelinated nerve fibers and nerve cell bodies.

White matter

area that contains the myelinated nerve fibers.

Interneurons or association neurons

completes the pathway between afferent and efferent neurons

Cutaneous sense organs

Sensory receptors in the skin

proprioceptors

Sensory receptors in the muscles and tendons