Chapter 12: The Nervous System
The fastest nerve fibers in the body can conduct impulses up to approximately:
130 meters per second
The nervous system is organized to do which of the following?
Detect changes in the external environment Detect changes in the internal environment Evaluate changes in the environment
Which of the following is the deepest connective tissue layer of a nerve?
Endoneurium
Bundles of unmyelinated fibers make up what is referred to as white matter.
False
Ependymal cells engulf and destroy microbes and cellular debris in inflamed or degenerating brain tissue.
False
Microglia are functionally and developmentally very close to neurons.
False
Myelinated axons without gaps in the myelin (nodes of Ranvier) conduct impulses more efficiently than axons with nodes of Ranvier.
False
Regeneration of nerve fibers is impossible, even if the cell body is intact and the fibers have a neurilemma.
False
Unipolar neurons have no axon.
False
Which of the following is not a function of the central nervous system(CNS)?
Integrating sensory information Evaluating the information Initiating an outgoing response
Schwann cells have a similar function in the peripheral nervous system as these cells have in the central nervous system.
Oligodendrocytes
The myelin sheath is formed by:
Schwann cells
Which of the following statements does not apply to ependymal cells?
They make up part of the blood-brain barrier
Damage to a single neuron can have a "domino" effect causing the shutdown of an entire nerve pathway.
True
Gray fibers probably do not have nodes of Ranvier.
True
Most injuries to the brain and spinal cord cause permanent damage.
True
Most tumors of the nervous system do not develop directly from neurons.
True
Multiple sclerosis is the most common primary disease of the CNS.
True
Myelinated fibers conduct impulses faster than unmyelinated fibers.
True
Oligodendrocytes form myelin sheaths around nerve fibers in the CNS.
True
Part of the function of the astrocyte is to help feed the neurons.
True
Regeneration of nerve fibers will occur only if the cell body is intact and the fibers have a neurilemma.
True
Small, lipid-soluble molecules can diffuse easily across the blood-brain.
True
The microglia engulf and destroy microorganisms and cellular debris.
True
The name of the astrocyte comes from its shape.
True
The peripheral nervous system includes both efferent and afferent nerves.
True
There are differences between the central and peripheral nervous systems concerning the repair of damaged fibers.
True
There is a time when a neuron will not send a nerve impulse no matter how strong the stimulus is.
True
When "central" and "peripheral" are used as directional terms in the nervous system, a nerve fiber may be called peripheral if it extends from the cell body away from the central nervous system.
True
One of the components of the blood-brain barrier is:
astrocytes
Along a neuron, the correct pathway for impulse conduction is:
dendrite, cell body, and axon
The autonomic nervous system functions chiefly in the:
innervation of smooth muscle in the viscera
In the human nervous system:
most of the cells are glia cells
A neuron that has only one axon but several dendrites is classified as a:
multipolar neuron
The white matter of the nervous system is made up of:
myelinated fibers
Astrocytes attach to:
neurons blood vessels
The peripheral nervous system includes:
only cranial nerves, spinal nerves, and their branches
Fascicles are held together by a connective tissue layer called the:
perineurium
Nerves that contain mostly afferent fibers are called:
sensory nerves
A neuron that transmits a nerve impulse toward the central nervous system is called a(n):
sensory neuron
The autonomic nervous system does not stimulate:
skeletal muscles
The part of the nervous system that transmits impulses from the CNS to the skeletal muscle is the:
somatic nervous system
The autonomic nervous system consists of the:
sympathetic and parasympathetic nervous systems
Dendrites conduct impulses:
toward cell bodies
Sensory neurons are usually:
unipolar
