Nervous System 7
The Schwann cell forms a myelin sheath around the ____.
axon
The part of the neuron that typically conducts nerve impulses away from the cell body is the ____.
axon
The term central nervous system refers to the ____.
brain and spinal cord
Which ion causes neurotransmitter vesicles to fuse with the axon's membrane during the conduction of a nerve impulse from one neuron to the next?
calcium
Ganglia are collections of ____.
cell bodies
The nervous system is structurally subdivided into two systems: ____ nervous system and ____ nervous system.
central; peripheral
What canal connects the third ventricle of the diencephalon to the fourth ventricle?
cerebral aqueduct
The major role of the interneuron (association neuron) is to ____.
connect motor and sensory neurons in their pathways
What connects the cerebral hemispheres
corpus callosum
The neuron processes that normally receive incoming stimuli are called ____.
dendrites
A stroke in the primary motor area has caused Don to lose control over his skeletal muscles on the right side of his body. What lobe of his brain was damaged?
frontal lobe
The two major functional properties of neurons are ____.
irritability and conductivity
Neurons with several processes branching off the cell body, such as motor neurons and interneurons (association neurons), are structurally classified as ____.
multipolar
Impulse conduction is fastest in neurons that are ____.
myelinated
Support cells in the central nervous system are collectively called ____.
neuroglia
The substance that is released at axonal endings to propagate a nervous impulse is called ____.
neurotransmitter
The gaps between Schwann cells found at regular intervals in peripheral system neurons are called ____.
nodes of ranvier
Which of these neuroglial cells forms the myelin sheath in the central nervous system?
oligodendrocytes
During the resting state, a neuron is ____.
polarized with more sodium ions outside the cell and more potassium ions inside the cell
Immediately after an action potential is propagated, which one of the following ions rapidly diffuses out of the cell into the tissue fluid ____.
potassium
Sensory receptors located in muscles and tendons are termed ____.
proprioceptors
Nerve impulse transmissions occurring along myelinated neurons are called ____.
saltatory conduction
An action potential is caused by an influx of these ions into the cell ____.
sodium
During repolarization, ____ ions are pumped out of the cell.
sodium
Fibers that carry information from the skin, joints, and skeletal muscles to the central nervous system are ____.
somatic sensory
The gap between two communicating neurons is termed ____.
synaptic cleft
What is the relay station for sensory impulses passing upward to the sensory cortex?
thalamus
Neurons either conduct action potentials along the length of their axons, or they remain at rest. This statement best describes ____.
the all-or-none response
Bundles of nerve fibers (neuron processes) running through the CNS are called ____, whereas in the PNS they are called ____.
tracts; nerves
Ependymal cells beat their cilia to help circulate cerebrospinal fluid (CSF). T/F
true
Gray matter contains collections of unmyelinated fibers and cell bodies in the central nervous system. T/F
true
Sally has a brain injury; she knows what she wants to say but can't vocalize the words. The part of her brain that deals with the ability to speak is the ____.
Broca's area
____ connect sensory and motor neurons in neural pathways and their cell bodies are typically located in the central nervous system.
Interneurons (association neurons)
____ disease results from a degeneration of the dopamine-releasing neurons of the substantia nigra.
Parkinson's
____ cells form the myelin sheaths around nerve fibers in the PNS.
Schwann
