What accounts for the gray color of gray matter?
|A)||presence of Nissl bodies|
|B)||absence of myelin|
|C)||both of the above|
|D)||neither of the above|
Bundles of neurofilaments extending into dendrites and axons to provide structural support are called
|A)||nodes of Ranvier|
The phrase "terminally differentiated," as applied to mature neurons, means that they
|A)||cannot regenerate damaged parts|
|B)||process energy differently after reaching maturity|
|C)||cannot divide mitotically to produce daughter cells|
|D)||have axon terminals specialized for impulse conduction|
Although they outnumber ____________ by as much as ten to one, ____________ account for only about half of the total volume of the nervous system.
|B)||neurons; glial cells|
|C)||interneurons; sensory neurons|
Their methods are different, but ____________ in the CNS and ____________ in the PNS perform similar functions.
|C)||microglia; satellite cells|
|D)||ependymal cells; satellite cells|
Which glial cells behave much like certain leukocytes?
Although classified as glial cells, ____________ are also ____________ that line the cavities in the brain and spinal cord and help form the choroid plexus.
|C)||ependymal cells; epithelial cells|
|D)||oligodendrocytes; epithelial cells|
In the PNS, an axon may be enveloped by ____________ without being ____________.
|C)||satellite cells; in a ganglion|
|D)||endoneurium; in a nerve|
Which glial cells participate in the repair of damaged nerves?
|A)||satellite and ependymal cells|
|D)||astrocytes and microglia|
Which nervous system divisions or components contain no afferent neurons?
|A)||somatic and visceral sensory|
|B)||CNS and PNS|
|C)||PNS and ANS|
|D)||ANS and SNS|
Ironically, a ____________ neuron typically has more dendrites than a ____________ neuron.
A multipolar neuron that synapses on a gland cell is functionally classified as
|A)||a visceral motor neuron|
|B)||a somatic motor neuron|
|C)||a sensory neuron|
In terms of nerve impulse conduction, unmyelinated is to ____________ as myelinated is to ____________.
A nerve impulse involves ____________ across a neuron's plasma membrane.
|A)||changes in voltage|
|B)||movement of ions|
|C)||both a and b|
|D)||neither a nor b|
Axon regeneration in the CNS is restricted by which of the following factors?
|A)||oligodendrocytes do not release a nerve growth factor|
|B)||crowded axons in the brain and spinal cord complicate regrowth|
|C)||astrocytes and connective tissue coverings may form obstructive scar tissue|
|D)||all of the above|
At a chemical synapse, ____________ are found only in the plasma membrane of the ____________ cell.
|B)||receptor proteins; postsynaptic|
|D)||receptor proteins; presynaptic|
Synapses are categorized on the basis of
|A)||point of contact and mode of impulse transmission|
|B)||direction of signal and speed of impulse transmission|
|C)||size of synaptic knob and mode of impulse transmission|
|D)||shape of synaptic knob and speed of impulse transmission|
Which structural classes of neurons are always sensory in function?
|A)||multipolar and unipolar|
|B)||unipolar and bipolar|
|C)||bipolar and multipolar|
|D)||unipolar, bipolar, and multipolar|
The ____________ is the only functional class of neuron entirely restricted to the ____________ nervous system.
|A)||association neuron; central|
|B)||sensory neuron; central|
|C)||motor neuron; peripheral|
Which of the following are structural, as opposed to functional, divisions of the nervous system?
(1) CNS (2) SNS (3) PNS (4) ANS
|A)||1 and 2|
|B)||2 and 4|
|C)||3 and 4|
|D)||1 and 3|
With regard to control of effectors, ____________ is to involuntary as ____________ is to voluntary.
Sensory neurons in which of the following locations receive and transmit only visceral input?
(1) skin (2) joints (3) heart (4) fascia (5) stomach
|A)||1 and 2|
|B)||3 and 5|
|C)||3, 4, and 5|
|D)||2, 3, 4, and 5|
Touch, vibration, and proprioception are examples of
|A)||special visceral senses|
|B)||general visceral senses|
|C)||special somatic senses|
|D)||general somatic senses|
Which statement is false regarding neural circuits?
|A)||converging circuits provide multiple input to a single postsynaptic neuron|
|B)||diverging circuits spread information from one neuron or pool to several others|
|C)||in parallel-after-discharge circuits, a single input leads to multiple individual outputs|
|D)||in reverberating circuits, feedback repeatedly stimulates the circuit in a cyclic pattern|
Increased dietary intake of vitamin B12 and ____________ during pregnancy can dramatically reduce the incidence of neural tube defects such as ____________.
|A)||ascorbic acid (vitamin C); neuritis and demyelination|
|B)||folic acid (folate); anencephaly and spina bifida|
|C)||pantothenic acid; amyotrophic lateral sclerosis|
|D)||iron; Guillain-Barré syndrome|