Mastering A&P Intro into the Nervous System
Within the white matter of the CNS, axons traveling to similar destinations are bundled together in __________.
tracts
Most neurons in the body are multipolar neurons.
true
Which of the following sequences puts the components of a reflex arc in the correct order of their activation?
receptor, sensory neuron, CNS integration center, motor neuron, effector
Less than 15% of all neurons are interneurons.
False
The somatic motor subdivision of the peripheral nervous system is considered to be an involuntary nervous system.
False
The white matter is the site where neuron cell bodies are clustered.
False
The majority of neurons in the body are
multipolar.
A nerve cell is the same as a
neuron.
The chemical substance that is released at axon terminals is called a
neurotransmitter.
This neuronal region transmits electrical impulses away from the cell body.
axon
This tends to be the longest cytoplasmic projection from a neuron.
axon
Action potentials travel along the
axon membrane.
The entire nerve is surrounded by a tough fibrous sheath called the
epineurium
Gray matter in the CNS contains all of the following except
fiber tracts
Which cells provide the myelin sheath for neurons in the CNS?
oligodendrocyctes
Glial cells that provide the myelin sheath in the CNS are __________.
oligodendrocytes
Motor neurons __________.
form junctions with effector cells, stimulating muscles to contract or glands to secrete
A somatic motor neuron carries
motor commands to the skeletal musculature.
Nerve fascicles are bound into bundles by a wrapping of connective tissue called __________.
perineurium
The covering of a fascicle within a nerve is the
perineurium
Which of the following statements describes interneurons?
Interneurons are multipolar neurons that are confined to the CNS and are linked together in chains that form complex neuronal pathways.
Which cells provide the myelin sheath for neurons in the PNS?
Schwann cells
The difference between myelinated and unmyelinated axons is that
Schwann cells wrap around myelinated axons in concentric layers
Which of the following statements concerning sensory neurons is incorrect?
They contain only dendrites.
What is the function of Nissl (chromatophilic) bodies?
They continually renew cell membranes and proteins of the cytosol.
General visceral sensory impulses include pain, temperature, nausea, and hunger.
True
Special somatic senses have receptors that are located mostly in the head, including hearing and balance and vision.
True
The processes of __________ are in contact with neurons, allowing this type of cell to sense the release of glutamate from neurons. They extract glucose from capillaries to obtain energy.
astrocytes
Of the following, which is the only structure that is found in the PNS, as opposed to in the CNS?
a ganglion
These regions of a neuron are also referred to as terminal boutons.
axon terminal
Which relatively rare type of neuron has two processes extending from opposite sides of the cell body?
bipolar
__________neurons are rare neurons, but are located in the retina and in the olfactory mucosa.
bipolar
This region of the neuron contains a single nucleus surrounded by cytoplasm.
cell body
Most synapses transmit communicating signals using
chemical signaling molecules-neurotransmitters.
Nonmyelinated axons
conduct impulses more slowly than myelinated axons.
Ciliated neuroglial cells that form an epithelium and play an active role in forming and moving cerebrospinal fluid are
ependymal cells.
The peripheral nerve fibers that measure the degree of stretch in the biceps brachii muscle and its tendons are classified as
general somatic sensory.
The peripheral nerve fibers that speed up the movement of the digestive tract are classified as
general visceral motor (efferent).
Most tumors in the brain originate from
glial cells.
__________matter is a mixture of neuronal cell bodies, dendrites, unmyelinated axons, and neuroglia.
gray
Where is the structural link between the CNS and PNS located?
in the gray matter of the CNS
The somatic sensory division of the PNS __________.
includes general senses of pressure, pain, vibration, and temperature in body wall and limbs
A node of Ranvier (myelin sheath gap)
is a bare region of axonal membrane in myelinated axons only.
Which part or parts of the neuron are found in the white matter of the central nervous system?
long axonal processes
These glial cells arise from embryonic white blood cells.
microglia
Which cells are the macrophages of the CNS?
microglial cells
The simplest type of reflex, in which there is no interneuron between the sensory and motor neuron, is called a __________reflex.
monosynaptic
These glial cells surround the cell bodies of sensory neurons within ganglia of the PNS.
satellite cells
Myelin on axons functions to
speed the rate of impulse conduction and insulate neighboring axons from one another.
What is the function of synaptic vesicles inside axon terminals?
store and release neurotransmitters
Chemical signals diffuse between neurons at this location.
synapse