nervous system Flashcards
Which of these is not a function of the nervous system?
secreting hormones into the bloodstream to affect far-away organs
Which of the following is true regarding the basic divisions of the nervous system?
The central nervous system is in charge of integrating incoming sensory information with past experiences and dictating motor responses.
A somatic motor neuron carries
motor commands to the skeletal musculature.
A nerve cell is the same as a
neuron
Which of the following is not a characteristic of neurons?
ability to survive without oxygen
This region of the neuron contains a single nucleus surrounded by cytoplasm.
cell body
This region of a neuron contains chromatophilic substance or Nissl bodies.
cell body
Neurofibrils
prevent the neuron from being pulled apart when subjected to tensile forces.
Ganglia represent
groups of neuron cell bodies in the PNS.
This region of a neuron is characterized by numerous, short cytoplasmic extensions and is often referred to as receiving regions.
dendrite
All of the following are characteristics of dendrites except that they
always conduct action potentials.
This neuronal region transmits electrical impulses away from the cell body.
axon
Which of the following statements about an axon is false?
It carries nerve impulses toward the cell body.
This tends to be the longest cytoplasmic projection from a neuron.
axon
In this part of a neuron, neurofilaments, actin microfilaments, and microtubules are particularly abundant, providing structural support and a transport network.
axon
Action potentials travel along the
axon membrane
This part of the neuron may have branching collaterals.
axon
Mitochondria are particularly abundant here.
axon terminal
This is the site of communication between neurons.
synapse
Most synapses transmit communicating signals using
chemical signaling molecules-neurotransmitters.
In an axodendritic synapse, the region of the postsynaptic neuron that binds the released neurotransmitter is the
dendrite
The ________ of a presynaptic neuron associates with the dendrite of a postsynaptic neuron.
axon terminal
An axosomatic synapse occurs between the axon terminals of one neuron and the ________ of a proximal neuron.
cell body
The chemical substance that is released at axon terminals is called a
neurotransmitter.
Vesicles containing neurotransmitters are located in
axon terminals.
Which of the following is the correct path an impulse takes across a synapse?
axon of presynaptic neuron, synaptic cleft, dendrite of postsynaptic neuron
The majority of neurons in the body are
multipolar.
Which relatively rare type of neuron has two processes extending from opposite sides of the cell body?
bipolar
Which of the following statements concerning sensory neurons is incorrect?
They contain only dendrites.
Interneurons are found
only in the CNS
Astrocytes perform all of the following functions except
produce cerebrospinal fluid
Which cells are the macrophages of the CNS?
microglial cells
These glial cells arise from embryonic white blood cells.
microglia
Ciliated neuroglial cells that form an epithelium and play an active role in forming and moving cerebrospinal fluid are
ependymal cells.
These glial cells surround the cell bodies of sensory neurons within ganglia of the PNS.
satellite cells
Which cells provide the myelin sheath for neurons in the CNS?
oligodendrocyctes
Which cells provide the myelin sheath for neurons in the PNS?
Schwann cells
Myelin on axons functions to
speed the rate of impulse conduction and insulate neighboring axons from one another.
A node of Ranvier (myelin sheath gap)
is a bare region of axonal membrane in myelinated axons only.
Nonmyelinated axons
conduct impulses more slowly than myelinated axons.
The difference between myelinated and unmyelinated axons in the PNS is that
Schwann cells wrap around myelinated axons in concentric layers.
The type of axon that conducts impulses most slowly is
thin, unmyelinated.
Gray matter in the CNS contains all of the following except
fiber tracts.
Special somatic senses have receptors that are located mostly in the head, including hearing and balance and vision.
true
A neuron is a collection of nerve fibers in the PNS.
false
All of the neuron’s organelles are localized to the cell body.
false
Any long axon is called a nerve fiber.
true
Chromatophilic bodies are clusters of rough ER and free ribosomes that produce the large amount of proteins needed by a neuron.
true
Most neurons in the body are multipolar neurons.
true
Less than 15% of all neurons are interneurons.
false
Microglia are ciliated to help circulate cerebrospinal fluid (CSF).
false
Oligodendrocytes and Schwann cells myelinate neurons within the peripheral nervous system.
false
The supporting cells of the nervous system that surround and wrap neurons are derived from embryonic neuroepithelial cells from the ectoderm.
true
The white matter is the site where neuron cell bodies are clustered.
false
