Which of these components is usually absent from a neuron?
The afferent division of the PNS___.
carries sensory information
Which of the following is not a function of the nervous system? sense the internal and external environments integrate sensory information direct long-term functions, such as growth coordinate voluntary and involuntary activities control peripheral effectors
direct long term functions such as growth
The ____ nervous system is composed of the brain and spinal cord.
The ____ nervous system controls the skeletal muscles
The part of the peripheral nervous system that carries sensory information to the CNS is designated ____.
The efferent division of the peripheral nervous system innervates:
Which of the following is not a recognized structural classification for neurons?
The most abundant class of neuron in the central nervous system is ___.
The rabies virus travels to the CNS via
retrograde axoplasmic transport
The site of intercellular communication between neuron and another cell is the ___
Neurons that are rare, small, and lack features that distinguish dendrites from axons are called __>
Neurons in which dendritic and axonal processes are continuous and the soma lies off to one side are called ___.
Neurons that have one axon and one dendrite, with the soma in between are called ___.
Neurons that have several dendrites and a single axon are called ___.
___ neurons are the most common class in the CNS
___ neurons form the afferent division of the PNS.
The basic functional unit of the nervous system is the ____
Which is the largest and most abundant type of neuroglia?
Which of these types of neuroglia are abundant in peripheral ganglia?
The largest and most numerous of the glial cells in the central nervous system are the ?
Functions of astrocytes include all of the following except .. guiding neuron development. maintaining the blood-brain barrier. responding to neural tissue damage. conducting action potentials. forming a three-dimensional framework for the CNS.
conducting action potential
Which of the following is a type of glial cell found in the peripheral nervous system?
___ account for roughly half of the volume in the nervous system.
The neuroglial cells that participate in maintaining the blood brain barrier are the ___
The function of the astrocytes in the CNS include which of the following
ALL: repairing damaged neural tissue, maintain the blood brain barrier, adjusting the composition of the interstitial fluid, guiding neuron development
The myelin sheath that covers many CNS axons is formed by ___.
___ line the brain ventricles and spinal cord.
Small, wandering cells that engulf cells that engulf cell debris and pathogens in the CNS are called___.
The neurilemma of axons in the peripheral nervous system is formed by __.
Glial cells that surround the neurons in the ganglia are ___.
Regions of the CNS with an abundance of myelinated axons constitute the ___ .
The events that occur at a functioning cholinergic synapse cause___.
The most abundant intracellular cation is ___ while the most abundant extracellular anion is ___.
Which type of ion channel is always open?
The sodium potassium exchange pump stabilizes resting potential at about___
____ open or close in response to binding specific molecules
___ channels open or close in response to physical distortion of the membrane surface.
Any stimulus that opens ___ ion channels will produce a graded potential.
ALL: a sodium, a mechanically gated, a chem gated, a voltage gated
Ions can move across the plasma membrane in which of the following ways?
ALL: through chemically-gated channels as in neuromuscular transmission, by ATP-dependent ion pumps like the sodium-potassium exchange pump, through passive or leak channels, through voltage-gated channels as in the action potential
Voltage gated sodium channels have both an activation gate and an ____ gate.
During propagation of the action potential ____.
ALL: the axon hillock depolarizes the initial segment, local currents depolarize a spot adjacent to the active zone, after threshold is reached sodium channels open rapidly
Which of these is the earliest step in the generation of an action potential?
Sodium channels open
The all or none principle states that __>
all stimuli great enough to bring the membrane to threshold will produce identical action potentials
A threshold stimulus is the ___.
depolarization necessary to cause an action potential
Which of the following is true about threshold for an action potential.
It is more positive than the resting potential
Compared to type A axons, type C axons are ___
slower propagated, unmyelinated, smaller diameter
Which of these axons will conduct an action potential most quickly?
Type A fiber
Which of the following does not influence the time necessary for a nerve impulse to be transmitted?
whether or not the impulse begins in the CNS
The effect of a nerve impulse on a postsynaptic neuron depends on the ____.
ALL: quality of neurotransmitter released, kind of neurotransmitter released by the presynaptic neuron, characteristics of the receptor on the post synatpic neuron,
A neuron that receive neurotransmitter from one neuron is called ___
the postsynaptic neuron
Which type of synapse is most common in the nervous system>
The ion that triggers the release of acetylcholine into the synaptic cleft is ___.
Cholinergic synapses release the neurotransmitter ___.
Which of these neurotransmitters does not bind to a plasma membrane receptor?
Which of these neurotransmitters is released at CNS adrenergic synapses?
Which of these neurotransmitters do adrenergic synapses use?
Which of the following is not a possible drug effect on synatpic function>
change the type of receptor found in the postsynaptic membrane
Which of the following is a recognized class of opoid neuromodulators?
enkenphalins, endomorphins, dynorphins, enorphins ALL
The neurotransmitter glutamate opens channels that are permeable to sodium ions. What effect does glutamate produce on a postsynaptic neuron?
The neurotransmitter GABA blocks presynaptic voltage gated calcium channels. Consequently, GABA produces ___.