Exam 3 Flashcards
The sensory division of the PNS is further subdivided into the ______ sensory division, which carries signals from receptors in the skin, muscles, bones, and joints, and the ______ sensory division, which carries signals from organs of the thoracic and abdominal cavities.
somatic, visceral
Afferent neurons are what type of neurons?
sensory
The soma of a neuron gives rise to branch-like processes called what? They are the primary sites for receiving signals from other neurons.
dendrites
The autonomic nervous system is subdivided into the ______ division which tends to arouse the body for action and the ______ division which tends to have a calming effect.
sympathetic, parasympathetic
Which correctly describes axonal transport?
It involves the transport of proteins within the axon (i.e. synaptic knob enzymes or proteins that maintain the axolemma).
It is bidirectional (retrograde and anterograde transport).
______ cells protect the neurons and help them function.
glial
Which terms refers to the part of the PNS that carries signals from various receptors to the CNS?
sensory division
Which types of glial cells are found in the central nervous system?
Ependymal cells
Oligodendrocytes
Astrocytes
Microglia
Which glial cell insulates nerve fibers from extracellular fluids and speeds up signal conduction in the brain?
Oligodendrocyte
Unmyelinated nerve fibers (axons) in the PNS are enveloped in Schwann cells.
True
Which of the following contributes to the development of the resting membrane potential in neurons?
K+ is more concentrated in the ICF than in the ECF.
Which type of glial cell aids in the regeneration of damaged peripheral nerve fibers by forming a regeneration tube to help reestablish the former connection?
Schwann cells
Characteristics of local potentials.
Decremental
Graded
All that are properties of action potentials.
Self-propagating
Nondecremental (signal maintains amplitude)
All or none
In order for local potentials to trigger an action potential, the membrane must depolarize up to a level called which of the following?
Threshold
Which ion has the greatest influence on the resting membrane potential of most neurons?
Potassium (K)
The refractory period in which it is possible to trigger a new action potential, but only with an unusually strong stimulus is the ______ refractory period.
Relative
Action potentials occur only where there are voltage-gated ion channels.
True
Which best describes signal conduction in unmyelinated axons?
A wave of depolarization opens more voltage-gated channels immediately distal to the action potential.
The all-or-none law of action potentials states which of the following?
A neuron will fire at maximum voltage if a stimulus depolarizes it to threshold.
Which term refers to the period of time after a nerve cell has responded to a stimulus in which it cannot be excited by a threshold stimulus?
Refractory period
Which best describes an electrical potential?
A form of potential energy that can produce current
Which term is used to describe signal conduction along a myelinated axon?
Saltatory
Choose all of the following statements that are true about signal conduction along unmyelinated fibers.
A zone of depolarization excites voltage-gated channels immediately distal to the action potential.
Unmyelinated fibers have voltage-gated channels along their entire length.
At a synapse, the neuron that responds to the neurotransmitter is the ______ neuron.
postsynaptic
Electrical synapses are able to integrate information and make decisions more rapidly than chemical signals.
False
Which statements are true about signal conduction along myelinated fibers?
Ions can be exchanged with the ECF only at the nodes of Ranvier.
Action potentials occur only at the nodes of Ranvier.
There are few voltage-gated ion channels at the myelin-covered internodes and multiple channels at the nodes of Ranvier.
At a synapse, the neuron that releases neurotransmitters is the ______ neuron.
presynaptic
Which term refers to the microscopic physical gap between the presynaptic and postsynaptic neurons at a chemical synapse?
synaptic cleft
Which scientist conclusively demonstrated that neurons communicate by releasing chemical messages?
Otto Loewi
Categories of neurotransmitters based on chemical composition.
Monoamines
Amino acids
Neuropeptides
Acetylcholine
In electrical synapses, electrical signals move quickly from cell to cell through which of the following?
Gap junctions
Which term refers to a synapse that releases acetylcholine from the presynaptic axon terminal?
Cholinergic
All neurotransmitters have an excitatory effect.
False
In a chemical synapse, synaptic vesicles full of neurotransmitters are docked at release sites on the membrane of the presynaptic neuron, while neurotransmitter receptors are found on the membrane of the
Postsynaptic neuron
Choose all that would cause postsynaptic stimulation to end.
Reuptake of neurotransmitter into the presynaptic knob
Enzymatic degradation of neurotransmitter in the synaptic cleft
Cessation of signals in the presynaptic nerve fiber
Diffusion of neurotransmitter from the synaptic cleft into extracellular fluid
Which alter synaptic transmission by adjusting the sensitivity of postsynaptic neurons to neurotransmitters or by affecting the breakdown and/or removal of a neurotransmitter?
Neuromodulators
Choose all the statements that characterize neurotransmitters?
They bind to receptors and alter the physiology of the postsynaptic cell.
They are synthesized by presynaptic neurons.
They are released in response to stimulation.
The more synapses a neuron has, the lesser its information-processing capability.
False
Some neurotransmitters can have either excitatory or inhibitory effects depending on which of the following?
The type of receptors on the postsynaptic cell
Stimulation of the postsynaptic neuron will end when nerve signals stop arriving at the presynaptic axon terminal or when which of the following occurs?
Neurotransmitter is removed from postsynaptic receptors.
Which term describes the ability of neurons to process information, store and recall it, and make decisions?
Neural integration
Neural integration is based on the combining together of which of the following?
Postsynaptic potentials
The nervous system must interpret quantitative and qualitative information about its environment, thus it converts information to a meaningful pattern of action potentials. This process is called neural
Coding
Choose all that are characteristics of neural pools.
They consist of complex patterns of interneurons.
They may be concerned with a particular body function
The ability of synapses to change is called synaptic plasticity. Which term refers to the neuronal pathways formed during learning?
Memory traces
Choose all statements that are true regarding postsynaptic potentials?
They include EPSPs and IPSPs.
They are changes in the membrane potential of the postsynaptic terminal of a chemical synapse.
They are caused by neurotransmitters.
There are two ways in which EPSPs can add up to produce enough activity to make a postsynaptic cell fire. They are temporal and spatial
Summation
What is the role of neural pools in the CNS?
To process information
Synapses are not fixed for life. In response to experience, they can be modified to make transmission easier or harder. The ability of synapses to change is called synaptic
Plastisity
Which type of memory is important as you read (e.g. remembering the previous words in a sentence)?
Immediate
Looking up a new phone number and then dialing it from memory utilizes which type of memory?
Working
Choose all that are types of long-term memory?
Declarative and Procedural
Which may be the basis for learning and long-term memory at the neuronal level?
long-term potentiation
What is long-term potentiation (LTP)?
A persistent strengthening of synapses based on recent patterns of activity that can vary in length of time. It also increases the likelihood to fire an action potential.
If a mouse is placed in a pool of murky water, it will swim about until it finds a hidden platform to climb out on. With repetition, the mouse soon learns to locate the platform more quickly. This is an example of ________ .
long-term potentiation (LTP)
Immediate memory, which is the ability to hold something in mind for a few seconds, might be based on activity in which type of neural circuit?
Reverberating
Choose all that are symptoms of Alzheimer’s disease.
Memory loss
Reduced attention span
Loss of the ability to talk or eat
Deterioration of personality