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
Which type of memory allows you to remember things from up to a few hours ago?
Short term
Parkinson disease is due to the progressive degeneration of dopamine-releasing neurons in which brain area?
Substantia nigra
Long-term potentiation may be involved in long-term memory. Choose all of the following that are molecular changes that occur in long-term potentiation.
Entrance of calcium into the dendrite
The release of nitric oxide which triggers more glutamate release
Binding of glutamate to NMDA receptors
What happens during a weak synapse?
A graded potential occurs.
- The synapse is far apart
- Reduced amount of receptors to receive NT
- Sending neurons may have a lower amount of NT to release
What happens during a strong synapse?
An action potential occurs.
- The synapse is smaller
- They have more NT to release
- They have more receptors
What is an NMDA receptor?
It is an excitatory ionotropic glutamate receptor that controls calcium channels and is blocked by MG2+ ions. This receptor is also ligand (glutamate) and voltage (-50) dependent.
Which disease is associated with the anatomical findings of shrunken folds of cerebral tissue, neurofibrillary tangles, and senile plaques containing beta-amyloid protein?
Alzheimer disease
________ prime certain areas of the brain for neurotransmitters. modulating (modifying or controlling influence) effects
Neuromodulator
Two effects that neurotransmitters have on postsynaptic membranes are _______ (EPSP) or ______ (IPSP).
Depolarization: Hyperpolarization
Choose all that are common symptoms of Parkinson disease.
Slurred speech
Progressive loss of motor function
Change in gait; smaller and slower steps
Alzheimer disease affects about what percentage of the US population over the age of 65?
11%
An action potential arriving at the presynaptic terminal causes what to occur?
Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell.
What happens as a result of ion flow at a presynaptic terminal?
Synaptic vesicles migrate to the plasma membrane and release acetylcholine.
Acetylcholine has which effect on the postsynaptic neuron?
Ligand-gated sodium ion channels open, and sodium diffuses in.
Why does depolarization occur?
More sodium ions diffuse into the cell than potassium ions diffuse out of it.
A typical neuron will have a membrane voltage of about ___ at the time when sodium gates close and potassium ions begin rapidly leaving the cell.
Damaged neurons in the PNS can regenerate if their _____ is intact and they can form a _____.
Soma ; Regeneration tube
The correct sequence of voltage-regulated gates opening and closing in an action potential?
Na+ gates opening; K+ gates opening; Na+ gates closing
Blood capillaries of the brain are enveloped by
Astrocytes
In ___, the additive effects of EPSPs and IPSPs determine whether a neuron fires.
Synaptic potentiation
Mature neurons lack centrioles. You would expect these neurons to be unable to
Undergo Mitosis
A reverberating circuit produces repeated output in response to a single input.
True
A neuron fires only when its membrane reaches
threshold potential
The bodies of the Schwann cells constitute the
neurilemma
The norepinephrine receptor is a ligand-gated ion channel.
False
The most common structural neuron is the _____ neuron, which includes
multipolar; motor neurons and interneurons.
Which one of the following best describes the order of a somatic reflex?
somatic receptor → afferent nerve fiber → interneuron → efferent nerve fiber → skeletal muscle
Your spinal cord was unable to form any denticulate ligaments. Your spinal cord would most likely lose
side-to-side stability.
The neurilemma is covered by the loose connective tissue called the
endoneurium.
Why does hyperpolarization occur?
The increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level.
the incorrect statement regarding how the nervous system coordinates homeostasis in the body.
The spinal cord and brain process information without regard to past experiences, and determine what response, if any, is appropriate to the circumstances.
What is(are) the fundamental physiological properties that enable nerve cells to communicate with other cells?
The ability to respond to environmental changes, the ability to produce electrical signals that are quickly conducted to other cells at distant locations, and the ability to secrete a chemical that will stimulate the next cell when an electrical signal reaches the end of a nerve fiber
Which of the following is true of interneurons?
They are contained entirely within the CNS and carry signals from one neuron to another.
Choose the correct statement about myelin.
It is best not to give children under two years of age a low-fat diet because myelin formation requires lipids.
The resting membrane potential is negative due to which of the following?
There are more negatively charged particles on the inside of the membrane than on the outside.
Some __________ neurons are specialized to detect stimuli, whereas __________ neurons send signals to the effectors of the nervous system.
afferent; efferent
Inhibitory postsynaptic potentials (IPSPs) are associated with which of the following?
Hyperpolarization of the cell membrane
Functions of the spinal cord include which of the following?
Conduction, locomotion, reflexes
In an adult, the spinal cord ends at which vertebra?
L1
The superior most region of the spinal cord is which of the following?
Cervical region
The bundle of nerves inferior to the medullary cone of the spinal cord is called the
cauda equina
the meninges in order from superficial (at the top) to deep (at the bottom).
Dura mater, arachnoid mater, and pia mater
What is the dural sheath around the spinal cord made of?
Dura mater
Where does the spinal cord arise from the medulla oblongata?
At the foramen magnum
What are the regions of the spinal cord?
Thoracic, lumbar, cervical, sacral
Where is the epidural space around the spinal cord?
Between the vertebral bones and the dural sheath
Which are a series of fibrous connective tissue membranes covering the central nervous system?
Meninges
The cerebrospinal fluid circulates in the __________space between the meninges.
subarachnoid
The matter of the spinal cord that contains the synapses and therefore is the site of synaptic integration is called
Gray matter
What is the white matter of the spinal cord?
Bundles of myelinated and unmyelinated axons found superficial to the gray matter
is located between the vertebrae and the dural sheath around the spinal cord.
Epidural space
The horns of the spinal cord that contain the cell bodies of outgoing somatic motor neurons are
anterior horns
Where is the white matter in the spinal cord?
Superficial to the gray matter
Within the spinal cord, which tracts carry information up to the brain?
Ascending
In which disease does sclerosis of the lateral spinal cord occur, with destruction of motor neurons?
Amyotrophic lateral sclerosis
What is a nerve?
A cord of nerve fiber bundles bound together by connective tissue
What are two examples of nerves that carry only sensory information?
Optic and olfactory nerves
What type of nerve is a nerve containing only fibers carrying outgoing nerve signals from the CNS?
Motor
Within the spinal cord, what type of information do the descending tracts carry?
Motor
The poliovirus destroys which neurons in the brainstem and anterior horn of the spinal cord?
Motor
Which describes a mixed nerve?
A nerve containing both sensory and motor nerve fibers
How many spinal nerves are in each region of the spinal cord in order from superior to inferior?
8,12,5,5,1 = 31
Moving peripherally from the spinal cord, the anterior and posterior _____ forms the spinal nerve
Roots
What type of fiber is a nerve fiber carrying nerve signals away from the central nervous system?
efferent
The anterior rami of spinal nerves form which nerve plexuses?
Cervical, lumbar, sacral
Choose all that are nerve plexuses of the body.
Lumbar
Cervical
Sacral
Brachial
The brainstem in order from the most rostral at the top to the most caudal.
Diencephalon
Midbrain
Pons
Medulla Oblongata
What are the three major divisions of the brain?
Brainstem
Cerebrum
Cerebellum
Which divides the cerebrum into right and left hemispheres?
Longitudinal fissure
The gray matter of the cerebrum forms which of the following?
Cortex
Which term refers to the thick folds of tissue found on each of the cerebral hemispheres?
Gyri
Which best describes the cerebral cortex?
Surface layer of gray matter on the cerebrum
Which embryonic structure develops first?
Neural plate
How many ventricles are located in the brain?
The brain has four fluid filled ventricles: two lateral ventricles, and the third and fourth ventricle.
Bundles of axons make up which of the following?
White matter
Within the first three weeks of embryonic development, the neural plate sinks and its edges thicken to form which of the following?
Neural groove
The cerebral aqueduct passes CSF down the core of the midbrain and into which of the following?
Fourth ventricle
How much CSF does the brain produce per day?
500 mL
Which is least likely to get through the blood-brain barrier?
Urea
Which term refers to the pore that transports CSF from the lateral ventricles to the third ventricle?
Interventricular foramen
The embryonic hindbrain consists of which two secondary vesicles?
Myelencephalon
Metencephalon
The boundary between the spinal cord and the medulla oblongata corresponds to which of the following structures?
Foramen magnum
The blood-brain barrier consists of tight junctions between which of the following?
Capillary endothelial cells
Which cranial nerves begin or end in the pons?
Cranial nerves V, VI, VII, and VIII
The medulla oblongata develops from which of the following?
Myelencephalon
The posterior part of the midbrain, which includes the corpora quadrigemina, is called the
tectum
The tectum is which part of the midbrain?
Posterior
Which structure is sometimes called the “gateway to the cerebral cortex?”
Thalamus
