The nervous system that controls skeletal muscles?
The part of the peripheral nervous system that carries sensory information to the CNS is designated
The most abundant class of neuron in the central nervous system is _______.
Clusters of RER and free ribosomes in neurons are called _______.
Branches that may occur along an axon are called
The site of intercellular communication between a neuron and another cell is the
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
Sensory neurons of the PNS are
________ neurons form the afferent division of the PNS.
________ are the most numerous type of neuron in the CNS.
Most CNS neurons lack centrioles. This observation explains
D) why CNS neurons cannot divide to regenerate damaged tissue.
Which of the following is a type of glial cell found in the peripheral nervous system?
A) satellite cells
The largest and most numerous of the glial cells in the central nervous system are the
Functions of astrocytes include all of the following:
-responding to neural tissue damage
-maintaining the blood-brain barrier
-forming a three-dimensional framework for the CNS
-guiding neuron development
except conduct action potential D
The neuroglial cells that participate in maintaining the blood-brain barrier are the
The myelin sheath that covers many CNS axons is formed by
________ line the brain ventricles and spinal canal.
E) Ependymal cells
Small, wandering cells that engulf cell debris and pathogens in the CNS are called
The neurilemma of axons in the peripheral nervous system is formed by
A) Schwann cells.
Many medications introduced into the bloodstream cannot directly affect the neurons of the CNS because
C) the endothelium of CNS capillaries forms a blood-brain barrier.
Extensive damage to oligodendrocytes in the CNS could result in
B) loss of sensation and motor control.
Damage to ependymal cells would most likely affect the
E) formation of cerebrospinal fluid.
After a stroke, what type of glial cell accumulates within the affected brain region?
Which of the following is NOT involved in the establishment of a neuron's resting potential?
Electrical forces push sodium ions out of the cell.
Ion channels that are always open are called ________ channels.
Opening of sodium channels in the axon membrane causes
Voltage-gated channels are present
D) in the membrane that covers axons.
The sodium-potassium ion exchange pump
E) moves sodium and potassium opposite to the direction of their electrochemical gradients.
________ open or close in response to binding specific molecules.
E) Chemically-gated channels
If the permeability of a resting axon to sodium ion increases,
B) inward movement of sodium will increase and the membrane will depolarize.
C) may be either a depolarization or a hyperpolarization.
If the potassium permeability of a resting neuron increases above the resting permeability, what effect will this have on the transmembrane potential?
A) The inside of the membrane will become more negative.
If acetylcholine (ACh) causes inhibition of a postsynaptic neuron, to what type of membrane channel did the ACh bind?
E) chemically-regulated potassium channel
A stimulus that changes a neuron membrane potential from the resting -75 mV to -85 mV is:
B) an inhibitory stimulus
If the axolemma becomes more permeable to potassium ion:
a stronger stimulus will be required to cause an action potential
Main steps in the generation of an action potential.
1. A graded depolarization brings an area of an excitable membrane to threshold.
2. Sodium channel activation occurs.
3. Sodium ions enter the cell and depolarization occurs.
4. Sodium channels are inactivated.
5. Potassium channels open and potassium moves out of the cell, initiating repolarization.
6. Sodium channels regain their normal properties.
7. A temporary hyperpolarization occurs.
The all-or-none principle states that
B) all stimuli great enough to bring the membrane to threshold will produce identical action potentials.
The same ________ can have different effects depending on the properties of the ________.
E) neurotransmitter; receptor
Which of the following statements about the action potential is false?
A) The rapid depolarization phase is caused by the entry of potassium ions.
B) Repolarization occurs as potassium ions leave the axon.
C) In the after-hyperpolarization phase, membrane potential approaches the potassium equilibrium potential.
D) During the repolarization phase, sodium channels close and potassium channels open.
E) During the depolarization phase, membrane potential becomes positive.
The rapid depolarization phase is caused by the entry of potassium ions.
During repolarization of a neuron
B) potassium ions move out of the cell.
How would a chemical that prevents the opening of voltage-regulated Na+ channels affect the function of a neuron?
neuron will only be capable of producing graded potentials
A threshold stimulus is the
depolarization necessary to cause an action potential.
What is threshold for an action potential?
B) It is more positive than the resting potential.
Puffer fish poison blocks voltage-gated sodium channels like a cork. What effect would this neurotoxin have on the function of neurons?
A) The axon would be unable to generate action potentials.
Which of the type of nerve fiber possesses the fastest speed of impulse propagation?
C) type A
Sensory information from skeletal muscles travels over ________ fibers.
A) type A
In what would the rate of impulse conduction be the greatest?
C) a myelinated fiber of 10-μm diameter
Rapid impulse conduction from "node" to "node" is called
E) saltatory propagation.
Which type of synapse is most common in the nervous system?
The steps involved in transmission at a cholinergic synapse: C) 4,2,6,7,1,8,3,5.
4. An action potential depolarizes the synaptic terminal at the presynaptic membrane.
2. Calcium ions enter the synaptic terminal.
6. Acetylcholine is released from storage vesicles by exocytosis.
7. Acetylcholine binds to receptors on the postsynaptic membrane.
1. Chemically-gated sodium channels on the postsynaptic membrane are activated.
8. Calcium ions are removed from the cytoplasm of the synaptic terminal.
3. Acetylcholinesterase hydrolyzes acetylcholine.
5. The synaptic terminal reabsorbs choline.
If the chemically-gated sodium channels in the postsynaptic membrane were completely blocked,
C) synaptic transmission would fail.
The effect that a neurotransmitter has on the postsynaptic membrane depends on:
-the frequency of neurotransmitter release
-the quantity of neurotransmitters released.
-the nature of the neurotransmitter.
-the characteristics of the receptors.
Each of the following is an example of a neuroeffector junction, except the junction between a neuron and a(n)
A) nerve cell.
B) exocrine gland cell.
C) smooth muscle cell.
D) endocrine gland cell.
E) skeletal muscle cell.
nerve cell. a)
What triggers the release of acetylcholine from a synaptic terminal?
E) diffusion of calcium ions into the synaptic terminal
After acetylcholinesterase acts, the synaptic terminal
D) reabsorbs the choline.
A postsynaptic neuron will have an Excitatory Postsynaptic Potential (EPSP) when
A) chemically-regulated sodium channels are open and sodium is diffusing into the cell.
The site in the neuron where EPSPs and IPSPs are integrated is the
C) axon hillock.
IPSPs (inhibitory postsynaptic potentials)
D) are local hyperpolarizations.
When a second EPSP arrives at a single synapse before the effects of the first have disappeared, what occurs?
B) temporal summation
Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated
D) spatial summation.
Spinal nerves are
A) both sensory and motor.
The dorsal root ganglia mainly contain
A) cell bodies of sensory neurons.
The dorsal root of a spinal nerve contains
C) axons of sensory neurons.
The ventral root of a spinal nerve contains
D) axons of motor neurons.
The tough, fibrous, outermost covering of the spinal cord is the
dura mater-"dura mother"
If the dorsal root of a spinal nerve is severed,
C) sensory input would be blocked.
The subdural space lies between
C) the dura mater and the arachnoid mater.
The layer of the meninges in direct contact with the spinal cord is the
E) pia mater.
A dorsal and ventral root of each spinal segment unite to form a
C) spinal nerve.
Cerebrospinal fluid flows within the
B) subarachnoid space.
Blood vessels that supply the spinal cord run along the surface of the
D) pia mater.
Samples of CSF for diagnostic purposes are normally obtained by placing the tip of a needle in the
D) subarachnoid space.
The white matter of the spinal cord is mainly
myelinated and unmyelinated axons.
The gray horns of the spinal cord contain mainly
D) nerve cell bodies.
The posterior horns of the spinal cord contain mainly
B) sensory nuclei.
The anterior horns of the spinal cord contain mainly
B) somatic motor nuclei.
Nerve tracts or fasciculi make up the
A) white columns.
In the spinal cord, white matter is separated into ascending and descending tracts organized as
Axons crossing from one side of the spinal cord to the other within the gray matter are found in the?
E) gray commissures.
The white matter of the spinal cord contains?
B) bundles of axons with common origins, destinations, and functions.
The outermost connective-tissue covering of nerves is the
Postganglionic fibers of the autonomic nervous system that innervate internal organs do not rejoin the spinal nerve but form
B) sympathetic nerves.
The layer of connective tissue that surrounds a fascicle within a peripheral nerve is the
A viral disease that destroys the cells of the anterior gray horn will
lead to skeletal muscle weakness or paralysis.
The complex, interwoven network formed by contributions from the ventral rami of neighboring spinal nerves is termed a(n)
Each of the following nerves originates in the lumbar plexus, except the ________ nerve.
The layer of connective tissue that surrounds individual axons within a peripheral nerve is termed the
If a person has a crush injury to the C3-C5 spinal segments, you would expect that he
might be unable to breathe on his own.
Which nerve approaches the knee, than divides into two branches, the fibular nerve and the tibial nerve.
Which nerve arises in the cervical plexus, innervates the diaphragm.
The brachial plexus gives rise to all of the following nerves?
Recognized neuronal circuit patterns include:
- parallel processing.
What are neural reflexes functions?
- are the simplest form of behavior.
- are automatic motor responses.
- help preserve homeostasis.
- involve at least two neurons.
EXCEPT cannot be modified by the brain.
Reflexes based on synapses formed during development are
D) innate reflexes
Reflexes can be classified by:
- where information processing occurs.
- the motor response.
- their development.
- the complexity of the neural circuit.
EXCEPT whether they are sensory or motor.
All of the following are true of muscle spindles, except that they
EXCEPT found in tendons.
-consist of specialized fibers called intrafusal fibers.
- are the receptor for the stretch reflex.
- are found within skeletal muscle.
- are innervated by gamma motor neurons.
The reflex that prevents a muscle from exerting too much tension is the:
D) tendon reflex
Spinal inter neurons inhibit antagonist motor neurons in a process called
D) reciprocal inhibition.
Neurons in which dendritic and axonal processes are continuous and the soma lies of to one side are called?
Within each hemisphere, deep to the floor of the lateral ventricles, you will find the?