which of the following is not a function of astrocytes?

# which of the following is not a function of astrocytes?

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The all-or-none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place. True Or FalseFALSE
Reflexes are rapid, automatic responses to stimuli. True or FalseTRUE
Efferent nerve fibers may be described as motor nerve fibers. True or FalseTRUE
Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system. True or FalseTRUE
Myelination of the nerve fibers in the central nervous system is the job of the oligodendrocyte. True or FalseTRUE
During depolarization, the inside of the neuron's membrane becomes less negative. True or FalseTRUE
Neurons in the CNS are organized into functional groups. True or FalseTRUE
Strong stimuli cause the amplitude of action potentials generated to increase. True or FalseFALSE
The oligodendrocytes can myelinate several axons. True or FalseTRUE
Enkephalins and endorphins are peptides that act like morphine. True or FalseTRUE
In myelinated axons the voltage-regulated sodium channels are concentrated at the nodes of Ranvier. True or FalseTRUE
A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons. True or FalseTRUE
Large-diameter nerve fibers conduct impulses much faster than small-diameter fibers. True or FalseTRUE
The nodes of Ranvier are found only on myelinated, peripheral neuron processes. True or FalseFALSE
Unipolar neurons have axons structurally divided into peripheral and central processes. True or FalseTRUE
A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane. True or FalseTRUE
If bacteria invaded the CNS tissue, microglia would migrate to the area to engulf and destroy them. True or FalseTRUE
The overlapping functions of the nervous system are sensory input, integration, and motor output. True or FalseTRUE
The autonomic nervous system is under voluntary control; whereas, the somatic nervous system is involuntary. True or FalseFALSE
Axon diameter and degree of myelination determine nerve impulse conduction velocity. True or FalseTRUE
The action potential is caused by permeability changes in the plasma membrane. True or FalseTRUE
Some neurotransmitters can be either excitatory or inhibitory depending upon the receptor. True or FalseTRUE
Which of the following is not a function of astrocytes? A) support and brace neurons B) anchor neurons to blood vessels C) guide the migration of young neurons, synapse formation, and helping to determine capillary permeability D) control the chemical environment around neurons E) provide the defense for the CNSE) provide the defense for the CNS
Which of the choices below describes the ANS? A) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands B) motor fibers that conduct nerve impulses from the CNS to skeletal muscles C) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS D) sensory and motor neurons that supply the digestive tractA) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands
What are ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid called? A) ependymal cells B) Schwann cells C) oligodendrocytes D) astrocytesA) ependymal cells
What does the central nervous system use to determine the strength of a stimulus? A) origin of the stimulus B) type of stimulus receptor C) frequency of action potentials D) size of action potentialsC) frequency of action potentials
Bipolar neurons are commonly ________. A) motor neurons B) called neuroglial cells C) found in ganglia D) found in the retina of the eyeD) found in the retina of the eye
Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? A) cholinesterase B) norepinephrine C) acetylcholine D) gamma aminobutyric acidC) acetylcholine
Which of the following describes the nervous system integrative function? A) senses changes in the environment B) analyzes sensory information, stores information, makes decisions C) responds to stimuli by gland secretion or muscle contractionB) analyzes sensory information, stores information, makes decisions
The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. A) resting period B) repolarization C) depolarization D) absolute refractory periodD) absolute refractory period
Which of the following is not characteristic of neurons? A) They conduct impulses. B) They have extreme longevity. C) They are mitotic. D) They have an exceptionally high metabolic rate.C) They are mitotic.
The part of a neuron that conducts impulses away from its cell body is called a(n) ________. A) axon B) dendrite C) neurolemma D) Schwann cellA) axon
Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials? A) mechanically gated channel B) voltage-gated channel C) leakage channel D) ligand-gated channelB) voltage-gated channel
An impulse from one nerve cell is communicated to another nerve cell via the ________. A) cell body B) synapse C) receptor D) effectorB) synapse
What is the role of acetylcholinesterase? A) act as a transmitting agent B) amplify or enhance the effect of ACh C) destroy ACh a brief period after its release by the axon endings D) stimulate the production of acetylcholineC) destroy ACh a brief period after its release by the axon endings
Which of the following is not a function of the autonomic nervous system? A) innervation of smooth muscle of the digestive tract B) innervation of cardiac muscle C) innervation of glands D) innervation of skeletal muscleD) innervation of skeletal muscle
Collections of nerve cell bodies outside the central nervous system are called ________. A) nuclei B) nerves C) ganglia D) tractsC) ganglia
The term central nervous system refers to the ________. A) peripheral and spinal nerves B) brain, spinal cord, and peripheral nerves C) brain and spinal cord D) spinal cord and spinal nervesC) brain and spinal cord
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________. A) ion B) cholinesterase C) neurotransmitter D) biogenic amineC) neurotransmitter
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. A) efferent neuron B) afferent neuron C) association neuron D) glial cellC) association neuron
Saltatory conduction is made possible by ________. A) the myelin sheath B) large nerve fibers C) diphasic impulses D) erratic transmission of nerve impulsesA) the myelin sheath
Which of the following is not a chemical class of neurotransmitters? A) acetycholine B) amino acid C) biogenic amine D) ATP and other purines E) nucleic acidE) nucleic acid
Which of the following is false or incorrect? A) An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold. B) A nerve impulse occurs if the excitatory and inhibitory effects are equal. C) An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane.B) A nerve impulse occurs if the excitatory and inhibitory effects are equal.
Select the correct statement regarding synapses. A) Cells with gap junctions use chemical synapses. B) The release of neurotransmitter molecules gives cells the property of being electrically coupled. C) Neurotransmitter receptors are located on the axons terminals of cells. D) The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.D) The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
Which of the following correctly describes a graded potential? A) long distance signaling B) amplitude of various sizes C) voltage stimulus to initiate D) voltage regulated repolarizationB) amplitude of various sizes
Neuroglia that control the chemical environment around neurons by buffering potassium and recapturing neurotransmitters are ________. A) astrocytes B) oligodendrocytes C) microglia D) Schwann cellsA) astrocytes
Schwann cells are functionally similar to ________. A) ependymal cells B) microglia C) oligodendrocytes D) astrocytesC) oligodendrocytes
Immediately after an action potential has peaked, which cellular gates open? A) sodium B) chloride C) calcium D) potassiumD) potassium
Nerve cell adhesion molecules (N-CAMs) ________. A) release nerve growth factor B) are found on "pathfinder" neurons C) are crucial in the production of neurotransmitters D) are crucial for the development of neural connectionsD) are crucial for the development of neural connections
An inhibitory postsynaptic potential (IPSP) is associated with ________. A) a change in sodium ion permeability B) hyperpolarization C) opening of voltage-regulated channels D) lowering the threshold for an action potential to occurB) hyperpolarization
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A) Specific sodium gates will open. B) Specific potassium gates will open. C) Sodium gates will open first, then close as potassium gates open. D) A single type of channel will open, permitting simultaneous flow of sodium and potassium.D) A single type of channel will open, permitting simultaneous flow of sodium and potassium.
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________. A) postsynaptic potential B) excitatory potential C) action potential D) generator potentialD) generator potential
Which of the following is not true of graded potentials? A) They are short-lived. B) They can form on receptor endings. C) They increase amplitude as they move away from the stimulus point. D) They can be called postsynaptic potentials.C) They increase amplitude as they move away from the stimulus point.
Which of the following is true about the movement of ions across excitable living membranes? A) Ions always move actively across membranes through leakage channels. B) Ions always move passively across membranes. C) Sodium gates in the membrane can open in response to electrical potential changes. D) Ions always move from an area of higher concentration to an area of lower concentrationC) Sodium gates in the membrane can open in response to electrical potential changes.
A second nerve impulse cannot be generated until ________. A) the membrane potential has been reestablished B) the Na ions have been pumped back into the cell C) proteins have been resynthesized D) all sodium gates are closedA) the membrane potential has been reestablished
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________. A) positively charged and contains less sodium B) negatively charged and contains less sodium C) negatively charged and contains more sodium D) positively charged and contains more sodiumB) negatively charged and contains less sodium
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________. A) the impulse would move to the axon terminal only B) muscle contraction would occur C) the impulse would spread bidirectionally D) the impulse would move to the axon terminal only, and the muscle contraction would occurC) the impulse would spread bidirectionally
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone? A) acetylcholine B) endorphin C) serotonin D) nitric oxideB) endorphin
Which of the following describes the excitatory postsynaptic potential? A) short distance hyperpolarization B) short distance depolarization C) opens K+ or Cl- channels D) moves membrane potential away from thresholdB) short distance depolarization
That part of the nervous system that is voluntary and conducts impulses from the CNS to the skeletal muscles is the ________ nervous system.somatic
Neuroglia found in the CNS that bind axons and blood vessels to each other are called ________.Astrocytes
A chemical messenger that does not directly cause ESPSs or IPSPs but does affect the strength of synaptic transmission is a ________.Neuromodulator
The synapse more common in embryonic nervous tissue than in adults is the ________.electrical synapse
When information is delivered within the CNS simultaneously by different parts of the neural pathway, the process is called ________ processing.parallel
Potentials that are short-lived, local changes in membrane potential that can be either depolarized or hyperpolarized are called ________ potentials.Graded
When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of the postsynaptic membrane than would result from a single EPSP; this event is called ________ summation.temporal
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