ЁЯУХChapter 7
The mechanism that allows many Na+ ions move into the axon is answers: negative feedback positive feedback equilibrium feedback none of the choices are correct
positive feedback
Sensory neurons answer: Are multipolar and carry impulses toward the CNS Are pseudounipolar and carry impulses away from the CNS Are bipolar and carry impulses away from the CNS Are multipolar and carry impulses away from the CNS
are pseudounipolar and carry impulses toward the CNS
The blood- brain barrier results mostly from the action of __________, a type of glial cell. answers: ependymal cells microglia astrocytes oligodendrocytes
astrocytes
The most numerous of all cells of the CNS nervous tissue are the answers: astrocytes neurons Schwann cells microglia
astrocytes
Which cells are needed for the formation of synapses in the CNS? answers: ependymal microglia astrocytes dendrites
astrocytes
What action produces an IPSP on the postsynaptic membrane? answers: influx of Na+ ions opening of Ca2+ channels into the neuron outflow of K+ ions opening of Cl- channels into the neuron
opening of Cl- channels into the neuron
Which ion's movements is responsible for repolarization? answers: influx of K+ influx of Na+ outward diffusion of K+ outward diffusion of Na+
outward diffusion of K+
What type of autonomic fibers release ACh at effectors? answers: parasympathetic sympathetic somatic sensory
parasympathetic
The brain and spinal cord comprise the answers: Central nervous system Peripheral nervous system Peripheral ganglia Spinal nerves
Central nervous system
In a ligand-gated channel, the neurotransmitter receptor and the channel are separate proteins. answers: T or F
F
Most synapses in the body are electrical answers: T or F
F
Nerve cells depolarize due to the influx of K+ answers: T or F
F
Nicotinic receptors utilize G-proteins to regulate the opening of ion channels. answers: T or F
F
Once an EPSP is created on the postsynaptic neuron, a new action potential is produced down the axon. answer: T or F
F
Sensory nerves cause muscle contraction answers: T or F
F
Somatic motor neurons innervate involuntary effectors answers: T or F
F
The average resting membrane potential of a neuron is -85mV answers: T or F
F
The greater the number of depolarization regions on an axon, the faster the action potential will be conducted. answers: T or F
F
The nerve is the basic structural and functional unit of the nervous system. answers: T or F
F
Muscarinic ACh receptors act through ____________ activation of K+ channels. answers: cGMP G-protein M- protein ATP
G-protein
The most common neurotransmitter in the brain is ________? answers: glycine acetylcholine serotonin GABA
GABA
Which type of cell of the CNS is phagocytotic? answers: Microglia Satellite cells Ependymal cells Oligodendrocytes
Microglia
Which of the following is NOT a functional classification of neurons? Answers: Motor or efferent Interneuron or association Multipolar Sensory or afferent
Multipolar
Blocking ____________ channels would prevent neuron depolarization. answers: K+ Cl- Na+ Mg2+
Na+
What medication acts by increasing the action of nitric oxide as a treatment for erectile dysfunction? answers Viagra marijuana prozac naloxone
Viagra
What is present at the axon hillock that allows the production of action potentials? answers: Voltage-gated channels ligand-gated channels muscarinic receptors chemical-gated channels
Voltage-gated channels
Cholinergic fibers use ____ as the neurotransmitter. answers: norepinephrine acetylcholine dopamine serotonin
acetylcholine
Which of the following is NOT true of dendrites? answers: Transmits action potential toward the cell body Are thin extensions of the cell body Transmit graded electrochemical impulses toward the cell body Contain receptive area
Transmits action potential toward the cell body
The average resting membrane potential of an axon is answers: -70mV -85mV 0mV +30mV
-70mV
An axon will depolarize only if the membrane potential reaches between -70mV and -55mV. This follows the ______? answers: All-or-none law recruitment law graduated law threshold law
All-or-none law
Which division of the nervous system innervates involuntary effectors? answers: Central nervous system Somatic nervous system Autonomic nervous system Associate nervous system
Autonomic nervous system
Excitable cells are incapable of maintaining a constant resting membrane potential. answers: T or F
F
Cocaine blocks the release of dopamine, norepinephrine, and serotonin answers: T or F
F
Electrical synapses are functionally linked by tight junctions. answers: T or F
F
The binding of a neurotransmitter to its receptor protein causes ion channels to open in the post synaptic membrane. What type of gates are these? answers: chemically-regulated gates voltage-regulated gates ligand- regulated gates Chemically-regulated gates and ligand-regulated gates are correct
Chemically-regulated gates and ligand-gates are correct
A lack of extracellular Ca2+ would cause increased release of neurotransmitters __________________? answers: T or F
F
All axons in the PNS have a myelin sheath. answers: T or F
F
An EPSP is conducted decrementally to the axon hillock, where voltage-gated Na+ and K+ channels are opened to created an action potential in the first segment of the axon. answers: T or F
F
Axons require ATP to produce an action potential. answers: T or F
F
Both neurons and neuroglia will easily divide by mitosis answers: T or F .
F
What type of neuron is found entirely in the CNS? answers: Sensory neuron Interneuron Association neuron Interneuron and association neuron are correct
Interneuron and association neuron are correct
The membrane of resting nerve cells is more permeable to _________________ ions than _______________ ions. answers: Na+/ K+ Ca+ / K+ K+/ Na+ Cl-/ K+
K+/ Na+
During an action potential answers: Na+ efflux causes depolarization K+ influx causes repolarization Na+ influx causes depolarization K+ influx causes after-hyperpolarization
Na+ influx causes depolarization
What process is needed to return a membrane to its resting membrane potential with all ions in the correct locations? answers: after-hyperpolarization all-or-none-law Na+/K+ pump refractory period
Na+/K+ pump
Which of the following is true of axons? answers: Contain receptive areas Very thin and short Originates at the axon hillock on the cell body Transmits graded electrochemical impulses
Originates at the axon hillock on the cell body
Muscarinic ACh receptors are found in all of the following locations EXCEPT ___________? answers: Skeletal muscle Smooth muscle Cardiac muscle Glands
Skeletal muscle
All cells have a membrane potential answers: T or F
T
An inhibitory postsynaptic potential would be produced by a neurotransmitter opening Cl- channels. answers: T or F
T
Cells become more negative during hyperpolarization. answers: T or F
T
Conduction without decrement means that action potentials transmitted down an axon will not decrease in amplitude answers: T or F
T
Ganglia are clusters of nerve cell bodies located in the peripheral nervous system. answers: T or F
T
Glycine and GABA stimulate opening of Cl- channels answers: T or F
T
Myelinated axons transmit action potential more rapidly than unmyelinated sheath is the answers: T or F
T
Parkinson's disease is associated with the loss of dopaminergic neurons. answers: T or F
T
Schwann cells and oligodendrocytes have similar functions answers: T or F
T
The blood-brain barrier may prevent medications from reaching brain tissue. answer: T or F
T
The nicotinic ACh receptor is ligand-gated channels answers: T or F
T
both excitatory and inhibitory postsynaptic undergo summation. answer: T or F
T
postsynaptic inhibition is caused by neurotransmitters that produce hyperpolarization. answers: T or F
T
Neurotransmitter release would be inhibited by ___________? answers: stimulating repolarization of the axon terminal blocking Ca+ influx in the axon terminal blocking repolarization of the axon terminal stimulating protein kinase activity
blocking Ca2+ influx in the axon terminal
Which of the following is NOT true of norepinephrine? answers: released in both the CNS and PNS released by sympathetic neurons to smooth muscle, cardiac muscle, and glands amphetamines stimulate norepinephrine pathways causes depression in the CNS
causes depression in the CNS
In a myelinated axon, Na+ channels are answers: along the whole length of the axon every 5 mm concentrated at the nodes of Ranvier less numerous at the nodes of Ranvier
concentrated at the nodes of Ranvier
In a mylelinated axon. Na+ channels are answers: along the whole length of the axon every 5 mm concentrated at the nodes of Ranvier less numerous at the nodes of Ranvier
concentrated at the nodes of Ranvier
What type of neural pathway involves one neuron forming synapses with several postsynaptic neurons? answers: convergent oscillating divergent plastic
divergent
Which type of cell lines the ventricles of the brain and help produce cerebrospinal fluid? Answers: microglia satellite cells ependymal cells oligodendrocytes
ependymal cells
Chemical synapses, the use neurotransmitters as messenger __________________? answers: have delayed impulse transmission utilize gap junctions occur when one neuron cell are in direct contact with any other cell do not require the release of neurotransmitters
have delayed impulse transmission
Which of the following is NOT classified as a catecholamine? answers: norepinephrine epinephrine histamine dopamine
histamine
At what region of the neuron are action potentials first produced? answers: dendrites cell body initial segment of an axon axon hillock
initial segmant of an axon
White matter is answers: myelinated axons in the CNS myelinated axons in the PNS nonmyelinated cell bodies and dendrites in the CNS nonmyelinated axons in the CNS
myelinated axons in the CNS
Chemicals that stimulate action potentials in postsynaptic cells are called _________? answers: hormones enzymes neurotransmitters neurotrophins
neurotransmitter
Chemical that stimulate action potentials in postsynaptic cells are called ________________? answers: hormones enzymes neurotransmitters neurotrophins
neurotransmitters
The gap of exposed axon in the myelin sheath is the answers: neurilemma node of Ranvier sheath of Schwann white matter
node of Ranvier
The myelin sheaths of CNS neurons are produced by Answers: schwann cells oligodendrocytes ependymal cells leukocytes
oligodendrocytes
As the intensity of a stimulus increases, more axons will become activated. This process is called ________? answers: threshold refraction recruitment none apply
recruitment
Conduction of an action potential in a myelinated axon is called ___________? answers: point to point conduction saltatory conduction refractory conduction cable conduction
saltatory conduction
Condution of an action potential in a myelinated axon is called _________? answers: point to point conduction saltatory conduction refractory conduction cable conduction
saltatory conduction
18.) The myelin sheaths of PNS neurons are produced by Answers: schwann cells oligodendrocytes ependymal cells leukocytes
schwann cells
Action potential transmission in the PNS is decreased if which cells are damaged? answers: astrocytes microglia oligodendrocytes schwann cells
schwann cells
What is the predominant affect of stimulation of nicotinic-gated channels? answers: stimulation due to outflow of K+ ions inhibition due to outflow of K+ ions stimulation due to influx of Na+ ions inhibition due to influx of Cl- ions
stimulation due to influx of Na+ ions
What is NOT true of conduction through dendrites and cell bodies of neurons? answers: they are EPSPs they are spread by capable properties they can summate to reach threshold they are action potentials
they are action potentials
Serotonin is synthesized from the amino acid answers: alanine glycine tryptophan serine
tryptophan
What amino acids are dopamine, norepinephrine, and epinephrine derived from ______? answers: histidine tyrosine tryptophan serine
tyrosine
Neurotransmitters answers: are released by endocytosis all bind to the same receptor usually regulate ion channels are actively transported across the synaptic cleft
usually regulate ion channels
Ion channels that open in response to depolarization are called answers: ion-gated channels voltage-gated channels stimulation-gated channels potential- gated channels
voltage-gated channels