ANPH - Nervous System Cells & Signalling CH 18&19 Flashcards
Which of the following is/are classified as nerve fibers?
a. axon
b. dendrites
c. both a and b
d. none of the above
c. both a and b
Which of the following conduct impulses toward the cell body?
a. axons
b. dendrites
c. Nissl bodies
d. none of the above
b. dendrites
A neuron with one axon and several dendrites is a:
a. multipolar neuron.
b. unipolar neuron.
c. bipolar neuron.
d. none of the above
a. multipolar neuron.
Which type of neuron lies entirely within the CNS?
a. afferent
b. efferent
c. interneuron
d. none of the above
c. interneuron
Which sequence best represents the course of an impulse over a reflex arc?
a. receptor, synapse, sensory neuron, motor neuron, effector
b. effector, sensory neuron, synapse, motor neuron, receptor
c. receptor, motor neuron, synapse, sensory neuron, effector
d. receptor, sensory neuron, interneuron, motor neuron, effector
d. receptor, sensory neuron, interneuron, motor neuron, effector
A complete nerve, consisting of numerous fascicles and their blood supply, is held together by a fibrous coat called the:
a. endoneurium.
b. perineurium.
c. epineurium.
d. fascicles.
c. epineurium.
Small, distinct regions of gray matter within the CNS are usually called:
a. white matter.
b. nuclei.
c. ganglia.
d. fascicles.
b. nuclei.
Nerves that contain mostly efferent fibers are called:
a. sensory nerves.
b. motor nerves.
c. mixed nerves.
d. Schwann nerves.
b. motor nerves.
Gray matter in the CNS consists of:
a. nerve fibers.
b. neuroglia.
c. axons.
d. cell bodies.
d. cell bodies.
Most nerves in the human nervous system are:
a. sensory nerves.
b. motor nerves.
c. mixed nerves.
d. reflex nerves.
c. mixed nerves.
Evidence now indicates that neurons may be replaced.
True or False
True
Regeneration of nerve fibers will occur if the cell body is intact and the fibers have a neurilemma.
True or False
True
There are no differences between the CNS and PNS concerning the repair of damaged fibers.
True or False
False
______ axon
a. Neurons or b. Neuroglia
a. Neurons
______ supporting cells
a. neurons or b. neuroglia
b. Neuroglia
______ astrocytes
a. neurons or b. neuroglia
b. Neuroglia
______ sensory
a. neurons or b. neuroglia
a. Neurons
______ conduct impulses
a. neurons or b. neuroglia
a. Neuro
______ form the myelin sheath around central nerve fibers
a. neurons or b. neuroglia
b. Neuroglia
______ phagocytosis
a. neurons or b. neuroglia
b. Neuroglia
______ efferent
a. neurons or b. neuroglia
a. Neurons
______ multiple sclerosis
a. neurons or b. neuroglia
b. Neuroglia
______ multipola
a. neurons b.Neuraligia
a. Neurons
Compared with the inside of the cell, the outside of most cell membranes is:
a. positive.
b. negative.
c. equal.
d. none of the above.
a. positive.
The difference in electrical charge across a plasma membrane is called:
a. depolarization.
b. membrane potential.
c. both a and b.
d. none of the above.
b. membrane potential.
A neuron’s resting membrane potential is:
a. 70 mV.
b. –70 mV.
c. 30 mV.
d. –30 mV.
b. –70 mV.
Which of the following statements is true concerning the sodium-potassium pump?
a. Three sodium ions are pumped out of the neuron for every two potassium ions pumped into the neuron.
b. Two sodium ions are pumped out of the neuron for every three potassium ions pumped into the neuron.
c. Three sodium ions are pumped out of the neuron for every three chloride ions pumped into the neuron.
d. Three sodium ions are pumped out of the neuron for every three potassium ions pumped into the neuron.
a. Three sodium ions are pumped out of the neuron for every two potassium ions pumped into the neuron.
A membrane that exhibits a membrane potential is said to be polarized.
True or False
True
A slight shift away from the resting membrane potential in a specific region of the plasma membrane is often called a stimulus-gated channel.
True or False
False
Chlorine ions (Cl–) are the dominant extracellular cations.
True or False
False
During a relative refractory period:
a. an action potential is impossible.
b. an action potential is possible only in response to a very strong stimuli.
c. an action potential is occurring.
d. none of the above.
b. an action potential is possible only in response to a very strong stimuli.
Voltage-gated channels are:
a. membrane channels that close during voltage fluctuations.
b. ion channels that open in response to voltage fluctuations.
c. membrane channels that are altered from an extremely high stimulus.
d. none of the above.
b. ion channels that open in response to voltage fluctuations.
When current leaps across an insulating myelin sheath from node of Ranvier to node of Ranvier, the type of impulse conduction is:
a. repolarization.
b. refraction.
c. saltatory conduction.
d. diffusion.
c. saltatory conduction.
The larger the diameter of a nerve fiber:
a. the slower the speed of conduction.
b. the faster the speed of conduction.
c. Fiber diameter does not influence speed of conduction.
d. the more the speed fluctuates.
b. the faster the speed of conduction.
Action potential and nerve impulse are synonymous.
True or False
. True
When repolarization has occurred, an impulse cannot be conducted.
True or False
False
The action potential is an all-or-none response.
True or False
True
Many anesthetics function by inhibiting the opening of sodium channels and thus blocking the initiation and conduction of nerve impulses.
True or False
True
Which of the following structures is not a main component of a chemical synapse?
a. synaptic knob
b. synaptic cleft
c. synaptic process
d. plasma membrane of postsynaptic neuron
c. synaptic process
A synaptic knob is located on the:
a. synaptic cleft.
b. axon.
c. dendrite.
d. cell body.
b. axon.
Which of the following is true of spatial summation?
a. Neurotransmitters released simultaneously from several presynaptic knobs converge on one postsynaptic neuron.
b. Simultaneous stimulation of more than one postsynaptic neuron occurs.
c. Impulses are fired in a rapid succession by the same neuron.
d. Speed of impulse transmission is increased when several neurotransmitters are released.
a. Neurotransmitters released simultaneously from several presynaptic knobs converge on one postsynaptic neuron.
In an adult, the nervous system is replete with both electrical synapses and chemical synapses.
True or False
False
Rapid-succession stimulation of a postsynaptic neuron by a synaptic knob can have a cumulative effect over time that can result in an action potential.
True or False
True
Ca++ ions cause the release of neurotransmitters across the synaptic cleft.
True or False
True
Neurotransmitters are released in a synapse and bind to:
a. presynaptic terminals.
b. the synaptic cleft.
c. the base of the axon.
d. receptors on the postsynaptic terminal.
d. receptors on the postsynaptic terminal.
The main chemical classes of neurotransmitters include all of the following except:
a. acetylcholine.
b. norepinephrine.
c. amino acids.
d. amines.
b. norepinephrine
Which of the following is not an example of an amine neurotransmitter?
a. serotonin
b. histamine
c. glycine
d. dopamine
c. glycine
Severe depression can be caused by a deficit in which of the following neurotransmitters?
a. acetylcholine
b. amino acids
c. amines
d. neuropeptides
c. amines
Which of the following is not a catecholamine?
a. epinephrine
b. norepinephrine
c. dopamine
d. serotonin
d. serotonin
Many biologists now believe that neuropeptides are the most common neurotransmitters in the CNS.
True or False
. False
Cocaine produces a temporary feeling of well-being by blocking the uptake of dopamine.
True or False
True
Multiple sclerosis is a myelin disorder.
True or False
True
Physical injury, causing nerve damage, can cause local or widespread loss of sensation and/or motor control.
True or False
True
Nerve conduction does not occur due to fluctuations in the concentration of ions.
True or False
False
Myasthenia gravis is a bacterial disorder.
True or False
. False
Parkinson disease is a failure to release adequate dopamine at the synapse of certain motor pathways.
True or False
True
Tracey was having a root canal procedure. Her dentist assured her that he would give her an anesthetic such as Marcaine that would keep her pain free the entire time.
How does Marcaine prevent pain?
Marcaine, procaine, and similar drugs produce anesthesia by inhibiting the opening of the sodium channels and thus blocking the initiation and conduction of nerve impulses.
Susan was a cocaine abuser.
Explain how the temporary feeling of well-being is achieved and the risk that abusing cocaine can be to the body.
Cocaine, which is often used in medical practice as a local anesthetic, produces a temporary feeling of well-being in cocaine abusers by similarly blocking the uptake of dopamine. Unfortunately, cocaine and similar drugs can also adversely affect blood flow and heart function when taken in large amounts—leading to death in some individuals.
A synaptic knob is a tiny bulge at the end of the (presynaptic or postsynaptic) neuron’s axon.
presynaptic
Acetylcholine is an example of a (neurotransmitter or protein molecule receptor).
neurotransmitter
Neurotransmitters are chemicals that allow neurons to (communicate or reproduce) with one another.
communicate
Neurotransmitters are distributed (randomly or specifically) into groups of neurons.
specifically
Endorphins and enkephalins are neurotransmitters that inhibit conduction of (fear or pain).
pain
A synonym commonly used for action potential is (nerve impulse or depolarization).
nerve impulse
In myelinated fibers, action potentials in the membrane occur only at the nodes of Ranvier. This type of impulse conduction is called (saltatory conduction or postsynaptic conduction).
saltatory conduction
A membrane that exhibits a membrane potential is said to be (polarized or myelinated)
polarized
The function of a neurotransmitter is determined by the postsynaptic receptor.
True or False
True
Neurotrophins stimulate neuron development but also can act as neurotransmitters or neuromodulators.
True or False
True
