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week 7 physi
physiology chapter 7
Question | Answer |
---|---|
The difference in electrical charge between the inside and outside of a membrane is called the membrane potential. True or False | True |
The speed of a nerve impulse depends on the neuron’s resting potential. True or False | False |
A synapse can occur only between an axon and: | a dendrite. a cell body. another axon. Correct Answer any of the above. |
Which chemicals allow neurons to communicate with one another? | neurotransmitters |
Whether an impulse is continued through the neuron depends on the magnitude of the voltage in the axon hillock. True or False | True |
In a myelinated fiber, the action potential jumps from one node of Ranvier to the next. True or False | True |
The active transport mechanism in the plasma membrane that transports sodium and potassium ions in opposite directions and at different rates is the | sodium-potassium pump. |
If the magnitude of the local depolarization surpasses a limit called the _____, voltage-gated Na+ channels are stimulated to open. | threshold potential |
A term commonly used as a synonym for action potential is | nerve impulse. |
An ion channel that opens in response to a sensory stimulus is a(n) | stimulus-gated channel. |
In a myelinated neuron, the impulse can travel under the myelin between nodes of Ranvier. True or False | True |
When neurotransmitters from synaptic knobs stimulate a postsynaptic neuron in rapid succession, their effect can add up over a brief period to produce an action potential. This is called | temporal summation. |
A neurologist is using a voltmeter to measure potential. The membrane potential of a neuron was recorded at +30 mV. This is what type of membrane potential? | Action |
The action potential seems to “leap” from node to node along a myelinated fiber. This type of impulse regeneration is called __________ conduction. | saltatory |
The brief period during which a local area of an axon's membrane resists re-stimulation is called the __________ period. | refractory |
Neurons are the only living cells that maintain a difference in the concentration of ions across their membranes. True or False | False |
The sodium-potassium pump actively pumps three potassium ions out of the neuron and two sodium ions into the neuron. True or False | False |
A membrane that exhibits a membrane potential is said to be | polarized |
What mechanism quickly terminates the action of a neurotransmitter once it binds to its postsynaptic receptor? | Neurotransmitter molecules are transported into nearby glial cells, neurotransmitter molecules are metabolized into inactive compounds, neurotransmitter molecules are transported back into the synaptic knobs ( All of the above are correct ) |
The membrane potential maintained by a nonconducting neuron’s plasma membrane is called the _____ membrane potential. | resting |
Movement of the membrane potential away from zero (below the usual RMP) is called | hyperpolarization. |
There are two types of synapses—the electrical synapse and the __________ synapse. | chemical |
The mechanisms that produce and maintain the resting membrane potential do so by producing a | slight excess of positive ions on the outer surface of the plasma membrane. |
The tiny bulge at the end of a terminal branch of a presynaptic neuron’s axon is called a(n) | synaptic knob. |
In depolarization the membrane potential moves toward zero, whereas in hyperpolarization the membrane potential moves away from zero. True or False | True |
The magnitude of the action potential peaks when the sodium channels close. True or False | True |
Which membrane receptor acts to directly change ion permeability when stimulated? | Gated-channel receptor |
The difference between sodium and potassium in the generation of action potential is that: | sodium causes depolarization of the cell membrane, and potassium causes repolarization of the cell membrane. |
When a neuron is resting, the inner surface of its plasma membrane is slightly positive compared with its outer surface. True or False | False |
If the threshold potential is surpassed, the full peak of the action potential is always reached. True or False | True |