Action potential – Brief (~1 ms) electrical event typically generated in the axon that signals the neuron as 'active'. An action potential travels the length of the axon and causes release of neurotransmitter into the synapse.
The neurotransmitter can either help (excite) or hinder (inhibit) neuron B from firing its own action potential. In an intact brain, the balance of hundreds of excitatory and inhibitory inputs to a neuron determines whether an action potential will result.
20 msec The length of an action potential for a pyramidal neuron is approximately 15-20 msec. At which frequency of stimulation would the length of the action potential be longer than the time between simulations?
At the junction between two neurons ( synapse ), an action potential causes neuron A to release a chemical neurotransmitter. The neurotransmitter can either help (excite) or hinder (inhibit) neuron B from firing its own action potential.
17. The equilibrium potential of K+ ions in nerve cells is about -90 mV. The membrane potential of typical nerve cells at rest is -70 mV.
A postsynaptic neuron has three presynaptic inputs - from neurons X, Y, and Z. Stimulation of neuron X causes the postsynaptic neuron to depolarize by 0.5 mV. When X and Y are stimulated simultaneously, the postsynaptic neuron depolarizes by 1 mV.
B. Preganglionic neurons are short and synapse in ganglia located near the spinal cord. C. Preganglionic neurons release acetylcholine at synapses with postganglionic neurons.
B. Neurons outnumber glial cells 10 to 1 in the nervous system.
The relative refractory period of an excitable membrane refers to the period of time during which no stimulus, however strong, will elicit a second action potential in the membrane. True False. f. 86.
C. Catecholamines are the most abundant neurotransmitters in the central nervous system. D. Opiate drugs, such as morphine, are antagonists of a class of neurotransmitters called endorphins. E. Gamma-aminobutyric acid (GABA) is a major excitatory transmitter in the central nervous system. a.
A. The plasma membrane is most permeable to sodium ions.
Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon. Drag the labels onto the table to indicate which type (s) of gated ion channels are found in each membrane associated with a chemical synapse.
You may use a label once or not at all. Drag the appropriate labels onto the graph to indicate the status (open or closed) of the voltage-gated Na+ and K+ channels during each phase of an action potential. Labels may be used once, more than once, or not at all.
Rank the axons from slowest to fastest conduction speed. If two axons have the same conduction speed, place one on top of the other.
After the first channel opens, the movement of many types of ions (both inside and outside the cell) alters the distribution of charges near the second channel, causing it to open . Enter the sequence in which the action potential would pass through the points. Enter the letters in the correct order separated by commas.
Labels can be used once, more than once, or not at all. Drag the labels onto the flowchart to indicate the sequence of events that occurs in the presynaptic cell (orange background) and the postsynaptic cell (blue background) after an action potential reaches a chemical synapse. a.
Collect solution around the nerve end from heart #1 without stimulating the vagus nerve and apply to heart #2.
Repolarization would occur, but much more slowly .