Explain: How is an AP propagated along an unmyelinated axon? That is, how does the signal travel over sometimes long distances without decay?
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In a simulation we have an unmyelinated axon that then becomes myelinated. What happens to the action potential as it moves from the unmyelinated portion to the myelinated axon segment. In particular, what is different about the rising phase? What axon properties account for this?
What happens to the action potential that began in the myelinated axon segment? Why? Discuss amplitude, velocity etc..
What is the effect of temperature on the ability of the action potential to transition into the bare axon segment? How does a change in temperature have this effect?
Signals of varying strength travel through the nervous system -either as incoming sensory input or commands to effectors to dowork.
Explain how signal strength is varied during the followingevents:
a. during synaptic transmissionb. during processing of incoming signals from the receiving regionof a neuron to the axon hillockc. during action potential propagation along the axon
1. Discuss how an action potential is propagated along an axon,including all relevant molecules andprocesses. Be sure to discuss how resting membrane potential isrestored. How is the signal transmitted tothe next neuron?
2. Explain the process of contraction in a skeletal muscle,starting with how the signal enters a muscle cell atthe neuromuscular junction. Include all relevant ions, structures,and processes in your explanation.
3. Using your knowledge of both animal behavior and evolution,define and explain altruistic behavior. Underwhat sorts of circumstances would we expect to see altruisticbehavior, and why? Under what sorts ofcircumstances would we expect natural selection to favor allelesassociated with behaving altruistically?
4. Use your understanding of population ecology to describe andexplain the global human population overthe last one or two thousand years. What can you predict for thefuture of the global human population, andwhy? (Your predictions should be based on population ecology!) Whatpolicy changes, if any, do you thinkare advisable given the predictions you have made?
5. Define symbiosis and explain the major categories ofsymbiotic interactions, including how each type ofinteraction may be shaped by natural selection. To support yourexplanation, give at least two examples oftype of symbiosis, explaining how each species is affected (e.g.,helped, harmed, or unaffected) and why.
6. Describe the flow of energy in an ecosystem. Where does theenergy initially come from? Why isn