Honors and AP Biology Homework Chapter 28: Neurons and the Nervous System
Textbook assignment: Chapter 28: The Nervous System, sections 1 - 9.
- 28.1 The nervous system receives sensory input, integrates it with prior input, and responds by signalling other systems to react. The central nervous system (brain and spinal column) interneurons integrate data sent to them by the perpheral nervous system sensory neurons, then stimulate resons through motor neurons.
- 28.2 A neuron receives a signal through one of its many short fibers (dendrites), processes the signal, and if stimulated adequately, sends it out along the single long axon to the synaptic knobs at the end. Signal loss is prevented by Schwann cells encasing the axon.
- 28.3 A cell has a normal slight potential charge of -70mV which can be changed by the infusion of of positively-charged ions like Na+ or K+.
- 28.4 The change in potential must raise the charge to -50mV, at which point the cell membrane changes, allowing many positive ions to flood in and rapidly change the internal potential to a positive action potential (usually below +50mV).
- 28.5 The action potential is still a difference between inside and outside. The local change to the membrane propagates along the neuron tissue because it can't all change at once. The potential travels down the axon (not up it) because the area it has just left won't accept the charge.
- 28.6-7 When the potential reaches the synaptic knobs, it causes the vesicles there to produce chemicals, neurotransmitters, that are released from the end of the neuron into the synaptic gap or space between the neuron and the next cell.
- 28.8-9 Different neurotransmitters create different responses, so complex information can be transmitted. These transmitters can be mimicked by drugs which can stimulate similar responses directly.
- 28.10 Researchers submit papers for publication when research findings support their expectations for outcomes, but rarely when evidence is negative, which creates a bias in the literature.
Read the following weblecture before chat: The Human Nervous System.
Take notes on any questions you have, and be prepared to discuss the lecture in chat.
Perform the study activity below:
Use the HHMI click-and-learn activity to study the Electrical Activity of Neurons.
- Click on the "Start Click and Learn" link. This activity has 13 slides, some of which have short animations.
- What are Aplysia neurons? Why are they useful for studying neuron behavior?
- How were the experiments conducted to gather information about Aplysia neurons?
- What happens when low-voltage impulses are used to stimulate the neuron? What happens when the voltage reaches the threshhold level for neuron response?
- What is a radical reductionist approach to learning about neurons? How does this approach help us understand what is happening when a neuron receives input and "fires"?
Chat Preparation Activities
- Essay question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
- Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.
- No quiz yet: the Chapter Quiz opens when we finish the chapter.
Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.
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