1.Neurons communicate with other neurons and stimulate both ______________ and ______________. (think about effecter organs).
2.Match the following parts of the neuron and their function: Dendrites ______________ conductive region; generates an action potential Soma (cell body)______________ input area; receives signals from other neurons Axon ______________ input area; main nutritional and metabolic area 3.Signals from other neurons are received at junctions called ______________, located primarily on the ______________ and ______________, the receptive and integrative regions of the neuron. 4.The area where the axon emerges from the soma is called the ______________ ______________. This is also the area where the outgoing signal, called a/an ______________ ______________ is generated. 5.An axon can branch, forming axon collaterals. At the end, axons branch to form many axon _________________________. 6.What support cell type forms the myelin sheath? _________________________ Myelin is found around which part of the neuron? ______________ The tightly wound cell membrane around the axon forms the myelin sheath and acts as ______________. 7.The gaps between the Schwann cells, called the _________________________, are essential for the conduction of the action potential. 8.The most common central nervous system neuron, which is the major neuron type in CNS and consists of many processes. This type of neuron is called a/an _________________________ neuron. 9.Neurons have (only one or many) axon/axons.
Axons are (never or frequently) branched.
Dendrites have (only one or many) branch/branches.
Nervous System I: Ion Channels
1. What structures in the cell membrane function as ion channels?
2.Ion channels are selective for specific ions. What two characteristics of the ions are important for this selectivity? 1.
3.Channels can be classified as either gated or nongated channels. A sodium channel that is always open would be classified as a/an ________________________ channel. 4.Would sodium ions move into or out of the neuron through these channels? _______________ 5.Voltage-gated potassium channels open at what voltage? __________ mV 6.Acetylcholine (ACh) and GABA are neurotransmitters that open chemically gated channels. What ions pass into the cell when these channels are activated? a.ACh: ________________________ ions
b.GABA: ________________________ ions
7.Ion channels are regionally located and functionally unique. List all the areas on the neuron and the type of potential dependent on the following types of ion channels:
|Channels |Areas on the Neuron |Type of Potential | |Passive | | | |Chemically gated | | | |Voltage gated | | |
8.Place an “X” by the characteristics of voltage-gated sodium channels. _____ Always open
_____ Found along the axon
_____ Important for action potential
_____ Opened and closed by gates
_____ Found on the dendrites and cell bodies
_____ Important for resting membrane potential
9.Name one channel (gated or nongated) through which chloride ions could pass into the cell. _________________________
10.a.The Japanese puffer fish contains a deadly toxin (tetrodotoxin). What type of channels does this toxin block? _______________________________...