Nerve cell?

Question

What changes take place along a nerve cell membrane as it moves from a resting potential to an action potential?

Answer 1

When resting potential is retained, the relative charge inside the cell membrane is negative, as a result of more positive charges outside the cell (Na+ and K+). When the electrical potential passes the threshold, the sodium channel opens up, allowing the external Na+ ions to move into the cell, resulting in a more positive charge inside the cell membrane, the concentration of positive charges inside the cell triggers the opening of the potassium channel, and the closing of the sodium channel, the potassium channel allows the K+ ions to travel out of the cell, restoring the negative resting potential. This rapid change of charge inside the cell, causes the positively charged Na+ inside the membrane to move along the neuron towards the negative charge, resulting in an action potential.

Answer 2

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RE:
Nerve cell?
What changes take place along a nerve cell membrane as it moves from a resting potential to an action potential?

Answer 3

The topic of brain cell regeneration is still being debated in the scientific community. Neuroscience dogma says the cells within your nervous system do not regenerate - you are born with all the brain cells to last your life time. Recent finding, however, shows that they can and do regenerate. It is actually incorrect to say that it takes 7-8 years for all your cells in your body to be renewed. Cells within some organ constantly regenerate in as little as 3-5 days. For example, you are constantly shedding skin cells. There are other cells that only regenerate when they are injured. For example, if you donate half of your liver, it will regenerate itself in 8 months. And there are cells that don't regenerate at all. For example, your spinal cord will not regrow if severed.

Answer 4

Nerve Cells:
The nervous system regulates all aspects of bodily function and is staggering in its complexity. The human brain the control center that stores, computes, integrates, and transmits information contains about 1012 neurons (nerve cells), each forming as many as a thousand connections with other neurons. Millions of specialized neurons sense features of both the external and internal environments and transmit this information to the brain for processing and storage. Millions of other neurons regulate the contraction of muscles and the secretion of hormones. The nervous system also contains glial (neuroglial) cells that occupy the spaces between neurons and modulate their functions (see chapter opening figure).

The structure and function of individual nerve cells is understood in great detail, perhaps in more detail than for any other type of cell. The function of a neuron is to communicate information, which it does by two methods. Electric signals process and conduct information within a cell, while chemical signals transmit information between cells, utilizing processes similar to those employed by other types of cells to signal each other (Chapter 20). Sensory neurons have specialized receptors that convert diverse types of stimuli from the environment (e.g., light, touch, sound, odorants) into electric signals. These electric signals are then converted into chemical signals that are passed on to other cells called interneurons, which convert the information back into electric signals. Ultimately the information is transmitted to muscle-stimulating motor neurons or to other neurons that stimulate other types of cells, such as glands.

The output of a nervous system is the result of its circuit properties, that is, the wiring, or interconnections, between neurons, and the strength of these interconnections. Complex aspects of the nervous system, such as vision and consciousness, cannot be understood at the single-cell level, but only at the level of networks of nerve cells that can be studied by techniques of systems analysis. The nervous system is constantly changing; alterations in the number and nature of the interconnections between individual neurons occur, for example, in the development of new memories.

picture of communication between nerve cells
http://www.cerebromente.org.br/n12/fundamentos/neurotransmissores/cover1.jpg

What triggers the release of a neurotransmitter?
Some mechanism must exist whereby the action potential causes the transmitter stored in synaptic vesicles to be expelled into the cleft.

The action potential stimulates the influx of Ca2+, which causes synaptic vesicles to attach to the release sites, fuse with the plasma membrane and expel their supply of transmitter. The transmitter diffuses to the target cell, where it binds to a receptor protein on the external surface of the cell membrane. After a brief period the transmitter dissociates from the receptor and the response is terminated. In order to prevent the transmitter from rebinding to the receptor and repeating the cycle, the transmitter is either destroyed by degradative action of an enzime or it is taken up, usually into the presynaptic ending. Each neuron can produce only one kind of transmitter.

for more information you can see the site
http://www.cerebromente.org.br/n12/fundamentos/neurotransmissores/neurotransmitters2.html

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Answer 5

http://www.emile-21.com/VRML/membPot0.html

http://faculty.washington.edu/chudler/ap.html