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Hey guys! I got first place in Anatomy at regionals, but the test was too easy. I don't know what to expect at the Southern California State competition. Last year, they made us label a bunch of diagrams. Do you know what they have had for years before?

hmath729 wrote:Could you guys help explain how a impulse works, with the Na+ and K+ transfer? I don't get it

Basically, when a neuron is at resting membrane potential, there is a higher concentration of Na+ ions outside the cell and a higher concentration of K+ ions inside the cell. However, there are fewer ions inside making it less positive or more negative. This means the cell is polarized when it is more negative inside. The action potential is the electrical current that travels through the neuron when it is stimulated. The minimum stimulus needed to achieve action potential is called the threshold stimulus. When a stimulus is received by the neuron, the Na+ gates open and because it is less negative on the inside of the cell and more positive on the outside, the Na+ ions come rushing into the cell. This is called depolarization because it makes the inside of the cell more positive than the outside. Then, the K+ gates open and K+ rushes out of the cell. This is called repolarization. At this point, the neuron is back to being more negative on the inside and more positive on the outside. However, Na+ is concentrated inside the cell and K+ is concentrated outside, which is the opposite of where they were concentrated when the cell was at resting membrane potential. So the Na+/K+ pump, with the help of ATP, pumps 3 Na+ ions out of the cell for every 2 K+ pumped in until the ion concentration on the inside and outside are back to normal.

That helps a lot. Thanks!!!

NO NERVOUS SYSTEM NEXT YEAR!!!!!

What do you guys think will be the new system next year????

So we will definitely have integumentary system but no nervous system?

hmath729 wrote:NO NERVOUS SYSTEM NEXT YEAR!!!!!

There will be no nervous system? are you sure?

I hope you're wrong

From what I've heard, the systems for Anatomy rotate every two years. Nervous system has been here for last year (2013) and this year (2014), so I doubt it will serve again next year.
I hope I'm wrong though. Nervous system is the best.

Sucks, doesn't it?
Which system is next? I think respiratory.