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A close-up illustration depicts the difference in charges across the cell membrane, and shows how Na+ and K+ cells concentrate more closely near the membrane.
At resting potential, Na + (blue pentagons) is more highly concentrated outside the cell in the extracellular fluid (shown in blue), whereas K + (purple squares) is more highly concentrated near the membrane in the cytoplasm or intracellular fluid. Other molecules, such as chloride ions (yellow circles) and negatively charged proteins (brown squares), help contribute to a positive net charge in the extracellular fluid and a negative net charge in the intracellular fluid.

From this resting potential state, the neuron receives a signal and its state changes abruptly ( [link] ). When a neuron receives signals at the dendrites—due to neurotransmitters from an adjacent neuron binding to its receptors—small pores, or gates, open on the neuronal membrane, allowing Na + ions, propelled by both charge and concentration differences, to move into the cell. With this influx of positive ions, the internal charge of the cell becomes more positive. If that charge reaches a certain level, called the threshold of excitation    , the neuron becomes active and the action potential begins.

Many additional pores open, causing a massive influx of Na + ions and a huge positive spike in the membrane potential, the peak action potential. At the peak of the spike, the sodium gates close and the potassium gates open. As positively charged potassium ions leave, the cell quickly begins repolarization. At first, it hyperpolarizes, becoming slightly more negative than the resting potential, and then it levels off, returning to the resting potential.

A graph shows the increase, peak, and decrease in membrane potential. The millivolts through the phases are approximately -70mV at resting potential, -55mV at threshold of excitation, 30mV at peak action potential, 5mV at repolarization, and -80mV at hyperpolarization.
During the action potential, the electrical charge across the membrane changes dramatically.

This positive spike constitutes the action potential    : the electrical signal that typically moves from the cell body down the axon to the axon terminals. The electrical signal moves down the axon like a wave; at each point, some of the sodium ions that enter the cell diffuse to the next section of the axon, raising the charge past the threshold of excitation and triggering a new influx of sodium ions. The action potential moves all the way down the axon to the terminal buttons.

The action potential is an all-or-none    phenomenon. In simple terms, this means that an incoming signal from another neuron is either sufficient or insufficient to reach the threshold of excitation. There is no in-between, and there is no turning off an action potential once it starts. Think of it like sending an email or a text message. You can think about sending it all you want, but the message is not sent until you hit the send button. Furthermore, once you send the message, there is no stopping it.

Because it is all or none, the action potential    is recreated, or propagated, at its full strength at every point along the axon. Much like the lit fuse of a firecracker, it does not fade away as it travels down the axon. It is this all-or-none property that explains the fact that your brain perceives an injury to a distant body part like your toe as equally painful as one to your nose.

As noted earlier, when the action potential arrives at the terminal button, the synaptic vesicles release their neurotransmitters into the synapse. The neurotransmitters travel across the synapse and bind to receptors on the dendrites of the adjacent neuron, and the process repeats itself in the new neuron (assuming the signal is sufficiently strong to trigger an action potential). Once the signal is delivered, excess neurotransmitters in the synapse drift away, are broken down into inactive fragments, or are reabsorbed in a process known as reuptake    . Reuptake involves the neurotransmitter being pumped back into the neuron that released it, in order to clear the synapse ( [link] ). Clearing the synapse serves both to provide a clear “on” and “off” state between signals and to regulate the production of neurotransmitter (full synaptic vesicles provide signals that no additional neurotransmitters need to be produced).

Questions & Answers

the madness will go away..
Miasco Reply
Hi
Sonic
Hello
MTH
So what is Psychology? Generally
Sonic
its a philysio thereapy
Yan
oh physio therapy
Sonic
right
Sonic
ha ha just kidding
Yan
the scientific study of the human mind and its functions, especially those affecting behaviour 
Yan
Hi everyone. My question is.. How can manage anger? Any therapy name which use in home to manage anger? If someone needs anger management which tips are helpful?
Madeeha Reply
i think that you can manage your anger buy avoiding things which can cause you to be angry just surround yourself with people who doesn't make you angry
Fiona
One of methods in releasing anger in a not-so chaotic way is to simply find a quite place, scream and cry.
Norina
I think allowing yourself to be angry is helpful
jojesstay
^ in my opinion, while being good, avoids the problem. Either confront anger, or/and overcome it. Think about why you feel angry and should you even be angry to even begin with. Its ok to be angry. Everyone is different and react to different situations with dif. emotions, but dont let anger win u.
Tomi
take anger as your best friend ,make it a source of motivation whenever you become angry don't take it as something others do as they take anger as a different entity rather than accepting it as a mere emotion(though the strongest of them all) , so accept anger as an emotional state and accept it...
Priyank
...when it comes just take a deep breath and say to yourself it's nothing or no one else but me and I can control it and after doing it for a time you'll be able to channel it or redirect it in a way which will help you in a lot of different ways that you can't even think or imagine of......
Priyank
just remember anger is not your enemy but just an emotion it's not different from you, it's you and it's your bestest and strongest friend of them all.
Priyank
when you angry just count 100 to 0
Prashanth
Hi, everyone anyone tells.What is the scope of psycholog?
Madeeha Reply
The subject-matter of our science is, then, the Soul or Mind. The psychologist investigates those phenomena which we call sensations, perceptions, thoughts, volitions, and emotions; he analyzes them, classifies them, and seeks to reduce them to the smallest number of fundamental activities.
Vibhu
hey madeeha this is your answer
Vibhu
its my point of view
Vibhu
What matters is how their mind perceives their spirituality. And every mind will perceive this differently. Remove your own spirituality from the equation when studying psychology in order to view the spirituality of others (or lack thereof) as objectively as possible.
Brent
yeah exactly r8
Vibhu
Okay, thanks
Madeeha
Why is Bipolar and Meth use so prevalent amongst bipolar individuals?
Brett Reply
honestly, they are probably diagnosed as bipolar because of the meth. once gotten off meth for any length of time. the symptoms of bipolar usually leave. but few are honest with dr. n tell they use meth
Barbara
Conversely, it's because they self medicate during depressive episodes and become addicted. Manic highs can also lead to feelings of invincibleness and reckless behavior that impair judgment. People in manic states just want to have the most fun possible and find it hard to say no to drugs, or even
Brent
Seek the drugs out. Once they are out of the manic state, they associate the meth with that state, and when depressed will continue to use meth to attain it.
Brent
what is a pneumatic depressant
Bill Reply
what is the symptoms of DID.
positive Reply
what is symptoms of DID(Multiple personality Disorder)
positive
4. As indicated in this section, Caucasian women from industrialized, Western cultures tend to be at the highest risk for eating disorders like anorexia and bulimia nervosa. Why might this be?
Shamy Reply
Is anyone know the exact cause of mental illnesses like Add, Adhd, Ocd, bipolar etc
Kartikey Reply
mental desorders are caused by many factors
riadh
a chemical imbalance with bipolar which if i remember correctly has somthing to do with OCD as well.....?
jessie
its also has to do with parts of the brain that recieve neurons and some that dont.
Natasha
Natasha...u from which country?
Philip
uSA
Natasha
no i need more explanation
Aminu
ADD, ADHD, bi polar, and OCD. the first 3 are mostly chemical imbalance to the brain. bi polar is a chemical imbalance that has to do with the emotional and creative parts of the brain. its cause from not getting the right amount of something or not enough of something. which is why amphetamines
Natasha
will either make them act more normal and or helps them concentrate. also can make the unleveled level out. desoxyn is methamphentimine hydrochloride its for obese add and adhd
Natasha
may I add that some studies have shown that children who have A.D.H.D were more than likely brought up in single parent family's and Im not a 100% sure of the stat's but believe that some studies have shown as many as 80% of children with A.D.H.D were brought up in a single parent inviroment.
Gavin
And I also remember A.D.H.D in the early days and ideas were put fourth of the cause and one that stood out was spending excessive amounts of time playing computer games as that was still quite anew phenomena at the time.
Gavin
not that anyone mentions that one any more lol.
Gavin
I don't believe there is such a thing as chemical imbalance. More research is needed and it's too easy and simple just to blame certain illnesses on a chemical imbalance. What is chemical imbalance? Maybe we should start there.
David
chemical imbalance is when you either lack a brain chemical such as seritonin, dopamine ex.
Natasha
gavin true to that. our enviroment is a big factor in our chemicals. when were happy because of something our bodies produce more dopamine
Natasha
for example. single parent families are stressful which studies have shown cause more damage then we think or relize including brain chemistry
Natasha
lol duh read a book every now an den u won't bee sow retar'ed. geez some people I swair jus aint gots no cents. ya knaw what eye sayin... lol
Brett
ask reinfield from dracula he suffers from psychotic ideation...lol
Rodney
what are the psychological effects of being a patient
Gloria Reply
why is the Synapse so important to biopsychologists
Susan Reply
I dnt know
Sam
because its very important
Deepak
Because that's where the exchange of information takes place which causes reactions in us and so biopsychologists need to study the info transmitted in order to study the reaction to explain a mental process/behaviour
Tina
synapse occurs as part of the brain activity. This is where everything seems to happen. Just imagine this synapse is like firing information, your feelings, and stuff
Ysa
so can i assume that if there is action potential in the pre synaptic cell but the neurotransmitter does not diffuse into the post synaptic cell that this would lead to some sort of mental dysfunction?
Susan
Or the opposite, too much neurotransmitter
George
how long does it takes to stabilize your sleeping hours?
Gabby Reply
15 minutes.
Philip
90 mnit +
Khadim
usually 24 hrs for me
Goof
30mins to 1hr
Joshua
😉
Sarfaraj
30 minutes
Bill
why do we get depression
meghna Reply
how to be a neuropsychologist?
mukhtar Reply
wo Kya hota h?
Gayatri
I speak English sorry... If you can translate: I suggest studying anatomy if you are still in high school. You will need a master degree. So about ten years of college.
Jen
Pay close attention to psychology as well. Biology is a must.
Jen
hmm
Gayatri
what are the factors affecting learning
Savoeda Reply
motivation is probably a big factor, but also intellectual ability, knowing from personal experience
Elaina
why do we get depression
meghna
yes
Natasha
you have it
Adam
low income families, poverty and a poor stimulating environment for children could be caused of learning disabilities or effects.
vincent
any advice on psychological statistics ?
Kurt Reply
I'm taking psychological statistics too
psychological statistic is a branch of psychology that deals with research and experimental aspect of psychology. It is an offshoot if experimental psychology, they make use of statistical tools in describing, predicting, analysing and make an inference about data collected in order to
babatunde
what about factors affecting learning
Savoeda

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Source:  OpenStax, Psychology. OpenStax CNX. Feb 03, 2015 Download for free at https://legacy.cnx.org/content/col11629/1.5
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