[-James-]

ahhh I just don't get it.

'after an action potential, the membrane remains insensitive to further stimuli until the resting potential is restored'

and i've seen diagrams with the refractory period labelled during hyperpolarisation.

help please!

Would really appreciate it, thanks!

[TrollerCoaster]

In sexuality, the refractory period is the recovery phase after (normally male) orgasm during which it is physiologically impossible for an individual to have additional orgasms. Most men are unable to maintain or achieve an erection during this time, and many perceive a psychological feeling of "satiation" and are temporarily uninterested in further sexual activity. The penis may be hypersensitive and further sexual stimulation may even feel painful during this time frame.
The refractory period varies widely among individuals and across species, ranging from minutes to days.[1] An increased infusion of the hormone oxytocin during ejaculation is believed to be chiefly responsible for the refractory period and the amount by which oxytocin is increased may affect the length of each refractory period.[2] Another chemical which is considered to be responsible for this effect is prolactin, which represses dopamine, which is responsible for sexual arousal.[3]
Unlike most men, most women do not experience a refractory period immediately after orgasm and in many cases are capable of attaining additional, multiple orgasms through further stimulation.[1] The female sexual response is more varied than that of men, and there are many women who experience clitoral hypersensitivity after orgasm, which effectively creates a refractory period. These women may be capable of further orgasms, but the pain involved in getting there makes the prospect undesirable.[4]
According to some studies, 18-year-old males have a refractory period of about 15 minutes, while those in their 70s take about 20 hours, with the average for all men being about a half-hour.[5] Although rarer, some males exhibit no refractory period or a refractory period lasting less than 10 seconds.[6][verification needed] This, however, is not a lack of a refractory period per se (the ability to achieve another orgasm), but rather the ability to maintain an erection and resume sex immediately, whether to orgasm or not.

[jessplease]

(Original post by -James-)
ahhh I just don't get it.

'after an action potential, the membrane remains insensitive to further stimuli until the resting potential is restored'

and i've seen diagrams with the refractory period labelled during hyperpolarisation.

help please!

Would really appreciate it, thanks!

When further along the axon sodium voltage channels open to create action potential, behind it the sodium voltage channel closes so that no more sodium ions can move into axon, this is the refractory period as the action potential cannot occur directly behind it.

[BIG-DAVE]

Between 5 o'clock and 6 o'clock.

LOL

[abisan777]

If you're talking about an action potential, it's to do with sodium channels. Sodium is allowed into the cell to make the membrane potential less negative (i.e. an AP)

Sodium channels exist in 3 states- open, closed and inactive. Normally, they are closed. When the threshold is reached, the channels become open, letting in sodium, making the membrane more positive. The channel has a little voltage sensor that will inactivate the channel at a certain voltage by pulling a little protein appendage into the pore of the channel. Once all the channels are inactivated, they cannot open again for a while until they reset. The time after a potential where all of the sodium channels are inactivated is the absolute refractory period as there is no way of making and action potential without them. When only a few are closed it is the relative refractory period where and AP is possible, but unlikely. The period is over when all the channels return to their closed state, ready to be stimulated again!

Hope that helps!