Changes

== Female ==

== Female ==

* The Hypothalamus contains a tonic GnRH centre and a preovulatory GnRH 'surge' centre.

* The [[Hypothalamus_-_Anatomy_%26_Physiology|Hypothalamus]] contains a tonic GnRH centre and a preovulatory GnRH 'surge' centre.

* Before puberty can occur, full neural activity of the surge centre must be achieved.

* Before puberty can occur, full neural activity of the surge centre must be achieved.

* GnRH neurons must fire frequently and release large quantities of GnRH in order to cause the pre-ovulatory LH surge.

* GnRH neurons must fire frequently and release large quantities of GnRH in order to cause the pre-ovulatory LH surge.

* The secretion of GnRH from the surge centre neurons is controlled by both positive and negative feedback.

* The secretion of GnRH from the surge centre neurons is controlled by both positive and negative feedback.

* Puberty is initiated when GnRH neurons can respond completely to the positive and negative feedback.

* Puberty is initiated when GnRH neurons can respond completely to the positive and negative feedback.

* The surge centre and the tonic centre in the Hypothalamus are anatomically distinct from one another.

* The surge centre and the tonic centre in the [[Hypothalamus_-_Anatomy_%26_Physiology|Hypothalamus]] are anatomically distinct from one another.

* The surge centre responds primarily to positive feedback stimulus.

* The surge centre responds primarily to positive feedback stimulus.

* In the pre-pubertal female, the sensitivity of the surge centre to the positive feedback of oestrogen is quite high, but ovlation does not occur.  This is because the immature ovaries do not produce enough oestrogen to activate the highly sensitive surge centre.

* In the pre-pubertal female, the sensitivity of the surge centre to the positive feedback of oestrogen is quite high, but ovlation does not occur.  This is because the immature ovaries do not produce enough oestrogen to activate the highly sensitive surge centre.