Difference between revisions of "Puberty Endocrine Events - Anatomy & Physiology"
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| − | + | = Hypothalamic Neurone Release of GnRH = | |
* Hypothalamic development occurs gradually with growth of the animal. | * Hypothalamic development occurs gradually with growth of the animal. | ||
| + | |||
| + | == Female == | ||
| + | |||
* The Hypothalamus contains a tonic GnRH centre and a preovulatory GnRH 'surge' centre. | * The 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. | ||
| + | * The pre-ovulatory LH surge is a series of rapid, high amplitude pulses. | ||
| + | * Inability of the surge centre to function will result in failure to ovulate. | ||
| + | * In addition to the surge centre in the female, at puberty the tonic centre must also reach a functional state. | ||
| + | * The tonic centre regulates the tonic frequency of GnRH pulses. | ||
| + | |||
| + | == Male == | ||
| + | |||
| + | * Does not develop a surge centre. | ||
| + | * The feedback system after puberty is a simple negative feedback loop. | ||
| + | * The negative feedback effect on GnRH is mainly due to some testosterone and mostly due to oestradiol because most testosterone is converted to oestradiol within the brain by aromatization. | ||
| + | * GnRH neurons become increasingly less sensitive to the negative feedback of testosterone and oestradiol as puberty approaches. | ||
| + | * Larger and larger quantities of testosterone and oestradiol are needed to inhibit the GnRH neurons. | ||
| + | * Thus, there is decreased sensitivity to the negative feedback of testosterone/oestrodiol. | ||
| + | * Therefore, the hypothalamus can produce increasing amounts of GnRH. | ||
| + | * Thus, more LH and FSH are produced until puberty is reached. | ||
Revision as of 09:30, 8 September 2008
|
Hypothalamic Neurone Release of GnRH
- Hypothalamic development occurs gradually with growth of the animal.
Female
- The 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.
- GnRH neurons must fire frequently and release large quantities of GnRH in order to cause the pre-ovulatory LH surge.
- The pre-ovulatory LH surge is a series of rapid, high amplitude pulses.
- Inability of the surge centre to function will result in failure to ovulate.
- In addition to the surge centre in the female, at puberty the tonic centre must also reach a functional state.
- The tonic centre regulates the tonic frequency of GnRH pulses.
Male
- Does not develop a surge centre.
- The feedback system after puberty is a simple negative feedback loop.
- The negative feedback effect on GnRH is mainly due to some testosterone and mostly due to oestradiol because most testosterone is converted to oestradiol within the brain by aromatization.
- GnRH neurons become increasingly less sensitive to the negative feedback of testosterone and oestradiol as puberty approaches.
- Larger and larger quantities of testosterone and oestradiol are needed to inhibit the GnRH neurons.
- Thus, there is decreased sensitivity to the negative feedback of testosterone/oestrodiol.
- Therefore, the hypothalamus can produce increasing amounts of GnRH.
- Thus, more LH and FSH are produced until puberty is reached.