Descrive the positive feedback loop between cervical stretch receptors,neurosecretory cells in the hypothalamu?

The is ultimately about childbirth, one of the only positive feedback cycles that takes place within humans. As the stretch receptors in the cervix 'sense' the pressure of childbirth, a signal is sent to the hypothalamus. The hypothalamus, in turn, secrets oxytocin, which increases contractions of childbirth. These contractions send additional signals to the hypothalamus, which in turn secrets more oxytocin and a cycle is created.

A positive feedback cycle has a definitive end - in this case, childbirth. Each of the events (cervical stretch and secretion of oxytocin) re-enforces the other. This will continue until the fetus is delivered.

A common example of a positive feedback cycle is the feedback you get from putting a microphone too close to a speaker. You get a louder and louder noise because a positive feedback cycle has been created which is self-re-enforcing.

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Descrive the positive feedback loop between cervical stretch receptors,neurosecretory cells in the hypothalamu?

Oxytocin,and the uterine smooth muscle.

Stretch Receptors

All climate change requires positive feedbacks. In natural climate change, the coming and going of ice ages have required feedback to amplify. The Milankovitch Cycle or plate techtronics that initiated past climate change were nowhere near powerful enough on their own to cause the dramatic changes. In past, natural climate change, CO2 has been a primary feedback as the oceans naturally throw off CO2 as they warm. The albedo effects of growing or diminishing ice cover has also been a primary feedback in both the coming and going of ice ages. Among the positive feedbacks that will amplify global warming are the albedo effect (as ice surface diminishes, less energy is reflected by the white ice and more is absorbed by the exposed dark water), the release of vast stores of methane which is stored in the frozen tundra (methane is a stronger greenhouse gas), increased water vapor in the atmosphere due to increased evaporation (water vapor is also more powerful as a greenhouse gas than is CO2), a poleward shift of forested areas reducing the reflective powers of the surface, more fires which put more CO2 into the air, warming of the ocean reduces it's ability to absorb CO2. There are a few expected negative feedbacks. Clouds have been debated and it seems the may be either a positive or negative feedback. It's theorized that more CO2 can help plants, though it is not clear whether other changes will harm overall plant growth; more plants will use more CO2. Increased desertification and land degradation would cause more soil to be blown into the atmosphere which would have a cooling, dimming effect. Of all these, the greatest feedback will likely be the increase of methane in the atmosphere as that has always been a major component of global climate change.