| 翻訳と辞書 |
| Ferguson reflex ： ウィキペディア英語版 |
Ferguson reflex
The Ferguson reflex is the name given to the neuroendocrine reflex comprising the self-sustaining cycle of uterine contractions initiated by pressure at the cervix or vaginal walls. It is an example of positive feedback in biology. The Ferguson reflex occurs in mammals.
== Mechanism ==
Upon application of pressure to the internal end of the cervix, oxytocin is released, which stimulates uterine contractions, which in turn increases pressure on the cervix (thereby increasing oxytocin release, etc.), until the baby is delivered.
Sensory information regarding mechanical stretch of the cervix is carried in a sensory neuron, which synapses in the dorsal horn before ascending to the brain in the anterolateral columns (ipsilateral and contralateral routes). Via the median forebrain bundle, the efferent reaches the PVN and SON of the hypothalamus. The posterior pituitary releases oxytocin due to increased firing in the hypothalamo-hypophyseal tract. Oxytocin acts on the myometrium, on receptors which have been upregulated by a functional increase of the estrogen-progesterone ratio. This functional ratio change is mediated by a decrease in myometrial sensitivity to progesterone, due to an increase in progesterone receptor A, and a concurrent increase in myometrial sensitivity to estrogen, due to an increase in estrogen receptor α. This causes myometrial contraction and further positive feedback on the reflex.〔Martin H. Johnson, Essential Reproduction 6th edition (2007). Blackwell Publishing〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Ferguson reflex」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|