[申覆]醫學(二) 4
1、 根據國考生理學指定用書:Ganong's Riview of Medical Physiology 23rd edition
168頁 寫到:
The threshold for activation of warmth receptors is 30℃, and they increase
their firing rate up to 46℃.
因此本題D選項的敘述,「受到高於45℃的溫度刺激時,warm receptors興奮性增加,
warm fibers的動作電位頻率大增(注)」,這段敘述應正確。
2、 168頁也寫到:
Two types of vanilloid receptors respond to noxious heat(VR1 and VRL-1).
The VR1 receptors respond not only to capsaicin but also to protons and to
potentially harmful temperatures above 43℃. VRL-1,which responds to
temperatures above 50℃ but not to capsaicin.
因此Warm receptors可區分為VR1及 VRL-1兩類,其中VR1受器不僅可以對辣椒素
(capsaicin)此類致痛物質有反應,對於H+及高於 43℃的有害溫度也有反應。
3、167頁寫到:Warmth(heat) receptors are on C fibers.
168頁寫到:There may be many types of receptors on single peripheral C fiber
endings, so single fibers can respond to many different noxious stimuli.
所謂的Warm receptors其實是感受痛覺的C fibers的裸露神經末梢,而單一C fiber又
連結了許多的receptors,因此同時可以感受來自不同的有害刺激。
因此D選項後半段敘述:「warm receptors可同時偵測痛覺」,應是可以接受的敘述。
故本題(醫學二第4題)無正確選項,應一律送分。
註:
153頁寫到:
The frequency of the action potentials generated in a sensory nerve fiber is
also related to the intensity of the initiating stimulus by a power function.
即敘述感覺神經纖維受到刺激後,所產生的動作電位頻率跟最初的刺激強度有關,也就
是刺激愈強,產生的動作電位頻率愈高。
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