動作電位(Action Potential)模擬網頁 PhET

https://phet.colorado.edu/zh_TW/simulations/neuron 請利用此模擬網頁回答問題: 當神經為靜止時, 請觀察哪些離子通道為開啟的?哪些為關閉的?( Observe the membrane closely while the axon is at rest. Which membrane channels are open? Which membrane channels are closed?)

• K⁺無閘門通道 (K⁺ leak) 開啟

• Na⁺無閘門通道 (Na⁺ leak) 關閉

• Na⁺無閘門通道 (Na⁺ leak) 開啟

• Na⁺電壓閘門通道 (Na⁺ gated) 開啟

• K⁺電壓閘門通道 (K⁺ gated) 關閉

當膜電位為靜止時，大部分的離子通道是開啟還是關閉的? (Are there more open or closed channels present in the membrane when the axon is at rest?)

• open

• closed

細胞內外的鈉和鉀離子的濃度不同，當促進性擴散發生時兩者的移動方向為何?

• Na+流入細胞

• Na+流出細胞

• K+流入細胞

• K+流出細胞

膜電位靜止時，神經細胞的哪一側為負電? (Which side of the neuron is negatively charged - inside the neuron or outside?)

• 內側 Inside為負

• 外側 Outside為負

Now it’s time to stimulate your neurons! 請畫出一個動作電位，並標示出閾值並對應時期的名稱、離子進出方向。

Answer explanation

Complete the table below by writing the answer or circling the correct word. Pay close attention to +/- signs on the membrane potential values

Answer explanation

請利用放大功能觀察模擬軟體中，動作電位發生時的閘門通道開關變化，請問閘門通道的開啟順序為何? (Observe the sodium and potassium ions passing across the membrane during the simulation. You might want to slow down the simulation speed and use the zoom feature to get a closer view. )

• Na+ 閘門通道先開、 K+ 閘門通道後開

• K+ 閘門通道先開、 Na + 閘門通道後開

• 兩者同時打開

細胞靜止時為內鉀多外鈉多，請問Na+或K+通道開啟時，會造成膜電位有何變化?

(What is happening to the membrane potential as each of these channels open? ) 

• Na+閘門通道開啟使膜電位變正

  As Na+ opens, the potential is becoming positive.

• Na+閘門通道開啟使膜電位變負

  As Na+ opens, the potential is becoming negative

• K+閘門通道開啟使膜電位變負

  As K+ opens, it is becoming negative

• K+閘門通道開啟使膜電位變正

  As K+ opens, it is becoming positive.

動作電位完成後，需要鈉鉀幫浦協助離子回覆到原本的位置，此模擬的網頁缺少了鈉鉀幫浦的圖示，請問此幫浦的離子運輸方向和數目何者正確?並口述是否需要耗能

• 3鈉出

• 3鈉進

• 2鉀出

• 2鉀進

"不反應期":指神經元剛產生神經衝動後的一段時間內，細胞膜的興奮性下降，不能立即接收新的刺激而產生新的神經衝動。請利用軟體觀察此時的膜電位為何?並推測是何種閘門通道仍開啟所造成?

• > -70mV

• < -70mV

• K+閘門通道開啟，使K+持續流入

• K+閘門通道開啟，使K+持續流出

• Na+閘門通道開啟，使Na+持續流入