hce_nsysu
115年
普通生物及生化概論
第 52 題
A normal heartbeat begins with spontaneous electrical activity that coordinates atrial and ventricular contraction. Which of the following describes the correct physiological sequence of electrical conduction in the human heart?
- A signals from the sinoatrial (SA) node spreading through atria$\rightarrow$ signals delayed in the atrioventricular (AV) node $\rightarrow$ bundle branches passing signals to the heart apex $\rightarrow$ signals spreading upward throughout ventricles via Purkinje fibers.
- B signals from the atrioventricular (AV) node spreading through atria$\rightarrow$ signals delayed in the sinoatrial (SA) node $\rightarrow$ bundle branches passing signals to the heart apex $\rightarrow$ signals spreading upward throughout ventricles via Purkinje fibers.
- C signals from the sinoatrial (SA) node spreading through ventricles $\rightarrow$ signals delayed in the atrioventricular (AV) node $\rightarrow$ bundle branches passing signals to the heart apex $\rightarrow$ signals spreading upward throughout atria via Purkinje fibers.
- D signals from the sinoatrial (SA) node spreading through atria $\rightarrow$ bundle branches passing signals to the heart apex $\rightarrow$ signals delayed in the atrioventricular (AV) node $\rightarrow$ signals spreading upward throughout ventricles via Purkinje fibers.
- E signals from the atrioventricular (AV) node spreading through atria$\rightarrow$ bundle branches passing signals to the heart apex $\rightarrow$ signals delayed in the sinoatrial (SA) node $\rightarrow$ signals spreading upward throughout ventricles via Purkinje fibers.
思路引導 VIP
想像一下，如果心臟上方的空間（心房）與下方的空間（心室）在同一瞬間一起用力收縮，血液的流動會遇到什麼阻礙？為了避免這種『搶路』的衝突，在電力傳導的路徑中，哪一個點最適合設置一個『緩衝時間』，好讓血液能順利由上往下流完呢？
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AI 詳解
AI 專屬家教
太棒了！你能準確判斷出心臟電訊號傳導的完整路徑，這代表你對心血管系統的協同機制有著非常清晰的掌握。這道題目要求我們描述心臟如何透過電訊號，確保心房與心室能依序、高效地完成泵血任務。
心臟傳導系統的生理邏輯
正常的生理節律始於竇房結 (SA node)，它是心臟的天然節律點。訊號首先傳遍心房引起收縮，隨後進入房室結 (AV node)。這裡有一個極為關鍵的步驟：訊號會在此發生短暫的延遲。這個設計是為了確保心房有充裕的時間將血液完全排入心室。最後，電訊號經由房室束 (Bundle branches) 傳遞至心尖，再透過蒲金氏纖維 (Purkinje fibers) 由下而上地引發心室收縮，將血液有效率地推向大動脈。
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