心電圖分析ppt課件-文庫吧資料
2025-01-20 17:20本頁面
【正文】 態(tài) 膜內電位 － 90mV 細胞內 K+↑ 細胞外 Na+ ↑ 膜通透性 K+ ↑ Na+ ↓ What makes the “squiggles”? Heart muscle is made of long thin heart muscle cells What makes the “squiggles”? Na Na Na Ca Ca Ca K K K K K Potassium Na Sodium Ca Calcium Negative Charge Positive Charge Cell membrane Heart Muscle Cell The membrane pumps sodium ions into the cells at a faster rate than it pumps sodium and calcium ions out. This results in a higher concentration of positive ions outside the cell. The cell is POLARIZED. Depolarization and Repolarization _ _ _ _ _ _ _ _ _ _ _ _ + + + + + + + + + + + + Repolarization and Relaxation Depolarization and Repolarization _ _ _ _ _ _ _ _ _ _ _ _ + + + + + + + + + + + + Depolarization and contraction When a heart muscle cell depolarizes, the rapid flow of ions across the membrane causes a wave of electrical current which causes the muscle to contract. This current called the depolarization wave spreads rapidly through the heart. Depolarization and Repolarization _ _ _ _ _ _ _ _ _ _ _ _ + + + + + + + + + + + + Repolarization and Relaxation 除極、復極形成動作電位 ? 除極：快 Na+通道開放 Na+內流 ? 復極：快速復極相 Cl內流 緩慢復極相 K+外流 Ca2+內流 快速末期復極相 K+外流 +30mV 0 30mV 60mV 90mV 0 1 2 3 4 心電圖為心電向量環(huán) 兩次投影結果 ? 電偶學說：電穴、電源形成電偶 除極：電穴 → 電源 心內膜 → 心外膜 復極：電源 → 電穴 心外膜 → 心內膜 ? 心電向量、綜合心電向量：有大小、方向 ? 立體心電向量環(huán)： P環(huán)、 QRS環(huán)、 T環(huán) ? 額面向量環(huán)投影在六軸系統形成肢導 ECG ? 橫面向量環(huán)投影在胸導系統形成胸導 ECG 心臟傳導系統 心電圖的導聯 肢導六軸系統 胸導聯系統 心臟一次激動的各波意義 正常心電圖的描記及閱讀 ?描記一份 “ 漂亮 ”
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