Ch. I 内钾外钠 K IN, NA OUT Ch. II 血压 · 不只是钠 BP: MORE THAN SALT Ch. III 加工食品的反向组… THE PROCESSED-FOOD INVERSION Ch. IV 运动中的离子流 IONS IN EXERCISE Ch. V Zn Cu 补剂要谨慎 SUPPLEMENT CAUTION Ch. VI 水重不是脂肪 WATER WEIGHT ISN'T FAT Back
Potassium & Sodium 钾 · 钠 Page 1 of 2 Every cell in the body maintains the same gradient: K⁺ inside (~140 mmol/L), Na⁺ outside (~140 mmol/L). This mirror-image relationship is the power source for every excitable tissue. The worker maintaining this gradient is the Na⁺/K⁺ ATPase pump : it works thousands of times per second on every cell; each cycle uses 1 ATP adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it. and pumps out 3 Na⁺ and pumps in 2 K⁺. Body-wide, this pump consumes 20–30% of resting energy — second only to the respiratory chain itself. The outcome: a resting membrane potential of ~ -70 mV (inside negative, outside positive) — the 'standby state' for nerves and muscles; during an action potential, Na⁺ channels open and Na⁺ rushes in, the membrane potential flips to +30 mV, the signal propagates; immediately after, K⁺ channels open and K⁺ rushes out, the membrane returns to baseline, and the cell readies for the next firing. So K and Na aren't a 'pair of electrolytes' — they're the positive and negative terminals of the same electrical system. Anything that throws the gradient off (heavy sweating + lots of plain water = dilutional hyponatremia; severe diarrhea = loss of potassium) simultaneously affects nerve conduction, muscle contraction, and cardiac rhythm. GUIDE · A GUIDE · A
BP: more than salt Next Educational content, not medical advice — consult a clinician.