Nervous system/overview of neurons/Crush syndrome/effect of hyperkalemia on cardiac muscle

POINT!

When a muscle is crushed, K+ in blood is increased, and in cardiac muscle cells, diffusion of K+ through K+ channel is less, resting membrane potential is less, stability of the cell is less, causing arrythmia.

narrated animation

Both the high intra-cellular potassium (K⁺) and low extra-cellular potassium (K⁺) bring about the difference, which is the driving force of the diffusion of potassium ion (K⁺) through channel. With more diffusion, the intracellular resting membrane negative potential increases, and with more intracellular resting membrane potential, the cell becomes more stable.

When the legs are compressed for a long time, such as in earthquake-destroyed buildings, a muscle is crushed, potassium (K⁺) is released and then increased in the blood. Hyperkalemia means extracellular potassium is NOT as low, which also means that the difference between extra- and intra- cellular potassium (K⁺) is less. There will be less diffusion of K⁺ through the K⁺ channel, resting membrane potential decreases, and the stability of the cardiac muscle cell decreases, causing arrhythmia.

Challenge Quiz

1.

When a muscle is crushed, K⁺ in blood is increased decreased  正解!, and in cardiac muscle cells, diffusion of K⁺ through K⁺ channel is less more  正解!, resting membrane potential is less more  正解!, stability of the cell is less more  正解!, causing arrythmia.