anatomy and physiology mcqs

Question #154

Increases in cytosolic Ca2+ concetration in cardiac muscle cells:

In cardiac muscle cells increases in cytosolic calcium concentration occur mostly as a result of calcium induced calcium release (CICR). Membrane depolarisation results in the opening of membrane L-type Ca2+ channels, with the resulting increase in cystosolic concentration triggering further calcium release from intracellular stores via action on sarcoplasmic reticulum ryanodine receptors.

Since cardiac muscle is a syncitium, force generation must be controlled at the single cell level. Much of this control is effected by modulating intracellular calcium concentration through control over CICR.

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