Lesson 9: Calcium

Calcium, or [katex]Ca^{2+}[/katex] ions are essential in the movement of organisms:

  • In synapses, calcium ions regulate the transmission of impulses from different neurons.
  • [katex]Ca^{2+}[/katex] also stimulate muscle contraction
    • When an impulse reaches a muscle fibre, [katex]Ca^{2+}[/katex] is released from something called the sarcoplasmic reticulum.
    • This calcium ion binds to troponin C, removing the tropomyosin from the myosin-binding sites.
  • This allows actin-myosin cross-bridges to form when a muscle fibre contracts.
  • [katex]Ca^{2+}[/katex] can help to regulate protein channels, which affects the permeability.
  • Many enzymes are activated by [katex]Ca^{2+}[/katex].
  • The presence of [katex]Ca^{2+}[/katex] is also necessary to aid blood clotting.
    • It's known as a clotting factor.