Cardiac muscle

Striations

cardiac muscles

intercalated discs

found between cardiac muscle cells.

They have extensions of plasma membrane this allows communication with the neighbouring cells

role of calcium ions

Myosin head cant bind to the binding site which is needed for contraction.

binding site is blocked by tropomyosin.

tropomyosin is held in place by troponin

when calcium ion is released by sarcoplasmic reticulum.

the calcium binds with the troponin

this changes the shape of the troponin which pulls the tropomyosin out of the way.

the myosin head can can then bind with the actin can carry out muscle contraction.

m