Which Statement About Cardiac Muscle Cells Is True

Multiple Choice

Which statement about cardiac muscle cells is true?

A) The DHP proteins are in the sarcoplasmic reticulum membrane.
B) There is a physical connection between DHP and ryanodine receptors.
C) The T tubules are smaller than those of skeletal muscle cells.
D) Ryanodine receptors are ion-gated Na⁺ channels.
E) Extracellular Ca²⁺ flows into the cytoplasm through DHP channels and then opens calcium channels in the sarcoplasmic reticulum.