Hi Natasha,

Do smooth and cardiac muscle also have a sarcoplasmic reticulum with Ca2+?

Cardiac and skeletal muscle have SR with Ca2+, and while it is known as the ER for smooth muscle cells, smooth muscle cells also use it to store Ca2+ in a similar fashion.


Do cardiac and smooth muscle cells also use tropomysin and troponin?


Tropomyosin and Troponin can also be found in cardiac muscle. I think there are some minor variations between cardiac and skeletal muscle, but for the level of the MCAT I would treat them as largely similar processes. \

Smooth muscle cells are kind of the odd one out here - they don't contain troponin but instead calmodulin.

I hope this helps,

Katt