Question

multiple choice question

what are the end-sacs of the sarcoplasmic reticulum called?

triads
terminal cisternae
myofibrils
t tubules

Explanation:

Identify the target structure

The question asks for the name of the end-sacs of the sarcoplasmic reticulum.

Analyze the options

• Triads: A triad is a structure formed by one T-tubule and two adjacent terminal cisternae.
• Terminal cisternae: These are the enlarged end-sacs of the sarcoplasmic reticulum that store calcium ions and flank a T-tubule.
• Myofibrils: These are the long, cylindrical contractile organelles found within muscle cells.
• T tubules: Transverse tubules are invaginative extensions of the sarcolemma that penetrate into the cell.

Select the correct term

The enlarged end-sacs of the sarcoplasmic reticulum are specifically called terminal cisternae.

Answer:

• Triads
• Terminal cisternae (Correct answer)
• Myofibrils
• T tubules