What is the role of the sarcoplasmic reticulum prior to a muscle contraction?
Correct answer: D. It releases calcium once an action potential reaches the sarcolemma.
- A. It actively pumps calcium ions into its lumen.
- B. It releases calcium ions by active transport.
- C. It creates the proteins needed to cover the actin filaments.
- D. It releases calcium once an action potential reaches the sarcolemma.
Explanation
The sarcoplasmic reticulum is a critical storage site for calcium ions, taking up the ions from the cytoplasm. It also releases calcium ions when the muscle cell is triggered by nerve stimuli, resulting in muscle contraction.
Last updated
About Support and Movement
Support and movement covers the axial and appendicular skeleton, bone structure, joints and the arrangement of skeletal muscles. Muscle contraction is explained through actin, myosin, sliding filaments, calcium ions and ATP, while arthritis is distinguished as a disorder of joints rather than a normal part of movement.
Practise Support and Movement
738 free Support and Movement MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Biology questions like this
Biology is on 6 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.