--%>

How calcium ions contribute in the muscle contraction

How do calcium ions contribute in the muscle contraction? Why do both muscle relaxation and muscle contraction spend energy?

E

Expert

Verified

In muscle cells, calcium ions are stored in the sarcoplasmic reticulum. Whenever a motor neuron emits stimulus for muscle contraction neurotransmitters termed as acetylcholine are liberated in the neuromuscular junction and sarcolemma is excited. The excitation is conduced to sarcoplasmic reticulum which then liberates calcium ions into the sarcomeres.

In sarcomeres, the calcium ions join to troponin molecules related to actin activating myosin joining sites of actin. The myosin, then capable to join to actin, pulls this protein and sarcomere shortens. The summation of simultaneous contraction of sarcomeres and myofibrils comprises the muscle contraction. Throughout muscle relaxation, the calcium ions return back to sarcoplasmic reticulum. For myosin to join to actin, and therefore for the contraction to take place, hydrolysis of one ATP molecule is essential. Throughout relaxation, the return of calcium ions to the sarcoplasmic reticulum is an active procedure which spends ATP too. Therefore both muscle contraction and relaxation are energy-spending procedures.

   Related Questions in Biology

  • Q : Ethnocentrism-Barriers to Diversity -

    A tendency to regard one's own group, culture, or nation as superior to others. This is what sometimes occurs in a selective club, religious sect, or political organization. People who are  ethnocentric see their group-related customs or beliefs as 'right ' and evaluate other, beliefs or pra

  • Q : Ingestion of vegetable fibers Why does

    Why does the ingestion of vegetable fibers enhance the bowel habit in people which suffer from hard stools?

  • Q : Explain Statistical Process Control or

    Statistical Process Control (SPC): It is commonly termed to as SPC, is a technique for monitoring, controlling, and enhancing a process via statistical analysis. The philosophy defines that all processes show natural variation, or arbitrariness. Thoug

  • Q : Role of strategies and policies Role of

    Role of strategies and policies Strategies and policies are important in all types of organizations - business or non business, public sector or private sector, smal

  • Q : Why amino acids significant for protein

    Why is the immediacy between ribosomes and amino acids significant for the protein formation? And also write down enzyme which catalyzes that reaction?

  • Q : Name the cells with delimited nucleus

    Name the cells with delimited nucleus. And, also write down the main elements of the nucleus?

  • Q : Characteristics of a good policy

    Characteristics of a good policy To be effective, a policy must be formulated after carefully considering all aspects of the situation to which it is to be applied.

  • Q : Classification of Birds Characterize

    Characterize the birds according to examples of representing beings, skin, basic morphology, respiration, circulation, nitrogen waste, types of reproduction and thermal control?

  • Q : Explanation of water cycle Give a brief

    Give a brief explanation of water cycle.

  • Q : Wall resistance of plant cells

    Illustrate out the wall resistance of plant cells? Does this resistance assist or make tricky the access of water in the cell?