+
Muscle Contractions: Micro Level

Muscle Contractions: Micro Level

Author: Aaron Mullally
Description:

This lesson will go into more detail describing how a muscle contracts.

(more)
See More
Try a College Course Free

Sophia’s self-paced online courses are a great way to save time and money as you earn credits eligible for transfer to over 2,000 colleges and universities.*

Begin Free Trial
No credit card required

25 Sophia partners guarantee credit transfer.

221 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 20 of Sophia’s online courses. More than 2,000 colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.

Tutorial
TERMS TO KNOW
  • Sarcomere

    The functional and contractile units of skeletal and cardiac muscles; created by a specific arrangement of myofilaments called actin and myosin; each sarcomere is bordered by a z-line.

  • Actin

    Referred to as the thin filament of a sarcomere, creates the lighter color within a sarcomere and interacts with myosin to create movement.

  • Myosin

    Referred to as the thick filament of a sarcomere, creates the darker colors within a sarcomere and contains various heads that pull on actin filaments to create movements.

  • ATP

    The primary energy molecule that cells use for energy; composed of adenosine and three phosphate groups; when the bonds that hold the phosphates together are broken energy is released for work.

  • Action potential

    The technical term for a nervous impulse; when a wave of depolarized electrical energy travels down the length of a cell/tissue.

  • Calcium

    A mineral/ion that has many physiologic uses to humans; calcium is stored in the sarcoplasmic reticulum (SR) of skeletal muscles and when released it prepares actin and myosin for interaction.

  • Sarcoplasmic reticulum (SR)

    A specialized form of smooth endoplasmic reticulum (SER) found within skeletal muscles used for calcium storage.

  • Contraction

    A muscle fiber generates tension, causing the muscle to shorten.

  • Twitch

    The way a skeletal muscle contracts, sarcomeres quickly pull inward and create a quick, jerky twitch.

  • Tetanus

    A term used to described a prolonged muscle contraction; often used to describe a person who has been exposed to Clostridium tetani toxin.

  • Sliding filament mechanism

    A theory used to describe how the microfilaments within the sarcomere interact with one another; actin and myosin cling together and slide past one another.

  • Motor unit

    The term used to describe one motor neuron and all of the muscle fibers it innervates at once.