Use Sophia to knock out your gen-ed requirements quickly and affordably. Learn more
×

Muscle Contractions: Micro Level

Author: Amanda Soderlind

Source: Video and Images Created by Amanda Soderlind

Video Transcript
Terms to Know
Actin

A protein referred to as the thin filament of a sarcomere; creates the lighter color within a sarcomere and interacts with myosin to create movement.

Action Potential

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

Adenosine Triphosphate (ATP)

The primary form of energy used by cells to perform work; is the nucleotide adenine (A) with three phosphate groups instead of one.

Calcium

A mineral necessary for the proper development and mineralization, as well as proper nerve and muscle function

Contraction

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

Motor Unit

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

Myofibrils

Muscle cells (aka muscle "fibers") contain myofibrils, which are long chains of myofilaments.

Myofilaments

Myofilaments are made up of proteins (mostly actin and myosin). Myofilaments make up myofibrils within muscle cells (aka muscle "fibers").

Myosin

A protein 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.

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.

Sarcoplasmic Reticulum (SR)

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

Sliding Filament Mechanism

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

Tetanus

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

Twitch

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