The Muscular System

Vocabulary-style flashcards covering the types, functions, and mechanisms of the human muscular system based on the lecture notes.

Muscular system

The anatomical system of a species that allows it to move, consisting of discrete organs constructed of muscle tissue, blood vessels, tendons, and nerves.

Muscle Fibres

Elongated cells that form a covering over the skeleton and are responsible for all body movements.

Tendon

A tough structure formed from the flexible or movable end of a muscle.

Voluntary or Skeletal Muscles

Muscles under the control of our will that surround the bones and move joints; they constitute about $40$ to $50$ percent of total body weight.

Spasm

A painful state muscles may enter if they work hard but do not get enough energy from blood to work properly.

Involuntary Muscles (Smooth Muscles)

Muscles found in internal organs like the intestines, stomach, and blood vessels whose action is not under conscious control and do not tire.

Cardiac Muscles

Muscles found only in the walls of the heart that contract automatically to squeeze the heart walls inward about $100,000$ times each day.

Intercalated discs

Transverse structures that, along with branching fibres and central nuclei, characterize the appearance of cardiac muscles.

Myofibrils

Thousands of small structures within muscle fibres where the actual contraction occurs.

Muscle contraction

The process that occurs when a muscle fibre is signaled by the brain via nerves to activate and increase tension within the muscle.

Contraction mechanism

When muscles contract, they become shorter and thicker; when they relax, they return to their original length.