kinesiology 30

The Muscular System

Tissue

Masses of cells that are similar in function and form along with the intercellular substances they produce.

Muscle Tissue

A collection of cells that shorten during contraction, creating tension that results in bodily movement.

Smooth Muscles

Type of involuntary muscle tissue found surrounding internal organs and blood vessels, known for slow contraction and long-lasting tension.

Cardiac Muscles

Striated muscle tissue unique to the heart, responsible for pumping blood and controlled by the autonomic nervous system.

Skeletal Muscles

Voluntary muscles attached to bones, responsible for bodily movement and comprising 30-40% of body weight.

Agonist Muscle

The muscle primarily responsible for movement of a body part.

Antagonist Muscle

The muscle that counteracts the agonist and lengthens when the agonist contracts.

Origin

The point where a muscle attaches to the more stationary bone of the axial skeleton.

Insertion

The point where a muscle attaches to the bone that is moved the most during contraction.

Muscle Twitch

A single nervous impulse and the resulting contraction.

Neuromuscular Junction

The contact point between a nerve and a muscle where a neurotransmitter is released to stimulate muscle contraction.

Delayed Onset Muscle Soreness (DOMS)

Muscle soreness occurring after unaccustomed exercise, believed to be due to microscopic tearing of muscle fibers.

Tendonitis

An overuse injury causing pain and irritation in a tendon, often named after the affected joint.

Sliding Filament Theory

A description of muscle contraction where actin and myosin filaments slide over one another to shorten the muscle.

Calcium Ions

Ions that trigger muscle contraction by enabling interaction between myosin and actin filaments.

Proprioceptors

Specialized receptors that provide sensory information about the muscle state and body position.

Muscle Spindles

Proprioceptors that detect changes in muscle length and play a key role in muscle tension adjustment.

Golgi Tendon Organs

Receptors located at the junction of tendons and muscles that detect tension and prevent muscle injury.

Reflex Arc

A neural pathway that mediates a reflex action, involving sensory and motor neurons.

All-or-None Principle

The principle stating that a motor unit will either contract fully or not at all when stimulated.