Interactions of Skeletal Muscle and Fascicle Organization

Vocabulary flashcards based on lecture notes covering anatomy, physiology, and muscle classifications.

Origin

The fixed attachment of the muscle.

Insertion

The attachment of the muscle to the bone or body part that will move as a result of contraction.

Agonist

The main (principal) mover of a joint.

Antagonist

The muscle that opposes the action of the agonist and returns the joint to its original position.

Synergist

A muscle that helps another muscle do its action.

Fixator

A muscle that stabilizes a joint while another muscle performs its action.

Tremor

A condition where both agonist and antagonist muscles are contracting at the same time and are in conflict.

Fascicle Organization

The arrangement of muscle fibers within a fascicle.

Parallel-Fusiform

Fascicles that run parallel; contraction enlarges the muscle belly.

Parallel-Non-fusiform

Fascicles that run parallel; contraction does not enlarge the middle of the muscle.

Circular Muscles

Muscles that make an opening smaller when they contract.

Sphincters

Muscles that serve as circular muscles, controlling openings.

Convergent Muscles

Muscles with fibers that converge at a single point.

Pennate Muscles

Muscles with fascicles arranged like feathers.

Unipennate

Muscles with short 'feathered' fascicles running in one direction.

Bipennate

Muscles with short 'feathered' fascicles running in two directions.

Multipennate

Muscles with short 'feathered' fascicles running in multiple directions.

Shape of Skeletal Muscles

Skeletal muscles typically come in seven different general shapes.