Page 1 Flashcards
What is the insertion of a muscle?
Attachment of the muscle’s tendon to the movable bone, usually distal and pulled toward the origin.
What is the origin of a muscle?
Attachment of a muscle’s tendon to a stationary bone, usually proximal.
What is the body or belly of a muscle?
Fleshy portion of the muscle between tendons.
What are the main movements that occur when a muscle contracts called?
Actions.
What is Reverse Muscle Action (RMA)?
Positions of origin and insertion of a specific muscle are switched during specific movements.
What types of contractions are there?
- Isometric contraction
- Isotonic contraction
What occurs during isometric contraction?
Tension increases, but muscle length stays the same.
What occurs during isotonic contraction?
Tension remains the same, but muscle length decreases.
What is muscle tone?
Small percentage of muscle fibers contracting tetanically responsible for posture.
What are slow-twitch fibers better suited for?
Aerobic respiration.
What are fast-twitch fibers adapted for?
Anaerobic respiration.
What is the arrangement of fascicles in parallel muscles?
Fascicles parallel to longitudinal axis, terminating at either end in flat tendons.
Describe fusiform muscle arrangement.
Fascicles nearly parallel to longitudinal axis, tapering toward tendons.
What is the arrangement of fascicles in circular muscles?
Fascicles in concentric arrangements forming sphincter muscles that enclose an orifice.
What characterizes triangular muscle arrangement?
Fascicles spread over a large area and converge at thick central tendons, giving a triangular appearance.
What is unique about pennate muscle arrangements?
Short fascicles in relation to total muscle length with tendons extending nearly the entire length of muscle.
What is the difference between unipennate and bipennate arrangements?
- Unipennate: fascicles arranged only at one side of tendon
- Bipennate: fascicles arranged on both sides of centrally positioned tendons.
What does a multipennate arrangement involve?
Fascicles attached obliquely from many directions to several tendons.
How does fascicular arrangement affect muscles?
It affects the muscle’s power and range of motion.
What is the role of an agonist muscle?
Muscle causing a specific movement.
What is the role of an antagonist muscle?
Muscle causing the opposite movement.
What is the function of a synergist muscle?
Works together with the prime mover to assist in movement.
What does a fixator muscle do?
Stabilizes the origin of the prime mover to act more efficiently.
What is a compartment in muscular anatomy?
Group of skeletal muscles, blood vessels, and nerves with a common function.
What factors influence the nomenclature of skeletal muscles?
- Pattern of muscle’s size
- Shape
- Number of origins
- Location
- Function
What is the action of an extensor muscle?
Increases the angle at a joint.
What is the action of a flexor muscle?
Decreases the angle at a joint.
What does an abductor muscle do?
Moves limb away from the midline of the body.
What does an adductor muscle do?
Moves the limb toward the midline of the body.
What is the action of a levator muscle?
Moves the insertion upward.
What is the action of a depressor muscle?
Moves the insertion downward.
What does a rotator muscle do?
Rotates the bone along its axis.
What is the function of a sphincter muscle?
Constricts an opening.
