Chr. 11 - Muscular System Flashcards
(128 cards)
[11.1] What is an origin?
The attachment of a muscles tendon to the stationary bone.
[11.1] What is the insertion?
The attachment of a muscles tendon to the moving bone.
[11.1] What is the belly of a muscle?
The fleshy portion of a muscle between the tendons which is responsible for contraction and stretching.
[11.1] What are muscle actions and reverse muscle actions?
Actions are the main movement that occurs when a muscle contract.
A reverse action is a movement which switching position of origin and insertion.
[11.1] What is a lever?
A rigid structure that moves around a fixed point, called the fulcrum.
[11.1] What is a fulcrum?
The fixed point which a lever moves around.
[11.1] What is effort and load?
Effort is the force that causes movement.
Load is the resistance that opposes movement.
[11.1] What is the effort arm and the load arm?
The effort arm is the distance between the fulcrum and the effort.
The load arm is the distance between the fulcrum and the load.
[11.1] Describe mechanical advantage and mechanical disadvantage.
Mechanical advantage is a force multiplier present when a lever’s effort arm is longer than the load arm.
Mechanical disadvantage is a force divider present when a levers load arm is longer than the effort arm.
[11.1] List and describe the classes of levers, as well as stating if they provide mechanical advantage or disadvantage.
First-class lever, the fulcrum exists between the load arm and the effort arm. Can provide either mechanical advantage or disadvantage based on the length of the arms.
Second-class lever, the load exists between the fulcrum and effort. Always provides mechanical advantage as the effort arm will always be longer than the load arm.
Third-class levers, the effort exists between the fulcrum and the load. Always produces mechanical disadvantage as the load arm will always be longer than the effort arm.
[11.1] What are fascicles?
Bundles of muscle fibers where all muscle fibers are parallel.
[11.1] What are the patterns of fascicle arrangement, and why are they important?
Parallel, fusiform, circular, triangular, and pennate. They affect a muscles power and range of motion.
[11.1] Describe parallel fascicles
Fascicles parallel to longitudinal axis of muscle, terminate at either end in flat tendons.
[11.1] Describe fusiform fascicles.
Fascicles almost parallel to longitudinal axis but have wide belly deviating from axis slightly. Terminate at either end in flat tendons.
[11.1] Describe circular fascicles.
Fascicles arranged in concentric circles, form sphincter muscles. Tendons on either side attach at same location.
[11.1] Describe triangular fascicles.
Fascicles spread over a broad area that taper as they converge on a thick central tendon.
[11.1] Describe pennate fascicles and the three varieties.
Fascicles with tendons that extend entire length of muscle. Arranged in:
Unipennate, fascicle exists on one side of tendon.
Bipennate, fascicle exists on both sides of a centrally-positioned tendon.
Multipennate, consists of a fan-like arrangement of bipennate fascicles that all attach to a singular tendon at termination.
[11.1] Describe muscle layout at joints.
Arranged in pairs at joints (some exceptions) composed of a prime mover and antagonist.
[11.1] Describe prime movers and antagonists.
A prime mover is a muscle that contracts to causing movement.
An antagonist is an opposing muscle to the prime mover that stretches and yields to the force of a prime mover.
[11.1] What is a synergist?
Muscles that prevent unwanted movement at intermediate joints or aid movement of the prime mover.
[11.1] What is a fixator?
Muscles that stabilize the origin of the prime mover.
[11.1] What is a compartment in relation to the muscular system?
A group of skeletal muscles and their associated blood vessels and associated nerves.
[11.2] List the two main ways to name a muscle?
By feature of the muscle, such as size, shape, action, number of origins, and location.
By sites of origin and insertion.
[11.4] List the scalp muscles and their action.
Occipitofrontalis:
- Frontal draws scalp anteriorly, raises eyebrows, and wrinkles skin of forehead.
- Occipital belly, draws scalp posteriorly.