Chr. 11 - Muscular System Flashcards
[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.
[11.4] List the mouth muscles and their action.
Orbicularis oris, closes and protrudes lips, compresses lips against teeth, shapes lips while speaking.
Zygomaticus major, draws angle of mouth superiorly and laterally.
Buccinator, presses cheeks against teeth and lips, draws mouth laterally, assists in mastication.
[11.4] List the muscle of the orbit/eyebrow and its action.
Orbicularis oculi, closes eye.
[11.6] What are the term for the muscles that move the mandible and TMJ?
The muscles of mastication.
[11.6] List the major muscles that move the mandible and assist in mastication and speech, and their actions.
Masseter, elevates mandible.
Temporalis, elevates and retracts mandible
[11.6] List the origin and insertion of the masseter.
Origin: maxilla and zygomatic arch
Insertion: angle and ramus of the mandible.
[11.6] List the origin and insertion of the temporalis.
Origin: temporal bone
Insertion: coronoid process and ramus of mandible.
[11.9] List the muscles of the neck that move the head and it’s action/reverse action
Sternocleidomastoid, flexion of cervical vertebrae, extension of head, lateral flexion of neck and head, lateral rotation of head.
Reverse action, elevate sternum during forced inhalation.
[11.9] List the origin and insertion of the sternocleidomastoid.
Origin: at manubrium of sternum and medial third of clavicle.
Insertion: at mastoid process of temporal bone and lateral half of superior nuchal line of occipital bone.
[11.10] List the muscles of the abdomen that protect abdominal viscera and move vertebral column.
- Rectus abdominis
- External oblique
- Internal oblique
- Transversus abdominis.
[11.10] List origin, insertion, and action of rectus abdominis.
Origin: pubic crest and pubic symphysis
Insertion: Cartilage of ribs 5-7, xiphoid process.
[11.10] What are the actions and reverse muscle action of the rectus abdominis?
Action: Flexes vertebrae column, compresses abdomen
Reverse muscle action: flexes pelvis
[11.10] List actions of external oblique.
Compresses abdomen, flexes vertebral column, laterally flexes vertebral column, rotation of vertebral column.
[11.10] List the action of the internal oblique.
Compresses abdomen, flexion of vertebral column, lateral flexion of vertebral column, rotation of vertebral column.
[11.10] List the insertion and action of the transversus abdominus.
Insertion: xiphoid process, linea alba, and pubis.
Action: Compresses abdomen.
[11.10] What are the rectus sheaths?
The aponeuroses of external and internal oblique and transversus abdominus that enclose the rectus abdominus muscles. The sheaths meet to form the linea alba.
[11.10] What is the linea alba?
A tough fibrous band extending from the xiphoid process to the pubic symphysis.
[11.11] List the muscles of the thorax that assist in breathing.
Diaphragm, external intercostals, internal intercostals.
[11.11] What is the action of the diaphragm?
Contraction increases vertical dimension of thoracic cavity resulting in inhalation. Relaxation causes expansion of the muscle, decreasing thoracic cavity volume resulting in exhalation.
[11.11] What is the central tendon of the diaphragm?
A strong aponeurosis in the center of the diaphragm formed by the convergence of multiple other tendons of the diaphragm.
[11.11] What is the action of the external intercostals
Elevate ribs and increase anteroposterior and lateral dimensions of thoracic cavity for inhalation. Relaxation returns thoracic cavity to anatomical position and results in exhale.
[11.11] What is the action of internal intercostals?
Draws adjacent ribs together to decrease thoracic cavity volume during exhalation.
[11.14] List the anterior and posterior muscles of the thorax that move the pectoral girdle.
Anterior thoracic muscles: pectoralis minor, serratus anterior.
Posterior thoracic muscles: trapezius, levator scapulae, rhomboid major.
[11.14] List the action and reverse action of pectoralis minor
Action: abducts scapula and inferior rotation.
Reverse action: elevates ribs 3-5 during forced inhalation.
[11.14] List the origin and insertion of serratus anterior.
Origin: ribs 1-8
Insertion: vertebral border and inferior angle of scapula.
[11.14] List the action of serratus anterior.
Action: Abducts scapula and superior rotation.
Reverse action: elevates ribs.
[11.14] List the origin and insertion of the trapezius.
Origin: superior nuchal line of occipital bone, ligamentum nuchae, and spines of C7-T12
Insertion: Clavicle and acromion/spine of scapula.
[11.14] List the action and reverse action of the trapezius.
Action: superior rotation of scapula, adduction of scapula
Reverse action: extension of head.
