Muscular System Flashcards
The origin of a muscle is usually ________ and the insertion is usually ______
Proximal; Distal
Muscle takes origin from the _________ bone and inserted into the ______ bone
Stationary bone; moveable bone
________ is the fleshy portion of the muscle between tendons
Belly (body)
_______ is a rigid structure that can move around a fixed point call the fulcrum
Lever
_______, which causes movement or muscular contraction
________ or resistance, which opposes movement
Effort; load
The load opposes movement and consists of the weight of the ______ + weight of the _______
Weight of the body part + weight of the object
How does motion occur in relation to a lever system?
When effort applied to the bone at the insertion, exceeds the load
Describe the mechanical advantage
if the load is closer to the fulcrum and the effort farther from the fulcrum, so only small effort is needed to move a load.
Describe mechanical disadvantage in relation to the lever systems (effort and load)
If the load is farther from the fulcrum and the effort is applied closer to the fulcrum, then a large effort is required to move a small load
What are the 3 classes of lever systems?
First class Second class third class
________ class levers, fulcrum is between the effort and the load
First class levers
Describe second class levers
Load is between the fulcrum and the effort
Describe third class levers
The effort is between the fulcrum and the load
** most common in musculoskeletal system
The longer the fibers in a muscle , the ______ the range of motion it can produce
Greater
What does the power of the muscle depend on?
Total cross sectional area
Fascicles form patterns with respect to the _______
Tendon
Describe parallel fascicles
Fascicles parallel to longitudinal axis of muscle
Ex: sternohyoid muscle
Describe fusiform fascicles
Parallel to longitudinal axis of muscle
Flat in the middle and tapers in both ends
Ex: digastric muscle
Describe circular fascicles
Form sphincter muscles that close an orifice
Ex: orbicularis oculus
Describe triangular fascicle arrangement
Formed of broad fibers that converge toward the central tendon
Pectoralis major
What are the 3 types of pennate fascicle arrangement
Unipennate, bipennate, multipennate
Describe unipennate fascicle arrangement
Fascicles arranged only one side of tendon
Ex: extensor digitorum longus
Describe bipennate fascicle arrangement
Fascicles arranged on both sided of centrally positioned tendons
Ex: rectus femoris
Describe multipennate fascicle arrangement
Fascicles attach obliquely from many directions to the tendon
Ex: deltoid
In _______ contractions, tension remains constant as muscle length increases or decreases
Isotonic
What are isotonic contractions used for?
Body movements and for moving objects
What are the two types of isotonic contractions
Concentric contraction
Eccentric contraction
Describe concentric contraction
Muscle shortens and produce movement to reduce the angle at a joint
Picking up a book from the table is an example of a _________ contraction
Lowering a book to the table is an example of a _______ contraction
Holding a book steady by using an outstretched arm is an example of a ________ contraction
Concentric
Eccentric
Isometric
Describe eccentric contraction
Muscle lengthens during contraction
In ________ contractions the muscle does not change length
Isometric
________ are the main muscles that contracts to cause an action
Prime mover or agonist
________ the muscle that opposes the action of the prime mover- relaxes the muscle
Antagonist
The biceps and triceps are ________ muscles
Antagonistic
Antagonist and prime mover are usually located on ______ sides of the bone or joint
Opposite
__________, the muscles that contract and stabilize the intermediate joints to prevent unwanted movements
Synergist
_______, the muscles that stabilize the origin of the prime mover so that the primate mover can act more efficiently
Fixator
Muscles of the head that produce facial expressions lie within the __________
Subcutaneous layer
Muscles of the head that produce fascial expression usually originate in the _______ or _______________ and insert into the ______
Fascia or bones of the skull; and insert into the skin
Orbicularis Oculi: Origin, Insertion, Action, innervation
ORBICULARIS OCULI Origin: Medial wall of orbit. Insertion: Orbital margin Action: Closes the eye Innervation: Facial nerve
Occipitofrontalis muscle’s Frontal Belly: origin, insertion, action, innervation
Origin, Epicranial aponeurosis.
Insertion, Skin superior to supraorbital margin
Action, Draws scalp anteriorly and raises eyebrows.
Innervation, Facial nerve
Occipitofrontalis occipital belly: Origin, insertion, action
Occipital belly
Origin: Occipital bone
Insertion: Epicranial aponeurosis.
Action: Draws scalp posteriorly
Buccinator: Origin, insertion, Action
BUCCINATOR
Origin: Alveolar processes of maxilla and mandible.
Insertion: Orbicularis oris.
Action: Presses cheeks against teeth and lips, as in whistling, blowing, and sucking.
Orbicularis oris: origin, insertion, action
ORBICULARIS ORIS
Origin, Muscle fibers surrounding opening of mouth.
Insertion, Skin at corner of mouth.
Action: Closes and protrudes lips
____________ muscles move the jaw for the purpose of chewing
Muscles of mastication
MASSETER
Origin –
Insertion –
Action –
MASSETER
Origin – maxilla and zygomatic arch
Insertion – angle and ramus of mandible
Action – elevates mandible
Temporalis: Origin, Insertion, Action
TEMPORALIS
Origin – temporal fossa
Insertion – coronoid process and ramus of mandible
Action – elevates mandible
_________, move the eyeball superiorly
_________, move the eyeballs inferiorly
__________, move the eyeballs laterally
__________, move the eyeballs medially
Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
________ moves the eyeballs inferiorly and laterally
________ moves the eyeballs Superiorly and laterally
_______________ raises the upper eyelids/ opens the eyes
Superior oblique moves the eyeballs inferiorly and laterally
Inferior oblique moves the eyeballs Superiorly and laterally
Levator palpebrae superioris raises the upper eyelids/ opens the eyes
Muscles of the neck that move the head are the ______ and _______
Sternocleidomastoid and sternohyoid
Sternocleidomastoid: origin, insertion, action
Sternocleidomastoid
Origin – manubrium and medial third of clavicle
Insertion – mastoid process and lateral half of superior nuchal line
Action – bilaterally causes flexion, unilaterally causes head to rotate to opposite side of muscle belly
Sternohyoid
Origin –
Insertion-
Action -
Sternohyoid
Origin – manubrium and medial end of clavicle
Insertion – body of hyoid bone
Action – lowers (depresses) hyoid bone
