the muscular system
are muscles that oppose or reverse a particular movement.
They serve as primary movers
help prime movers (agonists) by adding a little extra force to the movement.
When synergists act as stabilizers by immobilizing a bone or a muscle's origin, they are called
Sphincters have a __________ arrangement of fascicles.
A convergent arrangement of fascicles will generate
a fan-shaped muscle.
In pennate arrangements, the fascicles are
short and they attach obliquely to a central tendon that runs the length of the muscle.
Muscles that have a parallel fascicle arrangement can
have a strap-like shape or a spindle shape.
Muscle power depends more on the
length, type, and number of muscle fibers than on the degree of shortening upon contraction.
Muscles with parallel fascicle arrangement
shorten a great deal upon contracting, [ these types of muscles do not tend to be powerful]
the stocky bipennate and multipennate muscles
shorten only a little upon contraction, yet these muscles are powerful.
Standing on your toes is an example of a
Second-class levers sacrifice
speed and range of motion in favor of strength.
Most skeletal muscles of the body act as
applied force between the fulcrum and the resistance
Third-class lever systems allow
a muscle to be inserted close to the joint across which movement occurs.
Muscles that form the floor of the oral cavity.
The suprahyoid muscles (the digastric, stylohyoid, mylohyoid, and geniohyoid muscles)
Infrahyoid muscles are
straplike muscles that depress the hyoid bone and larynx during swallowing and speaking.
Sternohyoid, sternothyroid, thyrohyoid, and omohyoid muscles
The prime movers of back extension are the
erector spinae muscles
The major head flexor muscles are the
The scalene muscles elevate
the first two ribs and flex and rotate the neck.
The latissimus dorsi is
the prime mover of arm extension.
The muscle that separates the thoracic and abdominopelvic cavities is
The diaphragm is the prime mover of
In its relaxed state, the diaphragm has a dome shape.
When the diaphragm contracts, it moves
inferiorly and flattens, increasing the volume of the thoracic cavity.
As the volume of the thoracic cavity increases,
inhalation occurs and air is drawn into the lungs.
Voluntary control of urination is facilitated by the
external urethral sphincter
Form the pelvic floor (or pelvic diaphragm).
The levator ani and the coccygeus
The deep transverse perineal muscle
supports pelvic organs.
The external urethral sphincter surrounds
the urethra and allows for voluntary control of urination.
The prime mover of arm extension is the
The styloglossus is involved in
retracting and elevating the tongue.
Muscles that are involved in chewing and biting movements
muscles that help the prime mover by contracting at the same time to add more force or stabilize a part so the movement is more effective.
The hamstrings are fleshy muscles of
the posterior thigh.
They cross the hip joint and knee joint.
The hamstrings and the gluteus maximus are the
primary thigh extensors.
The iliopsoas is the
primary thigh flexor.
The sartorius is able to
flex, abduct, and laterally rotate the thigh.
the most powerful movement of the foot and ankle.
plantar flexion [lifts the entire weight of the body]
The suffix -glossus means
Damage to which muscle would hinder inspiration?
The eleven pairs of the external intercostals lie between
adjacent ribs on each side to elevate ribs and increase the volume of the thoracic cavity during inspiration.
Pollicis comes from the root pullex, which means
Rectus abdominis and external oblique are
two large muscles of the abdominal wall.
is a large, thick, triangular muscle forming a rounded mass over the shoulder and upper humerus that abducts the arm.
No muscle names indicate
the myofibril composition of a muscle.
The extensor digitorum muscle is an example of a
innervated by the facial nerve.
All of the extrinsic tongue muscles are innervated by the
The ________ divides the neck into two triangles.
The ______ increases the intra-abdominal pressure
The ______ flexes and rotates the lumbar region of the vertebral column.
_______ adducts the wrist and fingers.
Flexor carpi ulnaris
The prime mover for flexion of the thigh is the ______ muscle.
The _____ is a common site for injections in infants who have poorly formed buttocks.
The _____ is innervated by L5 and S1.
The __________ is the prime mover of dorsiflexion of the foot.
Shin splints are caused by __________.
inflammation of the tibialis anterior
Muscles that are innervated by the sciatic nerve
- biceps femoris
The obturator nerve supplies what muscles
- adductor brevis
- adductor magnus
rotator cuff muscles
The __________ assists the triceps brachii in forearm extension.
muscles of the facethat are innervated by the facial nerve
- orbicularis oculi