a&p chapter 11 (the muscular system)

ways we name muscles

location, size, number of attachment points, location/direction of fibers, attachments (origin and insertion), muscle action, a combination

ex. of muscle named by location

tibialis anterior, muscle anterior to the tibia

ex. of muscle named by size

gluteus maximus, its the biggest gluteal muscle (Maximus=big)

ex. of muscle named by number of attachments

biceps brachii, biceps means 2 attachments (long head and short head)

ex. of muscle named by location/direction of fibers

transversus abdomninis, the muscle fibers are transverse

ex. of muscle named by attachments (origin and insertion)

stylohyoid, attached to the styloid process and hyoid bone

ex. of muscle named by muscle action

levator scapulae, levitates the scapula

ex. of muscle named by a combination

fibularis longus, fibularis refers to its location (by the fibula), longus refers to its size/shape (long)

how do muscle produce movement? (physical)

when they contract they exert force on a tendon which pulls on bones and other supporting structures, in order to produce movement around a joint, one bone must move while another stays still (if you bend your elbow, your upper arm stays mostly still while your forearm moves towards it)

origin

the point of attachment to the stationary (and usually proximal) bone

insertion

the point of attachment to the moving (and usually distal) bone

do most muscles work individually or as a group?

as a group

how are most muscles arranged at joints?

in antagonistic (opposing) pairs (ex. biceps brachii and triceps brachii)

agonist

aka prime mover, the muscle primarily responsible for causing the desired movement

antagonist

stretches and yields to the effects of the prime mover (the muscle that would be the agonist for the opposite movement)

synergist

muscles used to precent unwanted movements at intermediate joints, or otherwise aid the movement of the prime movers

fixator muscles

a type of synergist muscle that is used to steady the proximal joints of a prime mover

what to muscles of facial expression move?

skin (as opposed to bone)

punching muscle

serratus anterior

crossing legs muscle

sartorius

smiling muscle

zygomaticus

kissing muscle

orbicularis oris

swimming muscle

latissimus dorsi