CHP10TheMuscularSystem

Mover produces most of the force synergist aids prime

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ement produced by a muscle 4 categories of action= prime mover, synergist, antagonist, categories fixator fixator • Prime mover= produces most of the force • Synergist= aids prime mover; adds more power, may help to aids stabilize or produce a more specific movement stabilize • Antagonist= opposes prime mover; moderates movement by opposes not allowing prime mover excessive movement not • Antagonist pair= muscles that act on opposite sides of a joint • Flex & extend; abduct & adduct, etc. Flex • Fixator= prevents bone from moving by holding it steady while prevents another muscle is pulling on it (scapula held in place by rhomboids while biceps flex) rhomboids biceps Muscles of Head & Neck Muscles Muscles can be either intrinsic or extrinsic intrinsic extrinsic • Movements of hand ex. of both Muscles are supplied w/ nerves (innervation) from PNS (spinal from & cranial nerves) cranial • Head & neck supplied by cranial nerves (I-XII) • Spinal nerves named for vertebrae exiting out of Muscles named for size, shape, location, # of heads, Muscles orientation, & action (Table 10.1) orientation, Muscles of head & neck- muscles inserted in dermis contract to muscles form facial expression form • 8 muscles of facial expression (table 10.2) • 5 muscles for chewing/swallowing (table 10.3) • 4 muscles of throat/neck region (table 10.4, 10.9) Muscles of Head & Neck Muscles Muscles of Head & Neck Muscles Scalp muscle= occipitofrontalis (or occipitalis & frontalis) iis 2 Scalp occipitofrontalis occipitalis frontalis s muscles connected by galea aponeurotica (broad tendon) galea • Moves scalp, forehead, eyebrows Eyes encircled by orbicularis oculi- ring of muscle that Eyes orbicularis ring closes eye closes • Levator palpebrae superioris opens eye opens Mouth encircled by orbicularis oris- closes lips Mouth orbicularis • Other muscles meet o.o. from all directions Zygomaticus major originates near ear & inserts @ upper corner of mouth (w/ others, produces smiles) corner Mouth corners depressed (frown) by depressor anguli oris Mouth depressor • Additional muscles attach to lower lip to draw it downward Muscles of Head & Neck (cont.) Muscles Cheek muscle= buccinator; blowing, sucking, chewing Cheek buccinator blowing, (holds & pushes food btw teeth) Platysma= thin superficial muscle of shoulder/chest Platysma – Inserts along mandible (tightens during shaving, depresses Inserts mandible, & opens/widens mouth) mandible, Chewing/swallowing muscles Chewing/swallowing Chewing (mastication) muscles- also affect facial expression, also but primary functions are chewing, tongue movements, swallowing swallowing Buccinator (+ tongue muscles) move food btw molars, then 4 paired muscles breakdown food in mouth paired Temporalis= broad muscle originating @ temporal lines broad (parietal & frontal bone) & inserting on coronoid process of mandible mandible Masset...
View Full Document

Ask a homework question - tutors are online