CHP10TheMuscularSystem

Muscles chewingswallowing medial lateral pterygoids

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Unformatted text preview: er= shorter, superficial to temporalis; origin @ zygomatic arch & inserts on lateral surface of mandible angle arch • Pair of muscles elevate mandible to bite & chew • 2 of the most powerful muscles of body Chewing/swallowing muscles Chewing/swallowing Medial & lateral pterygoids= orgins @ pterygoid processes of orgins sphenoid & insert on medial surface of mandible sphenoid • Elevate, protract mandible • Lateral excursions (grinding) Suprahyoid group= 8 hyoid muscles • • • Elevate/depress mandible, hyoid Protract/retract mandible Movements of larynx during Movements swallowing, speech Process of swallowing~ Process • Food enters pharynx, muscles contract to force food down Food towards esophagous esophagous • @ same time, thyroid cartilage of larynx raises up & meets same thyroid epiglottis (flap that temporarily closes windpipe (trachea) so epiglottis so food will enter the ‘proper’ passageway food Head/Neck Head/Neck Muscles acting on head~ 5 to learn, many more actually Muscles Sternocleiodomastiod= prime mover (principle flexors of neck, + Sternocleiodomastiod prime 3 prs of scalenes) scalenes • Passes obliquely across neck from manubrium & clavicle to Passes mastoid process mastoid • Both contracted to flex head forward & down; 1 contracts to Both move head down & towards opposite side move Levator scapulae= flexes neck when scapula fixed; also rotates flexes also scapula to tilt glenoid cavity downward, elevates scapula scapula • Origin @ transverse processes (C1-C4) & inserts on superior Origin angle to medial border of scapula angle Trapezius= 1 of 3 primary extensors of head/neck • Triangular muscle of upper back/neck; abducts & extends neck Triangular (more functions listed in Table 10.9) (more Neck (cont.) Neck Trapezius (cont.)~ • Origin @ external occipital probtuberance, nuchal ligament, Origin spinous processes (C7-T12) & inserts on clavicle, acromion, scapular spine scapular Splenius capitus= lies deep to trap’s on neck • Oblique fascicles orginate @ spinous processes of C7-T-3/4 & Oblique insert on mastoid process, superior nuchal line insert • Rotates head, extends neck Respiration Respiration 3 muscle groups involved w/ breathing- diaphragm, external muscle & internal intercostals internal **Lungs have no skeletal muscle, & so, do NOT ventilate **Lungs themselves themselves Diaphragm= muscular dome forming ‘floor’ of thoracic cavity muscular dome • • • Fasicles angle inwards to a central tendon Fasicles Openings for esophagous, bld vessels (aorta, vena cava) Contractions flatten diaphram…increasing volume w/in t.c. & Contractions creating a ‘vacuum’ that draws air into lungs creating Respiration (cont.) Respiration External intercostals= external muscles btw ribs; extend external obliquely down & anteriorly from each rib to the 1 below it...
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