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Muscles of the face, head, and neck Functions of muscles • 1. Movement • 2. Heat production • 3. Maintain posture/body position Types of muscle • There are approx. 640 muscles in the body (~320 pairs). These muscles are grouped into 3 categories. • Skeletal muscle (striated): Muscle that is under voluntary control. Most are attached to the skeleton by tendons at one or both ends, but some are attached to skin, cartilage, or organs. • Smooth muscle(non-striated): muscle that is involuntary. Most of this muscular tissue is found in internal organs. It is under the control of the autonomic nervous system so it doesn’t involve voluntary control. • Cardiac muscle(striated): Special muscle only found in the heart. Although it’s striated like skeletal, it’s involuntary. This muscle generates its own electrical impulses and requires a constant supply of oxygen. Characteristic Skeletal muscle Smooth muscle Cardiac muscle Location Attached to skeleton Walls of intestines, blood vessels, etc. Walls of heart Type of control Voluntary Involuntary Involuntary Striations Present Absent Present Speed of contraction Most rapid Slowest Intermediate Ability to remain contracted Least Greatest Intermediate Energy Production • The energy required for muscle contraction is derived from the metabolism of glucose (sugar). Muscle fibers need to continually resynthesize ATP (energy) because they can only store small amounts. The oxidation of glucose produces carbon dioxide and water, which in turn produces lactic acid. • Only 1/3 of the energy muscles receive is used for work, the remainder is released in the form of heat to maintain body temperature. Our muscles can create heat through voluntary activity (walking) or involuntary activity (shivering) Helpful hints for naming muscles • • • • • • • • • • • • Size: Vastus Maximus Longus Minimus Brevis Shape: Deltoid Latissimus Teres Trapezius Rhombus • • • • • • • • • • • • • Location: Pectoralis Gluteus Brachii SupraInfraSubLateralis Medialis Intermedius Direction of muscle fibers: Rectus Oblique • • • • • • • • • • Action: Adductor abductor flexor Extensor Levator Number of attachments: Triceps Biceps Quadriceps More terms!!! • Prime mover: Muscle whose contraction is the major source of a particular movement • Antagonist: muscle that opposes the action of a prime mover or initiates an opposite movement. • Tendon: Band that connects muscle to bone • Origin: Typically, a muscle’s proximal attachment and most stationary point • Insertion: Typically, a muscle’s distal attachment that moves with the bone during contraction. Helpful hints for naming muscles • • • • • • • • • • Size: vastus (huge) maximus (large) longus (long) minimus (small) brevis (short) Shape: Deltoid (triangle) latissimus (wide) teres (round) trapezius (trapezoid) rhombus (rhomboid). • • • • • • • • • • Location: Pectoralis (chest) gluteus (buttock) brachii (arm) supra-(above) infra-(below) sub-(under, beneath) lateralis (lateral) Direction of muscle fibers: Rectus (Straight) Oblique (Angular) • • • • • • • • • Action: adductor (towards midline) abductor (away from midline) flexor (flexes) extensor (extends) levator (to lift or elevate) Number of attachments: Triceps (3 attachments) Biceps (2 attachments) Quadriceps (4 attachments) Frontalis Frontalis Zygomaticus minor Frontalis Zygomaticus minor Zygomaticus major Frontalis Zygomaticus minor Zygomaticus major Risorius Frontalis Zygomaticus minor Zygomaticus major Risorius Mentalis Frontalis Orbicularis oculi Zygomaticus minor Zygomaticus major Risorius Mentalis Frontalis Orbicularis oculi Zygomaticus minor Zygomaticus major Risorius Mentalis Levator labii superioris Frontalis Orbicularis oculi Zygomaticus minor Zygomaticus major Risorius Mentalis Levator labii superioris Orbicularis oris Frontalis Orbicularis oculi Zygomaticus minor Zygomaticus major Levator labii superioris Orbicularis oris Risorius Mentalis Depressor labii inferioris Muscles of head/neck Temporalis Muscles of head/neck Temporalis Occipitalis Muscles of head/neck Temporalis Occipitalis Sternocleidomastoid Muscles of head/neck Temporalis Occipitalis Sternocleidomastoid Trapezius Muscles of head/neck Temporalis Occipitalis Sternocleidomastoid Platysma Trapezius Muscles of head/neck Temporalis Occipitalis Masseter Sternocleidomastoid Platysma Trapezius Muscles of head/neck Temporalis Occipitalis Buccinator Sternocleidomastoid Masseter Platysma Trapezius Actions of facial muscles • Orbicularis Oculi-Closes eye as in blinking • Frontalis & Occipitalis-Together are known as the epicranius and are responsible for raising the eyebrows, wrinkling the skin of the forehead • Zygomaticus major: Elevates and retracts corner of the mouth • Zygomaticus minor: Elevates and retracts upper lip • Levator labii superioris: Elevates and puckers upper lip • Risorius: Moves corners of mouth laterally • Orbicularis oris: Closes lips (kissing muscle) • Depressor labii inferioris: Depresses lower lip (frown) • Mentalis: Moves lower lip forward • Masseter: Closes jaw • Buccinator: Compresses cheeks against teeth (sucking), allows cheeks to expand during blowing (trumpeter muscle). Actions of head/neck muscles • Temporalis: closes jaw • Platysma: Depresses mandible, draws corner of mouth downward, tenses skin of neck • Sternocleidomastoid: Flexes and rotates neck • Trapezius: Extends and rotates neck