Anatomy & Physiology B Chapter 6: Muscles
Warm-up What are the three types of muscle tissue? Where are each located? Which are voluntary and which are involuntary? Which are striated which are unstriated? Which are multinucleated? 2
3 Types of Muscle Tissue Skeletal muscle multinucleated attaches to bone, skin or fascia striated with light & dark bands visible with scope voluntary control of contraction & relaxation
3 Types of Muscle Tissue Cardiac muscle striated in appearance involuntary control Uninucleated autorhythmic because of built in pacemaker
3 Types of Muscle Tissue Smooth muscle Uninucleated attached to hair follicles in skin in walls of hollow organs -- blood vessels & GI nonstriated in appearance involuntary
What are the functions of Muscles? Producing body movements Stabilizing body positions Regulating organ volumes bands of smooth muscle called sphincters Movement of substances within the body blood, lymph, urine, air, food and fluids, sperm Producing heat involuntary contractions of skeletal muscle (shivering)
Connective Tissue Components
Connective Tissues of a Muscle Epimysium covers whole muscle belly blends into connective tissue that separates muscles Perimysium slightly thicker layer of connective tissue surrounds a bundle of cells called a fascicle Endomysium thin layer of areolar tissue surrounding each cell allows room for capillaries and nerve fibers
Aponeurosis Bicipital Aponeurosis Epicranial Aponeurosis Palmar Aponeurosis 9
MOTION TERMS FLEXION: reduces the angle of the joint from the anatomical position. Flex elbow EXTENSION: movement that returns you to anatomical position. Extend elbow. 10
MOTION TERMS ABDUCTION: move body part away from midline; arm, fingers, thumb ADDUCTION: bring back to midline; arms, fingers, thumb 11
MOTION TERMS ROTATION: pivot on an axis; shake head no ; can rotate head and shoulder CIRCUMDUCTION: to draw a circle with body part; shoulder, head 12
MOTION TERMS PRONATION (to lie prone is on stomach). Turn hands downward. SUPINATION: refers to arms; want a bowl of soup, supinate
ANKLE MOTION TERMS Some terms relate only to certain areas, such as the ankle: INVERSION: when sole of foot points inward EVERSION: sole of foot points outward. DORSIFLEXTION: lift up toes PLANTARFLEXION: move toes down
Coordinated Muscle Actions Prime Mover : agonist, produces most of force Synergist : aids the prime mover stabilizes the nearby joint modifies the direction of movement that occurs Antagonist opposes the prime mover preventing excessive movement and injury Fixator prevents movement of bone that prime mover is attached to
Frontalis Origin: Epicranial aponeurosis Insertion: Skin over forehead Action: Elevates eyebrows and wrinkles skin of forehead 16
Occipitalis Origin: Occipital and temporal bones Insertion: Epicranial aponeurosis Action: Fixes epicranial aponeurosis and pulls scalp posteriorly 17
Orbicularis Oculi Origin: Medial orbital margin and zygomatic bone Insertion: Skin surrounding eye Action: Closes eyelids and depresses skin of forehead 18
Temporalis Origin: Temporal fossa Insertion: Coronoid process of mandible Action: Elevates and retracts mandible 19
Masseter Origin: Zygomatic process and arch Insertion: Angle and ramus of mandible Action: Elevates mandible 20
Orbicularis Oris Origin: By muscular skips to surround muscles Insertion: Muscles interlace to surround mouth Action: Closes and purses lips 21
Zygomaticus Major Origin: Zygomatic arch Insertion: Corner of mouth Action: Elevates corner of mouth 22
Zygomaticus Minor Origin: Lateral infraorbital margin Insertion: skin and muscle of upper lip Action: Elevates the upper lip 23
Buccinator Origin: External margins of maxilla and mandible Insertion: fibers of the orbicularis oris Action: tenses cheeks in blowing and whistling, aids in chewing and closing of mouth 24
Muscles of Mastication
Platysma Origin: infraclavicular and supraclavicular regions Insertion: base of mandible Action: Draws the corners of the mouth inferiorly and widens it 26
Sternocleidomastoid Origin: Manubrium and medial third of clavicle Insertion: Mastoid process Action: Rotates head to opposite side, extends head, and flexes vertebral column 27
Trapezius Origin: External occipital protuberance, superior nuchal line and spinous process of C 7 -T 12 Insertion: Anterior border of scapular spine, acromion process, lateral third of clavicle Action: Elevates, adducts, and depresses scapula 28
Latissimus Dorsi Origin: Spinous processes of lower 6 thoracic vertebrae, thoracolumbar fascia, crest of ilium Insertion: Intertubercular groove of humerus Action: Extends, rotates humerus medially, draws shoulder down and backward 29
Erector Spinae Origin: Sacrum, iliac crest, spinous processes of lumbar vertebrae and T11,12 Insertion: Angles of the ribs. Spinous & Transverse processes of vertebrae Action: Extension of vertebral column 30