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Connective tissue components 1.Endomysium - Muscle fibers are covered with a delicate connective tissue membrane 2.Perimysium - Groups of skeletal muscle fibers (fascicles) are bound together by a tougher connective tissue 3.Epimysium - the muscle as a whole is covered by a coarse sheath 4.Tendon - fibrous structures that attach muscles to bones 5.Aponeurosis 6.Tendon sheath - Size, shape, and fiber arrangement Parallel Convergent Pennate Bipennate Sphincter Attachment of muscles - point of attachment that does not move when the muscle contracts -point of attachment that does move when the muscle contracts Muscle actions • Functional classification of muscle groups – always function in groups/pairs; some contract as some relax – Prime mover (agonist) – Muscle most responsible for movement; “action” or “function” of that muscle – Antagonist – Muscle responsible for the movement opposite of the prime mover; provides precision and control during contraction of prime mover; relaxes while prime mover contracts – Synergist – Muscles that aid the prime mover; contract at same time as prime mover – Fixator – joint stabilizer; maintains posture or balance during contraction of prime mover 2nd Class Levers 1st Class Levers Bone = lever Joint = Fulcrum (F) Contracting Muscle = Force (P) Load (L) 3rd Class Levers How Muscles Are Named Features used in naming muscles 1. Location – gluteus, brachii 2. Function 3. Shape - deltoid 4. Direction of fibers – rectus abdominus 5. Number of heads or divisions – points of origin -cep = head 6. Points of attachment -sternocleidomastoid 7. Size of muscle – relative size, maximus, minimus Hints on how to deduce muscle actions 1. Be familiar with name, shape, and location 2. From shape and location, deduce name of origin and insertion bone 3. Determine which bone moves when muscle contracts 4. Deduce action—insertion moves toward origin 5. Deduce which muscle gives a specific action Muscles Named According To: Overall Shape Deltoid Shaped like delta Δ Orbicularis Circular Platy Flattened; platelike Quadratus Square Rhomboideus Diamond-shaped Trapezius Trapezoidal Triangularis Triangular Muscles Named According To: Relative Size Brevis Short Longus Long Magnus Large Maximus Largest Medius Moderately sized Minimus Small Muscles Named According To: Direction of Fibers Oblique Diagonal to body’s midline Rectus Parallel to midline Sphincter Circling an opening Transversus Right angle to midline Muscles Named According To: Actions Produced Abductor Abducts a part Adductor Adducts a part Depressor Depresses a part Extensor Extends a part Flexor Flexes a part Levator Elevates a part Rotator Rotates a part Muscles Named According To: Regions Found Brachialis Arm Frontalis Frontal (bone) Femoris Femur Gluteus Posterior of hip/thigh Oculi Eye Radialis Radius Ulnaris Ulna 1. 2. 3. 4. 5. 6. Muscles of Facial Expression occipitofrontalis – raise eyebrows corrugator supercilii – frowning forehead orbicularis oculi – blinking zygomaticus major – laughing orbicularis oris – puckering buccinator Muscles of Mastication (chewing) 1. masseter 2. temporalis 3. pterygoids 1. 2. 3. 4. Muscles that Move the Head sternocleidomastoid semispinalis capitis splenius capitus longissimus capitus Posture • Good posture – body alignment that favors function, with least work – Standing position: head and chest held high; chin, abdomen and buttocks pulled in; knees bent slightly; feet firmly on ground 6 in. apart. • Poor posture – puts abnormal strain on ligaments and bones • How Maintained – Muscle Tone (Tonicity) – when muscles exert a pull against gravity Cycle of Life • During infancy and childhood, muscle coordination and control allows developmental sequences to occur • Degeneration of muscles with age includes replacement with connective tissue