BSC 2085 Lab 7 - Muscular System PDF

BSC 2085 Lab 7 MUSCULAR SYSTEM Hernan Aviles  MUSCLE STRUCTURE  muscles are made of muscle fibers  When stimulus travels down a neuron to a muscle fiber, this fiber contracts  fascicles: group of fibers  perimysium: layer that...

BSC 2085 Lab 7 MUSCULAR SYSTEM Hernan Aviles  MUSCLE STRUCTURE  muscles are made of muscle fibers  When stimulus travels down a neuron to a muscle fiber, this fiber contracts  fascicles: group of fibers  perimysium: layer that surrounds each fascicle  endomysium: tissue filling the space between fibers (extension forms tendons)  epimysium: tough tissue surrounding all fascicles 2 3  origen: end of muscle attached to the immovable bone insertion: end attached to the movable bone movements must be coordinate, smooth and precise (many muscles involved) agonist: primary muscle involved in any movement (biceps in flexion of elbow) antagonist: oppose the agonist (triceps oppose the action of biceps) synergist: contract at the same time as the agonist (brachioradialis helps biceps in flexion) Fixators: help the agonist by fixing the bone in the origen of muscle (fix the scapula in elbow’s flexion 4  MUSCLE MOVEMENTS  flexion: bending a joint  extension: straightening a joint  dorsiflexion: flexing foot towards the shin  plantar flexion: extending ankles (pointing the toes)  abduction: away from the midline  adduction: toward the midline  supination: turning palm anteriorly  pronation: turning palm posteriorly 5  protraction: moving a part of the body anteriorly  retraction: moving a part of the body posteriorly  elevation: raising a body part  depression: lowering a body part  inversion: turning the sole of the foot inward (foot only)  eversion: turning the sole of the foot outward (foot only)  Circumduction: circular movement (shoulder); combination of flexion, extension, aduction, abduction 6  opposition: opposable thumb (tool use)  rotation: moving a body part around its axis (between first two vertebrae, hip and shoulder joints) 7  NAMING MUSCLES  direction of fibers: rectus (straight), transverse (horizontal), oblique (diagonal)  location: pectoralis (chest), brachialis (arm), external (outer), internal (inner), ventralis (front), abdominal (abdomen)  shape: deltoid (triangular), trapezius, longus (long)  origen and insertion: sternocleidomastoid (sternum, clavicle and mastoid process of temporal)  number of origens: biceps, triceps, quadriceps  action: flexor, extensor, levator, adductor, supinator, masseter (to masticate= to chew). 8 HISTOLOGY OF MUSCLE AND TENDONS skeletal muscle (multiple peripheral nuclei)  long, cylindrical, unbranched cells with striations SKELETAL  movement, facial expression, posture, breathing, speech, swallowing  voluntary cardiac muscle (one central nucleus per cell)  short branched cells with striations and intercalated discs CARDIAC  involuntary (heart) smooth muscle (one central nucleus) SMOOTH  Short fusiform cells; nonstriated viscera; iris; hair follicles, sphincters GI tract functions, labor contractions, control of airflow, erection of hairs, control of pupil 9 SKELETAL CARDIAC SMOOTH 10 11 12  HEAD AND NECK  orbicularis oculi * *  orbicularis oris * * *  frontalis * *  occipitalis * *  temporalis  zygomaticus major  zygomaticus minor  buccinator  sternocleidomast oid  masseter 13 14 15 16  ABDOMEN  rectus abdominis  external oblique  internal oblique  transverse abdominis  diaphragm 17 18 19  CHEST  pectoralis major, pectoralis minor, serratus anterior 20  BACK  latissimus dorsi, trapezius 21