EXSS 175 Week 2 Notes
EXSS 175 Week 2 Notes EXSS 175
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This 9 page Class Notes was uploaded by Lynde Wangler on Saturday January 23, 2016. The Class Notes belongs to EXSS 175 at University of North Carolina - Chapel Hill taught by Dr. Johna Register-Mihalik in Spring 2016. Since its upload, it has received 39 views. For similar materials see HUMAN ANATOMY in Physical Education at University of North Carolina - Chapel Hill.
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Date Created: 01/23/16
EXSS Week 2 Notes – 2 Muscular System: Muscle Functions: movement, stabilization, regulate volume of organs (via bands of smooth muscle called sphincters), movement of substances (blood, lymph, urine, air, food and fluids, sperm, etc.), heat production (shivering – involuntary muscle contractions) Properties of Muscles: Excitability (responds to external stimuli and conducts electrical signals), Contractility (ability to contract – shorten – and produce force), Extensibility (flexibility – must be able to extend without impairing muscle), Elasticity (return to normal length after being stretched), Thermal (heat production) Origin and Insertion: o Origin – site where muscles and tendon attach to unmoving bone o Insertion – site of attachment for muscles and tendons on the moving bone Types of Muscle Tissue: o Skeletal Muscle – attaches to bone, skin, and fascia; striated (banded look due to arrangement of proteins); voluntary control; multi- nucleated cells o Cardiac Muscles – striated; involuntary control (regulated by internal pacemaker); only one nucleus per cell o Smooth Muscles – attached to hair follicles; exist in walls of hollow organs (blood vessels and GI tract, for ex.); non-striated; involuntary Arrangement of Fascicles (bundles of muscle fibers that make up a muscle) – parallel, fusiform, circular, triangular, pennate (unipennate, bipennate, multipennate) Composition & Structure of Muscles – fascicles, muscle fibers, myofibrils, sarcomeres, filaments Connective Tissue Structures: o Epimysium – envelops muscle (fascia) o Perimysium – covers the fascicles o Endomysium – covers individual muscle fibers Composition: o Myofibrils – main constituent of muscle fibers; contractile elements of the muscle o Sarcomere – functional unit of contraction o Both are composed of protein filaments Myofibrils: serves as the contractile element of muscles; composed of many sarcomeres that extend from Z-line to Z-line; sarcomeres are composed of thick and thin filaments Thick (myosin) and Thin (actin, troponin, tropomyosin) filaments are composed of contractile and regulatory proteins Myosin: component of thick fibers; each molecule has two myosin heads (extend toward thin filament) and one tail; molecule held in place by M line proteins Actin: each actin molecule has a myosin-binding site that is covered by tropomyosin in relaxed muscles; thin molecules held in place by Z lines (Z line to Z line is a sarcomere) Motor Units: functional unit of skeletal muscle; constituents: one motor neuron, muscle fibers that it innervates; one motor endplate on each muscle cell each cell has one nerve and one nerve can innervate many muscle cells Fine Tuning of Neuromuscular Control: fewer motor-units per nerve = more fine-tuned movement capabilities (finger dexterity); muscles like the quads do not need to be as specific, so there are many more motor-units per nerve; motor-units innervate muscles with similar qualities (contractile and metabolic) Muscular Contraction Chain of Events – action potential travels down the motor neuron to the axon terminal which releases the neurotransmitter, acetylcholine (Ach) into the synaptic cleft Ach binds to receptors on the motor endplate electrical impulse is sent to the muscle fiber; spreads through the muscle cell membrane and down to the t-tubules sarcoplasmic reticulum releases calcium into the muscle fiber calcium binds to troponin causing tropomyosin to move away from binding sites on axons myosin heads bind to actin; myosin heads pivot to shorten length of sarcomere muscle contraction is stopped when acetylcholinerase (AChE) is released into the synaptic cleft to break down the Ach calcium goes back to sarcoplasmic reticulum troponin and tropomyosin go back to covering the binding sites on actin FINALLY sarcomere returns to relaxed state/length Cross-bridges: action is analogous to pulling a rope hand-over-hand Isometric tension is greatest at physiological resting length Isotonic and Isometric Contraction: o Isotonic Contraction – moving a load Concentric Contraction: muscle shortens to produce force or movement Eccentric Contraction: muscle lengthens while maintaining force & action o Isometric Contraction – no movement; tension is created without a shortening of the muscles (ex. maintaining posture or objects in fixed positions) 1/20 Lecture Axis of Movement animation video Review: o Movement occurs in a plane (frontal, sagittal, transverse) o Movement occurs about an axis (AP, mediolateral, longitudinal Types of Movements: o Flexion/Extension – in sagittal plane, about mediolateral axis o AB-duction/AD-duction – in frontal plane, about AP (anterioposterior) axis o Rotation – in transverse (horizontal) plane, about the longitudinal axis Motions of forearm – supination (radius and ulna parallel); pronation (radius and ulna cross over) ex. beauty pageant wave Wrist motions – ulnar deviation (toward the ulna), radial deviation (toward the radius); ex. waving – occurs in frontal plane about the mediolateral axis Dorsiflexion (lifting foot off gas pedal)/ Plantar flexion (pressing down on the gas pedal) Inversion (pulling sole of foot inside); associated with ankle sprains/Eversion (sole of foot faces outward); associated with high ankle sprains (pulls tibia and fibula apart – takes a longer time to heal) o Specific Joint Motions of the Scapula: Elevation/Depression Adduction (retraction)/ Abduction (protraction – as in punching something/one) Upward and Downward Rotations (scapula is actually rotating) Have a thorough understanding of movement types/planes/axes in order to be able to talk about muscles Muscles 1 (reference Dr. Johna Register-Mihalik muscle slides) How are different muscles named? – attachments, actions, anatomical location, region, shape, & size Deep Back – Erector Spinae, Transversospinalis, Multifidis, Rotatores Erector Spinae: Iliocostalis Cervicis Thoracis Lumborum Origin Superior 6 ribs Inferior 6 ribs Iliac crest Insertion TP of C4-C6 Superior 6 ribs Inferior 6 ribs Action Together: Extend Separately: and maintain laterally flex erect posture of vertebral column spine of respective region Innervation Spinal Nerves Erector Spinae: Longissimus Capitis Cervicis Thoracis Origin TP of T1-T4 TP of T4-T5 TP of L1-L5 vertebrae and articular processes of C4-C7 Insertion Mastoid process TP of C2-C6 TP of thoracic and lumbar vertebrae, ribs 9 and 10 Action Together: extend Alone: laterally vertebral column flex vertebral at respective column of region respective region Innervation Spinal Nerves Erector Spinae: Spinalis Capitis Cervicis Thoracis Origin Arises with Ligamentum Spinous processes semispinalis nuchae and of superior lumbar capitis spinous process of and inferior C7 thoracic vertebrae Insertion Occipital bone Spinous process of Spinous processes axis of superior thoracic vertebrae Action Together: extend vertebral column at respective regions Innervation Spinal Nerves Transversospinalis Capitis Cervicis Thoracis Origin TP of C7 and T1-T7 TP of T1-T6 TP of T6-T10 and AP of C4-C6 Insertion Occipital bone Spinous processes Spinous processes of C1-C5 of C6-C7 and T1- T4 Action Together: extend Alone: rotate head vertebral column to the opposite at respective side region Innervation Spinal Nerves Multifidus Origin Sacrum, illium, transverse processes of lumbar, thoracic, and C4-C7 Insertion Spinous processes of a more superior vertebra Action Together: extend vertebral column; Alone: laterally flex vertebral column and rotate head to opposite side Innervation Spinal Nerves Rotatores Origin Transverse processes of all vertebrae Insertion Spinous process of vertebra superior to the one of the origin Action Together: extend vertebral column; Alone: rotate vertebral column to the opposite side Innervation Spinal Nerves Neck – Scalenes interior, scalenes middle, scalenes posterior, sternocleidomastoid, platysma Scalenes Anterior Origin Transverse processes C3-C6 Insertion First rib st Action Together: flex neck and raises 1 rib during deep inhalation; Alone: laterally flex and rotate neck to the same side Innervation Cervical Nerves Scalene Middle Origin Transverse processes C2-C7 Insertion First rib Action Together: flex neck and raises first rib during deep inhalation; Alone: laterally flex and rotate neck to the same side Innervation Cervical nerves Scalenes Posterior Origin Transverse processes C4-C6 Insertion Second rib Action Together: flex neck and raises second ribs during deep inhalation; Alone: laterally flex and rotate neck to the opposite side Innervation Cervical Nerves Sternocleidomastoid Origin Sternum and clavicle Insertion Mastoid process Activation Together: flex cervical portion of vertebral column, extend head, and elevate sternum during forced inhalation; Alone: laterally flex and rotate neck to the opposite side Innervation Spinal Accessory Platysma Origin Fascia over deltoid and pectoralis major muslces Insertion Mandible, muscles around angle of mouth, and skin of lower face Activation Depresses mandible, depresses lower lip laterally, draws up skin of chest Innervation Facial Nerve Anterior Thorax – external intercostals, internal intercostals, external oblique, internal oblique, transverse abdominus, rectus abdominus, quadratus lumborum, diaphragm External Intercostals Origin Inferior border of rib above Insertion Superior border of rib below Action Contraction creates inhalation by elevating ribs; relaxation depresses the ribs resulting in exhalation Innervation Intercostal nerves Internal Intercostals Origin Superior border of rib below Insertion Inferior border of rib above Action Contraction draws adjacent ribs together during forced exhalation Innervation Intercostal nerves External Oblique Origin Inferior 8 ribs Insertion Iliac crest and linea alba Action Together: compress abdomen and flex vertebral column; Alone: laterally flex and rotate vertebral column to the opposite side Innervation Intercostal Nerves Internal Oblique Origin Iliac crest, inguinal ligament, and thoracolumbar fascia Insertion Cartilage of last four ribs and linea alba Action Together: compress abdomen and flex vertebral column; Alone: laterally flex and rotate vertebral column to the same side Innervation Intercostal Nerves Transverse Abdominus Origin Iliac crest, inguinal ligament, lumbar fascia, and cartilages of inferior six ribs Insertion Xiphoid process, linea alba, and pubis Action Compress abdomen Innervation Intercostal nerves Rectus Abdominus Origin Pubic crest and pubic symphysis th th Insertion Cartilage of 5 -7 ribs and xiphoid process Action Flexes trunk and compresses abdomen Innervation Intercostal nerves Quadratus Lumborum Origin Iliolumbar ligament and iliac crest Insertion Inferior border of 12 rib and transverse processes of L1-L4 Action Together: pull 12 ribs inferior during forced exhalation, extend vertebral column; Alone: laterally flex vertebral column Innervation T12-L1 Diaphragm Origin Xiphoid process, cartilage of the lower six ribs, and lumbar vertebrae Insertion Central Tendon Action Contraction causes it to flatten and increase vertical dimension of the thoracic cavity, resulting in inhalation; relaxation causes it to move superiorly and decrease the vertical dimension of the thoracic cavity, resulting in exhalation Innervation Phrenic Nerve Muscle Lecture 2 Superficial Back – Trapezius, latissimus dorsi, rhomboid major, rhomboid minor, levator scapulae, serratus anterior Trapezius Origin Superior nuchal line of occipital bone, ligamentum nuchae, and spines of C7 and T1-T12 Insertion clavicle, acromion, and spine of scapula Action Upper trap: elevate scapula, upwardly rotate the scapula and extend head; Middle trap: retract scapula; Lower trap: depress scapula and upwardly rotate the scapula Innervation Spinal Accessory Nerve Latissimus Dorsi Origin Spines of T7-T12 and L1-L5, sacrum and ilium, inferior four ribs Insertion Bicipital groove Action Extends, adducts, and internally rotates the arm at the shoulder joint; draws arm inferiorly and posteriorly Innervation Thoracodorsal nerve Rhomboid Major Origin Spines of T2-T5 Insertion Medial border of scapula inferior to spine Action Elevation, retraction and downward rotation of the scapula Innervation Dorsal Scapular Nerve Rhomboid Minor Origin Spines of C7-T1 Insertion Medial border of scapula superior to spine Action Elevation, retraction, and downward rotation of the scapula Innervation Dorsal Scapular Nerve Levator Scapulae Origin Transverse processes of C1-C4 Insertion Superior medial border of scapula Action Elevation and downward rotation of the scapula Innervation Dorsal Scapular Nerve Pectoral Region – pectoralis major, pectoralis minor Pectoralis Major Origin Clavicle, sternum, and costal cartilages of ribs 2-6 Insertion Greater tuberosity and bicipital groove Action Shoulder adduction and internal rotation and assists with flexion Innervation Medial and Lateral Pectoral Nerves Pectoralis Minor Origin Ribs 2-5 Insertion Coracoid process Action Scapular protraction and downward rotation Innervation Medial Pectoral Nerve Serratus Interior Origin Superior 9 ribs Insertion Medial border of scapula Action Protraction and upward rotation of the scapula Innervation Long Thoracic Nerve
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