Exercise Science Section 3: The Muscular System

Transcription

1 Exercise Science Section 3: The Muscular System An Introduction to Health and Physical Education Ted Temertzoglou Paul Challen ISBN

2 Major Functions of Muscles Movement v Includes: breathing, eating, and the beating of our hearts Support Heat production There are over 600 muscles in the human body.

3 Three Types of Muscle Tissue Skeletal muscles: v Voluntary, striated, and attach to bones by tendons and other tissue Cardiac muscles: v Involuntary, striated, and found in one place the heart Smooth muscles: v Involuntary, non-striated, and surround the body s internal organs Skeletal muscle Cardiac muscle Smooth muscle

4 Properties of Muscle Fibre Irritability Refers to muscle responding to stimuli Contractibility Elasticity Extensibility Refers to muscle shortening in length Refers to muscle stretching and returning to normal position Refers to muscle extending in length Conductivity Refers to muscle transmitting nerve impulses

5 Neuromuscular Junction Axon Neurotransmitter acetylcholine (Ach) Axon Terminal Synaptic Cleft Sarcolemma Receptor

6 The Motor Unit Dendrites Neuron cell body Axon hillock Motor neuron Direction of action potential Myelin sheath Neurolemma Neuromuscular junction Terminal branches Muscle fibres Motor end plate

7 The Anatomy of Skeletal Muscle Muscle fibre looking outward: v Perimysium Binds muscle fibres together v Epimysium Sheath enveloping entire muscle Muscle fibre looking inward: v Endomysium Sheath of connective tissue surrounding muscle fibre v Sarcolemma Contains cytoplasm (sarcoplasm) v Myofibrils Contain actin and myosin v Sarcomeres Contains myosin and actin Perimysium Muscle fibre Tendon Muscle belly Epimysium Endomysium

8 Muscle Fibre Muscle belly Epimysium Perimysium Z line Sarcomere Z line Tendon Muscle Fibre Thick filament Thin filament Sarcomere Sarcolemma Sarcoplasmic reticulum Myofibril

9 How Muscles Are Named Action/Function Flexion/Extension Direction of Fibres Rectus/Transversus Location Anterior/Posterior Number of Divisions/Heads Number of heads Shape Deltoid/Trapezius Points of Attachment Sternum/Clavicle/Mastoid process

10 How Muscles Attach to Bone Indirect attachment: v Epimysium extends past muscle as a tendon v Attaches to periosteum of bone Direct attachment: v Epimysium adheres to and fuses with the periosteum Point of attachment

11 Antagonistic Pairs Examples Agonist (Prime Mover) Antagonist (Counteracts) Elbow flexion Biceps brachii Triceps brachii Shoulder abduction Deltoid Latissimus dorsi Medial shoulder rotation Pectoralis major Infraspinatus Knee extension Quadriceps Hamstrings Wrist flexion Flexor carpi radialis Extensor carpi radialis Dorsi flexion Tibialis anterior Gastrocnemius Trunk flexion Rectus abdominis Erector spinae group Hip flexion Iliopsoas Gluteus maximus

12 Origin, Insertion, and Function Origin: v Proximal attachment Where muscle attaches to the least moveable area of the bones of the axial skeleton Insertion: v Distal attachment Function: Where muscle attaches to the bone that is moved most v Action/motion What the muscle does when activated Origin Insertion

13 Types of Muscle Contraction Concentric: v Muscle fibres shorten Eccentric: v Muscle fibres lengthen Isometric: v Muscle fibres do not change in length

14 Muscle Contraction During Exercise Isotonic exercise v Controlled shortening and lengthening of the muscle Isometric exercise v No motion muscle fibres maintain a constant length throughout contraction Isokinetic exercise v Use machines to control speed of contractions v Combines best features of both isotonic and isometric training istockphoto.com/ Max Delson

15 The Sliding Filament Theory Summary of Sliding Filament Theory v Message release from the brain to contract muscle in central nervous system v Message then travels down spinal cord (223 mph, 100 m/s) go to peripheral nervous system more proximal to contracting muscle v Message then travels down axon branch to axon terminal where message is carried through to axon terminal v Message is carried via acetylcholine (Ach) to sarcolemma down the T tubules adjacent to the sarcoplasmic reticulum (SR) (light weight few axon stimulate, heavier weight more axons are stimulated) v Ach causes sarcoplasmic reticulum (SR) to release calcium ions (Ca+) v Ca+ ions find their way to troponin which is on actin s tropomyosin and exposes binding sites for myosin s head, where they bind to the actin v ATP (adenosine triphosphate) broken down by ATPase (enzyme) to ADP and an inorganic phosphate producing energy and causing a power stroke and muscular contraction (the sliding or overlap of the actin and myosin filaments) v Causes sarcomere to contract (muscle contraction) v When the brain tells the muscles to stop contracting the T-tubules pump the Ca+ out and the tropomyosin returns to original position and covers the binding sites for the myosin on the actin filament and the muscle will return resting state v Known as the sliding filament theory

16 The Sliding Filament Theory Myosin crossbridges (small bridges on the thick filaments that extend to the thin filaments): v Attach, rotate, detach, and reattach in rapid succession v Results in the sliding or overlap of the actin and myosin filaments v Causes sarcomere to contract (muscle contraction) v Known as the sliding filament theory

17 The Role of Adenosine Triphosphate The sliding filament theory at the molecular level: v Nerve impulse transmitted through the muscle fibre and releases calcium ions Calcium (in presence of troponin and tropomyosin) facilitates the interaction of myosin and actin molecules v Adenosine triphosphate (ATP) is the energy source behind the release of calcium ATP detaches myosin from the actin molecule ATP must be replaced through food metabolism for process to continue

18 The Sliding Filament Theory Myosin crossbridges (small bridges on the thick filaments that extend to the thin filaments)

19 The Sliding Filament Theory Myosin crossbridges v Attach, rotate, detach, and re-attach in rapid succession

20 The Sliding Filament Theory Myosin crossbridges v Results in the sliding or overlap of the actin and myosin filaments v Causes sarcomere to contract (muscle contraction)

21 The Role of Calcium Sarcolemma Outer vessicle of sarcoplasmic reticulum (Terminal cisternae) Longitudinal tubules of sarcoplasmic reticulum Transverse tubule (T-tubule) Triad Terminal cisternae Transverse tubule Terminal cisternae H zone A band Z line I band Myofibrils

22 Muscle Fibre Responses to Training Hypertrophy defined as muscle growth in response to overloading principle Two types of hypertrophy Transient hypertrophy (edema or blood causing pump Chronic Hypertrophy Muscle size increased due to increased capillary density Muscle size increased due to increased muscle proteins Muscle size increased due to increased storage capacity for glucose, glycogen, ATP and CP (creatine-phospahte) Hyperplasia fibre splitting (formation of 2 daughter cells to date only proven in animals Muscle Atrophy Occurs when not exercise and muscle shrinks in size Under use or disease

23 The Anatomy of Skeletal Muscle how calcium and the sliding filament theory works v=2nptiynunre Perimysium Muscle fibre v=f0mdfp7qn1y&feature=fvwrel v=1lywojk4cce Epimysium Endomysium Muscle belly Tendon

24 Anterior Muscles

25 Posterior Muscles

26 Muscles of the Neck Semispinalis capitis Splenius Sternocleidomastoid Scalenus medius Scalenus anterior

27 Muscles of the Vertebral Column Nuchal line Occipital bone Mastoid process Spinalis Longissimus Iliocostalis Erector spinae group

28 Muscles of Respiration Internal thoracic artery and vein Sternum Internal intercostals Transversus thoracis Diaphragm (thoracic) Transversus abdominis

29 Muscles of the Abdomen Rectus abdominis External oblique Quadratus lumborum (deep)

30 Muscles of the Shoulder Clavicular head of pectoralis major Sterncostal head of pectoralis major

31 Muscles of the Shoulder cont d Supraspinatus Infraspinatus Infraspinatus Latissimus dorsi

32 Muscles of the Rotator Cuff Supraspinatus Teres minor Infraspinatus

33 Muscles of the Rotator Cuff cont d Subscapularis

34 Muscles that Act on the Scapula Trapezius Teres major Levator scapulae Rhomboid minor Rhomboid major

35 Muscles that Act on the Scapula cont d Teres major

36 Muscles that Move the Humerus Deltoid (anterior and lateral heads) Coracobrachialis

37 Muscles that Move the Humerus cont d Coracobrachialis Pectoralis minor Serratus anterior

38 Elbow Flexors / Extensors Anterior Biceps brachii Brachialis Pronator teres Brachioradialis

39 Elbow Flexors / Extensors Posterior Triceps brachii (short head) Triceps brachii (long head)

40 Muscles of the Forearm Anterior Biceps brachii Pronator teres Brachioradialis Pronator quadratus (deep)

41 Muscles of the Forearm Posterior Brachioradialis Triceps brachii (lateral head) Anconeus

42 Muscles of the Forearm Posterior (deep) Supinator

43 Extrinsic Hand Muscles Anterior Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Flexor digitorum superficialis

44 Extrinsic Hand Muscles Posterior Extensor carpi radialis longus Extensor digitorum Extensor carpi ulnaris Extensor carpi radialis brevis Extensor digit minimi

45 Intrinsic Hand Muscles Thenar eminence Hypothenar eminence

46 Muscles of the Hip Anterior Psoas minor Psoas major Iliacus Tensor fasciae latae Sartorius Rectus femoris Iliotibial tract (band) Iliopsoas Pectineus Gracilis

47 Muscles of the Hip Posterior Gluteus medius Gluteus maximus (cut) Gluteus minimus Gracilis

48 Muscles of the Hip Anterior (adductors) Pectineus (cut) Adductor brevis Adductor group Adductor longus Adductor magnus

49 Muscles of the Thigh Anterior Rectus femoris Vastus intermedius (underneath) Quadriceps femoris group Vastus lateralis Vastus medialis

50 Muscles of the Thigh Posterior Semitendinosus Biceps femoris Hamstring muscle group Semimembranosus

51 Extrinsic Foot Muscles Anterior Extensor digitorum longus Tibialis anterior Extensor hallucis longus

52 Extrinsic Foot Muscles Posterior Gastrocnemius (medial and lateral heads) Soleus Calcaneal tendon (Achilles tendon)

53 Extrinsic Foot Muscles Posterior (deep) Popliteus Tibialis posterior Flexor digitorum longus Fibularis (Peroneus) longus Flexor hallucis longus Fibularis (Peroneus) brevis

54 Intrinsic Foot Muscles Superficial Flexor digitorum brevis

55 Intrinsic Foot Muscles Intermediate Quadratus plantae

56 Intrinsic Foot Muscles Deep Flexor hallucis brevis

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