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The unit of contraction

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Presentation on theme: "The unit of contraction"— Presentation transcript:

1 The unit of contraction
Anatomy of muscles The unit of contraction

2 Vocabulary of muscle fiber
Periosteum Tendon Deep fascia (epimysium) Skeletal muscle Perimysium Endomysium Sarcoplasm Myofibril Aponeurosis

3 Vocabulary of muscle Rectus Transverse Oblique Maximus Medius Minimus
Longus Brevis Latissimus Longissimus Magnus Major Minor Deltoid- Serratus- Rhomboid- Quadratus- Flexor/Extensor Abductor/adductor Insertion/Origin

4 Info on muscle fibers Myofibrils: Myofilament: Myosin: Actin:
Hundreds to thousands of myofibril (1/100 the diameter of a hair) are in a single sarcoplasm. Myofilament: Contains the apparatus that contracts the muscle cell Myosin and Actin Myosin: Thick filaments 16 nm in diameter (1/10,000 the diameter of hair) Actin: Thin filaments 6nm in diameter

5 Interior structure of muscle fiber
Sarcoplasm: The cytoplasm of muscle fiber Contains contractile components Protein filaments Glycogen Fat particle Enzymes Specialized organelles as mitochondria (produces enzymes for metabolic conversion of food to energy)

6 Types of muscle Smooth: Cardiac: Striated: Intestines, arteries, veins
Heart Striated: Skeletal muscle

7 Fiber types Slow Twitch (Type I): Fast Twitch (Type II):
Resist fatigue Large number of mitochondria High aerobic enzyme activity Fast Twitch (Type II): Type IIa: Oxidative glycolytic, some of the fatique resistance properties More mitochondria, greater aerobic enzyme activity Type IIb: Fast glycolytic Fatigues rapidly Few mitochondria and low aerobic enzyme activity

8 Types of muscle action Concentric muscle action
Muscle shortens with a contraction Eccentric muscle action Muscle lengthens with a contraction Sometimes refers to a negative lift.

9 Agonist vs antagonist Agonist muscles: Antagonist muscles: Example:
Muscle directly engaged in contraction as related to muscles that relax at the same time Antagonist muscles: Muscle that counteract the action of the agonist muscles Example: Contraction of the bicep= agonist Counteract of the bicep=triceps=antagonist

10 Origin and insertions of muscles
Ankle: Anterior compartment Tibialis anterior O=lateral tibial condyle and proximal 2/3 of tiba I= first cuneiform and 1st metatarsal A=dorsiflex and inversion Extensor hallucis longus O=middle fibula anterior I= distal phalanx of great toe A= extends great toe and dorsiflex/inversion

11 Origin and insertions of muscles
Ankle: Anterior compartment Extensor digitorum longus O= lateral condyle of tibia I= 2nd-5th phalanges A= extends toes and dorsiflex/eversion Peroneus tertius O= distal 1/3rd of fibula I= 5th metatarsal A= dorsiflex/eversion

12 Origin and insertions of muscles
Ankle: Lateral compartment Peroneus longus O= proximal 2/3rd of fibula I= 1st metatarsal and medial cuneiform A= plantarflexion/eversion Peroneus brevis O= distal 2/3rd of fibula I= 5th metatarsal

13 Origin and insertions of muscles
Ankle: Posterior compartment Gastrocnemius O= med/lat. Femoral condyles I= calcaneus with achilles tendon A= flexes lower leg and plantarflexion Soleus O= Proximal 1/3rd of fibula and middle 1/3rd of tibia A= plantarflexion of foot

14 Origin and insertions of muscles
Ankle: Posterior compartment Popliteus O= lateral femoral condyle I= proximal tibia A= flexes leg Flexor hallucis longus O= lower 2/3rd of fibula I= great toe A= flexes great toe/plantarflexion/inversion Flexor digitorum longus O= posterior tibia I= 2nd-5th toes A= flexes toes/plantarflexion/inversion Tibialis posterior O= posterior tibia/fibula I= navicula/cuneiforms/cuboid/2nd-4th metatarsal A=plantarflexion/inversion

15 Origin and insertions of muscles
Knee- flexion Biceps femoris O= Ischial tuberosity I= head of fibula A= knee flexion and some hip extension Semitendinosus/semimembranosus O= ischial tuberosity I= proximal posterior medial tibial condyle

16 Origin and insertions of muscles
Knee- extension/ Rectus femoris-hip flexion O= Anterior inferior spine of ilium I= base of patella Vastus intermedius O= anterior proximal 2/3 of femur Vastus medialis O= medial proximal femur I= medial border of patella Vastus lateralis O= Greater trochanter I= lateral border of patella

17 Origin and insertions of muscles gluteal region
Psoas major/minor O= Transvers processes lumbar vertebrae I= lesser trochanter of femur A= flexes hip Gluteus maximus O=ilium/sacrum/coccyx I= Gluteal tuberosity of femur A= extends and external rotates hip Sartorius O= Anterior superior spine of ilium I= anteromedial surface of tibial shaft next to tibial tuberosity A= hip flexion, abduction and lateral rotation with knee flexion

18 Origin and insertions of muscles gluteal region
Gluteus Medius O= ilium I= greater trochanter A= abducts and internal rotates hip Gluteus minimus I=greater trochanter Piriformis O=anterior surface of sacrum A= external rotation of hip

19 Origin and insertions of muscles thigh region
Pectineus O: pubis I: inferior to lesser trochanter A: adducts the hip Gracilis I: medial femoral condyle Adductor Magnus O: pubis I: medial femur A: adducts the hip Adductor Longus Adductor Brevis I: medial femur proximal 1/3

20 Origin and insertions of muscles shoulder region
Serratus anterior O= outer surfaces of 8-9 ribs I= superior angle and medial border of scapula A= scapular abduction and upward rotation Trapezius O= occiptal protuberance,spinous process of 7th cervical and T1-12 vertebrae I= acromion process, clavicle, spine of scapula A= shoulder adduction and elevation Levator scapula O= C1-4 vertebrae I= superior angle of scapula A= elevation of scapula

21 Origin and insertions of muscles shoulder region
Rhomboid major/minor O= spinous process of C7-T5 I= medial border of scapula A= scapula protraction Latissimus dorsi O= T6-L5 and some of sacrum I= posterior medial portion of humerus A= shoulder adduction and extension

22 Origin and insertions of muscles shoulder region
Supraspinatus O= supraspinatus fossa I= greater tubercle of humerus-lateral surface A= initiates abduction Infraspinatus O= infraspinatus fossa I= posterior surface of greater tubercle of humerus A= external rotation Teres Minor O= lateral border of scapula

23 Origin and insertions of muscles shoulder region
Subscapularis O= subscapularis fossa I= anterior surface of humerus lesser tubercle A= internal rotation and some adduction Teres Major O= inferior angle of scapula Pectoralis Major O= sternum and some of clavicle I= greater tubercle of humerus A= horizontal adduction

24 Origin and insertions of muscles shoulder region
Deltoid O=distal clavicle, acromion process, spine of scapula I= deltoid protuberance A= shoulder abduction Biceps brachii O= short head=coracoid process, long head posterior glenoid fossa I= proximal radius A= elbow flexion Tricep brachii O= superior lateral border of scapula and proximal posterior of humerus I= olecranon A= elbow extension

25 Origin and insertions of muscles wrist and forearm
Flexor carpi radialis O= medial epicondyle I= base of 2nd and 3rd metacarpal A= flexes the wrist Flexor carpi ulnaris I= pisiform/hamate/5th metacarpal A= flexes wrist

26 Origin and insertions of muscles wrist and forearm
Extensor Carpi radialis O= lateral epicondyle I= base of 3rd metacarpal A= extends the wrist Extensor Carpi unlaris I= base of 5th metacarpal Palmaris Longus O= medial epicondyle I= palmar aponeurosis in palm A= flexes wrist

27 Origin and insertions of muscles wrist and forearm
Flexor digitorum superficialis/profundus O=medial epicondyle I= superficialis: middle phalanx profundus: distal phalanx A= flexes phanlanges and some wrist Extensor digitorum communis/digiti minimi O=later epicondyle and digiti attaching to communis I= dorsal surface of 2nd-5th phalanges/digiti to 5th only A= extends phalanges and digiti to 5th only Extensor indicis O= ulna I= tendon of extensor digitorum communis to the index finger A= extends 2nd phalange

28 Origin and insertions of muscles thumb
Flexor pollicis longus O= radius I= distal phalanx of thumb A= flexes thumb Extensor pollicis longus/brevis O= ulna: longus & radius: brevis I= distal phalanx of thumb: longus base of 1st phalanx of thumb: brevis A= extends thumb Abductor pollicis longus O= radius/ulna I= base of 1st metacarpal A= abducts thumb


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