Exercise Sciences Flashcards
What are the major muscle groups? (12) Where are they located? (origin and insertion (ANATOMY BOOK)
Forearms Biceps Triceps Shoulders Quadriceps Hamstrings Calves Abdominals Chest Trapezius - neck, upper back Latissimus Dorsi - mid, low back Glutes
Major Muscles - Anterior (15) (O and I)
Deltoid Pectoralis Major Biceps Brachii Rectus Abdominis Brachialis External Oblique Brachioradialis Finger flexors (FIND) Adductor Longus Gracilis Sartorius Rectus Femoris Vastus Lateralis Vastus Medialis Tibialis Anterior
Major Muscles - Posterior (12) (O and I)
Trapezius Infraspinatus Teres Major Triceps Brachii Latissimus Dorsi Finger Extensors (FIND) Gluteus Maximus Semitendinosus Biceps Brachii Semimebranosus Gastrocnemius Soleus
Describe muscle organization from smallest to largest functional unit (???????????)
Myofilaments (actin, myosin) Myofibril Sarcoplasm Sarcolemma Endomysium (between fibers) Fasciculi Perimysium Muscle Fibers Epimysium
Components of the contractile unit
Motor neuron Neuromuscular junction Motor unit Sarcoplasm Myofibrils Myofilament (action and myosin)
Process of Sliding Filament Theory of muscle action (4)
1) States that actin filaments at each end of sacromere slide inward on myosin filaments, pulling Z-lines toward center of sacromere, thus shortening the muscle fiber.
2) As actin slides over myosin, both H-zone and I-band shrink.
3) The action of myosin cross-bridges pulling on actin is responsible for movement of actin.
4) B/c of very small displacement of action w/ each flexion of of myosin cross-bridge, very rapid, repeated flexions must occur in many cross-bridges throughout entire muscle for measurable movement to occur.
What are the different types of muscle actions? (3)
Concentric
Eccentric
Isometric
Discuss the difference in force production based on muscle action
https://www.youtube.com/watch?v=ERWQXiuwCFc
Concentric: as velocity increases, force decreases.
Eccentric: as velocity increases, force produced increases until plateau (doesn’t decrease).
Isometric: velocity is 0 b/c joint does not move, thus there is 0 force
you can lower more weighed eccentrically than you can push during concentric contraction.
What factors affect the production of force within a muscle? (9) pages 30-33
Neural Control Muscle Cross-Sectional Area Arrangement of Muscle Fibers Muscle Length Joint Angle Muscle Contraction Velocity Joint Angular Velocity Strength-to-Mass Ratio Body Size
Motor Unit
A motor neuron and the muscle fibers it innervates.
All muscle fibers of a motor unit contract together when they’re stimulated by the motor neuron.
Typically several hundred muscle fibers per motor unit.
Motor Unit structure
Nucleus Dendrites Axon Nodes of Ranvier Myelin Sheath NMJ on muscle
Motor Unit and Muscle Activation
when a motor neuron fires an impulse or AP, all fibers it innervates are simultaneously activated and develop force.
Motor units and precision movements
ex. eye muscles
The extent of control of a muscle depends on the number of muscle fibers within each motor unit.
Muscle req. greater precision can have motor units w/ as few as 1 muscle fiber per unit.
Changes in number of active motor units in small muscles can produce the extremely fine gradations in force that are necessary for precise movements of the eyeball.
Motor units and less precise movements
ex. quad muscles
may have several hundred fibers served by one motor neuron.
Motor unit abnormailities
weakness or loss of contraction strength of the muscle.
can result in muscle:
Atrophy
Fasciculations (involuntary twitches)
Hypotonia (decrease in tone of skeletal tone)
Hyporeflexia (decreased muscle stretch reflexes; rapid stretching)
