PS 1001:03 Lecture Notes - Lecture 7: Myocyte, Skeletal Muscle, Sarcomere
Describe the muscle tissue system
Types of muscle tissue
Skeletal
Moves parts of skeleton
Voluntary
Cardiac
Makes up heart
Voluntary
Smooth
Walls of hollow structures e.g. blood vessels, intestines
Understand and describe the fibre effects of fibre arrangement,
muscle size, fibre type, rate of contraction, age and gender on
muscle tension
Thick - myosin (head and tail)
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Thin - actin, troponin (proteins, blocking active sites), tropomyosin (stiffening)
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Covered by SR
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Sarcomere - unit of contraction
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Muscle belly with fibrous tendons at each end
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Skeletal muscle structure
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Myofibrils > sarcomere
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Factors that influence ability to produce motion
L2 - Mechanical properties of muscle
Tuesday, 13 March 2018
1:36 PM
Week 4 Page 1
Shape and soft tissue
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Passive ROM
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Fibre length
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Length of muscle's moment arm
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Active ROM
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Factors that influence ability to produce motion
Increase in sarcomeres = increase in shortening
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Parallel (longer fibres, so can shorten more) vs pennate
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Parallel fibres would produce larger joint excursion (if fibre length alone affected joint
ROM) BUT also depends length of movement arm
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Affected by muscle structure
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Fibre length effect on joint ROM
Force produces moment/torque
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Moment = Force x moment arm (F x d)
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Strength = force of a muscle
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Muscle size
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Muscle moment arm
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Stretch of muscle
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Contraction of velocity
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Fibre types
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Level of muscle fibre recruitment
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Factors
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Type of muscle fibre arrangement
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Size of muscle ie. No. of fibres
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Type of fibres recruited - type 1, type 2…
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Type of muscle contraction - concentric, eccentric, isometric
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Length tension factors
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Speed of contraction/rate of shortening
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Age and gender of person
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Neuromuscular control factors - #motor units recruited and frequency of firing of motor
units
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Amount of active tension/force sksletal muscle can develop depends on
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Factors that influence muscle strength
Fascicle arrangement of muscle
Week 4 Page 2
Document Summary
Smooth walls of hollow structures e. g. blood vessels, intestines. Understand and describe the fibre effects of fibre arrangement, muscle size, fibre type, rate of contraction, age and gender on muscle tension. Thin - actin, troponin (proteins, blocking active sites), tropomyosin (stiffening) Muscle belly with fibrous tendons at each end. Parallel (longer fibres, so can shorten more) vs pennate. Parallel fibres would produce larger joint excursion (if fibre length alone affected joint. Rom) but also depends length of movement arm. Moment = force x moment arm (f x d) Amount of active tension/force sksletal muscle can develop depends on. Type of fibres recruited - type (cid:1005), type (cid:1006) . Type of muscle contraction - concentric, eccentric, isometric. Neuromuscular control factors - #motor units recruited and frequency of firing of motor units. Fasciculi of parallel muscles approx parallel to line of pull of muscle. All shortening converted into movement, parallel muscle -> larger rom.
