KINE 2P97 Lecture Notes - Lecture 12: Endomysium, Delayed Onset Muscle Soreness, Troponin
8 May 2018
School
Department
Course
Professor
KINE 2P97
Muscle Physiology & Exercise Metabolism
Muscle
- Ancient tissue
- Thermogenesis
- Adaptable (plasticity)
- Low energy requirement at rest
Connective tissue Review
- Epimysium – surrounds entire muscle
- Perimysium – divides muscle into fascicles
- Endomysium – surrounds individual muscle fibers
- Tendon – attaches muscle to bone
Muscle Fibre
- Muscle fibre is a cell
- Muscle fibres are arranged in parallel to each other to form skeletal muscle
- In series (on top of each other)
- In parallel (beside each other)
- Multinucleated
Basal Lamina
- Extracellular membrane that holds everything in place
o When the muscle changes length, it keeps it contained
- Part of the extra-cellular matrix
- Close to and linked to sarcolemma
- Mostly protein and glycoprotein
- Collagen and laminin
Satellite cells
- Normal myofibre, eccentrically located myonucleus
- Regenerating myofibre, centrally located myonucleus
- Quiescent – inactive
- Two paths: micro tears due to exercise, regenerating a whole muscle fibre
- Nucleus sends out gene signals
- Simultaneous contraction of muscle fibres
Mitochondria
- Contains its own DNA
- Localization: sub sarcolemma – underneath, intermyofibrillar – in between
- Dark areas in fibres mitochondria
- Reticulum – filamentous bunches between myofibrils
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Document Summary
Muscle fibres are arranged in parallel to each other to form skeletal muscle. Extracellular membrane that holds everything in place: when the muscle changes length, it keeps it contained. Two paths: micro tears due to exercise, regenerating a whole muscle fibre. Localization: sub sarcolemma underneath, intermyofibrillar in between. Contains sarcomeres in series and in parallel. Actin and myosin force generating machinery of the cell. Different isoforms of myosin result in different speeds of contraction (rate of myosin. Myosin heavy chain fast from slow: the rate at which the myosin head breaks down atp, has binded and is ready to produce force. Each molecule has a active site that the myosin head can bind to. Thin filament also has a troponin and tropomyosin. 2 actin chains are a thin filament. Tropomyosin long thin protein, covers myosin binding sites. Troponin controls tropomyosin position, ca2+ binding site: regulatory signal for contraction. Can be referred to as scaffold proteins.
