Difference between revisions of "Muscles - Anatomy & Physiology"
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==Skeletal Muscle== | ==Skeletal Muscle== | ||
| + | *Each muscle is composed of multiple '''fascicles''', each of which consists of a bundle of muscle fibers | ||
| + | *Muscle "fiber" means a single cell, which are multi-nucleate, and known as '''syncitia''' | ||
| + | *Within each fiber are groups of parallel, longitudinal myofibrils | ||
| + | **Myofibrils are arranged as '''sarcomeres''', bound by Z-discs | ||
| + | **Each sarcomere contains 2 separate groups of myofilaments: | ||
| + | ***Thin filament, containing '''Actin''', located centrally | ||
| + | ***Thick filament, containing '''Myosin''', originating from either side of each Z-disc | ||
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*Skeletal muscle includes muscles of: | *Skeletal muscle includes muscles of: | ||
**Posture | **Posture | ||
**Movement | **Movement | ||
**Respiration | **Respiration | ||
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*Two basic types of skeletal myofibre: | *Two basic types of skeletal myofibre: | ||
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***High '''glycolytic''' activity | ***High '''glycolytic''' activity | ||
***Function - exercise | ***Function - exercise | ||
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==Tendon== | ==Tendon== | ||
Revision as of 13:18, 21 July 2008
Introduction
Muscular contraction is necessary for voluntary and involuntary movement of limbs, stabilization of joints, maintaining luminal diameter (in the case of arteries, bowel, etc), and to produce heat. Three types of muscle can be described:
- Skeletal (aka Striated, Somatic, Voluntary)
- Smooth (aka Visceral)
- Cardiac
Skeletal Muscle
- Each muscle is composed of multiple fascicles, each of which consists of a bundle of muscle fibers
- Muscle "fiber" means a single cell, which are multi-nucleate, and known as syncitia
- Within each fiber are groups of parallel, longitudinal myofibrils
- Myofibrils are arranged as sarcomeres, bound by Z-discs
- Each sarcomere contains 2 separate groups of myofilaments:
- Thin filament, containing Actin, located centrally
- Thick filament, containing Myosin, originating from either side of each Z-disc
- Skeletal muscle includes muscles of:
- Posture
- Movement
- Respiration
- Two basic types of skeletal myofibre:
- Type I
- Grossly red
- High myoglobin level
- Slow rate of contraction
- High oxidative activity
- Function - postural
- Type II
- Grossly white
- Low myoglobin level
- Fast rate of contraction
- High glycolytic activity
- Function - exercise
- Type I
Tendon
- Consists of dense collagen type 1 fibres and fibroblasts (tenocytes)