The Muscular System
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The Anatomy of Muscles: Structure and Function
1. Elasticity of Muscles
Muscles are elastic, capable of stretching and returning to their original length, similar to an elastic band. However, overstretching can lead to muscle tears.
2. Muscle Contraction and Movement
Muscles contract, bringing muscle ends closer together. These contractions result in movements of tendons and bones, facilitating locomotion and various body actions.
2.1 Response to Stimuli
The contraction and relaxation of skeletal muscles respond to stimuli, including neurotransmitters, hormones, and pH level changes.
3. Energy Expenditure and Heat Generation
Muscles can exert substantial force in short bursts or sustain force over prolonged periods due to their ability to adjust energy use as needed. Muscle activity generates heat, which is efficiently distributed throughout the body thanks to the rich blood supply within skeletal muscles.
3.1 Vascularity of Muscles
Muscles are vascular, indicating they possess a robust blood supply to support their functions.
4. Diversity of Skeletal Muscles
The human body contains numerous skeletal muscles, allowing for a wide range of movements through the controlled contraction and relaxation of voluntary muscle fibers.
4.1 Muscle Composition
Skeletal muscles consist of approximately 70% water, 23% proteins (actin and myosin), and minerals like calcium, potassium, phosphorus. Additionally, substances such as glycogen, glucose, and fatty acids make up the remaining 7%.
5. Connective Tissue and Tendons
Connective tissue is present throughout various muscle parts, forming tendons that attach muscles to bones. Tendons are strong, inelastic, and strap-like structures, providing essential connections between muscles and skeletal structures.
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