Week 7 - Muscles and muscular hydrostats
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## Sliding filament theory 滑動絲理論
- Activation of a motor unit creates a chemical reaction that causes muscles to contract
- <span class="highlight2">Actin</span> 肌動蛋白（細絲）
- Thin myofilaments
- Attached to Z-line
- <span class="highlight2">Myosin</span> 肌球蛋白（粗絲）
- Thick myofilaments
- Attached to M-line
- <span class="highlight1">Sacromere</span> 肌小節
- The basic contractile unit
- <span class="highlight1">z-disks</span> 分隔肌小節的構造 / Z線
- The boundaries between a sarcromere

<!-- Sliding filament theory graph -->
<img src="https://hackmd.io/_uploads/HkIIfcQG6.png" alt="Sliding filament theory">

## Muscular hydrostats 肌肉靜水器
- Muscles like elephant trunks, animal tongues, and octopus tentacles are <span class="highlight1">muscular hydrostats</span>
- They lack typical systems of skeletal support
- Their volume is **constant**, like a water baloon

<img src="https://hackmd.io/_uploads/H1SGw9XfT.png" alt="hydrostat">