Lesson · A.2.3
The muscular system
Learn the three muscle tissue types, the sliding filament mechanism, and how a nerve signal becomes a contraction, the way the HESI A2 tests it.
ObjectiveA.2.3Read5 minExam weightSupport and Movement ≈ 24% of Anatomy & Physiology
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See editions and pricing →What you will be able to do
- Tell skeletal, cardiac, and smooth muscle apart by structure, control, and location
- Walk through the sliding filament model from nerve signal to shortened sarcomere
- Match key muscular system terms, such as origin, insertion, and tendon, to their function
What the lesson concludes
- Skeletal muscle is voluntary and striated; cardiac muscle is involuntary and striated; smooth muscle is involuntary and nonstriated.
- A muscle fibre shortens when myosin heads pull actin filaments toward the centre of the sarcomere, the sliding filament model.
- Calcium released from the sarcoplasmic reticulum moves tropomyosin aside so myosin can bind actin.
- A tendon anchors muscle to bone; the origin stays fixed and the insertion moves when the muscle contracts.
- Skeletal muscle needs a steady ATP supply, so it draws on stored creatine phosphate, glycolysis, and aerobic respiration in that rough order.