Unit 5: Muscular system

What Students Should Know

(DCI)Focus: LS1.A: Structure and Function & LS1.C: Organization for Matter and Energy Flow.

Hierarchical Complexity (HS-LS1-2): How the muscular system is an integrated hierarchy of cells (myocytes), tissues (fascicles), and organs (skeletal muscles) that work together to provide movement.

The Mechanism of Contraction (HS-LS1-1): How DNA provides the instructions for building the proteins (actin/myosin) that govern muscle behavior.

Bioenergetics (HS-LS1-7): The cellular processes that transform food (glucose) into the chemical energy (ATP) needed for the mechanical work of contraction.

Thermoregulation (HS-LS1-3): How involuntary muscle contractions (shivering) act as a feedback mechanism to maintain a constant internal body temperature.

Focus: Developing models and conducting investigations.

Modeling Systems (HS-LS1-2): Create a physical or conceptual model of the sarcomere to illustrate how microscopic changes result in macroscopic movement.

Planning Investigations (HS-LS1-3): Design a controlled experiment to collect data on muscle fatigue, identifying how the body attempts to maintain homeostasis under high-stress conditions.

Mathematical Thinking (HS-LS1-4): Use ratios and scale to calculate the force production of different muscle groups based on cross-sectional area and lever arm length.

Scientific Argumentation (HS-LS1-1): Construct an evidence-based argument for how a specific genetic mutation (e.g., in the dystrophin gene) leads to a total system failure.

Focus: Performance Expectations and Evidence Statements.

• The "Homeostasis Challenge" (PE HS-LS1-3): Students must provide data-driven evidence (heart rate, respiration, and muscle force) to explain how the muscular system interacts with the circulatory system during exercise.

• Structure-Function Portfolio (PE HS-LS1-2): A collection of lab analyses (including a dissection or 3D simulation) that identifies how the shape and attachment of a muscle (e.g., the deltoid) dictate its range of motion.

• Molecular Explanation Paper (PE HS-LS1-1): A technical writing piece explaining how the hierarchical structure of a muscle fiber is a direct result of specialized protein synthesis.

• Energy Flow Analysis (PE HS-LS1-7): A group presentation modeling the "life of an $ATP$ molecule" within a muscle cell, from its creation in the mitochondria to its use in a single muscle twitch.