Brain DeCoded with CodeX - Mission 5, Objective 1: Motor Neurons

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Overview

Mission 5 is about movement, and this objective is the on-ramp. There is no code to write here. It is reading material, and it sets up the action potentials, timing, and rhythms students work with for the rest of the mission.

Students follow one signal on its whole trip. The brain sends an order, a motor neuron carries it as an action potential, and the signal hands off at the neuromuscular junction, where a synaptic transmission triggers the muscle to contract. Thinking about lifting your arm and actually lifting it are two ends of the same pathway.

Students finish with a written response reflection and an exit ticket where they recreate the motor neuron diagram from memory. They create a file in CodeSpace for that written response.

🎯 Project Goal: Students explain how the brain interacts with muscles.

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Learning Targets

I can explain what a motor neuron does.
I can explain how action potentials work.

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Key Concepts

The brain talks to muscles using motor neurons.
Signals that travel through motor neurons are called action potentials.
When the action potential arrives at the neuromuscular junction, it triggers a synaptic transmission and a contraction happens.

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Assessment Opportunities

Exit ticket: recreate the motor neuron diagram.
Written response reflection.

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Success Criteria

Summarize the motor neuron diagram
Complete the written response reflection
Create the written response file in CodeSpace

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Extensions & Cross-Curricular

ExtensionUse supplemental materials to go more in-depth about motor neurons.

ExtensionHave students create a video, web page, poster, or slide deck about motor neurons and present it to an audience.

Lang ArtsStudents write a summary of a topic covered in this objective.

Visual ArtsStudents create an art project or a 3D model of a motor neuron.

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Classroom Materials

▸Laptop/computer with Chrome browser, so students can create the written response file in CodeSpace
▸Optional: supplemental materials about motor neurons, such as articles, videos, or diagrams
▸Optional: modeling supplies for the visual arts extension, such as clay, pipe cleaners, or poster board

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Vocabulary

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Motor neuron - Special nerve cells that carry orders from the brain or spinal cord directly to your muscles.

Action potentials - Electrical impulses, or signals, generated by the brain and transmitted by motor neurons.

Neuromuscular junction - The meeting point between a muscle and a motor neuron where the action potentials are transmitted.

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Standards

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Physical Science

HS-LS1-2 LS1.A

Science & Engineering Practices

Developing and Using Models

Crosscutting Concepts

Systems and System Models

English Language Arts & Literacy

RST.11-12.1 RST.11-12.2

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Preparing for the Lesson

Read the objective through first so you know where the motor neuron diagram sits. That diagram is the exit ticket, so plan to spend real time on it rather than scrolling past.
Decide how students will read: silently, in pairs, or as a class read-aloud. The reading moves faster when it is broken up with discussion.
Decide how students will submit the written response. They still need to create the file in CodeSpace to meet the goal, even if the writing itself happens somewhere else.
Pull together any supplemental materials you want to add. Nothing extra is required, but this is a natural place for a short video on how nerves signal muscles.
Have blank paper or a whiteboard ready for the diagram recreation. Students remember the pathway better after drawing it once themselves.

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Teacher Notes

This objective is reading material for students. Feel free to supplement with any additional materials.
Students are asked to create a file in CodeSpace for their written response. Students can complete the response a different way, but they still need to create the file to meet the goal.
There is no code in this objective. Students only need a computer to reach CodeSpace.
Watch for students who use "motor neuron" and "action potential" as if they mean the same thing. The neuron is the wire, the action potential is the signal moving through it, and the rest of the mission depends on that distinction.
Extensions and cross-curricular projects are included to enhance the concepts in the objective. You can use the extensions to extend students' learning.

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Lesson Outline

🗣️Warm-up / Hook

Start with the gap between deciding and moving.

Have everyone raise a hand, then ask: "You decided to do that in your head. How did your arm find out?"
Ask: "How long did the message take to get there, and what do you think it traveled through?"

Teaching tip: Most students guess "the brain told it" and stop there. Push once for the middle of the story. The blank they hit is exactly what the reading fills in.

📖Reading & Discussion

Students work through the objective's reading on motor neurons.

Students read the objective, individually, in pairs, or as a class.
Stop after motor neurons are introduced. Have students say in their own words what the neuron's job is before moving on.
Cover action potentials next. Land the idea that the signal is electrical and that the neuron carries it, rather than being the signal itself.
Finish at the neuromuscular junction. The handoff is where the electrical signal becomes an actual muscle contraction.

Teaching tip: Trace the whole path on the board as you go: brain, motor neuron, junction, muscle. Four labels take a few minutes and give students a frame to hang the vocabulary on.

🔍Diagram Walkthrough

Short bridge activity before the writing.

Put the motor neuron diagram up and have students name each part out loud.
Ask a student to narrate one signal's trip from the brain to the contraction, using the diagram.
Have students sketch the diagram once from memory, then check it against the original and fix what they missed.

Teaching tip: That memory sketch is a free preview of the exit ticket. Whatever most of the room leaves out is what to review before they hand anything in.

💻Written Response

Students create their file in CodeSpace and write the reflection.

Students create the response file in CodeSpace. This is required to meet the goal, even if they draft their answer somewhere else.
Students summarize the motor neuron diagram in their own words.
Students explain what an action potential is and what happens when it reaches the neuromuscular junction.
Circulate and check that responses describe the full pathway, not just a list of the three vocabulary terms.

Teaching tip: Ask for the summary in order, brain to muscle. Students who can sequence it have understood the system, and sequencing is harder to fake than naming parts.

✏️Wrap-up & Exit Ticket

Close on the pathway.

Exit ticket: each student recreates the motor neuron diagram with the parts labeled.
Ask: "Which part of this trip do you think takes the longest?" Take a few guesses and leave it open.
Preview the mission: Objective 2 gets into how fast these signals actually move and why a neuron's diameter matters.

Teaching tip: Do not settle that timing question today. Leaving it hanging gives Objective 2 something to answer, and students come back to it on their own.

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