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A new approach to learning

Let curiosity take root.

Follow questions deeper without losing the thread.
Turn what you learn into connected notes, flashcards, and quizzes.

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01 / EXPLORE

Follow your curiosity.

Start with a question and keep asking why. Drill down to the first principles, with every follow-up and tangent connected so you can always find your way back.

Follow-upGo deeper into the reasoning behind an answer.

TangentFollow a related idea and see where it fits.

ROOT QUESTIONThe starting question

Why did the Roman Republic fall?

Political rivalries, civil wars, and the concentration of military power weakened republican government. Each opens another question to explore.

Select a question to read its answer.

02 / MIND MAP

History / First principles4 supporting concepts · 1 demonstrated · 1 gap
TARGET CONCEPT

Fall of the Roman Republic

4 concepts underneath

Select a concept to see the evidence behind its state.

See the ideas
underneath.

Drill down to the first principles. Arbor maps the concepts a topic rests on and connects them to evidence from your work.

Learning states. See what you’ve encountered, practiced, and demonstrated.

Gaps. Find what needs more attention and a question to explore next.

A sunlit, ivy-covered arch opening onto a lake.
A learning journey that stays connected

Every question is a branch.
Keep the whole tree.

Room to wander. A way back.

Your follow-ups, tangents, and sources stay connected. Explore a new direction and keep the reasoning that brought you there.

Explore the canvas
Hover or tap to explore

03 / ORGANIZE

How does a heartbeat begin?
Bird’s Eye ViewElectrical signals coordinate the heartbeat, moving from the atria to the ventricles so the chambers pump in sequence.
Major TermsSA node, AV node, atria, ventricles, cardiac conduction
Timing the heartbeat
  • The AV node briefly slows the electrical signal, giving the ventricles time to finish filling before they contract.
What is the AV node?
  • A group of specialized cells that conducts electrical signals from the atria toward the ventricles.
Why do the ventricles need time to fill?
  • It allows the atria to finish moving blood into the ventricles before ventricular contraction.
How does the signal reach the ventricles?
  • The signal travels through the His–Purkinje system to activate the ventricles.
Why do the atria contract first?
  • Atrial contraction moves blood into the ventricles before the ventricles pump it onward.
What are the atria and ventricles?
  • The atria are the two upper chambers that receive blood. The ventricles are the two lower chambers that pump blood out.
Where does blood go from the ventricles?
  • The right ventricle pumps toward the lungs; the left pumps toward the body.
What keeps blood moving in one direction?
  • Heart valves open and close as pressure changes, helping prevent backward flow.
FROM YOUR CANVAS
Why does the signal slow at the AV node?
  • The delay helps coordinate atrial and ventricular contraction.
Where the signal begins
  • Pacemaker cells in the sinoatrial (SA) node initiate the electrical signal in the right atrium.
What does “pacemaker” mean?
  • A source of regular electrical impulses that sets the pace of the heartbeat.
How does the signal reach the atria?
  • Electrical activity spreads from cell to cell through the atrial muscle.
How do neighboring cells pass the signal?
  • Gap junctions let electrical current pass between neighboring heart muscle cells.
FROM YOUR CANVAS
What starts a normal heartbeat?
  • The SA node normally sets the heart’s rhythm.
From signal to contraction
  • The signal spreads through the atria, passes through the AV node, and continues through the ventricles, coordinating their contraction.
How does calcium help muscle fibers contract?
  • Calcium allows the contractile proteins to interact and generate force.
How does the muscle relax again?
  • Calcium is removed from the cell’s cytoplasm, allowing the muscle to relax.
FROM YOUR CANVAS
How does an electrical signal make the heart contract?
  • Electrical activation triggers a rise in calcium inside heart muscle cells.
Example reading: How the heart beats · NHLBI ↗

Keep what you learned.

Arbor turns your exploration into organized notes. Keep the ideas together and revisit the questions behind them.

Traceable. See the canvas questions connected to a note.

Portable. Export a study guide as PDF or Markdown, or choose import-ready files for Notion and Google Docs.

Export study guide

Explore the formats available for your cardiology notes.

FORMAT

Preview only. Export your notes in any of these formats from Arbor.

04 / PRACTICE

Remember it.
Find the gaps.

Your notes become material for recall practice. Quizzes and written answers help you find what needs another look.

Review. Your recall ratings shape when saved notes return. Export your deck to Anki anytime.

Explain it. Written answers are checked against key concepts and your sources.

Quiz. Practice with multiple choice and short answers, with feedback after each answer.

History / ReviewThe late Republic
3 of 6
How well did you know it?

Example intervals. Reveal the answer to rate your recall.

Example session. In Arbor, written feedback is graded against your sources.

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