Human Heart, 4 Parts

Quick Answer: The 4 part heart model is a human heart model that dismantles into four pieces, giving more views of the interior than a two-part model. It is used in anatomy and nursing teaching to study each chamber, the valves and the internal walls of the heart in detail.

More Parts, More Views of the Interior

With four removable pieces, a heart model can be opened in stages, typically by lifting off the front wall and the upper part containing the atria, so that both atria and both ventricles can be examined separately and the valves seen from above as well as from the side. How the four parts of this model divide should be confirmed, as the split differs between makers.

Seen from above with the atria removed, the four valves lie close together in a fibrous framework, the cardiac skeleton, which anchors the valve rings and electrically insulates the atria from the ventricles. This view explains why the aortic valve is described as sitting at the centre of the heart, and why disease of one valve can affect its neighbours.

Staged dismantling also suits teaching the conduction system in words, even though a model cannot show electrical activity. The sinoatrial node in the wall of the right atrium near the superior vena cava sets the rhythm, the atrioventricular node near the septum delays the signal, and the bundle of His and its branches carry it down the septum to the ventricles.

Specifications

Applications

• Step-by-step dissection lessons that open the heart one layer at a time
• Viewing the four valves from above to explain the cardiac skeleton
• Locating the regions of the sinoatrial and atrioventricular nodes when teaching the ECG
• Detailed practical exams in medical and nursing anatomy

Care & Handling

• Lay the parts of the 4 part heart model out in order on a tray while it is open, so none roll away or get mixed with other models.
• Reassemble in reverse order and do not force a piece that does not seat easily.
• Count the four parts back into storage after each class.

Why Choose LabEquip

Medical, nursing and paramedical colleges tend to choose a four-part heart where the syllabus demands detailed internal anatomy. LabEquip lists it in biology lab products, alongside the simpler 2 part heart for school use and the jumbo heart for lecture halls. Enquire through the contact page.

Frequently Asked Questions

How is the 4 part heart different from the 2 part heart?

Both open to show the interior. The four-part model comes apart further, usually separating the atria from the ventricles as well as opening the front, so more internal surfaces and the valves from above can be studied.

What is the cardiac skeleton?

It is a framework of dense fibrous tissue around the four valve openings. It supports the valves and electrically separates the atria from the ventricles, so impulses must pass through the atrioventricular node.

Where is the sinoatrial node?

It lies in the wall of the right atrium near where the superior vena cava enters. It is the heart’s natural pacemaker and starts each heartbeat.

Why does the heartbeat pause at the AV node?

The atrioventricular node delays the electrical signal briefly, which gives the atria time to finish emptying into the ventricles before the ventricles contract.

Is the model suitable for secondary school?

It can be used there, but it is designed for detailed study. Many schools find a two-part model enough, while colleges use the four-part version for anatomy practicals.

How do I avoid losing parts?

Keep the parts together on a tray during lessons, reassemble the model before putting it away and check it against a labelled photo of the complete heart.

Last Updated: September 2026