Heart Structure and Valves
The heart is a double pump kept one-way by its valves - and for Edexcel you need the valve names. Learn the chambers, valves, vessels and the blood's route, plus gas exchange in the lungs.
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The double pump ❤️
The heart is really **two pumps side by side**. The **right side** sends deoxygenated blood to the **lungs** to collect oxygen; the **left side** pumps that oxygenated blood out to the **whole body**. Keeping blood flowing **one way** are the **valves** - and unlike some boards, Edexcel expects you to **name them**. This module builds the heart chamber by chamber, then follows the blood all the way round.
Inside the heart 🫀
Four structural terms come first - learn them exactly.
Match each valve to its position 🔀
- Tricuspid valve
- Bicuspid (mitral) valve
- Pulmonary semi-lunar valve
- Aortic semi-lunar valve
- Between the right atrium and the right ventricle
- Between the left atrium and the left ventricle
- At the exit from the right ventricle into the pulmonary artery
- At the exit from the left ventricle into the aorta
What do the valves do? 🚪
What is the main job of the heart valves?
- They open one way to prevent blood flowing backwards
- They add oxygen directly to the blood
- They are the muscle that pumps the blood
- They clot the blood to stop bleeding
The pulmonary swap 🔁
A rule you half-know: **arteries carry blood away from the heart, veins carry it back**. Usually arteries carry oxygenated blood - but the lungs create ONE famous exception: - The **pulmonary artery** carries **deoxygenated** blood (heart to lungs).\n- The **pulmonary vein** carries **oxygenated** blood (lungs back to heart). So remember arteries by **direction (away from the heart)**, not by oxygen. This swap is a classic exam trap.
Trace the blood ➡️
An interactive activity.
The odd one out 🩸
Which vessel is unusual because it is an artery that carries deoxygenated blood?
- The pulmonary artery
- The aorta
- The pulmonary vein
- The vena cava
Arteries vs veins ⚖️
The vessels are built for their jobs. Arteries handle high-pressure blood leaving the heart; veins return low-pressure blood to it.
True of arteries ✅
Select the TWO statements that are true of arteries.
- They have thick, muscular, elastic walls
- They carry blood away from the heart
- They contain valves along their length
- They carry blood at low pressure
Match each blood component 🧫
- Red blood cells
- White blood cells
- Platelets
- Plasma
- Carry oxygen using haemoglobin
- Fight infection as part of the immune system
- Help the blood to clot at a wound
- The liquid that carries nutrients, carbon dioxide and heat
The air path 🌬️
An interactive activity.
Blood under pressure 🧭
An interactive activity.
Explain gas exchange ✍️
An interactive activity.
The grade-9 habit 🌟
For Edexcel, two things separate top answers. First, **know the valve names and where they sit** - tricuspid on the right, bicuspid on the left, semi-lunar valves guarding the artery exits - because this board examines them where AQA does not. Second, **be fluent in the one-way route** vena cava, right atrium, right ventricle, pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta - and never forget the swap: the pulmonary **artery** carries deoxygenated blood, the pulmonary **vein** carries oxygenated blood. Get those and the cardio-respiratory marks are yours.