The Circulatory System

The circulatory system is a network of blood vessels which transport blood to various parts of the body. Every part of the body requires blood as it contains oxygen, nutrients, hormones and removes waste products - all essential for keeping us healthy and alive.

If you're a student revising anatomy, a lecturer delivering lessons, or a medical professional explaining cardiovascular function to patients, our circulatory system anatomy posters provide rich, accurate illustrations of the heart, vessels, and blood components. These large-format charts make ideal additions to clinics, classrooms, and study spaces, helping to break down complex systems into digestible visuals.

The circulatory system starts at the heart, which is the organ that pumps oxygenated and deoxygenated blood around our body. Deoxygenated blood is transported into the heart from the rest of the body via the veins. The blood is then transported to the lungs where it becomes oxygenated and flows back into the heart, from where it is transported back to the rest of the body through arteries.

The blood vessels are responsible for transporting blood around the body. Arteries carry oxygenated blood from the heart to the body. Arterioles are vessels that branch out from arteries and are much smaller. Arterioles then form into capillaries, which are very small blood vessels that supply blood to smaller structures within the body. Capillaries connect to venules (small veins), which then connect to veins and transport deoxygenated blood back to the heart.

There are two types of circulation: pulmonary circulation and systemic circulation. Pulmonary circulation is the circuit involving the heart and the lungs. Systemic circulation involves the circuit between the heart and the rest of the body. Coronary circulation is a form of systemic circulation and involves the blood supply to the heart via the veins and arteries of the heart.

Located between your lungs and protected by your ribs, the heart is the strongest organ in the body. The human heart is roughly the size of your fist. The heart pumps blood around the entire body and is part of the circulatory system. It has four chambers - two upper and two lower: the left and right atrium, and the left and right ventricle.

There are four valves involved in regulating your heart’s blood flow: the tricuspid valve, the pulmonary valve, the mitral valve and the aortic valve. These valves play an essential role in preventing backflow and ensuring blood flows efficiently through the heart.

Understanding the form and function of the heart and blood vessels is far easier with a 3D perspective. Our anatomical heart and circulatory system models are ideal for tactile, hands-on learning. Whether you're studying cardiac circulation or teaching about arterial health, these models provide a clear, realistic representation that aids retention and engagement.

The heart contracts and relaxes as it pumps blood. This causes a change in pressure that allows blood to circulate through the body. The relaxation phase is known as diastole, during which the heart fills with deoxygenated blood from the veins. The contraction phase is called systole, during which oxygenated blood is pumped into the arteries.

The heart’s electrical system regulates this pumping process via electrical impulses. In the right atrium is a collection of specialised cells called the sinoatrial node (SA node), which sets the rhythm and pace of your heartbeat.

The electrical impulse starts here and spreads across the atria, including the left atrium, causing both to contract. The signal then moves downwards but is delayed by the atrioventricular node (AV node) between the right atrium and ventricle. This delay gives the atria time to fully contract before the ventricles do.

The signal is then sent through a bundle of fibres called the Purkinje fibres, which distribute the impulse along the ventricle walls, prompting them to contract. Once the ventricles are emptied of blood, the cycle restarts as the SA node fires again.

Your blood is a thick fluid that flows throughout your body, delivering oxygen to your cells and removing carbon dioxide. It keeps you healthy by fighting off infections, carrying hormones, forming clots, and helping regulate body temperature.

Blood is made up of a combination of liquids and solids, which is why it’s thicker than water. It consists of:

This yellowish liquid makes up around 55% of your blood. Plasma is responsible for transporting waste products, nutrients, antibodies, hormones, and clotting proteins throughout the body.

These are responsible for transporting oxygen from your lungs to your tissues and carrying carbon dioxide back to the lungs. They contain haemoglobin, a protein with a red pigment called haem, which gives blood its colour. Blood type is determined by antigens on RBCs. They make up about 40–45% of blood.

Also known as leukocytes, these make up about 1% of blood and are the body's primary defenders against infection. Produced in the bone marrow, they have nuclei and include types such as neutrophils, lymphocytes, monocytes, basophils, and eosinophils.

Also called thrombocytes, these are responsible for blood clotting. Produced in the bone marrow, they help prevent excessive bleeding and make up less than 1% of blood

Understanding anatomy can be far more effective with high quality visual tools. Our range of anatomical models, posters and revision guides allow students and professionals to deepen their understanding through visual and tactile learning. Whether you're preparing for an exam, teaching a class, or working in a clinical setting, our resources provide a practical and engaging way to study human anatomy.