The Cardiovascular System


What is The Cardiovascular System?

The cardiovascular system consists of the heart and blood vessels (arteries, veins, and capillaries). It delivers oxygen and nutrients to the tissues and carries waste products to the organs responsible for elimination. The arteries carry blood from the heart to the rest of the body, and the veins carry blood back to the heart. Your body contains about five litres (eight pints) of blood, which your heart is continuously circulating. The movement of blood around the body, pumped by the heart, is called circulation. Your heart, blood and blood vessels together make up your cardiovascular system (or heart and circulatory system).

the cardiovascular system


How does blood travel around the heart?

There are two separate sides of the heart that work together. The right side of the heart receives dark, de-oxygenated blood which has circulated around the body. It pumps into the lungs, where it picks up a fresh supply of oxygen and becomes bright red again. The blood then returns to the left side of the heart, ready to be pumped back out of the rest of the body. There are four valves in the heart that act as gates that open and close, making sure that the blood travels in one direction through the heart. They are known as tricuspid valve and the pulmonary valve located on the right side of the heart. Located on the left side of the heart are the mitral valve and the aortic valve. The heart continuously needs a supply of fresh blood which comes from the coronary arteries which brand off from the main artery (aorta) as it leaves the heart.


How does blood travel around the body?

As the heart muscle contracts, it pushes blood through the heart. With each contraction or heartbeat, the heart pumps blood from its left side through the aorta (main artery leaving the heat) and into the arteries. The blood travels through the arteries, which divide into smaller and smaller branches of blood vessels and capillaries. Traveling through this network of capillaries blood reaches every part of the body. The de-oxygenated blood then travels back to the heart through the veins. Branches of veins join to form larger veins, which lead back to the right side of the heart. From here, the heart will pump the de-oxygenated blood to the lungs with its next heartbeat. As the heart relaxes in between each heartbeat or contraction, blood from the veins fills the right side of the heart. At the same time, blood that is freshly full of oxygen from the lungs fills the left side ready for the entire process to start again.

blood circulation through the heart


What are the Functions of the Cardiovascular System?

The cardiovascular system has three major functions: transportation of materials, protection from pathogens, and regulation of the body’s homeostasis.

cardiovascular system functions



1. Transportation:

The cardiovascular system transports blood to almost all of the body’s tissues. The blood delivers essential nutrients and oxygen and removes wastes and carbon dioxide to be processed or removed from the body. Hormones are transported throughout the body via the blood’s liquid plasma.


2. Protection:

The cardiovascular system protects the body through its white blood cells. White blood cells clean up cellular debris and fight pathogens that have entered the body. Platelets and red blood cells form scabs to seal wounds and prevent pathogens from entering the body and liquids from leaking out. Blood also carries antibodies that provide specific immunity to pathogens that the body has previously been exposed to or has been vaccinated against.


3. Regulation:

The cardiovascular system is instrumental in the body’s ability to maintain homeostatic control of several internal conditions. Blood vessels help maintain a stable body temperature by controlling the blood flow to the surface of the skin. Blood vessels near the skin’s surface open during times of overheating to allow hot blood to dump its heat into the body’s surroundings. In the case of hypothermia, these blood vessels constrict to keep blood flowing only to vital organs in the body’s core. Blood also helps balance the body’s pH due to the presence of bicarbonate ions, which act as a buffer solution. Finally, the albumins in blood plasma help to balance the osmotic concentration of the body’s cells by maintaining an isotonic environment.


What is Cardiovascular Disease?

Cardiovascular disease is a group of conditions which affect the heart or blood vessels. It is usually associated with a build-up of fatty deposits inside the arteries known as atherosclerosis and an increased risk of blood clots. It can be associated with damage to arteries in organs such as the brain, heart, kidneys and eyes.


What are the Risk Factors of Cardiovascular Disease?

• High Blood Pressure

• Smoking

• High Cholesterol

• Diabetes

• Inactivity

• Being overweight or obese

• Family History of Cardiovascular Disease

• Genetics/Age 

• Unhealthy diet

• Excessive alcohol consumption

cardiovascular disease risk factorshealthy heart vs heart disease


What are the different types of heart diseases?

• Coronary Heart Disease- This is when the flow of oxygen rich blood to the heart muscle is blocked or reduced. This puts increased strain on the heart and can lead to angina (chest pain caused by restricted blood flow to the heart muscle), heart attacks (where the blood flow to the heart muscle is suddenly blocked), and heart failure (where the heart is unable to pump blood around the body properly).

• Stroke- A stroke is where the blood supply to part of the brain is cut off, which can cause brain damage and possibly death.

• Peripheral Arterial Disease- Peripheral arterial disease occurs when there’s a blockage in the arteries to the limbs usually the legs. This can cause dull or cramping leg pain, which is worse when walking and gets better with rest. This can also cause hair loss on the legs and feet, numbness or weakness in legs, persistent ulcers (open sores) on the feet or legs.

• Aortic Disease- Aortic diseases are a group of conditions affecting the aorta. This is the largest blood vessel in the body which carries blood from the heart to the rest of the body.


How to look for signs of a heart attack

• Pressure, tightness, pain, or a squeezing or aching sensation in your chest or arms that may spread to your neck, jaw or back

• Nausea and abdominal pain

• Breathlessness

• Fatigue

• Light-headedness or sudden dizziness

• If you are experiencing these symptoms in a severe way it is best to call 999 immediately.

know the signs of a heart attack


How to look for signs of a stroke

• Face- the face may have drooled on one side, the person may be unable to smile, or their mouth or eye may have dropped.

• Arms- the person may not be able to lift both arms and keep them there because of arm weakness or numbness in one arm

• Speech- their speech may be slurred or garbled, or they may not be able to talk at all

• Time- it’s time to dial 999 immediately if you see any of these signs and symptoms

look for signs of a stroke