Blood Cells and the Heart

Structure and Function of Blood Cells

Blood is made of cells that float around in the plasma. The majority of the blood cells are red blood cells, and there are small numbers of white blood cells. Only a small number of platelets can be found in the bone marrow.

Structure and Function of Blood Vessels

Our blood vessels are essential as they carry blood __around the body. They allow blood to circulate around the body, which contains useful substances such as __oxygen __and __nutrients. It also removes waste products from the cells so that they can be taken away to be excreted.

There are different types of blood vessel:

Heart Circulatory System

The heart has __4 chambers __(Right and left ventricle, right and left atrium), and it is a __muscular pump __that circulates blood around the body.

1. The __right side of the heart __only pumps de-oxygenated blood towards the lungs so that it can pick up oxygen.
2. The__ left side of the heart__ only pumps oxygenated blood from the lungs to the rest of the body.
3. The heart is extremely important in__ transporting substances __such as food, water, oxygen, waste products around the body.
4. Humans have a double circulatory system, as deoxygenated blood has to be pumped through the lungs to become oxygenated, before it can return to the heart so that the heart can pump the oxygenated blood around the body.

The path taken by blood through the body:

→ Deoxygenated blood enters the right atrium __through the __vena cava

→ The blood is then pumped through a valve and into the __right ventricle __chamber

→ Blood goes up through the pulmonary valve, and into the pulmonary artery(which goes towards the lungs)

→ The blood is now oxygenated (having been in the lungs), and enters the __pulmonary veins __and into the left atrium

→ Blood is then pumped through a valve, and into the left ventricle

→ Blood then flows through the aortic valve, and out of the __aorta __towards the rest of the body.

(NOTE: Right and left are reversed when we talk about the heart. E.g. you’ll see that the right ventricle is on the left side of the heart.

The heart has a special type of muscle that is extremely thick, called the cardiac muscle. This is because the muscle is constantly contracting and relaxing, therefore it has to be quite tough.

The muscle has its own blood supply, through the coronary artery. This provides the heart with oxygen and glucose in order to function.

The heart has important valves to prevent the backward flow of blood, as deoxygenated blood is flows quite slow and with a low pressure.

How many chambers does the heart have?

4

What is the name of muscle that is found on the heart?

Cardiac Muscle

What type of blood cells can be found in the plasma?

Your answer should include: Platelets / White blood cells / Red blood cells