A journey inside our body

Do you know that the oxygen we breathe needs to travel throughout our body? But how does the oxygen we breathe through our mouths and noses get to places like our toes?

The answer to these questions is found in our circulatory system. Through this system, gases and nutrients travel through our body through the blood. The circulatory system is made up of the heart, blood, and tubes called blood vessels.

The heart is the muscle responsible for pumping blood to the lungs and blood vessels.

Our heart is divided into two halves separated by a wall called a septum. The left side of the heart is filled with oxygen-rich blood, while the right side is filled with oxygen-poor blood. The heart contains four chambers, two upper ones, called atria, and two lower ones, called ventricles.

Blood: Blood is made up of cells called blood cells. Red blood cells are responsible for transporting oxygen, while white blood cells fight infections and other diseases and keep the blood clean. Blood also contains platelets, these reduce bleeding when you cut yourself through a process called coagulation. Likewise, platelets help heal wounds. Finally, all these cells float in a liquid substance called plasma.

Blood vessels are a set of tubes that carry blood pumped by the heart. Its main function is to transport nutrients, oxygen and waste from the body. They are classified into arteries, arterioles, veins, venules and capillaries.

Arteries are the blood vessels that carry oxygen-rich blood (taken up through our lungs) from the heart to the capillaries of the body. The arteries get smaller as they move away from the heart. The smallest arteries that connect to the capillaries are called arterioles.

Veins are the blood vessels that carry oxygen-poor blood to the heart. The veins get larger as they get closer to the heart. The smallest veins are called venules.

Capillaries are found between arteries and veins. The capillaries are quite thin, hence the name which comes from the Latin capillus meaning “hair”.

Therefore, the movement of blood, known as circulation, occurs as follows:

heart → artery → arteriole → capillary → venules → vein → heart

types of blood circulation

There are two different circulations in the circulatory system:

The pulmonary or minor circulation is the part of the circulatory system that transports deoxygenated blood from the right ventricle of the heart to the lungs, and then returns oxygenated to the heart.

The systemic or greater circulation carries oxygenated blood from the left ventricle of the heart to all organs and tissues of the body, excluding the lungs.

Let’s move!

Stay very active, choose to run or jump instead of watching TV or playing video games. When you exercise, your muscles need even more oxygen because they are working harder. The faster your heart beats, the faster it can get more blood and oxygen to your muscles. So, get moving, your body will thank you.

Did you know . . . ?

✔ Your heart is the size of your fist.
✔ The heart is the muscle that works the hardest. It beats approximately 80 times per minute, which is equivalent to 4,800 beats per hour for a total of 115,200 times per day.
✔ Exercise causes a small increase in the size of the left ventricle, making it easier for the heart to do its job of supplying oxygenated blood to all the organs, muscles, and systems of the body.
✔ A single drop of blood contains about 250,000 platelets.a