Why is circulatory system important to humans

Privacy Policy. Skip to main content. Module The Circulatory System. Search for:. Blood Blood consists of: Red blood cells — to carry oxygen White blood cells — that make up part of the immune system Platelets — needed for clotting Plasma — blood cells, nutrients and wastes float in this liquid.

The heart The heart pumps blood around the body. It sits inside the chest, in front of the lungs and slightly to the left side.

The heart is actually a double pump made up of four chambers, with the flow of blood going in one direction due to the presence of the heart valves. The contractions of the chambers make the sound of heartbeats. The right side of the heart The right upper chamber atrium takes in deoxygenated blood that is loaded with carbon dioxide. The blood is squeezed down into the right lower chamber ventricle and taken by an artery to the lungs where the carbon dioxide is replaced with oxygen. The left side of the heart The oxygenated blood travels back to the heart, this time entering the left upper chamber atrium.

It is pumped into the left lower chamber ventricle and then into the aorta an artery. The blood starts its journey around the body once more. Blood vessels Blood vessels have a range of different sizes and structures, depending on their role in the body.

Arteries Oxygenated blood is pumped from the heart along arteries, which are muscular. Arteries divide like tree branches until they are slender. The largest artery is the aorta, which connects to the heart and picks up oxygenated blood from the left ventricle. Red blood cells live for up to 4 months and make approximately , round trips around the body before returning to the bone marrow, where they were born, to die. Between 2. Across the animal kingdom, heart rate is related to body size : in general, the bigger the animal, the slower its resting heart rate.

An adult human has an average resting heart rate of about 75 beats per minute, the same rate as an adult sheep. But a blue whale's heart is about the size of a small car, and only beats five times per minute. A shrew, on the other hand, has a heart rate of about 1, beats per minute. The ancient Egyptians believed the heart, rather than the brain, was the source of emotions, wisdom and memory, among other things.

After circulating within the body for about days, a red blood cell will die from aging or damage. Bone marrow constantly manufactures new red blood cells to replace those that perish. The oxygen-rich blood that flows through your arteries and capillaries is bright red. After giving up its oxygen to your bodily tissues, your blood becomes dark red as it races back to your heart through your veins.

Boost Your Child's Learning Today! Trial it for FREE today. We see and hear about hearts everywhere. A long time ago, people even thought that their emotions came from their hearts, maybe because the heart beats faster when a person is scared or excited.

Now we know that emotions come from the brain, and in this case, the brain tells the heart to speed up. Your heart is a very strong muscle that pumps blood around your body. It is made of four chambers, two upper chambers and two lower chambers.

Blood enters the upper chambers. These squeeze and push the blood into the lower chambers, which then squeeze and push the blood out of your heart. The heart works tirelessly — more than 2. Your pulse is a measure of how fast your heart is beating. It is the number of beats your heart makes in one minute. Your heart beats faster or slower depending on what you are doing. You can feel your pulse at certain points on your body.

The easiest place to feel it is in your wrist, using the first two fingers of your other hand. When you sit, the average heart beats about 80 times per minute. However, everybody is different, so your pulse could be higher or lower than this. When you exercise , your heart beats more quickly. Left atrium Medically reviewed by the Healthline Medical Network. Right ventricle Medically reviewed by the Healthline Medical Network. Heart Medically reviewed by the Healthline Medical Network.

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