Name
Cardiovascular system
Consist of
Heart | Blood | Blood vessels
Main function
Transports oxygen and nutrients to every cell while removing carbon dioxide and waste products
CARDIOVASCULAR
SYSTEM
Every cell in the body needs a constant supply of oxygen and nutrients and a way to eliminate waste. That’s where the circulatory system comes in. Made up of the heart, blood, and blood vessels, it keeps everything moving. Blood carries carbon dioxide to the lungs through a network of arteries, veins, and capillaries to exhale and pick up oxygen in return. It also collects nutrients from the small intestine and delivers them to cells throughout the body. The circulatory system is the body’s internal delivery and waste removal service, working non-stop to keep everything in balance.
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 oxygen-rich blood returns from the lungs to the left upper part of the heart (the atrium). It then moves down into the left lower chamber (the ventricle), which pumps it into the aorta—the body’s main artery. From there, the blood sets off on its journey around the body again, delivering oxygen and nutrients to the cells.
The left side
The right upper part of the heart (called the atrium) receives blood that's low in oxygen and full of carbon dioxide. From there, the blood moves down into the right lower chamber (the ventricle), then pumps it to the lungs. In the lungs, carbon dioxide is removed, and fresh oxygen is added, getting the blood ready to fuel the body again.
The right side
BLOOD
We all know that blood carries oxygen but does much more. It transports hormones, clears out waste, fights off infections, and directs oxygen to where it’s needed most. It can even show our emotions, like when we blush or go red with anger, and helps regulate body temperature. One drop of blood can hold thousands of different molecules, which is why doctors rely on blood tests—it’s full of useful information about what’s happening inside us.
Red blood cells
Carry oxygen
White blood cells
Part of the immune system
Platelets
Wound healing
Plasma
Liquid part of the blood
Arteries
Oxygen-rich blood is pumped out of the heart through arteries, which are strong and stretchy to handle the pressure. These arteries branch out like tree limbs, getting thinner and thinner as they spread through the body. The aorta is the biggest artery, carrying oxygenated blood straight from the left ventricle of the heart. The only exception is the pulmonary artery, which is the only artery that carries deoxygenated blood — it takes it from the heart to the lungs to pick up fresh oxygen.
Veins
Veins don’t have muscles like arteries—instead, they use one-way valves to keep blood flowing in the right direction and stop it from slipping backwards. Most of the time, veins carry deoxygenated blood from the body back to the heart so it can be sent to the lungs for a fresh supply of oxygen. The only exception is the pulmonary veins—they do the opposite, carrying oxygen-rich blood from the lungs back to the heart.
Capillaries
Arteries eventually branch out into the tiniest blood vessels called capillaries. These are so small that blood cells squeeze through one at a time. Here, oxygen and nutrients pass from the blood into the surrounding cells. Capillaries also connect to veins, allowing waste products from the cells to move back into the blood and start their journey out of the body.
BLOOD VESSELS
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