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trillions of cells with oxygen and nutrients. Blood can also carry waste material such as carbon dioxide away from cells. The heart is made of cardiac muscle that contracts automatically and never tires. A muscular wall, called the septum, divides the heart lengthways into left and right sides. A valve divides each side into two chambers: an upper atrium and a lower ventricle.
collect more oxygen. This exchange of gases is called respiration, which we usually call breathing.
Right Atrium
To Lungs
the valve down to the right ventricle.
Right Ventricle
What the heart does 1) Blood from the body arrives at the heart’s right atrium. It flows through
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2 EIN-O's INTRO
Even though there is an incredible variation in body shapes and sizes, all humans share common features and the same working parts. The human body is built from trillions of cells. Similar cells group together to form tissues (a Latin word that means “woven”). Types of tissues include nervous tissue, muscle tissue, connective tissue and epithelial tissue. And when tissues group together, they can make organs that pump blood (heart), digest food (stomach) and breath air (lungs). The Bio Signs series is an assortment of 6 human anatomy models. The detailed models are the: Brain and Skull, Eye, Head and Torso, Heart, Skin, and Teeth and Gums.
2) From the right ventricle, blood is pumped to the lungs.
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6 Summary
This I Know Guide provides an introduction to: the Heart
HEART The heart is a hollow muscle in the middle of our chest (and slightly to our left side). It pumps blood continuously around our body throughout our lives. The heart pumps blood around our whole body because blood is needed to supply our
3) Blood from the lungs arrives at the heart’s left atrium. It flows through the valve down to the left ventricle. To rest
Left Atrium
The heart pumps blood from the right side of the heart to the lungs. Then blood carrying oxygen returns to the left side of the heart and is pumped around the rest of the body.
of the Body
Q:Why is there a Right and a Left side of the heart? A:Because there are two circulatory routes in the body: Left Ventricle
4) From the left ventricle, blood is pumped to the rest of the body.
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•The pulmonary circulation is where the right side of the heart pumps blood through the lungs. Cells need oxygen and once cells have used oxygen to “burn fuel”, they give off carbon dioxide. The pulmonary circulation allows the body to carry carbon dioxide to the lungs for release, and to
•The systemic circulation is where the left side of the heart pumps blood through the rest of the body. The systemic circulation (also called the bloodstream) delivers oxygen and nutrients to the body tissues and cells and takes away their waste products, like carbon dioxide. The bloodstream also carries the cells that defend the body against disease and infections. Chemicals, called
8 Chemicals, called hormones, are also carried by the bloodstream. The heart is actually a pair of pumps, on each side of which the two atriums (upper heart chambers) collect incoming blood. The atriums pass blood through a one-way valve into the ventricles (lower heart chambers) beneath. These ventricles then contract strongly and push blood out of the heart and away to the lungs (from right ventricle) or to the rest of the body (from left ventricle).
Ein-O Fact Our circulatory blood system consists of a massive network of blood vessels. If spread out, the vessels would be
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over 100,000 km (60,000 miles) long. This network carries blood to all parts
number of beats you can feel in 10 seconds and then multiply by 6 to work out your heart rate per minute.
Ein-O Fact
Next, do some exercise and repeat your pulse count.
The human heart does not always beat at the same speed. At rest, the heart beats between 60 and 80 times a minute. During exercise or at times of stress or excitement, the heart rate may increase up to 200 beats a minute.
Activity You can check your pulse to find out how fast your heart beats at rest and after exercise. First, place two fingers of one hand on the inside of the other wrist. Count the
Next, do some exercise and repeat your pulse count. Compare your two heart rates. Also, compare your heart rates with your friends!
Ein-O Fact The heart is made of cardiac muscle that contracts automatically and never tires. It is an extremely efficient pump. In fact, the heart is more reliable and energy efficient than any pump ever created by man.