What does an electrocardiogram show?
This video shows how quickly an electrical impulse is conducted from the sinoatrial node to the ventricles. The Q, R, and S waves (QRS complex) shown in the electrocardiogram represent depolarization of the ventricles.
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© American Chemical Society (A Britannica Publishing Partner)Learn about the chemical process the human body uses to digest carbohydrates, proteins, and fats.
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© Behind the News (A Britannica Publishing Partner)Why not all people perceive colors the same way.
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Encyclopædia Britannica, Inc.An MIT study compared brain connectivity between people writing essays using Chat GPT, a search engine, or only their own brain.Media Editor: Casey Mendoza
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Encyclopædia Britannica, Inc.In a circuit through the cardiovascular system, red blood cells transport oxygen from the lungs to the body tissues and carry carbon dioxide from the body tissues back to the lungs.
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Encyclopædia Britannica, Inc.Bright swarms of Daphnia serve as the food source of many larger animals. The internal processes of Daphnia are easily studied through its transparent carapace. A single eye, sensitive to light, causes Daphnia to react in a sunlit river.
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© American Chemical Society (A Britannica Publishing Partner)Is your favorite sweet good for you?
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Encyclopædia Britannica, Inc.There are two major protein complexes that transport cholesterol through the bloodstream: high-density lipoproteins (HDL) and low-density lipoproteins (LDL). Cholesterol attached to LDLs is primarily that which builds up in atherosclerotic deposits in the blood vessels; for this reason, LDL is often described as the “bad” form of cholesterol. HDLs, on the other hand, may actually serve to retard or reduce atherosclerotic buildup, and hence HDL is often referred to as the “good” form of cholesterol.
