The Four-Chambered Heart Quotes by Anaïs Nin
The Heart and Circulatory System - How They Work
New Understanding of the Heart's Evolution
Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs. Why do our hearts have four chambers? Michael Roizen, MD. Internal Medicine.
The human heart does not look much like those Valentine's Day candies or the pictures we drew on our love notes when we were in elementary school. The current human heart is a large muscular organ with four chambers, a septum, several valves , and other various parts necessary for pumping blood all around the human body. However, this amazing organ is a product of evolution and has spent millions of years perfecting itself in order to keep humans alive. Invertebrate animals have very simple circulatory systems. Many do not have a heart or blood because they are not complex enough to need a way to get nutrients to their body cells.
Humans, like other warm-blooded animals, expend a lot of energy and need a lot of oxygen. Our four-chambered hearts make this possible. It gives us an evolutionary advantage: We're able to roam, hunt and hide even in the cold of night, or the chill of winter. The story starts with frogs, which have a three-chambered heart that consists of two atria and one ventricle. As the right side of a frog's heart receives deoxygenated blood from the body, and the left side receives freshly oxygenated blood from the lungs, the two streams of blood mix together in the ventricle, sending out a concoction that is not fully oxygenated to the rest of the frog's body. Turtles are a curious transition — they still have three chambers, but a wall, or septum is beginning to form in the single ventricle.
So why do you need four chambers if three worked just fine for frogs and lizards? Humans, and indeed all mammals not to mention birds! Warm bloodedness requires a great deal of oxygen, for the oxygen is used to generate both ATP and heat.
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