A field guide to the HUMAN HEART!!!
It is the fist-sized organ thats in your body and it is like the size of an orange and it has not paused for 4 weeks after you were conceived. Choose a tempo below and the entire page will connect to it and beat along with it. So try it!
The tempo
Your heart actually makes its own electricity which is measured by an electrocardiogram (ECG). This trace is the voltage it generates and it gets faster along with everything else on the page.
4872 133176 BPM
The loop
Two pumps share a wall in the heart and the right side sends blood to the lungs. And the left side basically fires fresh blood to ever fingertip, toe and overall every part that needs blood. Pick a part to read about it.
Every single cell in the body needs oxygen and it has to get delivered and waste also needs to get hauled away. Capillaries here are so narrow that the red cells fold right up to pass on a single file. Then the blood turns around and starts the whole loop again.
Your brain is 2 percent of your weight and it takes 15 percent of the flowThe arrivals hall. Blood coming home from your body and it is basically tired, dark, and full of carbon dioxide and it pours through two veins. A thin-walled holding room, not an actual serious pump
Wall thickness: about 2mm. It barely has to pushThis is basically the short-haul pump. It only moves blood a few centimetres into the lungs next door so its super light. And if it gets pushed any harder it will burst and delicate capillaries around your air sacs which is very terrible.
Peak pressure: ~25 mmHg - a fifth of the left side.Where blood changes colour it spreads into capillaries wrapping around a whopping 300 million air sacs and it is seperated from the air by less than a thousandth of a millimetre. The blood which is dark maroon turns into a bright scarley sort of colour in under a second which is wild.
It's unfolded and your lungs would cover half a tennis court which is CRAZY if you would think about it.This is the return desk of the heart. Freshly oxygenated blood comes from the lungs through four pulmonary veins and the only veins in your body carrying rich oxygen blood and it collect here before dropping down.
This is where atrial fibrillation usually begins. And it's basically chaotic electrical signals in the atria.The engine room. And that is the exact reason that the diagram shows one wall that is a bit thicker than the rest of them. It has to launch blood into your brain, your toes, and overall every where against resistance of your entire body. It twists as it contracts and it wrings itself out like a towel.
The peak pressure is ~120 mmHg and the top number in your blood pressure.These are one way doors that are tethered by small tiny cords so that they cannot blow inside-out. They open up to let a chamber fill and slam shut the instant it squeezes. This is also the reason why a heart makes any sound at all.
So lub = tricuspid and mitral closing. And the dub = pulmonary and aortic.Worth Knowing
Deoxygenated blood is actually a dark red color called maroon, not blue. Your veins look blue or green because oh how skin scatters light and the diagrams colour it blue or green including the one above so you can follow the loop.
Arteries carry blood away from the heart and the veins carry it back and that the whole process. The pulmonary vessels break the usualy pattern and confuse everybody which is a nice systematic flow.
The heart sits in a bath of blood and cannot use a drop, which is pretty scary if you think about it. It has its very own delivery system all over the outside. Block one of those and that patch of muscle dies...thats a heart attack and it happens A LOT around the world. For example in the USA a heart attack occurs every 40 seconds.
Roughly 35 million beats occur per annum and about 2.5 billion in an average lifetime, moving around 7,500 litres every single day with no maintenance window which is absolutely crazy.
A lot of people do not know this but around week four of gestation, before limbs, before eyelids, a tube of cells folds over and twitches. And that twitch has not stopped ever since.
A blue whale's heart weighs as much as a small car and beats twice a minute when diving. While a hummingbird's hits 1,200. So the smaller the animal is, the faster heart and also the shorter life.
Check yourself
Which chamber pumps blood to your entire body? Think carefully.
The left ventricle has the thickest wall out of all. Because it pressurizes your whole body at every single beat.
What actually makes the lub-dub sound?
Lub is the tricuspid and mitral closing and the dub is the pulmonary and aortic. A murmur is a valve that does not seal cleanly. For more scroll to the facts page.
What do the pulmonary veins carry?
They are the exception. "Vein" means basically heading toward the heart and it says nothing at all about oxygen content.
Where does each hearbeat actually begin???
The sinoatrial node fires on its own time and it is why a heart keeps beating with every nerve to it cut and actually also the reason why transplants work.