A journey inside your heart.

Hey guys.

On an average a car has a suitcase-sized engine weighing around 300 pounds. A jet engine is a couple of tons heavy and several people could fit inside it. But the most powerful engine out there is the size of your ✊ fist and weighs no more than a can of soup. It's the human heart.

How does it works 🤔 ? 

To start our journey we need to get inside a human body. 

This is "Harry" . We'll checkout-in while he is fast asleep 😜 . We'll get inside through Harry's mouth. 

He breathes the air in and we rush into his lung. Let's hold on to the oxygen molecule as it takes us with its ride on the red blood cell (RBC) . Great ! We have made it into the blood. Yeah ! Now much over here, the walls of tunnel are getting bigger as we are moving to the slightly bigger venules and then to the veins towards the heart. These blood vessels remind me the water pipes rides. They are soft and flexible, see how they can stretch and narrow in themselves. 

The blood moves with every heartbeat which means we'll get to the engine sooner or later. Plus the heart is in left around the corner hatched between the lungs. So you get that oxygen rich blood faster and send it throughout the body. For now we are moving pretty slow about walking pace. Harry is sleeping so his heartbeats are calm.

Ohhh ! hear the last snooze of Harry's alarm clock. He glances at the time and realises he is late for work. His brain  immediately tells his body to release a dose of adrenaline . This gets the blood pumping faster. Things are about to speed-up....! His heart rate is increased and BP goes up with his muscles full of Oxy- rich blood. He leaps out of the bed in a sec. And now we are closer to our goal, the walls are getting wider and wider.

 We can see we are approaching in a cage, the heart and lungs are protected in the sheild of ribs. Now on the main vein i.e pulmonary vein. Wooshhh ! Welcome to the heart. 

The heart is essentially a big muscle that constantly work and beat about 100000 times /day ; 40 M times /year and 2 B times in a lifetime. With each of a beat a ⅓ of a cup of blood moves through the heart. In a day that's upto 2000 gal (7,500 L) any other engine will breakdown under such loads but not the incredible human heart. 

Think that your heart is a big "food delivery centre" which gets fresh supply from lungs. We'll call them as "farmers" . Your RBC's are like "delivery trucks" which takes supplies throughout the city also known as your body. They lead to your organs, tissues and down to the cells all they are meant to supply oxygen. 

The heart makes a beat a valve opens like a gate and we go from left atrium down into the bigger left ventricle. The heart makes one more beat and pushes the blood out we make an exit through a huge and long aorta and we now officially go away from the heart, way through the artery highway. 

Heyy ! Don't worry we'll be back soon enough. Rushing fast through the body delivering oxygen supply to every organ, muscle, tissues and cells.

Here you go with the oxygen package to the kidneys. The tunnel gets smaller and smaller, as we get out of main artery highway to the finer arterioles tree and finally in the tiny alae like capillaries.

It seems Harry is going upstairs, so his leg muscles ordered a huge supply. The heart pumps harder and the BP is increased. Hold on tight 😉. 

All these citizens of this town get there belly full with the good stuff. Then they handover carbon-dioxide like a chicken bone down on your plate after eating all the meat.  Yup the oxygen and carbon dioxide exchange doesn't just happen in your lungs, it's going on in a cellular level. We now have a vein freeway towards the heart just like we did in the lungs. It starts from the capillaries and the tunnel gets bigger from their.

You might have believed "veins are blue and arteries are red ". No ! Blood is always red. It might just be little brighter when it's full of oxygen when moving through the arteries. 

The blue or sometimes green you see through your skin is because of the effect of light waves. It shows that blue rays are easily reflected towards your eyes. 

We are back. But this time we have come into the  right part of the heart. Here we flow through the valve and get back into the tunnel. Stop !!! We don't drive to the artery . Too late more on the way. We are not rushing all over the body again. We'll finally get rid of this carbon dioxide and we'll stock some oxygen through lungs. 

Harry exhales GOODBYE carbon-dioxide. Another breath in .... And then with new supply of oxygen we head back over to the left part of the heart to move in and the journey starts over. 

Each time you breath this is what happens in your body. 

But there's one thing we haven't covered "the power of the power house " : ELECTRICITY.

This is what makes the heart beat.

Hey check it out , we are into the special department called as the Sinus node (SA node). This is were complex reaction occur and create an electrical impulse to unlike say layer of the heart muscles. All the muscle tissue of heart is connected. So this electrical impluse strikes the whole heart. The impluse strikes and the heart contracts, with each contraction blood enters and leaves through the 4 chambers and that's how it all works. 

And finally as we say "THE BEAT GOES ON AND ON AND ON....." 

                                 THANK YOU