The heart, in its simplest form, is really just another muscle. And like other muscles, it needs fuel to operate. Without fuel (which for the body is oxygen) muscle cells quickly become unhappy. An unhappy leg muscle will cramp and become sore if it begins to get deprived of enough oxygen to function. If we stop running or doing squats, less oxygen is needed and our leg muscle begins to recuperate. No harm done.
The heart is a bit different. A muscle, yes, but a very special muscle. If the heart muscle is lacking enough oxygen to function, it will cramp (chest pain) and can begin to die. This is heart attack territory.
How does the heart muscle get its fuel? Coronary arteries. Here's how they work.
Water in the Desert
Picture in your mind a desert with a water bottling facility right smack in the middle of it, dividing it in two halves. A left side, which is much larger and more populous, and a smaller right side. Living in the desert, people there are demanding a constant supply of water, so the delivery trucks from the water plant are running in a continual stream to bring the people what they need.
There are two roads leading away from the bottle facility, the left highway and the right road. The left highway is a single road leading into the desert, but begins to branch into smaller and smaller roadways to supply water to all of the small villages in the desert. The right side of the desert has a similar configuration, but the roadways are smaller and there are fewer villagers to supply.
Now, on a good day when the water is plentiful and the trucks and roadways are running at full capacity, the people in the villages of these deserts are happy and hydrated. They can run and play and drink water all day long and the threat of death and dehydration are but a mere passing thought.
Caution: Roadwork Ahead
What would happen if one of the smaller roads to a single village had a sudden blockage and a delivery truck was not able to pass through and supply water to the people? With all of the running and playing going on in the desert, these people would quickly begin to suffer and would eventually die from dehydration. Tragic. Perhaps a slower crumbling of the road would be monitored by the trucking staff and a new road to the village could be constructed in time before complete disintegration. Good save.
Now, what would happen if one of these sudden blockages occurred at one of the larger branch points in the road? More people would suffer. Many more would die.
What would happen if this occurred at beginning of the left highway?? Complete and utter destruction to all of the villages.
Myocardial Infarction: Say what?
Myocardowho? Exactly. A myocardial (myo = muscle, cardial = heart) infarction (interruption of blood supply) is doctor speak for what is commonly referred to as a heart attack. Interruption of the blood supply to a portion of the heart muscle. Heart attacks come in many shapes and sizes, and this all depends on which road (or roads) gets blocked.
In our scenario, the water from the plant represents oxygen being carried in the blood (by the red blood cells, on a molecule called hemoglobin). The highways and roads are the coronary arteries, and the villagers are the heart muscle, or the individual muscle cells found there.
The left side of the heart is much larger and more muscular than the right side, as it is needed to pump blood from the heart to the rest of the body. The right side is smaller, but still important, as it pumps blood from the heart to the lungs and then back to the heart (see previous post on cardiac anatomy).
As a general rule, the heart can suffer damage to small individual villages with blockages in the smaller coronary arteries, and continue to function as almost normal. That's why people can walk around an say "I had a heart attack last March in the Canary Islands" and you can believe them without saying "Well, shouldn't you be dead then?". Some people have even had multiple heart attacks, damaging islands of muscle cells which collectively leads to some reduced heart function. Over time though, even if future heart attacks may continue to be "small", the heart won't be able to function with multiple areas of damage well enough to continue on beating effectively enough to fund the oxygen demands of the body as a whole.
The End
So why do people on TV have "heart attacks", clutch their chest, collapse to the floor, and are never heard from again? This can actually happen, and is usually termed "cardiac arrest" as opposed to heart attack, but can be caused by a blockage just like the smaller ones. As you can well imagine from our water bottling scenario, the first and only road leading out of the plant to supply the left side of the desert is very important. Without that road, water will not reach the entire left desert and all the villagers will perish. The first part of the coronary circulation that supplies the left side of the heart IS only a single vessel, and is called the LEFT MAIN artery. Blockage of this causes no oxygen to reach the rest of the heart muscle below it. The end.
Stay tuned for my next post - the heart electric.
The heart is a bit different. A muscle, yes, but a very special muscle. If the heart muscle is lacking enough oxygen to function, it will cramp (chest pain) and can begin to die. This is heart attack territory.
How does the heart muscle get its fuel? Coronary arteries. Here's how they work.
Water in the Desert
Picture in your mind a desert with a water bottling facility right smack in the middle of it, dividing it in two halves. A left side, which is much larger and more populous, and a smaller right side. Living in the desert, people there are demanding a constant supply of water, so the delivery trucks from the water plant are running in a continual stream to bring the people what they need.
There are two roads leading away from the bottle facility, the left highway and the right road. The left highway is a single road leading into the desert, but begins to branch into smaller and smaller roadways to supply water to all of the small villages in the desert. The right side of the desert has a similar configuration, but the roadways are smaller and there are fewer villagers to supply.
Now, on a good day when the water is plentiful and the trucks and roadways are running at full capacity, the people in the villages of these deserts are happy and hydrated. They can run and play and drink water all day long and the threat of death and dehydration are but a mere passing thought.
Caution: Roadwork Ahead
What would happen if one of the smaller roads to a single village had a sudden blockage and a delivery truck was not able to pass through and supply water to the people? With all of the running and playing going on in the desert, these people would quickly begin to suffer and would eventually die from dehydration. Tragic. Perhaps a slower crumbling of the road would be monitored by the trucking staff and a new road to the village could be constructed in time before complete disintegration. Good save.
Now, what would happen if one of these sudden blockages occurred at one of the larger branch points in the road? More people would suffer. Many more would die.
What would happen if this occurred at beginning of the left highway?? Complete and utter destruction to all of the villages.
Myocardial Infarction: Say what?
Myocardowho? Exactly. A myocardial (myo = muscle, cardial = heart) infarction (interruption of blood supply) is doctor speak for what is commonly referred to as a heart attack. Interruption of the blood supply to a portion of the heart muscle. Heart attacks come in many shapes and sizes, and this all depends on which road (or roads) gets blocked.
In our scenario, the water from the plant represents oxygen being carried in the blood (by the red blood cells, on a molecule called hemoglobin). The highways and roads are the coronary arteries, and the villagers are the heart muscle, or the individual muscle cells found there.
The left side of the heart is much larger and more muscular than the right side, as it is needed to pump blood from the heart to the rest of the body. The right side is smaller, but still important, as it pumps blood from the heart to the lungs and then back to the heart (see previous post on cardiac anatomy).
As a general rule, the heart can suffer damage to small individual villages with blockages in the smaller coronary arteries, and continue to function as almost normal. That's why people can walk around an say "I had a heart attack last March in the Canary Islands" and you can believe them without saying "Well, shouldn't you be dead then?". Some people have even had multiple heart attacks, damaging islands of muscle cells which collectively leads to some reduced heart function. Over time though, even if future heart attacks may continue to be "small", the heart won't be able to function with multiple areas of damage well enough to continue on beating effectively enough to fund the oxygen demands of the body as a whole.
The End
So why do people on TV have "heart attacks", clutch their chest, collapse to the floor, and are never heard from again? This can actually happen, and is usually termed "cardiac arrest" as opposed to heart attack, but can be caused by a blockage just like the smaller ones. As you can well imagine from our water bottling scenario, the first and only road leading out of the plant to supply the left side of the desert is very important. Without that road, water will not reach the entire left desert and all the villagers will perish. The first part of the coronary circulation that supplies the left side of the heart IS only a single vessel, and is called the LEFT MAIN artery. Blockage of this causes no oxygen to reach the rest of the heart muscle below it. The end.
Stay tuned for my next post - the heart electric.