Cardiac Muscle Function

Cardiac muscle function is an amazing thing to explore. Out of all the muscle types, the cardiac muscle is the most unique and least known of them. Read on to know how this muscle works continuously.

The job our heart does is no mean feat. Thanks to our constant requirement of oxygen, it never gets to rest! But jokes apart, on a serious note, the fact that the human heart functions properly is a reason of us being alive. Our heart, as we all know is composed of chambers, two atria and two ventricles. The atria act as receiving chambers and the ventricles pump out the blood. Now, this 'pumping' action is facilitated by the cardiac muscle. Cardiac muscle is one of the three major types of muscles, including the skeletal muscles and smooth muscles. The contraction of the cells of this muscle in the heart push the blood from the atria and the ventricles till the circulatory system's blood vessels. The cells of this cardiac muscle are like any other, depending on adequate blood supply for supplying oxygen and nutrients and removal of waste products. How does this cardiac muscle function and where is it exactly located in the heart? get to know in the text to come.

Cardiac Muscle Function and Location

Cardiac Muscle Location: Cardiac muscle is fundamentally an involuntary muscle and is located in the walls of the heart. To be precise, it is located in the myocardium. The myocardium is the layer of the heart between the other two layers, visceral and endocardium. All these three layers are packed with blood vessels.

Function of the Cardiac Muscle: The cardiac muscle functions with the help of its cardiac cells. These cells are responsible for the contraction of this muscle and sending blood to the atria and ventricles. That in turn, reaches the blood vessels of the circulatory system. For more on pumping of blood from heart read:

How Does the Heart Pump Blood

How Does the Circulatory System Work

Cardiac Muscle Fibers: The cardiac muscle is not linear, unlike the striated or smooth muscles. It forms instead, a complicated and crisscross network of muscle fibers, in any direction possible. The reason is that it performs the action of squeezing, what is called a bulb. Take an example of a water balloon being applied pressure on by a belt in a single direction. What will happen? Well, some amount of water will still be retained by the balloon. On the contrary, if you squeeze the balloon in all directions, there will be no water left in the balloon. Similarly, the muscle fibers of the cardiac muscle comprise of a mesh, squeezing the chambers of the heart, forcing the blood either in lungs or through the entire body.

Metabolism: Believe it or not, our cardiac muscle does not ever get tired! Imagine the amount of pressure we put on it, it still goes on working, unfettered. The secret to it not being tired lies in the mitochondria. The mitochondria act as fuel plants for the cardiac cells. They generate adenosine triphosphate or ATP, a major source of chemical energy for the muscle. Furthermore, lactate is converted into fuel by the cardiac muscles. This implies that even if the rest of the body is starved, the heart will always have fuel! This is one of the most striking aspects of the cardiac muscle function.

T-Tubules: Interestingly, there are pathways for electrical stimulation to reach and activate the muscle. These are called transverse tubules and even though there are fewer of these in the cardiac muscle, they are broader and larger. This facilitates better signal and activation of the muscle.

Electro Chemical System of the Muscle: If the heart has to function properly, the cardiac muscle needs a special electrical system for sending the correct signals to the corresponding muscle at the appropriate time. This then means that without a delay between the atrium and the ventricles for ensuring that all the blood is pumped out of the heart, it cannot happen. To facilitate this, the heart has sinoatrial node (SA node) for directing the electrical impulses to the right area of the heart at the right time. In addition to this, the SA node also maintains a tension on the muscles all the time. This helps in maintaining of blood pressure and keeps it ready for the next contraction.

That was all about cardiac muscle function. The functioning is attributed to the cells in the muscle. Interestingly, these cells were believed not to regenerate and a heart attack or a surgery was supposed to damage these cells. But now it has been proved that these cells are capable of regeneration.

Well that is the story of our cardiac muscle function it was amazing, wasn't it? It was certainly the case that a very well kept secret of our heart was uncovered!

I sign off here!