Here is what no one tells you about the heart- a cliché love story

Sunday night, you are lying in bed. You feel like your heart is aching. Is it a mini-heart attack, or a heartbreak 😊? You wonder how real heart attack would feel like. You start searching the symptoms and it is not long until the results come up; Google thinks there are few options; you are having a heart attack or you have breast cancer or you are about to die!

Even though you are probably having a simple case of stomach acid travelling up to the throat as known as ‘heartburn’ or just cortisol (stress hormone) levels rising up just because you are thinking how busy the Monday is going to be, in some scenarios people actually have heart attacks and die. Diseases of the heart and blood vessels (cardiovascular diseases) are the number 1 killer worldwide. So, it is worth getting concerned about that weird feeling in your chest. 

My project is about looking into structural cells of the heart tissue (fibroblast) and investigate their role in the contraction of the heart muscle cells (cardiomyocytes). This project hopefully will develop the knowledge about how the heart functions and in run allowing improved treatments for cardiovascular diseases. Firstly, the basics of the heart should be explained in order to talk more about my project.

The heart is made up of different types of functional units called cells. Muscle cells and fibroblasts are the main cell types. It is actually very interesting how muscle cells contract to pump the blood into the organs (and yes, the answer is not unicorns and magic). Muscle cells align themselves as functional units called sarcomeres which get shorter, then align to original state every time muscle contracts as shown in the first figure below. There are 3 main proteins; actin, myosin and troponin along with an ion; calcium that is involved in the contraction process. This is where I will tell the love story of actin and myosin.

Actin is desperately in love with handsome myosin, but she is stuck with troponin due to long-standing family commitments (yes, this stuff exists in the 21st century) so cannot get together with myosin, figure 2, 1. Troponin takes actin away from her true love myosin. When there is electrical activity in the heart muscle cell (I would like to think this as ‘the spark’ to fall in love); charming calcium coming from another land called ‘sarcoplasmic reticulum’ falls in love and gets together with troponin, seen in figure 2, 2. Troponin runs away with calcium and forgets about actin. Actin’s heart fills with joy as she gets together with his real love myosin. They get very passionate with each other; myosin is very excited and keeps actin moving along, figure 2, 3. With myosin moving actin along, the muscle units/sarcomeres become shorter therefore heart contracts, can be seen in figure 1.

Unfortunately following this, the spark between calcium and troponin is lost (electrical activity in the heart muscle cell), calcium goes back to its own land and troponin is forced to be with actin by his family thus keeping her away from her only true love myosin again, figure 2,4.

Figure 1- Shortening of sarcomeres; excited actin (red) moving myosin (blue) along- figure from: (, 2020).
Figure 2- Actin and myosin love story explained: 1- Troponin keeps actin away from myosin, 2- Calcium gets together with troponin allowing myosin to get together with actin, 3- Excited myosin moving actin along, 4- Calcium leaves to go his land and actin is stuck with myosin. Figure from: (, 2020)

This is basically what happens in the heart and the story repeats itself every time the heart muscles contract.

I am Nermin. This is all from me for now. Hopefully, I helped you understand how the heart works and made you smile with my cliché love story. Hopefully to meet again to talk more about the heart and its wonders including how fibroblasts relate to this story.

References (2020). Muscle Contraction | BioNinja. [online] Available at: [Accessed 6 Jan. 2020]. (2020). cardiomyopathy. [online] Available at: [Accessed 6 Jan. 2020].