Our heart is the strongest muscle from all of the muscles in our body. It main function is to pump the blood to every part of our body through the blood vessels. To perform this task, the heart using contractions movement in regular rhythm.
The heart is also produce a strong peptide hormone called “ANF” to regulate the blood pressure. The hormone is also influence the brain, adrenal glands, blood vein and also kidney’s regulatory region.
Our heart is actually located slightly to the left from the center in our chest below the sternum. Although our heart is the strongest muscle in our body, it is also quite fragile. Therefore, our heart is protected by a sac known as the pericardium and surrounded by our lungs.
In normal person, the weight of our heart is around 300 grams. It is divided in to four rooms consist of 2 upper atria and 2 ventricles at below. To control the blood circulation properly, our heart has valves between the atria and the ventricle.
Regulate the blood to every parts of our body is a big duty for our heart. Our heart’s beat consist from three events that happen in sequence which are; atrial systole, ventricular systole and complete cardiac diastole. This sequence is known as cardiac cycle.
In atrial systole, the atrioventricular valves is closed after the blood left from the atria to prevent the blood flowing back to the atria. You can feel this movement and know it as your own heartbeat. The valve is located between the atria and ventricular chamber.
The next events is the ventricular systole. The ventricles are contracted to flow the blood to the circulation system and then the aortic semilunar and pulmonary valves will closed to prevent the blood going back to the heart.
After the above events, the heart stop moving in very short time to let the blood entering the heart to restart the process from the first even. This event is called as the cardiac diastole.