Do you know about the Cardiac Cycle?

Ever wondered how your HEART works continuously..! Heart never stops it’s function even when either if you doing something or don’t..! It’s amazing thing in itself like working without a second of break. So, come with us we will explain you about heart and how it functions continuously.

• We all knows that heart beats average 72 times per minute i.e. over 100,000 times per day.
• Your heart pumps about 1.5 gallons of blood every minute.
• Your heart can weigh between 7 and 15 ounces.

Structure & Functions of heart:

The human heart is about the size of a human fist. Your heart is divided into four chambers:
You have two chambers on the top (atria) and two on the bottom (ventricles), one on each side of the heart.

• Right atrium
• Right ventricle
• Left atrium
• Left ventricle

Basically consisting of two atria and two ventricles, the atria receive blood, while the ventricles pump blood. The right atrium receives blood from the superior and inferior vena cavass and the coronary sinus, blood then moves to the right ventricle where it is pumped to the lungs.

There is four heart valves too, which keep blood flowing in the right direction, are the:

• Mitral
• Tricuspid
• Pulmonary
• Aortic valves

Each valve has flaps (leaflets) that open and close once per heartbeat.

There are 3 layers or walls of heart:

1. Epicardium
2. Myocardium
3. Endocardium

The arteries of heart:
Aorta, pulmonary trunk and right and left pulmonary arteries, right coronary artery, left main coronary artery.

The veins of heart:
Superior vena cava, inferior vena cava, right and left pulmonary veins, great cardiac vein, middle cardiac vein, small cardiac vein, anterior cardiac veins.

The main cells of heart:
Cardiac fibroblasts (CFs), Cardiomyocytes, smooth muscle cells (SMCs), and Endothelial cells (ECs).

The functions of the heart are:

1. Pumping oxygenated blood to other body parts.
2. Pumping hormones and other vital substances to different parts of the body.
3. Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.
4. Maintaining blood pressure.
5. Controls the rhythm and speed of your heart rate:

• Sinoatrial (SA) node– Referred to as the pacemaker of the heart, it sends electrical impulses that make your heartbeat.
• Atrioventricular (AV) node- Sends electrical impulses into the ventricles.

Hence, they’re responsible for maintaining rhythm of heartbeat.

Now, we will tell you about Cardiac cycle in detail as it is important to know that how it pumps blood or functions continuously. If you know once about it cycle and mechanism then you can make your heart happy with removing unnecessary loads on it & keep your heart healthy. In 2016, the estimated prevalence of CVDS in India was estimated to be 54.5 million. One in 4 deaths in India are now because of CVDs with heart disease and stroke responsible for >80% of this burden. That’s why it’s must to know about heart health.

Sometimes we all experiences the fast heartbeat while doing exercises, running, using stairs or lifting something heavy. If you doing this things regularly then you’ll definitely fit and fine but if you don’t then you only puts extra burden over your heart & pressurize it suddenly.

Let’s know about Cardiac Cycle..!

A healthy heart and a typical rate of 70 to 75 beats per minute, each cardiac cycle, or heartbeat, takes about 0.8 seconds to complete the cycle.

It consists of two periods: one during which the heart muscle relaxes and refills with blood, called Diastole, following a period of robust contraction and pumping of blood, called Systole.

1. When the cardiac cycle begins, all four chambers are relaxed, and the ventricles are partially filled with blood.
2. During atrial systole, the atria contract, completely filling the relaxed ventricles with blood. Atrial systole lasts 100 msec.
3. Atrial systole ends and atrial diastole begins and continues until the start of the next cardiac cycle. As atrial systole ends, ventricular systole begins. This period, which lasts 270 m sec, can be divided into two phases.
4. Ventricular systole first phase: Ventricular contraction pushes the AV valves closed but does not create enough pressure to open the semilunar valves. This is known as the period of isovolumetric contraction.
5. Ventricular systole second phase: As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is forced out of the ventricle. This is known as the period of ventricular ejection.
6. Ventricular diastole early: As the ventricles relax, the pressure in them drops; blood flows back against the cusps of the semilunar valves and forces them closed.
7. Blood flows into the relaxed atria but the AV valves remain closed. This is known as the period of isovolumetric relaxation.
8. Ventricular diastole -late: All chambers are relaxed. The ventricles fill passively to roughly 70% of their final volume.
9. Ventricular diastole lasts 530 m sec (the 430 m sec remaining in this cardiac cycle, plus the first 100 m sec of the next). Throughout the rest of this cardiac cycle, filling occurs passively, and both the atria and the ventricles are relaxed. The next cardiac cycle begins with atrial systole and the completion of ventricular filling.

You have to do to these things to keep your heart healthy…

• Exercise regularly.
• Sleep well.
• No stress.
• Healthy diet.
• Morning walk.
• Take a break.