Human Heart

BiologyHuman biology


The human heart is the center of the cardiovascular system and pumps blood to all body parts.

The heart weighs about 300 grams (10.6 ounces) and is a hollow, muscular organ about the size of a fist. It has four chambers− two upper atria and two lower ventricles. A layer of muscle tissue called the myocardium lines the inside walls of the heart chambers and separated them from each other. The muscle tissue also forms thick layers around each chamber wall that contract to pump blood through the heart.

Position of Heart in the Human Body

The heart is a muscular organ that pumps blood throughout the body. Blood, in turn, carries oxygen to all the organs and tissues of your body, including your brain. During times when you strain your cardiovascular system, such as during vigorous exercise, the heart beats faster and harder to keep up with the demand for oxygen. The heart is also a muscle whose size can be increased with regular exercise.

The heart is located on the left side of the chest, just behind the breastbone (sternum). It's about one-third (or four fingers width) down from the top of the breastbone.

It's called a muscle because it does not contain bone. Other muscles in your body contain both muscle tissue and bone tissue; skeletal muscles are attached to bones by tendons, and nerves control their actions from your spinal cord.

The heart contains only muscle tissue and is therefore located in an open space called a "cavity." Three flat bones protect this cavity called the "ribs" that surround it on each side. The upper two ribs join to form a structure called the "breastbone" or "sternum," which protects and supports the heart on its upper surface.

A protective muscle called the " diaphragm" separates the heart from other organs in the chest. The diaphragm is a muscular partition that divides your body cavity into two parts− one for breathing and another for circulation. The liver is located on the right side of your abdomen under the ribs, just above where your stomach empties its contents into the small intestine. It's about as big as a large football but weighs less than half a pound because it contains very little fat tissue.

The Function of the Heart

The heart is an incredibly important organ in the human body. It's the only muscle in the human body that never rests and pumps three to five liters of blood every minute. The heart is responsible for delivering oxygen-rich blood to all parts of your body, which provides nourishment and removes waste materials. It also helps maintain the right amount of fluid in your body and distribute essential nutrients and hormones. The heart is also capable of amazing feats−it can beat up to 100,000 times a day, or over 3 billion times during an average lifespan. In addition to pumping blood throughout your body, it can generate enough force to pump blood up to 25 feet!

Types of Circulation

There are three types of circulation, two of which you might be familiar with− pulmonary and systemic. Pulmonary circulation is the blood that goes from your heart to your lungs and back again. Systemic circulation is the blood that goes from your heart to the rest of your body. Both of these types of circulation are closed systems in that they take the same path. The third type of circulation is known as open system circulation because it doesn't take the same path.

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With open system circulation, a series of major veins carry oxygenated blood away from the heart and into smaller veins on the other side, which then carry it back to the heart through a separate series of capillaries. In this way, even though it doesn't go through your lungs, there's still a great deal of gas exchange happening in your body.

External Structure of Heart

The external structure of the heart consists of a tough, fibrous sac called the pericardium. This sac is attached to the heart by four cords called the white fibrous ropes (or white ligaments). The two upper cords are longer than the other two. They extend from the base of the heart to anchor points in the chest wall, at the sternum (breast bone), and in front of each shoulder.

The shorter lower cords connect to organs in your abdomen, near your kidneys, and your liver. These cords keep the lower part of your heart anchored and help prevent fluid collected around your lungs from moving upward into your heart.

The front of your heart is covered with a thin membrane called an epicardium. Several small muscles directly beneath this membrane also help circulate blood through your heart. The most important muscle, the apex muscle, pumps blood from beneath the apex (tip) toward its base.

Internal Structure of Heart

The muscular pump that transports blood throughout the body is the heart, which is the system's primary organ. Blood enters the heart through the atria on the left and right and exits through the atria on the left and right. The valves between chambers and those at points in the circulatory system where blood gets pumped out to different organs are also crucial to keeping blood flowing smoothly.

To circulate blood throughout your body, blood enters the right atrium, travels to the right ventricle, and then leaves.


The human heart is a fascinating and complex organ. It is responsible for pumping blood throughout the body and delivering oxygen and nutrients to the cells. The heart is also involved in many other important functions, such as regulating blood pressure and blood sugar levels. It is truly amazing how such a small organ can have such a big impact on our health and well-being.


1. What is the human heart?

The muscular heart of a human being is responsible for the body's blood circulation. All four chambers in the heart are located within the heart. At the base of the neck, the right atrium receives blood through veins and pumps it to the right ventricle, where it receives oxygen from the lungs. After returning from the lungs, blood is pumped to the left ventricle, where it is distributed throughout the body via arteries. Blood carries nutrients and oxygen from the digestive tract and lungs to all cells in our bodies.

2. What does the heart do?

The heart's main function is to continuously circulate blood throughout our bodies so that it can nourish every cell. The heart also acts as a pump for circulating blood throughout your body. In addition, it contains specialized cells called pacemaker cells that keep your heartbeat steady and regular even when you are not doing anything (e.g., sleeping).

3. How does a beating heart occur?

A healthy heart beats approximately 75 times per minute when you're at rest, or about 35 million times yearly! This means that your heart will beat over 2 billion times over your lifetime!

4. What happens when you have a heart attack?

Heart attacks occur when a blood channel carrying oxygen-rich blood to your heart muscle is stopped by a clot or plaque, resulting in tissue necrosis (infarction). If a heart attack goes untreated, it might be fatal.

5. Can you live without your heart?

Without a working heart, you would die within seconds because your lungs would not be able to get enough oxygen into your blood for your body to function properly

Updated on 13-Oct-2022 11:19:47