When the Heart Contracts and Relaxes

In a normal and healthy heart, there are only two audible heart murmurs: S1 and S2. S1 is the sound produced by the closure of the atrioventricular valves during ventricular contraction and is usually described as “lub” or first heart tone. The second cardiac tone, S2, is the sound of crescent-shaped valves that close during the ventricular diastole and is described as a “dub” (Figure 3). In both cases, when the valves close, the openings inside the atrioventricular septum protected by the valves are reduced, and blood flow through the opening becomes more turbulent until the valves are completely closed. There is a third heart tone, S3, but it is rarely heard in healthy people. It can be the sound of blood flowing through the atria, or blood sliding back and forth into the ventricle, or even tension in the chords tendineae. S3 can be heard in teenagers, some athletes and pregnant women. If the noise is heard later in life, it may indicate congestive heart failure, which warrants further testing. Some cardiologists refer to the collective sounds S1, S2 and S3 as “Kentucky gallops” because they mimic those produced by a galloping horse. The fourth cardiac tone, S4, results from the contraction of the atria pushing blood into a stiff or hypertrophic ventricle, indicating failure of the left ventricle. S4 occurs before S1 and the collective sounds S4, S1 and S2 are called by some cardiologists a “Tennessee gallop” because they resemble the sound of a galloping horse with a different gait.

Some people may have both S3 and S4, and this combined sound is called S7. The right side of the heart receives oxygen-depleted blood because most of it has been consumed by the brain and body. It pumps this into your lungs, where it absorbs a new supply of oxygen. The blood then returns to the left side of the heart, ready to be pumped to the brain and the rest of your body. At the beginning of a pumping cycle, oxygen-depleted blood, shown here in blue, returns to the heart after circulating through your body. Problems with your cardiovascular system include: During the early phase of ventricular diastole, when the ventricular muscle relaxes, the pressure on the blood remaining in the ventricle begins to decrease. When the pressure in the ventricles of the lung shaft and aorta falls below the pressure, the blood returns to the heart, creating the dicrotic notch (small hollow) seen in blood pressure measurements. The crescent-shaped valves close to prevent reflux into the heart. Because the atrioventricular valves remain closed at this site, the blood volume in the ventricle does not change, so the early phase of the ventricular diastole is called the isovole ventricular relaxation phase, also known as the isovolumetric ventricular relaxation phase (see figure below). Liquids, whether gases or liquids, are materials that flow according to pressure gradients, that is, they move from regions with higher pressure to regions with lower pressure. As a result, when the ventricles of the heart are relaxed (diastole), blood circulates pressure types in the atria.

When blood flows through the atria, the pressure increases, so the blood initially passively moves from the atria into the ventricles. When the action potential causes the muscles of the atria (atrial systemstole) to contract, the pressure inside the atria continues to increase and pumps blood into the ventricles. During ventricular systole, the pressure in the ventricles increases and pumps blood from the right ventricle to the pulmonary trunk and from the left ventricle to the aorta. Even if you look at this flow and connect it to the path of the line, the elegance of the system should become obvious. Eventually, your arteries can become so narrow that they can`t supply enough blood to your heart. This can cause angina pectoris – pain or discomfort in the chest, arm, neck, abdomen or jaw. Usually, your heart beats between 60 and 100 times per minute. This regular rhythmic beat depends on the electrical signals that are conducted into your heart. Figure 3. In this figure, the x-axis reflects time with a recording of the sounds of the heart.

The y-axis represents the pressure. If your heart muscle can`t meet your body`s needs for blood and oxygen, you may develop various symptoms, such as shortness of breath, extreme fatigue, and ankle swelling. This is called heart failure because your heart has failed to pump blood through the body and work efficiently. If your coronary arteries are narrowed or blocked, the blood supply to your heart will be affected. This is the most common form of heart disease, known as coronary artery disease (sometimes called coronary artery disease or ischemic heart disease). Blood pressure is the force of the blood that presses against the walls of the arteries. Strength is generated with each heartbeat when blood is pumped from the heart into the blood vessels. The size and elasticity of the walls of the arteries also affect blood pressure. Every time the heart beats (contracts and relaxes), pressure is created in the arteries. The open space in the ventricles may be limited by a heart muscle that “fills” due to overload or other causes, or that stiffens and loses its flexibility. Treatments that cardiac groups suggest might work include angioplasty or bypass surgery, when blood flow in cholesterol-blocked coronary arteries impairs heart function, and the use of diuretics, ACE inhibitors, beta-blockers, or calcium channel blockers to relieve symptoms. Observing salt and fluid intake, as well as regular exercise, can also be helpful.

Your heart is a pump. It is a muscular organ the size of your fist and is located slightly to the left of the center of your chest. The cardiac cycle involves complete relaxation and contraction of the atria and ventricles and lasts about 0.8 seconds. Starting with all the cavities of the diastole, blood passively flows from the veins into the atria and passes the atrioventricular valves into the ventricles. The atria begin to contract after depolarization of the atria (atrial systole) and pump blood into the ventricles. The ventricles begin to contract (ventricular systole), which increases the pressure in the ventricles. When the ventricular pressure rises above the pressure in the atria, blood flows to the atria, producing the first heart tone, S1 or Lub. When the pressure in the ventricles increases on two main arteries, the blood pushes to open the two crescent-shaped valves and moves into the pulmonary trunk and aorta in the ventricular ejection phase. After ventricular repolarization, the ventricles begin to relax (ventricular diastoles) and the pressure in the ventricles decreases. When ventricular pressure drops, blood from the main arteries tends to flow back into the atria, creating the dicrotic notch on the ECG and closing the two crescent-shaped valves. The second heart tone, S2 or dub, occurs when the crescent-shaped valves close.

When the pressure drops below that of the atria, blood travels from the atria to the ventricles, opens the atrioventricular valves and marks a complete cardiac cycle. The valves prevent blood from flowing back. Failure of the valves to function properly creates turbulent blood flow in the heart; The resulting heart murmur is often heard with a stethoscope. diastole:: Period of time when the heart muscle is relaxed and the chambers fill with blood These layers are surrounded by the pericardium, a thin outer skin that protects your heart. Initially, when the muscles of the ventricle contract, the blood pressure in the chamber increases, but it is not yet high enough to open the crescent-shaped valves (pulmonary and aortic) and be expelled from the heart. However, blood pressure rises rapidly above that of the atria, which are now relaxed and diastole. This increase in pressure causes blood to flow back to the atria, closing the tricuspid and mitral valves. Since no blood is expelled from the ventricles at this early stage, the volume of blood in the chamber remains constant. Therefore, this initial phase of ventricular systole is called isovolume contraction, also known as isovolumetric contraction (see figure below).

The conduction system keeps your beating heart in a coordinated and normal rhythm, which in turn maintains blood circulation. This results in a continuous exchange of oxygen-rich blood with oxygen-depleted blood, which is necessary to keep you alive. There are four chambers that form the heart – two on the left and two on the right. Figure 1. The cardiac cycle begins with the atrial sysstole and progresses to the ventricular systole, atrial diastole and ventricular diastole when the cycle begins again. Correlations with ecg are highlighted. In the second phase of ventricular systole, the ventricular ejection phase, the contraction of the ventricular muscle increased the pressure in the ventricle to such an extent that it is greater than the pressure in the pulmonary trunk and aorta. Blood is pumped out of the heart and squeezes the valves of the lung and aortic crescent. .