Location Of The Heart In Human Body – The heart is a muscular organ about the size of a closed fist that acts as the body’s circulatory pump. It takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before being pumped into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body). The heart is located in the chest cavity medial to the lungs and posterior sternum.
At its upper end, the base of the heart is attached to the aorta, mycontentbreak pulmonary arteries and veins, and the vena cava. The lower tip of the heart, known as the apex, rests just above the diaphragm. The base of the heart is located along the midline of the body with the apex pointing to the left side. Since the heart points to the left, about 2/3 of the heart’s mass is on the left side of the body and the other 1/3 is on the right.
- 1 Location Of The Heart In Human Body
- 2 Heart Block: Types, Causes, Symptoms, And Risk Factors
Location Of The Heart In Human Body
The heart sits in a fluid-filled cavity called the pericardial cavity. The walls and lining of the pericardial cavity is a special membrane called the pericardium. The pericardium is a type of serous membrane that produces serous fluid to lubricate the heart and prevent friction between the constantly beating heart and its surrounding organs. In addition to lubrication, the pericardium serves to hold the heart in place and maintain a hollow space for the heart to expand into when full. The pericardium has 2 layers – a visceral layer that covers the outside of the heart and a parietal layer that forms a sac around the outside of the pericardial cavity.
Heart Block: Types, Causes, Symptoms, And Risk Factors
The thickness of the heart wall varies in different parts of the heart. The heart’s atria have a very thin myocardium because they do not have to pump the blood very far – only to the nearby ventricles. The ventricles, on the other hand, have a very thick myocardium to pump blood to the lungs or throughout the body. The right side of the heart has less myocardium in its walls than the left because the left side has to pump blood throughout the body while the right only has to pump to the lungs.
The heart contains four chambers: right atrium, left atrium, right ventricle, and left ventricle. The atria are smaller than the ventricles and have thinner, less muscular walls than the ventricles. The atria act as receiving chambers for blood, so they are connected to the veins that carry blood to the heart. The ventricles are the larger, stronger pumping chambers that send blood out of the heart. The ventricles are connected to the arteries that carry blood away from the heart.
The chambers on the right side of the heart are smaller and have less myocardium in the heart wall compared to the left side of the heart. This difference in size between the sides of the heart is related to their functions and the size of the two circulatory loops. The right side of the heart maintains pulmonary circulation to the nearby lungs while the left side of the heart pumps blood all the way to the body’s extremities in the systemic circulatory loop.
The heart works by pumping blood both to the lungs and to the body’s systems. To prevent blood from flowing backward or “resurfacing” back into the heart, there is a system of one-way valves in the heart. The heart valves can be divided into two types: atrioventricular and semilunar valves.
Heart (right And Left Atrium): Anatomy And Function
The heart can both set its own rhythm and conduct the signals necessary to maintain and coordinate this rhythm throughout its structures. About 1% of the cardiac muscle cells in the heart are responsible for forming the conduction system that determines the rate of the rest of the heart muscle cells.
The conduction system begins with the heart’s pacemaker – a small bundle of cells called the sinoatrial (SA) node. The SA node is located in the wall of the right atrium inferior to the superior vena cava. The SA node is responsible for setting the heart rate as a whole and directly signals the atria to contract. The signal from the SA node is picked up by another mass of conducting tissue called the atrioventricular (AV) node.
The AV node is located in the right atrium in the lower part of the interatrial septum. The AV node picks up the signal sent by the SA node and sends it through the atrioventricular (AV) bundle. The AV bundle is a string of conducting tissue that runs through the interatrial septum and into the interventricular septum. The AV bundle divides into left and right branches at the interventricular septum and continues to run through the septum until they reach the apex of the heart. Many Purkinje fibers branch from the left and right branches that carry the signal to the walls of the ventricles, stimulating the heart muscle cells to contract in a coordinated manner to efficiently pump blood out of the heart.
The cardiac cycle includes all the events that take place during one heartbeat. There are 3 phases in the cardiac cycle: atrial systole, ventricular systole and relaxation.
Representing Human Heart Inside A Body High Res Vector Graphic
Oxygenated blood returning from the body first enters the heart from the superior and inferior vena cava. The blood enters the right atrium and is pumped through the tricuspid valve into the right ventricle. From the right ventricle, the blood is pumped through the pulmonary semilunar valve into the pulmonary trunk.
The pulmonary trunk transports blood to the lungs where it releases carbon dioxide and absorbs oxygen. The blood in the lungs returns to the heart through the pulmonary veins. From the pulmonary veins, blood enters the heart again in the left atrium.
The left atrium contracts to pump blood through the bicuspid (mitral) valve into the left ventricle. The left ventricle pumps blood through the aortic semilunar valve into the aorta. From the aorta, blood enters systemic circulation throughout the body tissues until it returns to the heart via the vena cava and the cycle repeats.
The electrocardiogram (also known as EKG or EKG) is a non-invasive device that measures and monitors the electrical activity of the heart through the skin. The EKG produces a distinct waveform in response to the electrical changes taking place in the heart.
Human Cardiovascular System Organs, Functions, Diseases
The first part of the wave, called the P wave, is a small increase in voltage of about 0.1 mV that corresponds to the depolarization of the atria during atrial systole. The next part of the EKG wave is the QRS complex which has a small voltage drop (Q), a large voltage peak (R) and another small voltage drop (S). The QRS complex corresponds to the depolarization of the ventricles during ventricular systole. The atria also repolarize during the QRS complex, but have almost no effect on the EKG because they are so much smaller than the ventricles.
The last part of the EKG wave is the T wave, a small peak that follows the QRS complex. The T wave represents the ventricular repolarization during the relaxation phase of the cardiac cycle. Variations in the waveform and spacing of EKG waves can be used clinically to diagnose the effects of heart attacks, congenital heart problems, and electrolyte imbalances.
The sounds of a normal heartbeat are called “thumps” and “thuds” and are caused by blood pushing against the heart valves. The “lub” sound comes first in the heartbeat and is the longer of the two heartbeats. The “thump” sound is produced by the closure of the AV valves at the beginning of ventricular systole. The shorter, sharper “thud” sound is similarly caused by the closing of the semilunar valves at the end of ventricular systole. During a normal heartbeat, these sounds are repeated in a regular thump-thump-pause pattern. Any additional sounds such as fluid rushing or gurgling indicate a structural problem in the heart. The most likely causes of these extraneous sounds are atrial or ventricular septal defects or valve leaks.
Cardiac output (CO) is the volume of blood pumped by the heart in one minute. The equation used to find cardiac output is: CO = Stroke volume x heart rate
Ch. 18 Lecture Outline
Stroke volume is the amount of blood pumped into the aorta during each ventricular systole, usually measured in milliliters. Heart rate is the number of heartbeats per minute. The average heart can push around 5 to 5.5 liters per minute at rest.
Heart disease is very common, disrupts the normal function of this important organ and often causes death. Visit our Diseases and Conditions section to learn more about common cardiovascular diseases and how we can prevent them. For information about your personal genetic risks for a variety of conditions involving the heart (such as those resulting from hemochromatosis or G6PDD, to name two very common inherited diseases), learn more about DNA health testing. The crucial importance of the heart is obvious. Assuming an average
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