Anatomy the the Heart

The heart is an body organ responsible because that pumping blood with the blood vessels making use of rhythmic contractions of cardiac muscle.

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Key Takeaways

Key PointsThe love is a four-chambered muscular organ containing an involuntary conduction system that initiates rhythmic contractions come pump blood transparent the body.The heart has its very own blood supply and also is controlled by self-regulating nerve bundles dubbed nodes.The SA and also AV nodes send impulses v the Purkinje yarn that reason muscle contractions to the heart.The love is composed of 3 layers: the epicardium (outer layer) which avoids excess development or activity of the heart, the myocardium (middle layer) i beg your pardon initiates contractions control the cardiac cycle, and the endocardium (inner layer) the lines the cavities and valves.The heart includes two top chambers dubbed atria and also two reduced chambers referred to as ventricles. The left and also right sides of the heart room separated through the septum.Valves avoid the backflow of blood and also separate the atria indigenous the ventricle and also the ventricle from the pulmonary artery or aorta.Key Termsheart: A fist-sized muscular body organ in the chest the pumps blood v the body utilizing involuntary contractions of cardiac muscle.ventricle: one of two reduced chambers of the heart that receives blood from the atria and also pumps the out right into pulmonary or systemic circulation, depending upon side.myocardium: The center of the 3 layers creating the wall of the heart, containing cardiac muscle tissue. Innervated by the Purkinje fibers.

The human being heart is the pump for the circulatory system, and in addition to the circulatory system is taken into consideration to it is in an organ of the cardiovascular system. It consists of four chambers and pumps blood through both systemic and pulmonary circulation to allow gas exchange and tissue oxygenation. The heart is located in the thoracic cavity between the lungs and also protected by the rib cage.

Structure that the Heart

The heart is composed of four chambers separated right into two sides. Each side consists of an atria i beg your pardon receives blood into the heart and flows it right into a ventricle, which pumps the blood the end of the heart. The atria and also ventricle on every side that the heart are attached together through valves that protect against backflow the blood. The wall that the end the left and also right side of the love is dubbed the septum.

The left heart deals with systemic circulation, when the best heart encounters pulmonary circulation. The left next of the heart receives oxygenated blood native the pulmonary vein and pumps it right into the aorta, if the ideal side of the heart receives deoxygenated blood native the vena cava and also pumps it into the pulmonary vein. The pulmonary vein and also aorta additionally have valves connecting them come their corresponding ventricle.

The heart has its own self-sustaining conduction mechanism that sends nervous impulses to cardiac tissue. The sinoatrial (SA) and atrioventricular (AV) nodes room bundles that nerve yarn that kind this conduction system. They are located in the left atrial wall surface of the heart and also send nerve impulses to a large, highly committed set of nerves called the Purkinje fibers, which consequently send those nerve impulses come the cardiac muscle tissue. These nodes have the right to send impulses come the love without central nervous system stimulation, however may be influenced by worried stimulation to alter heart rate. The heart likewise has its very own blood supply, the cardiac arteries that provide tissue oxygenation to the heart as the blood within the heart is not offered for oxygenation by the heart.

Cardiac Histology

The love is fastened in a double-walled protective membrane called the pericardium, which is a mesothelium organization of the thoracic cavity. The dual membrane the pericardium contains pericardial liquid which nourishes the heart and prevents shock. This composite sac protects the heart, anchors the to neighboring structures, and prevents the love from overfilling v blood.

The wall of the heart is written of three layers of various tissues. The external layer is referred to as the epicardium, or visceral pericardium, because it is likewise the inner wall surface of the pericardium. The middle layer the the heart, the myocardium, and contains committed cardiac muscle organization responsible because that contraction. Cardiac muscle organization is distinctive from skeleton or smooth muscle since it pumps involuntarily based upon conduction native the AV and also SA nodes. The inner class is dubbed the endocardium and is in call with the blood that the heart pumps. It also merges with the inside lining of blood vessels and covers heart valves. Cardiac tissue is permanent tissue the does no heal or regenerate once damaged. As a result, is vulnerable to scarring and also enlargement due to mechanical stress and also injury.


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The Mammalian Heart: The place of valves ensures suitable directional circulation of blood with the cardiac interior. Note the difference in the thickness of the muscled wall surfaces of the atrium and also the left and also right ventricle.


Key Takeaways

Key PointsThe pericardium is a mesothelium organization of the thoracic cavity which surrounds the heart. The outer layer, the fibrous pericardium, is consisted of of thick connective tissue that protects the heart, anchors it to the neighboring walls, and prevents that from overfilling.The inner class of the pericardium, the serous pericardium, is further split into two layers, an outer parietal layer and also an inside visceral layer with the pericardial cavity in in between the two layers.The serous pericardium attributes to lubricate the heart v pericardial fluid, i beg your pardon is save in the room between the parietal and also visceral layers.Pericarditis is inflammation that the pericardium, often as result of infection, which deserve to constrict and put harmful push on the heart.Key Termsfibrous pericardium: composed of thick connective tissue which protects the heart, anchors it to the surrounding walls, and also prevents the heart from overfilling v blood.serous pericardium: located deeper than the fibrous pericardium, this structure consists of two layers that lubricate the love to stop friction from arising during love activity.pericardium: A serous membrane the surrounds and protects the heart.

The pericardium is the thick, membranous, fluid-filled sac the surrounds the heart and also the root of the vessels the enter and leave this an essential organ, functioning as a protective membrane. The pericardium is just one of the mesothelium organization of the thoracic cavity, in addition to the pleura i m sorry cover the lungs. The pericardium is written of two layers, an outer fibrous pericardium and an within serous pericardium.


Membranes of the Thoracic Cavity: A transverse ar of the thorax, showing the contents of the middle and the posterior mediastinum. The pleural and pericardial cavities are exaggerated since normally over there is no space between parietal and visceral pleura and between pericardium and also heart.


Fibrous Pericardium

The fibrous pericardium is the outer layer the the pericardium. The is created of dense connective organization which anchors the love to the mediastinum that the chest wall. It prevents the heart from overfilling through blood and also protects the from surrounding infections by totally separating the from the remainder of the thoracic cavity. It is continuous with the outer fibrous great of the neighboring good blood vessels.

Serous Pericardium

The serous pericardium, the inner great of the pericardium, is created of two various layers. The external layer, the parietal layer, is completely adhered to the fibrous pericardium. The inner layer is recognized as the visceral layer, which covers and also protects the good vessels and heart. The room between the parietal and also visceral class is referred to as the pericardial cavity.

The visceral great is referred to as the epicardium in the locations where it is in direct contact with the heart. The space between these 2 serous layers, the parietal and the visceral, is the pericardial cavity, which includes pericardial fluid. The serous pericardium, v its 2 membranes and the fluid-filled pericardial cavity, provides protection to the heart and also a lubricated sliding surface ar within i beg your pardon the heart can move in an answer to its own contractions and to the movement of nearby structures such as the diaphragm and the lungs.

Function the the Pericardium

The pericardium is important because it protects the love from trauma, shock, stress, and even epidemic from the surrounding lungs. It support the heart and anchors it come the medastinum so it doesn’t relocate within the body. The pericardium lubricates the heart and prevents it from becoming too huge if blood volume is overloaded (though it will certainly not prevent chronic heart enlargement).

Despite these functions, the pericardium is still breakable to difficulties of that is own. Pericarditis is the term for inflammation in the pericardium, commonly due come infection. Pericarditis is often a severe disease because it can constrict and apply push on the heart and also work against its common function. Pericarditis come in many types depending ~ above which tissue layer is infected.


Layers the the heart Walls

The heart wall is made up of 3 layers: the outer epicardium, the middle myocardium, and also the inside endocardium.


Learning Objectives

Distinguish between the epicardium, myocardium, and also endocardium class of the heart wall


Key Takeaways

Key PointsThe epicardium is a slim layer the connective tissue and fat offer as an additional layer of security for the heart. It is taken into consideration a continuation of the serous pericardium.The myocardium is the muscle organization of the heart, composed of cardiac muscle cells called cardiomyocytes that receive nervous stimulation native the sinoatrial (SA) and also atrioventricular (AV nodes via the Purkinje fibers.Cardiomyocytes are much shorter than bones myocytes, and also contain under nuclei. Cardiac muscle is striated.The endocardium is composed of endothelial cells that carry out a smooth, non-adherent surface for blood collection and also pumping and also may help regulate contractility.An epidemic or inflammation that the endocardium is dubbed infective endocarditis.Key TermsPurkinje fibers: A bundle of nerve fibers located under the endocardium, which supply nervous impulses come the mycardium’s cardiac muscle tissues.endocardium: A thin serous membrane that lines the interior of the heart and also valves.cardiomyocyte: A cardiac muscle cell (or myocyte) in the heart, which makes up the cardiac muscle tissue.

The heart wall is consisted of of three layers, the epicardium (outer), myocardium (middle), and endocardium (inner). These organization layers space highly dedicated and perform various functions. Throughout ventricular contraction, the wave of depolarization from the SA and also AV nodes moves from within the endocardial wall through the myocardial layer to the epicardial surface ar of the heart.

Epicardium


The love Wall: The wall surface of the heart is composed of 3 layers, the thin external epicardium, the thick center myocardium, and also the very thin inside endocardium. The dark area ~ above the heart wall is scar from a vault myocardial infarction (heart attack).


The outer layer the the heart wall surface is the epicardium. The epicardium refers to both the external layer of the heart and also the inner layer of the serous visceral pericardium, i m sorry is attached to the outer wall of the heart. The epicardium is a slim layer that elastic connective tissue and fat the serves as secondary layer of defense from trauma or friction for the love under the pericardium. This layer includes the coronary blood vessels, i beg your pardon oxygenate the tissues of the heart through a blood it is provided from the coronary arteries.

Myocardium

The center layer of the heart wall is the myocardium—the muscle organization of the heart and also the thickest class of the heart wall. That is written of cardiac muscle cells, or cardiomyocytes. Cardiomyocytes are specialized muscle cells that contract like various other muscle cells, but differ in shape. Contrasted to bones muscle cells, cardiac muscle cells are shorter and have actually fewer nuclei. Cardiac muscle organization is likewise striated (forming protein bands) and also contains tubules and also gap junctions, unlike skeleton muscle tissue. As result of their consistent rhythmic contraction, cardiomyocytes call for a committed blood supply to provide oxygen and nutrients and remove waste assets such as carbon dioxide native the cardiac muscle tissue. This blood supply is listed by the coronary arteries.

Endocardium

The inner layer of the heart wall surface is the endocardium, written of endothelial cell that provide a smooth, elastic, non-adherent surface ar for blood collection and pumping. The endocardium may regulate metabolic garbage removal from love tissues and act as a barrier between the blood and also the love muscle, thus managing the composition of the extracellular liquid in which the cardiomyocytes bathe. This consequently can affect the contractility of the heart.

This tissue additionally covers the valves of the heart and is histologically continuous with the vascular endothelium that the significant blood ship entering and leaving the heart. The Purkinje fibers are located simply beneath the endocardium and also send nervous impulses indigenous the SA and also AV nodes exterior of the heart right into the myocardial tissues.

The endocardium can end up being infected, a significant inflammatory problem called infective endocarditis. This and also other potential troubles with the endocardium may damages the valves and impair the normal circulation of blood with the heart.


Chambers the the Heart

The heart has four chambers. The two atria obtain blood right into the heart and the 2 ventricles pump blood right into circulation.


Key Takeaways

Key PointsThe right and also left atria room the optimal chambers that the heart and receive blood right into the heart. The ideal atrium receives deoxygenated blood indigenous systemic circulation and the left atrium receive oxygenated blood native pulmonary circulation.The atria execute not have actually inlet valves, however are separated from the ventricles by valves. The atria facilitate circulation by enabling uninterrupted blood flow into the heart during ventricular systole.The atria have several instrument in location to ensure that venous blood flow isn’t impaired, such together the lack of valves and also the visibility of light and brief contractions throughout atrial systole.The right ventricle pumps deoxygenated blood right into pulmonary circulation. The left ventricle pumps oxygenated blood right into systemic circulation. The left ventricle is thicker due to the fact that systemic circulation requires a much bigger blood volume than pulmonary circulation.Systole defines contraction, as soon as blood is pumped indigenous the heart into circulation by the ventricles. The can likewise describe atrial systole, in i m sorry blood move from the atria to the ventricles during ventricular diastole.Diastole describes relaxation, when blood moves into the love while the ventricles prepare come eject that very same blood throughout systole.Key Termsdiastole: The relaxation and also dilation the the love chambers between contractions, during which they fill with blood.systole: The rhythmic contraction of the heart whereby blood is ejected from one chamber to the next, or out of the heart and into the arteries.

The heart is the complex pump of the circulatory system, pump blood throughout the body for the purposes of tissue oxygenation and also gas exchange. The love has 4 chambers with which blood flows: two sets the each form of room (atria and also ventricles), one every side, each with distinct functions. The left next of the heart deals with systemic circulation when the ideal side that the heart deals with pulmonary circulation.

The Atria

The atria room chambers in i m sorry blood beginning the heart. Lock are situated on the anterior end of the heart, through one atrium on every side. The ideal atrium receives deoxygenated blood native systemic circulation through the premium vena cava and inferior venae cavae. The left atrium receives oxygenated blood from pulmonary circulation v the left and also right pulmonary veins.

Blood passively flows into the atria there is no passing through valves. The atria relax and also dilate (expand) while lock fill through blood in a process called atrial diastole. The atria and also ventricles room separated through the mitral and tricuspid valves. The atria undergo atrial systole, a quick contraction that the atria that ejects blood from the atria with the valves and into the ventricles. The chordae tendinae space elastic tendons that connect to the valve from the ventricles and relax throughout atrial systole and also ventricular diastole, yet contract and close turn off the valve throughout ventricular systole.

One of the defining qualities of the atria is that they perform not impede venous circulation into the heart. Atria have 4 essential qualities that cause them come promote constant venous flow:

There are no atrial inlet valves to interrupt blood flow during atrial systole. The venous blood entering the heart has a an extremely low pressure compared to arterial blood, and also valves would need venous blood press to develop up over a long duration of time to get in the atria.The atrial systole contractions room incomplete and also do not block circulation from the veins v the atria right into the ventricles. Throughout atrial systole, blood not only empties native the atria come the ventricles, yet continues to flow uninterrupted from the veins appropriate through the atria into the ventricles.The atrial contractions room slight, preventing far-ranging back press that would impede venous flow.The be safe of the atria is combination to begin before the begin of ventricular contraction, which also helps protect against the love from beating too slowly.

Ventricles

The ventricles are situated on the posterior end of the love beneath their matching atrium. The right ventricle obtain deoxygenated blood native the ideal atria and also pumps it through the pulmonary vein and into pulmonary circulation, i beg your pardon goes right into the lungs for gas exchange. The left ventricle receive oxygenated blood from the left atria and pumps it with the aorta right into systemic circulation to it is provided the tissues of the body v oxygen.

The walls of the ventricles room thicker and also stronger than those of the atria. The physiologic fill on the ventricles, which pump blood transparent the body and also lungs, is much greater than the pressure generated by the atria to to fill the ventricles. Further, the left ventricle has thicker walls than the right due to the fact that it pumps blood throughout the body, while the appropriate ventricle pumps only to the lungs, i beg your pardon is a much smaller volume of blood.

During ventricular diastole, the ventricles relax and also fill through blood. During ventricular systole, the ventricles contract, pump blood through the semi-lunar valves right into systemic circulation.


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Structure the the heart: framework diagram that a coronal section of the human being heart from an anterior view. The two larger chambers room the ventricles.


Key Takeaways

Key PointsFive great vessels enter and leave the heart: the superior and inferior vena cava, the pulmonary artery, the pulmonary vein, and the aorta.The superior vena cava and also inferior vena cava space veins that return deoxygenated blood native circulation in the body and empty it into the appropriate atrium.The pulmonary artery carries deoxygenated blood from the best ventricle into the lungs because that oxygenation.The pulmonary veins bring oxygenated blood native the lungs right into the left atrium wherein it is went back to systemic circulation.The aorta is the largest artery in the body. It carries oxygenated blood from the left ventricle of the heart right into systemic circulation.The aorta has many subdivisions that branch off right into smaller arteries. These subdivisions space the ascending and also descending aorta, the aortic arch, and the thoracic and ab aorta.Key Termspulmonary arteries: The arteries the take deoxygenated blood away from the right side the the heart and also into the capillaries that the lungs because that the purpose of gas exchange.aorta: The good artery i beg your pardon carries the blood from the heart into systemic circulation.venae cavae: The two large vessels, the superior and inferior vena cava, that lug deoxygenated blood native systemic circulation come the heart.

The person circulatory device is a dual system, definition there are two separate systems the blood flow: pulmonary circulation and systemic circulation. The adult human being heart consists of two separated pumps, the right side (right atrium and ventricle,) i m sorry pumps deoxygenated blood into the pulmonary circulation, and also the left next (left atrium and also ventricle), which pumps oxygenated blood into the systemic circulation. Good vessels are the major vessels that bring blood into the heart and also away from the love to and also from the pulmonary or systemic circuit. The an excellent vessels collect and also distribute blood across the human body from plenty of smaller vessels.

The Venae Cavae


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The Systemic Circuit: The venae cavae and also the aorta type the systemic circuit, i beg your pardon circulates blood come the head, extremities and abdomen.


The superior and also inferior vena cava are jointly called the venae cavae. The venae cavae, together with the aorta, room the great vessels involved in systemic circulation. These veins return deoxygenated blood indigenous the body right into the heart, emptying it into the best atrium. The venae cavae room not separated from the appropriate atrium by valves.

Superior Vena Cava

The exceptional vena cava is a large, short vein that carries deoxygenated blood from the upper fifty percent of the human body to the right atrium. The right and also left subclavian veins, jugular veins, and thyroid veins feed right into the superior vena cava. The subclavian veins are far-ranging because the thoracic lymphatic duct drains lymph liquid into the subclavian veins, making the remarkable vena cava a website of lymph fluid recirculation into the plasma. The exceptional vena cava begins over the heart.

Inferior Vena Cava

The inferior vena cava is the largest vein in the body and carries deoxygenated blood from the lower half of the body right into the heart. The left and also right typical iliac veins converge to form the worse vena cava in ~ its shortest point. The worse vena cava starts posterior come the abdominal muscle cavity and travels come the heart next to the ab aorta. Along the method up the body from the iliac veins, the renal and suprarenal veins ( kidney and also adrenal glands), lumbar veins (from the back), and also hepatic veins (from the liver) all drain into the inferior vena cava.

The Aorta

The aorta is the biggest of the arteries in systemic circulation. Blood is pumped native the left ventricle v the aortic valve into the aorta. The aorta is a very elastic artery and also is able to dilate and constrict in solution to blood pressure and also volume. As soon as the left ventricle contracts to force blood with the aortic valve right into the aorta, the aorta expands. This development provides potential energy to assist maintain blood pressure during diastole, as soon as the aorta passively contracts. Blood push is highest possible in the aorta and also diminishes with circulation, reaching its lowest points in ~ the end of venous circulation. The distinction in pressure in between the aorta and right atrium accounts for blood circulation in the circulation, together blood flows from locations of high press to areas of low pressure.

Components that the Aorta

The aortic arch contains peripheral baroreceptors (pressure sensors) and also chemoreceptors (chemical sensors) the relay information worrying blood pressure, blood pH, and also carbon dioxide level to the medulla oblongata that the brain. This info is handle by the mind and the autonomic nervous device mediates the homeostatic responses that involve feedback in the lungs and kidneys. The aorta extends roughly the heart and travels downward, diverging into the iliac arteries. The five components of the aorta are:

The ascending aorta lies in between the heart and also the arch that aorta. It breaks off right into the aortic sinuses, some of which form the coronary arteries.The arch of aorta is the height of the aorta, which breaks off right into the left carotid artery, brachiocephalic trunk, and also the left subclavian artery.The diminish aorta is the section from the arch of aorta to the point where the divides right into the typical iliac arteries. That is subdivided into the thoracic and ab aorta.The thoracic aorta is the part of the to decrease aorta over the diaphragm. That branches off right into the bronchial, mediastinal, esophageal, and phrenic arteries.The ab aorta is the part of the descending aorta listed below the diaphragm, which divides into the iliac arteries and branches right into the renal and also suprarenal arteries. This component of the aorta is fragile to bursting and hemorrhage (aneurysm) indigenous persistently high blood pressure.

The Pulmonary Arteries

The pulmonary arteries carry deoxygenated blood from the best ventricle into the alveolar capillaries the the lungs to unloading carbon dioxide and also take increase oxygen. These room the only arteries that lug deoxygenated blood, and are considered arteries because they lug blood far from the heart. The short, large vessel branches into the left and right pulmonary arteries that provide deoxygenated blood come the particular lungs. Blood very first passes v the pulmonary valve together it is ejected right into the pulmonary arteries.


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Pulmonary circuit: chart of pulmonary circulation. Oxygen-rich blood is displayed in red; oxygen-depleted blood in blue.


The Pulmonary Veins

The pulmonary veins lug oxygenated blood native the lungs to the left atrium the the heart. In spite of carrying oxygenated blood, this great vessel is still considered a vein since it tote blood towards the heart. 4 pulmonary veins enter the left atrium. The best pulmonary veins happen behind the ideal atrium and also superior vena cava if the left happen in front of the to decrease thoracic aorta. The pulmonary arteries and veins are both considered component of pulmonary circulation.


Myocardial Thickness and Function

The myocardium (cardiac muscle) is the thickest ar of the heart wall and consists of cardiomyocytes, the contractile cell of the heart.


Key Takeaways

Key PointsCoordinated convulsion of cardiomyocytes reasons the love to contract and also expel blood right into circulation.The myocardium is thickest in the left ventricle, together the left ventricle must develop a lot of pressure come pump blood into the aorta and throughout systemic circulation.Cardiac muscle has a high density of mitochondria and also a large blood supply, which store it functioning continuously.Sarcomeres room the basic unit that muscle tissue, composed mainly of actin and myosin myofibrils.The heart’s thickness may change over time and also adapt to compensate for diseases, which frequently results in heart failure.Key TermsCardiac hypertrophy: an adaptive disease in i m sorry the walls of the heart come to be too thick to pump blood effectively. That is typically a complication of hypertension.sarcomere: The an easy contractile unit that contractile muscle, which includes myofibril filaments made the end of myosin and actin, the two proteins the slide previous one an additional to cause a muscle contraction.cardiomyocyte: A cardiac muscle cabinet (myocyte) in the heart.

The myocardium, or cardiac muscle, is the thickest section of the heart wall and consists of cardiomyocytes, the contractile cells of the heart. Together a kind of muscle tissue, the myocardium is unique amongst all various other muscle organization in the person body. The thickness of the myocardium identify the toughness of the heart’s capability to pump blood.

Myocardial Histology

The structure of cardiac muscle shares some characteristics with bones muscle, yet has countless distinctive attributes of that own. Cardiomyocytes are shorter than skeleton myocytes and have fewer nuclei. Each muscle fiber connects to the plasma membrane (sarcolemma) through distinctive tubules ( T-tubule ). At this T-tubules, the sarcolemma is studded v a big number the calcium networks which allow calcium ion exchange at a rate much quicker than that of the neuromuscular junction in skeleton muscle. The flux the calcium ions into the muscle cells reasons stimulates an activity potential, which causes the cell to contract.

Cardiac muscle, prefer skeletal muscle, is comprised of sarcomeres, the basic, contractile units of muscle. Sarcomeres are composed of long, fibrous proteins the slide previous each other once the muscles contract and also relax. Two of the crucial proteins found in sarcomeres space myosin, which develops the special filament, and also actin, which forms the thin filament. Myosin has a long, fibrous tail and a globular head that binding to actin. The myosin head also binds to ATP, the source of energy for to move metabolism, and is compelled for the cardiomyocytes to sustain us and role normally. Together, myosin and actin kind myofibril filaments, the elongated, contractile threads uncovered in muscle tissue. Cardiac muscle and skeletal muscle both save on computer the protein myoglobin, which shop oxygen.

Cardiac muscle is adapted to be very resistant to fatigue. Cardiomyocytes have actually a big number that mitochondria, enabling consistent aerobic respiration. Cardiac muscle additionally has a large blood supply loved one to that size, which offers a continuous stream that nutrients and oxygen while providing ample remove of metabolic waste.


Cardiac Muscle: The tissue framework of cardiac muscle consists of sarcomeres that space made of myofibrils through intercalated disks, the contain cardiomyocytes and also have numerous mitocondria.


Myocardial Thickness

The myocardium has actually variable level of thickness within the heart. Chambers the the heart with a thicker myocardium space able to pump blood with more pressure and force contrasted to chambers the the heart with a thinner myocardium. The myocardium is thinnest in ~ the atria, together these chambers mainly fill through passive blood flow. The right ventricle myocardium is thicker than the atrial myocardium, as this muscle should pump all blood return to the heart right into the lungs because that oxygenation. The myocardium is thickest in the left ventricle, together this chamber have to create comprehensive pressure to pump blood into the aorta and throughout systemic circulation.

The thickness of the myocardium may change in some individuals as a compensatory adaptation to disease, one of two people thickening and ending up being stiff or becoming thinner and flabby. Cardiac hypertrophy is a common result of hypertension (high blood pressure) in i beg your pardon the cells of the myocardium enlarge as an adaptive solution to pumping versus the higher pressure. Eventually, hypertrophy may become so major that heart fail occurs when the love becomes therefore stiff that it can no much longer pump blood. A flabby heart is commonly the an outcome of myocardial infections, in i beg your pardon the love muscle becomes so weak the it cannot properly pump blood, which likewise leads to love failure.


Right Ventricular Hypertrophy: If the love adapts to become too thick, it will not have the ability to pump blood as efficiently, and also heart failure might occur.


Key Takeaways

Key PointsThe cardiac skeleton consists of four bands of dense connective tissue, called fibrous rings, the surround the basic of the pulmonary trunk, aorta, and also mitral and also tricuspid valves.The love ‘s fibrous skeleton stop the circulation of electric currents between the chambers the the heart so that it only flows through the atrioventricular (AV) bundle. This reasons a delay in depolarization so the the ventricles contract after lock fill with blood.The AV bundle is a bundle of electrically-connected cardiomyocytes that transmit impulses indigenous the AV node come the apex of the heart. That is located in the center of the cardiac skeleton.The cardiac skeleton consists mainly of the protein collagen, a glycoprotein uncovered in every connective tissues.Key Termscollagen: A glycoprotein that develops elongated fibers, usually uncovered in the extracellular matrix of connective tissue.fibrous rings: Four thick bands of tough elastic organization that encircle the bases the the valves that the heart.

The cardiac skeleton, or fibrous skeleton that the heart, is the structure of thick connective tissue that separates the atria native the ventricles. The fibrous skeleton provides vital support because that the heart and separates the circulation of electric impulses through the heart.

Fibrous Ring Structure


Fibrous ring of the Heart: Transverse section of the heart reflecting the fibrous rings neighboring the valves.


The primary structure that cardiac skeleton is composed of four dense bands of difficult elastic tissue called fibrous rings the encircle the bases that the love valves. The fibrous skeleton is composed generally of collagen, a protein discovered in every form of connective tissue in the person body. Over there are 4 fibrous rings:

The aortic ring encircles the aortic valve. It offers support for the aortic valve so the it is open, yet does not have actually backflow.The pulmonary ring encircles the pulmonary valve. Similar to the aortic ring, it provides structural assistance for the pulmonary valve.The left fibrous ring encircles the bicuspid valve. This ring is the thickest and strongest of every the fibrous rings due to the thickness of the left ventricle, which requires more structural assistance than the other chambers that the heart. It additionally surrounds the coronary arteries and AV node.The best fibrous ring encircles the tricuspid valve. It additionally surrounds the coronary arteries and AV node.

The fibrous skeleton gives a good amount the structural and functional assistance for the valves of the heart by enabling them to continue to be open and provides a allude of attachment because that the valves to the wall of the heart.

Electrical Functions

The fibrous skeleton the the love acts together an insulator because that the circulation of electrical current across the heart. It stops the flow of electricity between the various chambers that the heart so that electric impulses execute not flow directly between the atria and also ventricles. The sinoatrial (SA) node lies ~ above the top of the heart, when the AV node is located at the facility of the fibrous skeleton, the just path through which electricity can flow through the heart.

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This electrical separation is important for cardiac function, because electrical impulses circulation from the optimal of the heart to the bottom the the heart. The separation enables the AV node and also AV bundle to hold-up the tide of depolarization so that the atria have the right to contract and also assist in ventricular filling prior to the ventricles themselves depolarize and contract. There is no the fibrous skeleton the the heart, the heart’s ability to pump blood would certainly be significantly less efficient due to the fact that the ventricles would certainly contract prior to filled come capacity. The fibrous skeleton the the heart also protects versus cardiac arrhythmias.