Anatomy of the Heart

The heart is an organ responsible for pumping blood through the blood vessels using rhythmic contractions the cardiac muscle.

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Key Takeaways

Key PointsThe heart is a four-chambered muscular body organ containing one involuntary conduction mechanism that initiates rhythmic contractions to pump blood transparent the body.The heart has actually its own blood supply and is managed by self-regulating nerve bundles called nodes.The SA and AV nodes send impulses v the Purkinje yarn that cause muscle contractions to the heart.The heart is created of 3 layers: the epicardium (outer layer) which avoids excess expansion or movement of the heart, the myocardium (middle layer) i beg your pardon initiates contractions steering the cardiac cycle, and also the endocardium (inner layer) the lines the cavities and valves.The heart contains two top chambers called atria and two reduced chambers called ventricles. The left and also right political parties of the heart are separated through the septum.Valves protect against the backflow that blood and also separate the atria native the ventricle and the ventricle from the pulmonary artery or aorta.Key Termsheart: A fist-sized muscular organ in the chest that pumps blood v the body using involuntary contractions of cardiac muscle.ventricle: one of two reduced chambers of the heart that receives blood native the atria and also pumps that out into pulmonary or systemic circulation, depending on side.myocardium: The middle of the 3 layers developing the wall of the heart, containing cardiac muscle tissue. Innervated by the Purkinje fibers.

The human heart is the pump because that the circulatory system, and along with the circulatory system is thought about to be an body organ of the cardiovascular system. It consists of four chambers and also pumps blood through both systemic and also pulmonary circulation to enable gas exchange and also tissue oxygenation. The heart is situated in the thoracic cavity in between the lungs and also protected by the rib cage.

Structure of the Heart

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

The left heart faces systemic circulation, if the right heart faces pulmonary circulation. The left side of the love receives oxygenated blood indigenous the pulmonary vein and also pumps it right into the aorta, when the appropriate side of the love receives deoxygenated blood from the vena cava and pumps it into the pulmonary vein. The pulmonary vein and also aorta additionally have valves connecting them come their respective ventricle.

The heart has its very own self-sustaining conduction system that sends out nervous impulses come cardiac tissue. The sinoatrial (SA) and also atrioventricular (AV) nodes are bundles that nerve fibers that form this conduction system. Lock are located in the left atrial wall surface of the heart and also send nerve impulses come a large, highly committed set of nerves called the Purkinje fibers, which in turn send those nerve impulses come the cardiac muscle tissue. These nodes deserve to send impulses to the love without main nervous device stimulation, yet may be influenced by concerned stimulation to transform heart rate. The heart additionally has its very own blood supply, the cardiac arteries that carry out tissue oxygenation to the heart together the blood within the love is not supplied for oxygenation through the heart.

Cardiac Histology

The heart is enclosed in a double-walled security membrane referred to as the pericardium, i m sorry is a mesothelium tissue of the thoracic cavity. The dual membrane of pericardium has pericardial fluid which nourishes the heart and also prevents shock. This composite sac protects the heart, anchors it to surrounding structures, and prevents the love from overfilling with blood.

The wall surface of the heart is created of 3 layers of various tissues. The outer layer is called the epicardium, or visceral pericardium, because it is additionally the inner wall of the pericardium. The center layer that the heart, the myocardium, and contains specialized cardiac muscle tissue responsible for contraction. Cardiac muscle tissue is unique from bones or smooth muscle due to the fact that it pumps involuntarily based on conduction indigenous the AV and also SA nodes. The inner class is dubbed the endocardium and is in call with the blood the the love pumps. It likewise merges v the inner lining the blood vessels and covers love valves. Cardiac tissue is irreversible tissue that does not heal or regenerate when damaged. Together a result, is prone to scarring and also enlargement due to mechanical stress and injury.


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

Key Takeaways

Key PointsThe pericardium is a mesothelium tissue of the thoracic cavity which surrounding the heart. The external layer, the fibrous pericardium, is consisted of of dense connective tissue that protects the heart, anchors it to the bordering walls, and also prevents it from overfilling.The inner class of the pericardium, the serous pericardium, is further divided into two layers, an outer parietal layer and also an inner visceral layer through the pericardial cavity in between the 2 layers.The serous pericardium functions to lubricate the heart v pericardial fluid, which is save in the room between the parietal and also visceral layers.Pericarditis is inflammation the the pericardium, often as result of infection, which deserve to constrict and put harmful push on the heart.Key Termsfibrous pericardium: composed of dense connective organization which protects the heart, anchors it to the surrounding walls, and prevents the heart from overfilling v blood.serous pericardium: situated deeper 보다 the fibrous pericardium, this structure consists of two layers that lubricate the love to avoid friction from arising during heart 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 the root of the vessels that enter and leave this critical organ, functioning together a safety membrane. The pericardium is one of the mesothelium tissues of the thoracic cavity, together with the pleura i m sorry cover the lungs. The pericardium is created of two layers, an external fibrous pericardium and an within serous pericardium.

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

Fibrous Pericardium

The fibrous pericardium is the outer layer that the pericardium. The is written of thick connective tissue which anchors the heart to the mediastinum of the chest wall. It stays clear of the heart from overfilling through blood and also protects it from nearby infections by fully separating the from the remainder of the thoracic cavity. It is continuous with the external fibrous great of the neighboring great blood vessels.

Serous Pericardium

The serous pericardium, the inner class of the pericardium, is created of two different layers. The outer layer, the parietal layer, is totally adhered to the fibrous pericardium. The inner class is known as the visceral layer, which covers and also protects the good vessels and also heart. The an are between the parietal and also visceral great is called the pericardial cavity.

The visceral class is described as the epicardium in the locations where the is in direct call with the heart. The an are between these 2 serous layers, the parietal and the visceral, is the pericardial cavity, which has pericardial fluid. The serous pericardium, through its 2 membranes and the fluid-filled pericardial cavity, gives protection come the heart and also a lubricated sliding surface ar within which the heart deserve to move in solution to its own contractions and also to the motion of adjacent structures such together the diaphragm and also the lungs.

Function that the Pericardium

The pericardium is important because it protects the love from trauma, shock, stress, and also even infections from the adjacent lungs. It support the heart and anchors it to the medastinum so that doesn’t move within the body. The pericardium lubricates the heart and prevents it from ending up being too huge if blood volume is overloaded (though it will not protect against chronic love enlargement).

Despite these functions, the pericardium is still vulnerable to problems of its own. Pericarditis is the term for inflammation in the pericardium, typically due to infection. Pericarditis is frequently a severe condition because it deserve to constrict and also apply press on the heart and also work versus its regular function. Pericarditis come in many species depending on which tissue layer is infected.

Layers that the heart Walls

The heart wall surface is consisted of of 3 layers: the outer epicardium, the center myocardium, and also the inner endocardium.

Learning Objectives

Distinguish in between the epicardium, myocardium, and endocardium great of the love wall

Key Takeaways

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

The heart wall is made up of 3 layers, the epicardium (outer), myocardium (middle), and also endocardium (inner). These organization layers room highly devoted and perform different functions. Throughout ventricular contraction, the wave of depolarization native the SA and also AV nodes move from within the endocardial wall through the myocardial layer come the epicardial surface ar of the heart.


The heart Wall: The wall surface of the heart is created of three layers, the thin outer epicardium, the thick middle myocardium, and also the very thin inside endocardium. The dark area top top the heart wall surface is scarring from a vault myocardial infarction (heart attack).

The outer layer of 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 beg your pardon is attached come the outer wall of the heart. The epicardium is a slim layer of elastic connective tissue and also fat that serves as secondary layer of security from trauma or friction for the heart under the pericardium. This layer contains the coronary blood vessels, i beg your pardon oxygenate the tissues of the heart with a blood it is provided from the coronary arteries.


The middle layer that the heart wall is the myocardium—the muscle tissue of the heart and also the thickest great of the heart wall. The is created of cardiac muscle cells, or cardiomyocytes. Cardiomyocytes are dedicated muscle cells the contract like various other muscle cells, yet differ in shape. Compared to skeleton muscle cells, cardiac muscle cells are much shorter and have fewer nuclei. Cardiac muscle organization is also striated (forming protein bands) and also contains tubules and also gap junctions, unlike skeletal muscle tissue. Due to their continuous rhythmic contraction, cardiomyocytes call for a devoted blood it is provided to supply oxygen and also nutrients and remove waste assets such as carbon dioxide indigenous the cardiac muscle tissue. This blood it is provided is listed by the coronary arteries.


The inner class of the heart wall is the endocardium, created of endothelial cell that administer a smooth, elastic, non-adherent surface ar for blood collection and also pumping. The endocardium may regulate metabolic waste removal from heart tissues and act together a barrier between the blood and also the heart muscle, thus controlling the composition of the extracellular fluid in i beg your pardon the cardiomyocytes bathe. This in turn can influence the contractility the the heart.

This tissue additionally covers the valves of the heart and is histologically constant with the vascular endothelium of the major blood vessels entering and also leaving the heart. The Purkinje fibers room located just beneath the endocardium and also send worried impulses from the SA and AV nodes external of the heart into the myocardial tissues.

The endocardium can become infected, a serious inflammatory condition called infective endocarditis. This and other potential difficulties with the endocardium may damage the valves and impair the normal circulation of blood v the heart.

Chambers the the Heart

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

Key Takeaways

Key PointsThe right and left atria are the height chambers the the heart and receive blood right into the heart. The appropriate atrium receives deoxygenated blood native systemic circulation and the left atrium obtain oxygenated blood indigenous pulmonary circulation.The atria do not have actually inlet valves, but are separated indigenous the ventricles by valves. The atria facilitate circulation by permitting uninterrupted blood flow into the heart throughout ventricular systole.The atria have actually several mechanisms in place to ensure that venous blood circulation isn’t impaired, such as the absence of valves and the visibility of light and brief contractions during atrial systole.The appropriate ventricle pumps deoxygenated blood into pulmonary circulation. The left ventricle pumps oxygenated blood right into systemic circulation. The left ventricle is thicker because systemic circulation requires a much bigger blood volume than pulmonary circulation.Systole defines contraction, when blood is pumped from the heart into circulation through the ventricles. It can also 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 heart while the ventricles prepare to eject that very same blood throughout systole.Key Termsdiastole: The relaxation and dilation that the love chambers in between contractions, during which lock fill v blood.systole: The rhythmic convulsion of the heart whereby blood is ejected from one room to the next, or the end of the heart and also into the arteries.

The heart is the facility pump of the circulatory system, pumping blood throughout the body for the purposes of organization oxygenation and gas exchange. The heart has four chambers through which blood flows: two sets of each type of chamber (atria and ventricles), one every side, each with unique functions. The left side of the heart encounters systemic circulation when the appropriate side the the heart encounters pulmonary circulation.

The Atria

The atria space chambers in i m sorry blood enters the heart. They are situated on the anterior finish of the heart, with one atrium on every side. The right atrium receive deoxygenated blood from systemic circulation v the exceptional vena cava and also inferior venae cavae. The left atrium receives oxygenated blood from pulmonary circulation with the left and right pulmonary veins.

Blood passively flows right into the atria without passing v valves. The atria relax and dilate (expand) while they fill with blood in a process called atrial diastole. The atria and ventricles space separated by the mitral and also tricuspid valves. The atria experience atrial systole, a brief contraction the the atria that ejects blood native the atria v the valves and into the ventricles. The chordae tendinae space elastic tendons that attach to the valve native the ventricles and relax during atrial systole and ventricular diastole, but contract and also close off the valve during ventricular systole.

One the the defining features of the atria is the they execute not impede venous circulation into the heart. Atria have 4 essential qualities that reason them come promote continuous venous flow:

There room no atrial inlet valves come interrupt blood flow throughout atrial systole. The venous blood start the heart has a very low pressure compared to arterial blood, and valves would require venous blood pressure to develop up end a long duration of time to enter the atria.The atrial systole contractions are incomplete and also do no block circulation from the veins v the atria right into the ventricles. During atrial systole, blood not just empties native the atria come the ventricles, yet continues to flow uninterrupted native the veins right through the atria right into the ventricles.The atrial contractions room slight, preventing significant back push that would certainly impede venous flow.The be safe of the atria is combination to begin prior to the begin of ventricular contraction, which likewise helps stop the love from beating as well slowly.


The ventricles are situated on the posterior finish of the love beneath their equivalent atrium. The ideal ventricle obtain deoxygenated blood native the ideal atria and pumps it v the pulmonary vein and into pulmonary circulation, which goes into the lungs for gas exchange. The left ventricle obtain oxygenated blood native 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 wall surfaces of the ventricles room thicker and stronger than those that the atria. The physiologic load on the ventricles, i m sorry pump blood throughout the body and lungs, is much greater than the pressure generated by the atria to to fill the ventricles. Further, the left ventricle has actually thicker walls than the right because it pumps blood transparent the body, if the ideal ventricle pumps just to the lungs, which is a lot smaller volume that blood.

During ventricular diastole, the ventricles relax and fill with blood. Throughout ventricular systole, the ventricles contract, pumping blood through the semi-lunar valves into systemic circulation.


Structure the the heart: structure diagram the a coronal ar of the human heart from an anterior view. The two larger chambers are the ventricles.

Key Takeaways

Key PointsFive an excellent vessels enter and also leave the heart: the superior and inferior vena cava, the pulmonary artery, the pulmonary vein, and also the aorta.The exceptional vena cava and also inferior vena cava space veins the return deoxygenated blood native circulation in the body and also empty it into the appropriate atrium.The pulmonary artery tote deoxygenated blood from the best ventricle right into the lungs for oxygenation.The pulmonary veins lug oxygenated blood indigenous the lungs into the left atrium whereby it is went back to systemic circulation.The aorta is the largest artery in the body. That carries oxygenated blood from the left ventricle the the heart into systemic circulation.The aorta has numerous subdivisions that branch off right into smaller arteries. These subdivisions are the ascending and descending aorta, the aortic arch, and also the thoracic and abdominal muscle aorta.Key Termspulmonary arteries: The arteries that take deoxygenated blood away from the best side of the heart and into the capillaries of the lungs for the purpose of gas exchange.aorta: The good artery which carries the blood native the heart into systemic circulation.venae cavae: The two large vessels, the superior and also inferior vena cava, that bring deoxygenated blood from systemic circulation to the heart.

The human circulatory system is a twin system, definition there are two separate systems that blood flow: pulmonary circulation and also systemic circulation. The adult person heart consists of two separated pumps, the appropriate side (right atrium and also ventricle,) which pumps deoxygenated blood into the pulmonary circulation, and the left next (left atrium and ventricle), which pumps oxygenated blood right into the systemic circulation. Good vessels space the major vessels that carry blood right into the heart and also away from the heart to and from the pulmonary or systemic circuit. The good vessels collect and also distribute blood across the body from numerous smaller vessels.

The Venae Cavae


The Systemic Circuit: The venae cavae and the aorta type the systemic circuit, i m sorry circulates blood come the head, extremities and abdomen.

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

Superior Vena Cava

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

Inferior Vena Cava

The inferior vena cava is the largest vein in the body and carries deoxygenated blood native the lower fifty percent of the body into the heart. The left and also right common iliac veins converge to kind the inferior vena cava at its shortest point. The inferior vena cava starts posterior to the abdominal cavity and also travels come the heart beside the abdominal aorta. Follow me the method up the human body from the iliac veins, the renal and suprarenal veins ( kidney and adrenal glands), lumbar veins (from the back), and hepatic veins (from the liver) all drainpipe into the inferior vena cava.

The Aorta

The aorta is the largest of the arteries in systemic circulation. Blood is pumped indigenous the left ventricle with the aortic valve right 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 contract to pressure blood v the aortic valve right into the aorta, the aorta expands. This expansion provides potential energy to aid maintain blood pressure during diastole, as soon as the aorta passively contracts. Blood pressure is highest in the aorta and also diminishes with circulation, reaching its shortest points at the end of venous circulation. The difference in pressure between the aorta and also right atrium accounts for blood circulation in the circulation, as blood operation from areas of high press to areas of short pressure.

Components that the Aorta

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

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

The Pulmonary Arteries

The pulmonary arteries bring deoxygenated blood native the right ventricle into the alveolar capillaries that the lungs to unload carbon dioxide and take up oxygen. These space the just arteries that carry deoxygenated blood, and also are taken into consideration arteries due to the fact that they lug blood far from the heart. The short, wide vessel branches into the left and right pulmonary arteries that supply deoxygenated blood to the corresponding lungs. Blood an initial passes with the pulmonary valve together it is ejected right into the pulmonary arteries.


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

The Pulmonary Veins

The pulmonary veins bring oxygenated blood native the lung to the left atrium the the heart. Regardless of carrying oxygenated blood, this great vessel is still considered a vein since it dead blood in the direction of the heart. 4 pulmonary veins go into the left atrium. The best pulmonary veins happen behind the appropriate atrium and also superior vena cava when the left happen in former of the to decrease thoracic aorta. The pulmonary arteries and veins room both considered part of pulmonary circulation.

Myocardial Thickness and also Function

The myocardium (cardiac muscle) is the thickest section of the heart wall surface and includes cardiomyocytes, the contractile cell of the heart.

Key Takeaways

Key PointsCoordinated contraction of cardiomyocytes causes the love to contract and expel blood right into circulation.The myocardium is thickest in the left ventricle, as the left ventricle must create a many pressure to pump blood right into the aorta and also throughout systemic circulation.Cardiac muscle has a high density of mitochondria and a large blood supply, which store it to work continuously.Sarcomeres are the basic unit the muscle tissue, composed primarily of actin and myosin myofibrils.The heart’s thickness may readjust over time and also adapt come compensate because that diseases, which regularly results in heart failure.Key TermsCardiac hypertrophy: an adaptive an illness in which the walls of the heart end up being too thick to pump blood effectively. The is typically a complication of hypertension.sarcomere: The an easy contractile unit of contractile muscle, which includes myofibril filaments made the end of myosin and also actin, the two proteins that slide previous one one more to cause a muscle contraction.cardiomyocyte: A cardiac muscle cabinet (myocyte) in the heart.

The myocardium, or cardiac muscle, is the thickest ar of the heart wall and includes cardiomyocytes, the contractile cells of the heart. As a kind of muscle tissue, the myocardium is unique among all various other muscle tissues in the human being body. The thickness the the myocardium determines the stamin of the heart’s ability to pump blood.

Myocardial Histology

The framework of cardiac muscle share some attributes with skeletal muscle, however has countless distinctive functions of that is own. Cardiomyocytes are shorter than skeletal myocytes and also have under nuclei. Every muscle fiber connects come the plasma membrane (sarcolemma) with distinctive tubules ( T-tubule ). At these T-tubules, the sarcolemma is studded v a huge number that calcium networks which permit calcium ion exchange in ~ a price much quicker than the of the neuromuscular junction in skeleton muscle. The flux the calcium ions right into the muscle cells causes stimulates an action potential, which reasons the cells to contract.

Cardiac muscle, choose skeletal muscle, is comprised of sarcomeres, the basic, contractile units of muscle. Sarcomeres are composed of long, fibrous proteins the slide previous each other when the muscles contract and also relax. Two of the essential proteins found in sarcomeres are myosin, which creates the thick filament, and also actin, which forms the thin filament. Myosin has actually a long, fibrous tail and also a globular head that binding to actin. The myosin head also binds come ATP, the resource of power for moving metabolism, and is forced for the cardiomyocytes come sustain themselves and function normally. Together, myosin and also actin type myofibril filaments, the elongated, contractile threads found in muscle tissue. Cardiac muscle and also skeletal muscle both save on computer the protein myoglobin, which stores oxygen.

Cardiac muscle is adjusted to be extremely resistant to fatigue. Cardiomyocytes have a big number the mitochondria, enabling continuous aerobic respiration. Cardiac muscle additionally has a big blood supply loved one to the size, which offers a consistent stream of nutrients and oxygen while giving ample removal of metabolic waste.

Cardiac Muscle: The tissue structure of cardiac muscle has sarcomeres that space made of myofibrils v intercalated disks, that contain cardiomyocytes and also have many mitocondria.

Myocardial Thickness

The myocardium has actually variable level of thickness in ~ the heart. Chambers of the heart through a more thickness myocardium room able come pump blood with more pressure and also force contrasted to chambers of the heart through a thinner myocardium. The myocardium is thinnest within the atria, together these chambers mainly fill v passive blood flow. The right ventricle myocardium is thicker than the atrial myocardium, as this muscle must pump every blood returning to the heart right into the lungs because that oxygenation. The myocardium is thickest in the left ventricle, as this chamber have to create substantial 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, either thickening and coming to be stiff or becoming thinner and flabby. Cardiac hypertrophy is a common an outcome of hypertension (high blood pressure) in i beg your pardon the cell of the myocardium enlarge together an adaptive response to pumping versus the greater pressure. Eventually, hypertrophy may end up being so serious that heart fail occurs as soon as the heart becomes for this reason stiff that it have the right to no much longer pump blood. A flabby heart is typically the result of myocardial infections, in i beg your pardon the heart muscle i do not care so weak the it cannot effectively pump blood, which additionally leads to love failure.

Right Ventricular Hypertrophy: If the heart adapts to end up being too thick, it will certainly not have the ability to pump blood together efficiently, and also heart failure might occur.

Key Takeaways

Key PointsThe cardiac skeleton consists of 4 bands of dense connective tissue, dubbed fibrous rings, the surround the base of the pulmonary trunk, aorta, and mitral and tricuspid valves.The love ‘s fibrous skeleton stops the flow of electric currents in between the chambers of the love so that it just flows through the atrioventricular (AV) bundle. This causes a delay in depolarization so that the ventricles contract after lock fill with blood.The AV bundle is a bundle that electrically-connected cardiomyocytes the transmit impulses from the AV node to the apex the the heart. The is located in the center of the cardiac skeleton.The cardiac skeleton is composed mainly of the protein collagen, a glycoprotein discovered in every connective tissues.Key Termscollagen: A glycoprotein that develops elongated fibers, usually discovered in the extracellular matrix of connective tissue.fibrous rings: Four dense bands of tough elastic tissue that encircle the bases of the valves the the heart.

The cardiac skeleton, or fibrous skeleton the the heart, is the structure of dense connective tissue that separates the atria indigenous the ventricles. The fibrous skeleton provides crucial support for the heart and separates the circulation of electrical impulses with the heart.

Fibrous Ring Structure

Fibrous ring of the Heart: Transverse section of the heart showing the fibrous rings bordering the valves.

The primary structure the cardiac skeleton is composed of four thick bands of challenging elastic tissue called fibrous rings the encircle the bases that the heart valves. The fibrous skeleton is composed primarily of collagen, a protein uncovered in every kind of connective organization in the person body. There are 4 fibrous rings:

The aortic ring encircles the aortic valve. It provides support for the aortic valve so that 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 also strongest of every the fibrous rings as result of the thickness that the left ventricle, i m sorry requires an ext structural assistance than the various other chambers of the heart. It also surrounds the coronary arteries and also AV node.The right fibrous ring encircles the tricuspid valve. It also surrounds the coronary arteries and also AV node.

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

Electrical Functions

The fibrous skeleton that the love acts as an insulator because that the flow of electric current throughout the heart. It stop the flow of electricity in between the various chambers the the love so that electric impulses execute not circulation directly between the atria and also ventricles. The sinoatrial (SA) node lies ~ above the optimal of the heart, while the AV node is located at the facility of the fibrous skeleton, the just path whereby electricity can flow through the heart.

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This electric separation is crucial for cardiac function, due to the fact that electrical impulses circulation from the top of the love to the bottom of the heart. The separation permits the AV node and also AV bundle to hold-up the wave of depolarization so that the atria can contract and also assist in ventricular filling prior to the ventricles us depolarize and contract. There is no the fibrous skeleton that the heart, the heart’s capacity to pump blood would be considerably less efficient due to the fact that the ventricles would contract prior to filled to capacity. The fibrous skeleton that the heart also protects versus cardiac arrhythmias.