Anatomy of the Heart

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

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Key Takeaways

Key PointsThe love is a four-chambered muscular organ containing an involuntary conduction mechanism that initiates rhythmic contractions come pump blood transparent the body.The heart has actually its very own blood supply and is controlled by self-regulating nerve bundles dubbed nodes.The SA and AV nodes send impulses with the Purkinje yarn that cause muscle contractions to the heart.The heart is created of 3 layers: the epicardium (outer layer) which prevents excess growth or activity of the heart, the myocardium (middle layer) i m sorry initiates contractions control the cardiac cycle, and the endocardium (inner layer) that lines the cavities and also valves.The heart consists of two upper chambers called atria and also two reduced chambers called ventricles. The left and also right political parties of the heart are separated through the septum.Valves stop the backflow the blood and separate the atria indigenous the ventricle and 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 making use of involuntary contractions of cardiac muscle.ventricle: among two reduced chambers that the heart that receives blood from the atria and also pumps the out into pulmonary or systemic circulation, relying on side.myocardium: The center of the three layers developing the wall of the heart, include cardiac muscle tissue. Innervated through the Purkinje fibers.

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

Structure the the Heart

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

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

The heart has its own self-sustaining conduction system that sends nervous impulses to cardiac tissue. The sinoatrial (SA) and also atrioventricular (AV) nodes room bundles that nerve fibers that kind this conduction system. Lock are located in the left atrial wall of the heart and also send nerve impulses to a large, highly committed set of nerves called the Purkinje fibers, which subsequently send those nerve impulses come the cardiac muscle tissue. These nodes can send impulses come the heart without main nervous system stimulation, however may be affected by nervous stimulation to change heart rate. The heart also has its very own blood supply, the cardiac arteries that administer tissue oxygenation come the heart together the blood within the heart is not offered for oxygenation through the heart.

Cardiac Histology

The love is enclosed in a double-walled safety membrane referred to as the pericardium, i beg your pardon is a mesothelium organization of the thoracic cavity. The dual membrane the pericardium includes pericardial fluid which nourishes the heart and prevents shock. This composite sac protects the heart, anchors the to neighboring structures, and prevents the heart from overfilling v blood.

The wall surface of the heart is composed of 3 layers of various tissues. The outer layer is referred to as the epicardium, or visceral pericardium, because it is likewise the inner wall surface of the pericardium. The center layer of the heart, the myocardium, and also contains devoted cardiac muscle organization responsible for contraction. Cardiac muscle tissue is distinct from bones or smooth muscle because it pumps involuntarily based upon conduction indigenous the AV and SA nodes. The inner great is called the endocardium and is in call with the blood that the love pumps. It also merges with the inside lining of blood vessels and covers love valves. Cardiac tissue is permanent tissue the does not heal or regenerate when damaged. As a result, is at risk to scarring and also enlargement because of mechanical stress and injury.


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The Mammalian Heart: The position of valves ensures suitable directional circulation of blood through the cardiac interior. Keep in mind the distinction in the thickness of the muscled walls of the atrium and the left and also right ventricle.


Key Takeaways

Key PointsThe pericardium is a mesothelium tissue of the thoracic cavity which surrounding the heart. The outer layer, the fibrous pericardium, is made up of thick connective tissue that protects the heart, anchors it come the bordering walls, and prevents that from overfilling.The inner class of the pericardium, the serous pericardium, is further divided into 2 layers, an outer parietal layer and an inner visceral layer through the pericardial cavity in between the 2 layers.The serous pericardium features to lubricate the heart with pericardial fluid, which is save in the room between the parietal and visceral layers.Pericarditis is inflammation of the pericardium, often as result of infection, which have the right to constrict and also put harmful press on the heart.Key Termsfibrous pericardium: composed of thick connective organization which protects the heart, anchors it come the surrounding walls, and prevents the love from overfilling with blood.serous pericardium: situated deeper than the fibrous pericardium, this structure consists of two layers the lubricate the love to protect against friction from emerging during heart activity.pericardium: A serous membrane that surrounds and also protects the heart.

The pericardium is the thick, membranous, fluid-filled sac that surrounds the heart and the root of the vessels that enter and leave this an important organ, functioning as a safety membrane. The pericardium is just one of the mesothelium tissues of the thoracic cavity, in addition to the pleura which cover the lungs. The pericardium is written of 2 layers, an outer fibrous pericardium and an inside serous pericardium.


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


Fibrous Pericardium

The fibrous pericardium is the outer layer of the pericardium. It is created of thick connective tissue which anchors the love to the mediastinum that the chest wall. It prevents the heart from overfilling through blood and also protects it from adjacent infections by fully separating the from the remainder of the thoracic cavity. It is continuous with the external 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 totally adhered come the fibrous pericardium. The inner layer is known as the visceral layer, i beg your pardon covers and also protects the great vessels and also heart. The an are between the parietal and visceral class is referred to as the pericardial cavity.

The visceral layer is described as the epicardium in the locations where the is in direct contact with the heart. The an are between these two serous layers, the parietal and also the visceral, is the pericardial cavity, which contains pericardial fluid. The serous pericardium, v its two membranes and the fluid-filled pericardial cavity, provides protection come the heart and also a lubricated sliding surface within which the heart can move in response to its very own contractions and to the activity of adjacent structures such together the diaphragm and also the lungs.

Function of the Pericardium

The pericardium is important due to the fact that it protects the love from trauma, shock, stress, and also even infections from the nearby lungs. It support the heart and anchors it come the medastinum so it doesn’t move within the body. The pericardium lubricates the heart and also prevents the 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 breakable to difficulties of that own. Pericarditis is the term because that inflammation in the pericardium, commonly due to infection. Pericarditis is frequently a severe condition because it deserve to constrict and also apply press on the heart and also work against its regular function. Pericarditis come in many types depending on which organization layer is infected.


Layers of the heart Walls

The heart wall surface is consisted of of three layers: the outer epicardium, the middle myocardium, and the inner endocardium.


Learning Objectives

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


Key Takeaways

Key PointsThe epicardium is a thin layer that connective tissue and also fat serving as secondary layer of security for the heart. It is thought about a continuation of the serous pericardium.The myocardium is the muscle organization of the heart, created of cardiac muscle cells dubbed cardiomyocytes that receive nervous stimulation indigenous the sinoatrial (SA) and atrioventricular (AV nodes via the Purkinje fibers.Cardiomyocytes are shorter than bones myocytes, and contain fewer nuclei. Cardiac muscle is striated.The endocardium is composed of endothelial cell that carry out a smooth, non-adherent surface ar for blood collection and pumping and may aid regulate contractility.An infection or inflammation of the endocardium is referred to as 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 the lines the interior of the heart and also valves.cardiomyocyte: A cardiac muscle cell (or myocyte) in the heart, which provides up the cardiac muscle tissue.

The heart wall surface is comprised of three layers, the epicardium (outer), myocardium (middle), and endocardium (inner). These organization layers are highly dedicated and perform different functions. During ventricular contraction, the tide of depolarization from the SA and AV nodes moves from within the endocardial wall through the myocardial layer to the epicardial surface ar of the heart.

Epicardium


The heart Wall: The wall surface of the heart is written of 3 layers, the thin external epicardium, the thick middle myocardium, and the really thin within endocardium. The dark area on the heart wall is scarring from a previous myocardial infarction (heart attack).


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

Myocardium

The middle layer that the heart wall surface is the myocardium—the muscle organization of the heart and also the thickest great of the heart wall. That is written of cardiac muscle cells, or cardiomyocytes. Cardiomyocytes are committed muscle cells the 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 tissue is additionally striated (forming protein bands) and contains tubules and also gap junctions, unlike bones muscle tissue. Due to their constant rhythmic contraction, cardiomyocytes require a committed blood it is provided to deliver oxygen and nutrients and remove waste assets such as carbon dioxide from the cardiac muscle tissue. This blood it is provided is noted by the coronary arteries.

Endocardium

The inner great of the heart wall surface is the endocardium, created of endothelial cell that provide a smooth, elastic, non-adherent surface ar for blood collection and pumping. The endocardium may regulate metabolic waste removal from love tissues and act as a obstacle between the blood and also the love muscle, thus regulating the ingredient of the extracellular liquid in which the cardiomyocytes bathe. This consequently can impact the contractility the the heart.

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

The endocardium can end up being infected, a serious inflammatory problem called infective endocarditis. This and also other potential problems with the endocardium may damage the valves and impair the normal flow of blood through the heart.


Chambers the the Heart

The love has four chambers. The 2 atria receive blood into the heart and also the two ventricles pump blood into circulation.


Key Takeaways

Key PointsThe right and also left atria are the peak chambers that the heart and also receive blood right into the heart. The best atrium receive deoxygenated blood indigenous systemic circulation and also the left atrium obtain oxygenated blood from pulmonary circulation.The atria execute not have actually inlet valves, but are separated indigenous the ventricles by valves. The atria facilitate circulation by allowing uninterrupted blood flow into the heart during ventricular systole.The atria have several mechanisms in place to ensure that venous blood flow isn’t impaired, such together the absence of valves and also the visibility of light and brief contractions throughout atrial systole.The appropriate ventricle pumps deoxygenated blood into pulmonary circulation. The left ventricle pumps oxygenated blood into systemic circulation. The left ventricle is thicker due to the fact that systemic circulation requires a much larger blood volume than pulmonary circulation.Systole defines contraction, as soon as blood is pumped from the heart right into circulation by the ventricles. The can likewise describe atrial systole, in i beg your pardon blood moves from the atria come the ventricles during ventricular diastole.Diastole explains relaxation, once blood moves into the heart while the ventricles prepare come eject that exact same blood during systole.Key Termsdiastole: The relaxation and also dilation of the heart chambers in between contractions, throughout which they fill with blood.systole: The rhythmic contraction of the heart whereby blood is ejected native one room to the next, or the end of the heart and also into the arteries.

The heart is the facility pump the the circulatory system, pump blood throughout the body for the functions of organization oxygenation and gas exchange. The love has four chambers v which blood flows: 2 sets that each kind of chamber (atria and ventricles), one per side, each with distinct functions. The left side of the heart deals with systemic circulation if the right side that the heart encounters pulmonary circulation.

The Atria

The atria are chambers in i m sorry blood beginning the heart. They are located on the anterior finish of the heart, v one atrium on every side. The right atrium receives deoxygenated blood indigenous systemic circulation through the premium vena cava and also inferior venae cavae. The left atrium obtain oxygenated blood native pulmonary circulation v the left and right pulmonary veins.

Blood passively flows right into the atria without passing through valves. The atria relax and also dilate (expand) while castle fill with blood in a procedure called atrial diastole. The atria and also ventricles are separated by the mitral and tricuspid valves. The atria experience atrial systole, a quick contraction of the atria the ejects blood indigenous the atria through the valves and also into the ventricles. The chordae tendinae are elastic tendons that attach to the valve from the ventricles and also relax during atrial systole and ventricular diastole, but contract and close turn off the valve throughout ventricular systole.

One the the defining features of the atria is the they carry out not impede venous flow into the heart. Atria have 4 essential qualities that reason them to promote constant venous flow:

There are no atrial inlet valves to interrupt blood flow during atrial systole. The venous blood start the heart has a an extremely low pressure compared to arterial blood, and also valves would require venous blood push to build up over a long duration of time to go into the atria.The atrial systole contractions are incomplete and do not block flow from the veins v the atria into the ventricles. Throughout atrial systole, blood not only empties native the atria to the ventricles, yet continues to flow uninterrupted from the veins best through the atria into the ventricles.The atrial contractions are slight, preventing far-reaching back pressure that would certainly impede venous flow.The relaxation of the atria is coordinated to begin before the begin of ventricular contraction, which also helps avoid the love from beating also slowly.

Ventricles

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

The walls of the ventricles space thicker and also stronger 보다 those the the atria. The physiologic fill on the ventricles, i m sorry pump blood transparent the body and lungs, is much higher than the pressure produced by the atria to to fill the ventricles. Further, the left ventricle has actually thicker walls than the right due to the fact that it pumps blood throughout the body, while the ideal ventricle pumps just to the lungs, i beg your pardon is a lot smaller volume that blood.

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


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


Key Takeaways

Key PointsFive great vessels enter and leave the heart: the superior and also inferior vena cava, the pulmonary artery, the pulmonary vein, and the aorta.The premium vena cava and inferior vena cava are veins the return deoxygenated blood native circulation in the body and also empty it into the best atrium.The pulmonary artery dead deoxygenated blood from the ideal ventricle right into the lungs for oxygenation.The pulmonary veins bring oxygenated blood native the lungs into the left atrium wherein it is went back to systemic circulation.The aorta is the biggest artery in the body. The carries oxygenated blood from the left ventricle the the heart into systemic circulation.The aorta has countless subdivisions that branch off right into smaller arteries. These subdivisions are the ascending and descending aorta, the aortic arch, and the thoracic and abdominal aorta.Key Termspulmonary arteries: The arteries the take deoxygenated blood away from the best side that the heart and also into the capillaries that the lungs because that the objective of gas exchange.aorta: The great artery which carries the blood indigenous the heart right into systemic circulation.venae cavae: The two big vessels, the superior and inferior vena cava, that lug deoxygenated blood native systemic circulation to the heart.

The human circulatory device is a double system, definition there are two different systems of blood flow: pulmonary circulation and systemic circulation. The adult person heart is composed of two separated pumps, the appropriate side (right atrium and also ventricle,) i beg your pardon pumps deoxygenated blood right into the pulmonary circulation, and the left next (left atrium and ventricle), i m sorry pumps oxygenated blood right into the systemic circulation. Great vessels room the significant vessels that lug blood into the heart and away from the heart to and also from the pulmonary or systemic circuit. The good vessels collect and also distribute blood throughout the human body from numerous smaller vessels.

The Venae Cavae


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The Systemic Circuit: The venae cavae and the aorta form the systemic circuit, which circulates blood to the head, extremities and also abdomen.


The superior and inferior vena cava are collectively called the venae cavae. The venae cavae, along with the aorta, are the good vessels associated in systemic circulation. These veins return deoxygenated blood native the body right into the heart, emptying it into the appropriate atrium. The venae cavae room not separated indigenous the appropriate atrium by valves.

Superior Vena Cava

The remarkable vena cava is a large, short vein the carries deoxygenated blood native the upper half of the human body to the ideal atrium. The right and also left subclavian veins, jugular veins, and thyroid veins feed right into the premium vena cava. The subclavian veins are far-reaching because the thoracic lymphatic duct drains lymph liquid into the subclavian veins, making the premium vena cava a website of lymph fluid recirculation into the plasma. The superior vena cava begins above the heart.

Inferior Vena Cava

The inferior vena cava is the biggest vein in the body and carries deoxygenated blood from the lower half of the body right into the heart. The left and right common iliac veins converge to form the worse vena cava at its shortest point. The inferior vena cava begins posterior to the abdominal muscle 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 also hepatic veins (from the liver) all drainpipe 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 with the aortic valve right into the aorta. The aorta is a extremely elastic artery and is able to dilate and also constrict in solution to blood pressure and volume. As soon as the left ventricle contracts to force blood with the aortic valve into the aorta, the aorta expands. This expansion provides potential power to assist maintain blood pressure throughout diastole, as soon as the aorta passively contracts. Blood pressure is highest possible in the aorta and also diminishes through circulation, getting to its shortest points at the end of venous circulation. The distinction in pressure between the aorta and right atrium accounts because that blood circulation in the circulation, together blood flows from locations of high press to areas of low pressure.

Components of the Aorta

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

The ascending aorta lies between the heart and also the arch the aorta. It breaks off right into the aortic sinuses, some of which type the coronary arteries.The arch of aorta is the optimal of the aorta, which breaks off into the left carotid artery, brachiocephalic trunk, and also the left subclavian artery.The to decrease aorta is the section from the arch that aorta to the point where it divides right into the common iliac arteries. The is subdivided right into the thoracic and abdominal muscle aorta.The thoracic aorta is the part of the descending aorta over the diaphragm. The branches off into the bronchial, mediastinal, esophageal, and phrenic arteries.The abdominal muscle aorta is the component of the descending aorta below the diaphragm, which divides right into the iliac arteries and branches into the renal and suprarenal arteries. This component of the aorta is vulnerable to bursting and hemorrhage (aneurysm) from persistently high blood pressure.

The Pulmonary Arteries

The pulmonary arteries carry deoxygenated blood native the best ventricle right into the alveolar capillaries the the lungs to discharge carbon dioxide and also take increase oxygen. These room the just arteries that lug deoxygenated blood, and are taken into consideration arteries due to the fact that they carry blood away from the heart. The short, large vessel branches right into the left and right pulmonary arteries that supply deoxygenated blood come the respective lungs. Blood very first passes through the pulmonary valve as it is ejected right into the pulmonary arteries.


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


The Pulmonary Veins

The pulmonary veins carry oxygenated blood from the lungs to the left atrium that the heart. Despite carrying oxygenated blood, this good vessel is still considered a vein due to the fact that it dead blood in the direction of the heart. Four pulmonary veins go into the left atrium. The appropriate pulmonary veins pass behind the best atrium and superior vena cava if the left happen in front of the descending thoracic aorta. The pulmonary arteries and also veins are both considered component of pulmonary circulation.


Myocardial Thickness and also Function

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


Key Takeaways

Key PointsCoordinated convulsion of cardiomyocytes reasons the love to contract and expel blood right into circulation.The myocardium is thickest in the left ventricle, as the left ventricle must develop a lot of pressure to pump blood into the aorta and also throughout systemic circulation.Cardiac muscle has actually a high thickness of mitochondria and also a large blood supply, which store it work continuously.Sarcomeres space the basic unit of muscle tissue, composed mostly of actin and myosin myofibrils.The heart’s thickness may readjust over time and adapt to compensate for diseases, which frequently results in heart failure.Key TermsCardiac hypertrophy: one adaptive disease in which the wall surfaces of the heart come to be too special to pump blood effectively. The is generally a complication of hypertension.sarcomere: The simple contractile unit of contractile muscle, which includes myofibril filaments made out of myosin and also 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 ar of the heart wall and contains cardiomyocytes, the contractile cell of the heart. Together a form of muscle tissue, the myocardium is unique among all other muscle tissues in the person body. The thickness the the myocardium identify the stamin of the heart’s capacity to pump blood.

Myocardial Histology

The structure of cardiac muscle shares some features with skeleton muscle, but has numerous distinctive features of the own. Cardiomyocytes are shorter than skeleton myocytes and have fewer nuclei. Each muscle fiber connects to the plasma membrane (sarcolemma) with distinctive tubules ( T-tubule ). At these T-tubules, the sarcolemma is studded through a large number that calcium channels which allow calcium ion exchange at a rate much faster than that of the neuromuscular junction in bones muscle. The flux of calcium ions into the muscle cells reasons stimulates an activity potential, which reasons the cell to contract.

Cardiac muscle, like skeletal muscle, is consisted of of sarcomeres, the basic, contractile systems of muscle. Sarcomeres are composed that long, fibrous proteins the slide past each other as soon as the muscle contract and relax. 2 of the important proteins uncovered in sarcomeres are myosin, which creates the special filament, and also actin, which forms the slim filament. Myosin has a long, fibrous tail and also a globular head that binds to actin. The myosin head additionally binds to ATP, the resource of power for to move metabolism, and also is compelled for the cardiomyocytes to sustain themselves and duty normally. Together, myosin and actin kind myofibril filaments, the elongated, contractile threads found in muscle tissue. Cardiac muscle and skeletal muscle both save on computer the protein myoglobin, which stores oxygen.

Cardiac muscle is adapted to be extremely resistant to fatigue. Cardiomyocytes have actually a large number that mitochondria, enabling consistent aerobic respiration. Cardiac muscle also has a large blood supply family member to that size, which gives a consistent stream the nutrients and also oxygen while giving ample removed of metabolic waste.


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


Myocardial Thickness

The myocardium has variable levels of thickness within the heart. Chambers the the heart v a more thickness myocardium room able come pump blood with an ext pressure and also force contrasted to chambers the the heart with a thinner myocardium. The myocardium is thinnest in ~ the atria, together these chambers primarily fill v passive blood flow. The appropriate ventricle myocardium is thicker than the atrial myocardium, together 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, together this chamber must create considerable pressure to pump blood right into the aorta and throughout systemic circulation.

The thickness of the myocardium may readjust in some individuals as a compensatory adaptation to disease, one of two people thickening and coming to be stiff or coming to be thinner and also flabby. Cardiac hypertrophy is a common result of hypertension (high blood pressure) in i beg your pardon the cells of the myocardium enlarge together an adaptive response to pumping against the higher pressure. Eventually, hypertrophy may end up being so significant that heart fail occurs as soon as the heart becomes so stiff that it can no longer pump blood. A flabby heart is frequently the an outcome of myocardial infections, in i beg your pardon the love muscle becomes so weak the it cannot successfully pump blood, which additionally leads to heart failure.


Right Ventricular Hypertrophy: If the love adapts to come to be too thick, it will not be able to pump blood together efficiently, and also heart failure may occur.


Key Takeaways

Key PointsThe cardiac skeleton consists of four bands of dense connective tissue, dubbed fibrous rings, the surround the base of the pulmonary trunk, aorta, and also mitral and tricuspid valves.The love ‘s fibrous skeleton stops the flow of electrical currents between the chambers that the heart so that it only flows with the atrioventricular (AV) bundle. This causes a delay in depolarization so that the ventricles contract after castle fill through blood.The AV bundle is a bundle that electrically-connected cardiomyocytes that transmit impulses from the AV node come the apex the the heart. That is located in the facility of the cardiac skeleton.The cardiac skeleton consists mainly that the protein collagen, a glycoprotein uncovered in all connective tissues.Key Termscollagen: A glycoprotein that develops elongated fibers, usually found in the extracellular matrix of connective tissue.fibrous rings: Four dense bands of difficult elastic tissue that encircle the bases the the valves the the heart.

The cardiac skeleton, or fibrous skeleton that the heart, is the structure of dense connective organization that separates the atria native the ventricles. The fibrous skeleton provides vital support for the heart and separates the flow of electrical impulses with the heart.

Fibrous Ring Structure


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


The main structure the cardiac skeleton is composed of four dense bands of difficult elastic tissue dubbed fibrous rings the encircle the bases that the love valves. The fibrous skeleton is composed mainly of collagen, a protein discovered in every form of connective organization in the person body. Over 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. Comparable to the aortic ring, it gives 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 because of the thickness the the left ventricle, which requires an ext structural assistance than the other chambers of the heart. It likewise surrounds the coronary arteries and also AV node.The appropriate fibrous ring encircles the tricuspid valve. It likewise surrounds the coronary arteries and also AV node.

The fibrous skeleton gives a an excellent amount the structural and functional assistance for the valves of the love by permitting them to stay open and also provides a suggest of attachment for the valves to the wall surface of the heart.

Electrical Functions

The fibrous skeleton the the love acts as an insulator for the flow of electric current across the heart. It stop the circulation of electricity in between the different chambers of the love so that electrical impulses perform not flow directly in between the atria and ventricles. The sinoatrial (SA) node lies on the height of the heart, when the AV node is located at the facility of the fibrous skeleton, the only path through which electricity can flow through the heart.

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This electric separation is crucial for cardiac function, since electrical impulses circulation from the optimal of the heart to the bottom the the heart. The separation enables the AV node and AV bundle to delay the wave of depolarization so that the atria can contract and also assist in ventricular filling prior to the ventricles us depolarize and contract. Without the fibrous skeleton that the heart, the heart’s capability to pump blood would certainly be significantly less efficient since the ventricles would certainly contract before filled come capacity. The fibrous skeleton the the heart likewise protects versus cardiac arrhythmias.