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Information about Left Atrium

Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow.
Interior of left side of heart.
Latinatrium sinistrum
Arterycircumflex branch of left coronary artery
Veinoblique vein of the left atrium
Dorlands/Elsevier a_71/12167887
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle.

Structure

Blood is pumped through the left atrioventricular orifice, which contains the mitral valve. A normal left atrium may be up to 5.5cm in maximum diameter; any larger than this is a sign of cardiac failure. This may occur in cases of mitral regurgitation.

The left atrium of a human faces more or less posteriorly. It is named 'left' based on the chamber's embryological and (putative) evolutionary origin. The term 'base' of the heart sometimes refers to the left atrium, though 'base' is an ambiguous term.

Attached to the left atrium is the left auricular appendix (auricle). This auricle is a common site for formation of thrombi, which may embolise causing stroke or ischemic gut. Atrial fibrillation makes this more likely.

Foramen ovale

Main article: Foramen ovale (heart)
There is a foramen ovale (oval hole) between the right and left atrium in the fetus. After birth, this should close over and become the fossa ovale. If it does not, this is an atrial septal defect (hole in the heart). In the fetus, the right atrium pumps blood into the left atrium, bypassing the pulmonary circulation (which is useless in a fetus). In an adult, a septal defect would result in flow in the reverse direction - from the left atrium to the right - which will reduce cardiac output, potentially cause cardiac failure and in severe or untreated cases, death.

Blood supply

The left atrium is supplied mainly by the left circumflex coronary artery, though the branches are too small to be identified in a cadaveric human heart and are not named.

The oblique vein of the left atrium is partly responsible for venous drainage; it derives from the embryonic left superior vena cava.

Animals

Many other animals, including mammals, also have four-chambered hearts, and have a left atrium. The function in these animals is similar. Some animals (amphibians, reptiles) have a three-chambered heart, in which the blood from each atrium is mixed in the single ventricle before being pumped to the aorta. In these animals, the left atrium still serves the purpose of collecting blood from pulmonary veins.

Additional images


Heart seen from above.

Base and diaphragmatic surface of heart.


See also

 •  • [ e]
Anatomy of torso, cardiovascular system: heart
Structuresatria (interatrial septum, musculi pectinati) • ventricles (interventricular septum, trabeculae carneae, chordae tendinae, papillary muscle) • valves • cusps
Regionsbase • apex • grooves (coronary/atrioventricular, interatrial, anterior interventricula, posterior interventricular) • surfaces (sternocostal, diaphragmatic) • borders (right, left)
Right heart(vena cavae, coronary sinus) → right atrium (auricle, fossa ovalis, limbus of fossa ovalis, crista terminalis, valve of the inferior vena cava, valve of the coronary sinus) → tricuspid valve → right ventricle (conus arteriosus, moderator band/septomarginal trabecula)  → pulmonary valve → (pulmonary artery and pulmonary circulation)
Left heart(pulmonary veins) → left atrium (auricle) → mitral valve → left ventricle → aortic valve (aortic sinus) → (aorta and systemic circulation)
Layerspericardium  (sinus) • epicardium • myocardium • endocardium • cardiac skeleton (fibrous trigone, fibrous rings)
Conduction systemCardiac pacemaker • SA node • AV node• bundle of His • Purkinje fibers
Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Arteries are muscular blood vessels that carry blood away from the heart.[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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The "LCX", or left circumflex artery (or circumflex artery, or circumflex branch of the left coronary artery) is an artery of the heart.

Course

It follows the left part of the coronary sulcus, running first to the left and then to the right, reaching nearly
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vein is a blood vessel that carries blood toward the heart. The majority of veins in the body carry low-oxygen blood from the tissues back to the heart; the exceptions being the pulmonary and umbilical veins which both carry oxygenated blood.
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The Oblique Vein of the Left Atrium (oblique vein of Marshall) is a small vessel which descends obliquely on the back of the left atrium and ends in the coronary sinus near its left extremity; it is continuous above with the ligament of the left vena cava (lig.
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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Heart chamber is a general term used to refer to any of the four of the mammalian heart (an organ):
  • Right atrium: receives oxygen-depleted blood from the body via the superior vena cava and the inferior vena cava and pumps it through the tricuspid valve into the right

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Editing of this page by unregistered or newly registered users is currently disabled due to vandalism.
If you are prevented from editing this page, and you wish to make a change, please discuss changes on the talk page, request unprotection, log in, or .
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heart is a muscular organ responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in the annelids, mollusks, and arthropods.
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2, −1
(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1

Atomic radius 60 pm
Atomic radius (calc.
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Blood is a specialized biological fluid consisting of red blood cells (also called RBCs or erythrocytes), white blood cells (also called leukocytes) and platelets (also called thrombocytes) suspended in a complex fluid medium known as blood plasma.
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The pulmonary veins carry oxygen-rich blood from the lungs to the left atrium of the heart. They are the only veins in the post-fetal human body that carry oxygenated (red) blood.

The pulmonary veins return the oxygenated blood from the lungs to the left atrium of the heart.
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The left ventricle is one of four chambers (two atria and two ventricles) in the human heart. It receives oxygenated blood from the left atrium via the mitral valve, and pumps it into the aorta via the aortic valve.
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The mitral valve (also known as the bicuspid valve or left atrioventricular valve), is a dual flap (bi = 2) valve in the heart that lies between the left atrium (LA) and the left ventricle (LV). In Latin, the term mitral means shaped like a miter, or bishop's cap.
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Heart failure
Classification & external resources

ICD-10 I 50.0
ICD-9 428.0

DiseasesDB 16209
MedlinePlus 000158
eMedicine med/3552  
MeSH D006333

Congestive heart failure (CHF), also called
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Mitral regurgitation
Classification & external resources

ICD-10 I 05.1 , I 34.0 , Q 23.3
ICD-9 394.1 , 424.0 , 746.6

DiseasesDB 8275

eMedicine emerg/314   Mitral regurgitation (MR), a valvular heart disease also known as
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The left auricular appendix (left auricula, left auricle, left atrial appendage) is a conical muscular pouch connected to the left atrium of the heart.
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thrombus, or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system (i.e. clotting factors).
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Atrial fibrillation
Classification & external resources

The P waves, which represent depolarization of the atria, are irregular or absent during atrial fibrillation.
ICD-10 I 48.
ICD-9 427.
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In the fetal heart, the foramen ovale (or ostium secundum of Born) allows blood to enter the left atrium from the right atrium. It is one of two shunts, the other being the ductus arteriosus, that allows blood entering the right atrium to bypass the pulmonary circulation.
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Atrial septal defect
Classification & external resources

Heart of human embryo of about thirty-five days
ICD-10 Q 21.1
ICD-9 745.5 - 745.6

OMIM 108800
DiseasesDB 1089

eMedicine med/3519  

MeSH C14.240.400.560.
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Heart failure
Classification & external resources

ICD-10 I 50.0
ICD-9 428.0

DiseasesDB 16209
MedlinePlus 000158
eMedicine med/3552  
MeSH D006333

Congestive heart failure (CHF), also called
..... Click the link for more information.
The "LCX", or left circumflex artery (or circumflex artery, or circumflex branch of the left coronary artery) is an artery of the heart.

Course

It follows the left part of the coronary sulcus, running first to the left and then to the right, reaching nearly
..... Click the link for more information.
The Oblique Vein of the Left Atrium (oblique vein of Marshall) is a small vessel which descends obliquely on the back of the left atrium and ends in the coronary sinus near its left extremity; it is continuous above with the ligament of the left vena cava (lig.
..... Click the link for more information.
The superior vena cava is a large, yet short vein that carries de-oxygenated blood from the upper half of the body to the heart's right atrium.

It is formed by the left and right brachiocephalic veins, (also referred to as the innominate veins) which receive blood from the
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The right atrium (in older texts termed the "right auricle") is one of four chambers (two atria and two ventricles) in the human heart. It receives de-oxygenated blood from the superior and inferior vena cavae and the coronary sinus, and pumps it into the right ventricle through
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Human anatomy is primarily the scientific study of the morphology of the adult human body.[1] It is subdivided into gross anatomy and microscopic anatomy.[1]
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Torso is an anatomical term for the central part of the many animal bodies (including that of the human) from which extend the neck and limbs. It is sometimes referred to as the trunk. The torso includes the thorax and abdomen.
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Circulatory System is a psychedelic rock musical ensemble formed by musician/painter Will Cullen Hart, and featuring Hannah Jones, Derek Almstead, Peter Erchick, John Fernandes, and Heather McIntosh.
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heart is a muscular organ responsible for pumping blood through the blood vessels by repeated, rhythmic contractions, or a similar structure in the annelids, mollusks, and arthropods.
..... Click the link for more information.


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