Left atrium

Jump to: navigation, search
Left atrium
Diagram of the human heart (cropped).svg.png
Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow.
Gray496.png
Interior of left side of heart.
Latin atrium sinistrum
Artery circumflex branch of left coronary artery
Vein oblique vein of the left atrium
Dorlands/Elsevier a_71/12167887

WikiDoc Resources for Left atrium

Articles

Most recent articles on Left atrium

Most cited articles on Left atrium

Review articles on Left atrium

Articles on Left atrium in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Left atrium

Images of Left atrium

Photos of Left atrium

Podcasts & MP3s on Left atrium

Videos on Left atrium

Evidence Based Medicine

Cochrane Collaboration on Left atrium

Bandolier on Left atrium

TRIP on Left atrium

Clinical Trials

Ongoing Trials on Left atrium at Clinical Trials.gov

Trial results on Left atrium

Clinical Trials on Left atrium at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Left atrium

NICE Guidance on Left atrium

NHS PRODIGY Guidance

FDA on Left atrium

CDC on Left atrium

Books

Books on Left atrium

News

Left atrium in the news

Be alerted to news on Left atrium

News trends on Left atrium

Commentary

Blogs on Left atrium

Definitions

Definitions of Left atrium

Patient Resources / Community

Patient resources on Left atrium

Discussion groups on Left atrium

Patient Handouts on Left atrium

Directions to Hospitals Treating Left atrium

Risk calculators and risk factors for Left atrium

Healthcare Provider Resources

Symptoms of Left atrium

Causes & Risk Factors for Left atrium

Diagnostic studies for Left atrium

Treatment of Left atrium

Continuing Medical Education (CME)

CME Programs on Left atrium

International

Left atrium en Espanol

Left atrium en Francais

Business

Left atrium in the Marketplace

Patents on Left atrium

Experimental / Informatics

List of terms related to Left atrium

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


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

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

See also


ta:இடது ஏட்ரியம்



Linked-in.jpg