Mitral Valve

Information about Mitral Valve



Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow. (Mitral valve labeled at center right.)

Base of ventricles exposed by removal of the atria. (Bicuspid valve visible at bottom left.)
Latin	valva atrioventricularis sinistra, valva mitralis
	subject #138 534
MeSH	Mitral+Valve
Dorlands/Elsevier	v_02/12843904

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. The mitral valve and the tricuspid valve are known collectively as the atrioventricular valves because they lie between the atria and the ventricles of the heart and control flow.

Overview

A normally functioning mitral valve opens to pressure from the superior surface of the valve, allowing blood to flow into the left ventricle during left atria systole (contraction), and closes at the end of atrial contraction to prevent blood from back flowing into the atria during left ventricle systole. In a normal cardiac cycle, the atria contracts first, filling the ventricle. At the end of ventricular diastole, the bicuspid valve shuts, and prevents backflow as the ventricle begins its systolic phase. Backflow may occur if the patient suffers from mitral valve prolapse, causing an audible heart murmur during auscultation.

Anatomy

The mitral valve has two cusps/leaflets (the anteromedial leaflet and the posterolateral leaflet) which guards the opening. The opening is surrounded by a fibrous ring known as the mitral valve annulus. (The orientation of the two leaflets were once thought to resemble a bishop's miter, which is where the valve receives its name.^[1]) The anterior cusp protects approximately two-thirds of the valve (imagine a crescent moon within the circle, where the crescent represents the posterior cusp). These valve leaflets are prevented from prolapsing into the left atrium by the action of tendons attached to the posterior surface of the valve, chordae tendinae.

The inelastic chordae tendineae are attached at one end to the papillary muscles and the other to the valve cusps. Papillary muscles are finger like projections from the wall of the left ventricle. Chordae tendinae from each muscle are attached to both leaflets of the mitral valve. Thus when the ventricle contracts, the intraventricular pressure forces the valve to close, while the tendons prevent the valve from opening in the wrong direction.

Normal physiology

During left ventricular diastole, after the pressure drops in the left ventricle due to relaxation of the ventricular myocardium, the mitral valve opens, and blood travels from the left atrium to the left ventricle. About 70-80% of the blood that travels across the mitral valve occurs during the early filling phase of the left ventricle. This early filling phase is due to active relaxation of the ventricular myocardium, causing a pressure gradient that allows a rapid flow of blood from the left atrium, across the mitral valve. This early filling across the mitral valve is seen on doppler echocardiography of the mitral valve as the E wave.

After the E wave, there is a period of slow filling of the ventricle.

Left atrial contraction (left atrial systole) (during left ventricular diastole) causes added blood to flow across the mitral valve immediately before left ventricular systole. This late flow across the open mitral valve is seen on doppler echocardiography of the mitral valve as the A wave. The late filling of the LV contributes about 20% to the volume in the left ventricle prior to ventricular systole, and is known as the atrial kick.

Surface anatomy

The opening and closing of the mitral valve is difficult to hear directly, but the flow of blood to the left ventricle is most audible at the apex of the heart, and so auscultation is usually performed at the intersection of the fifth intercostal space and the midclavicular line.

Additional images

Section of the heart showing the ventricular septum. (Bicuspid valve visible at center.)

Front of thorax, showing surface relations of bones, lungs (purple), pleura (blue), and heart (red outline). Heart valves are labeled with "B", "T", "A", and "P".

References

1. ^ Stedman's/LWW 1539731

External links

SUNY Figs 20:07-03 - "Valves of the heart."
Mitral Valve Repair at The Mount Sinai Hospital - "Mitral Valve Function"
Surgical Anatomy of the Mitral Valve at echoincontext.com

• • [ e] Anatomy of torso, cardiovascular system: heart
Structures	atria (interatrial septum, musculi pectinati) • ventricles (interventricular septum, trabeculae carneae, chordae tendinae, papillary muscle) • valves • cusps
Regions	base • 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)
Layers	pericardium (sinus) • epicardium • myocardium • endocardium • cardiac skeleton (fibrous trigone, fibrous rings)
Conduction system	Cardiac 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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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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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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In anatomy, the heart valves are valves in the heart that maintain the unidirectional flow of blood by opening and closing depending on the difference in pressure on each side. The mechanical equivalent of the heart valves would be the reed valves.
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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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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.
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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 MITRE Corporation is a public-interest not-for-profit organization that manages three federally funded research and development centers (FFRDCs): one for the Department of Defense (known as the DOD Command, Control, Communications and Intelligence FFRDC), one for the Federal
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The tricuspid valve is on the right side of the heart, between the right atrium and the right ventricle. The normal tricuspid valve usually has three leaflets and three papillary muscles.
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Atrioventricular (having to do with an atrium and ventricle) can refer to:

Left atrioventricular opening
Atrioventricular (band)
Atrioventricular fistula
Atrioventricular node

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Systole can mean the following:

Systole (medicine) is a term describing the contraction of the heart.
Systole (mathematics) is a term used in mathematics.
Systole (literature) is a term used to describe entry into the imagination/surreal in a text.

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Systole can mean the following:

Systole (medicine) is a term describing the contraction of the heart.
Systole (mathematics) is a term used in mathematics.
Systole (literature) is a term used to describe entry into the imagination/surreal in a text.

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Cardiac cycle is the term referring to all or any of the events related to the flow of blood that occur from the beginning of one heartbeat to the beginning of the next.^[1] The frequency of the cardiac cycle is the heart rate.
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Mitral valve prolapse
Classification & external resources

ICD-10 I 34.1
ICD-9 394.0 , 424.0

OMIM 157700
DiseasesDB .htm 8303
MedlinePlus .htm 000180
eMedicine /topic316 .
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Cardiac murmurs and other cardiac sounds
Classifications and external resources

ICD-10 R 01.
ICD-9 785.2 - 785.3

DiseasesDB 29151
MedlinePlus 003266

Murmurs
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For the ancient monasterial worker, see Auscultare

Auscultation is the technical term for listening to the internal sounds of the body, usually using a stethoscope.
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The chordae tendineae, or heart strings, are cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.
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In anatomy, the papillary muscles of the heart serve to limit the movements of the mitral and tricuspid valves. These muscles contract to tighten the chordae tendineae, which in turn prevent inversion. This occurs in response to pressure gradients.
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Diastole is the period of time when the heart relaxes after contraction. Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are relaxing.
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Myocardium is the muscular tissue of the heart.

Relationship to other layers

The other tissues of the heart are:

the endocardium (inner lining, effectively a specialized endothelium)

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An echocardiogram is an ultrasound of the heart. Also known as a cardiac ultrasound, it uses standard ultrasound techniques to image two-dimensional slices of the heart. The latest ultrasound systems now employ 3D real-time imaging.
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Systole can mean the following:

Systole (medicine) is a term describing the contraction of the heart.
Systole (mathematics) is a term used in mathematics.
Systole (literature) is a term used to describe entry into the imagination/surreal in a text.

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The apex of the heart is the lowest superficial part of the heart.

It is directed downward, forward, and to the left, and is overlapped by the left lung and pleura.

External anatomy

It lies behind the fifth left intercostal space, 8 to 9 cm.
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For the ancient monasterial worker, see Auscultare

Auscultation is the technical term for listening to the internal sounds of the body, usually using a stethoscope.
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The intercostal space is the space between two ribs (Lat. costa). Since there are 12 ribs on each side, there are 11 intercostal spaces.

Importance of intercostal space

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Mitral Valve

Information about Mitral Valve

Overview

Anatomy

Normal physiology

Surface anatomy

Additional images

See also

References

External links

Structure

Relationship to other layers

External anatomy

Importance of intercostal space