iPedia Free Information Center

Information about Interatrial Septum

Interior of right side of heart. (labeled at right, as 'atrial septum')
Interior of dorsal half of heart of human embryo of about thirty-five days.
subject #138 530
MeSH Heart+Septum
The interatrial septum is the wall of tissue that separates the right and left atria of the heart.

Development

The interatrial septum forms during the first and second months of fetal development. Formation of the septum occurs in several stages. The first is the development of the septum primum, a crescent-shaped piece of tissue forming the initial divider between the right and left atria. Because of its crescent shape, the septum primum does not fully occlude the space between left and right atria; the opening that remains is called the ostium primum. During fetal development, this opening allows blood to be shunted from the right atrium to the left.

As the septum primum grows, the ostium primum progressively narrows. Before the ostium primum is completely occluded, a second opening called the ostium secundum begins to form in the septum primum. The ostium secundum allows continued shunting of blood from the right atrium to the left.

To the right of the septum primum, the septum secundum begins to form. This thick, muscular structure initially takes on the same crescent shape as the septum primum, except that it originates anteriorly, whereas the septum primum originates posteriorly. As the septum secundum grows, it leaves a small opening called the foramen ovale. The foramen ovale is continuous with the ostium secundum, again providing for continued shunting of blood.

The ostium secundum progressively enlarges and the size of the septum primum diminishes. Eventually, the septum primum is nothing more than a small flap that covers the foramen ovale on its left side. This flap of tissue is called the valve of the foramen ovale. It opens and closes in response to pressure gradients between the left and right atria. When the pressure is greater in the right atrium, the valve opens; when the pressure is greater in the left atrium, the valve closes. Because the lungs are nonfunctional in fetal life, pressure in the pulmonary circulation is greater than that of the systemic circulation. Consequently, the right atrium is generally under higher pressures than the left atrium, and the valve of the foramen ovale is normally open.

At birth, there is a reversal in the pressure gradient between the atria, resulting in functional closure of the valve of the foramen ovale. Permanent anatomical closure of the foramen ovale occurs with time in normal infants. Inappropriate closure of the foramen ovale results in patent foramen ovale.

Disorders

  • Atrial septal defect is a relatively common heart malformation that occurs when the interatrial septum fails to develop properly.

References

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice, 39th ed. (2005). ISBN 0-443-07168-3
  • "Septum, interatrial." Stedman's Medical Dictionary, 27th ed. (2000). ISBN 0-683-40007-X

External links

 •  • [ 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
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
..... Click the link for more information.
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
..... Click the link for more information.
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.
..... Click the link for more information.
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.
Prenatal development is the process in which an embryo or fetus (or foetus) gestates during pregnancy, from fertilization until birth. Often, the terms fetal development, foetal development, or embryology are used in a similar sense.
..... Click the link for more information.
The introduction to this article provides insufficient context for those unfamiliar with the subject matter.
Please help [ improve the introduction] to meet Wikipedia's layout standards.

..... Click the link for more information.
ostium primum (interatrial foramen primum), below the free margin of the septum.

Closing of ostium primum

This opening is closed by the union of the septum primum with the septum intermedium, and the communication between the atria is reëstablished through an
..... Click the link for more information.
The ostium secundum (or foramen secundum) is a foramen in the septum primum.

It should not be confused with the foramen ovale, which is a foramen in the septum secundum.
..... Click the link for more information.
The introduction to this article provides insufficient context for those unfamiliar with the subject matter.
Please help [ improve the introduction] to meet Wikipedia's layout standards.

..... Click the link for more information.
The ostium secundum (or foramen secundum) is a foramen in the septum primum.

It should not be confused with the foramen ovale, which is a foramen in the septum secundum.
..... Click the link for more information.
The septum secundum, semilunar in shape, grows downward from the upper wall of the atrium immediately to the right of the primary septum and foramen ovale.

Shortly after birth it fuses with the primary septum, and by this means the foramen ovale is closed, but sometimes the
..... Click the link for more information.
There are multiple structures in the human body with the name foramen ovale (plural: foramina ovalia; Latin for "oval hole"):
  • In the fetal heart, the foramen ovale (heart) is a shunt from the right to left atrium.

..... Click the link for more information.
In atmospheric sciences (meteorology, climatology and related fields), the pressure gradient (typically of air, more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure changes the most rapidly around a particular location.
..... Click the link for more information.
lungs flank the heart and great vessels in the chest cavity.[1]]]

The lung is the essential respiration organ in air-breathing vertebrates, the most primitive being the lungfish.
..... Click the link for more information.
Pulmonary circulation is the portion of the cardiovascular system which carries oxygen-depleted blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. The term is contrasted with systemic circulation.
..... Click the link for more information.
Systemic circulation is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, and returns deoxygenated blood back to the heart. The term is contrasted with pulmonary circulation.
..... Click the link for more information.
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.
..... Click the link for more information.
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.
..... Click the link for more information.
GPnotebook is a British medical database for general practitioners (GPs).[1] It is an online encyclopaedia of medicine that provides an immediate reference resource for clinicians worldwide. The database consists of over 30,000 pages of information.
..... Click the link for more information.
Indiana University, founded in 1820, is a nine-campus university system in the state of Indiana. The IU system includes the following campuses:
  • Indiana University in Bloomington, Indiana

..... Click the link for more information.
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]
..... Click the link for more information.
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.
..... Click the link for more information.
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.
..... Click the link for more information.
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.
In anatomy, the atrium (plural: atria) refers to a chamber or space. As such it may for example be the atrium of the lateral ventricle in the brain or, popularly, the blood collection chamber of a heart.
..... Click the link for more information.
musculi pectinati (pectinate muscles).

In the left atrium, the musculi pectinati, fewer and smaller than in the right auricula, are confined to the inner surface of the auricula. This is due to the embryological origin of the auricles, which are the true atria.
..... Click the link for more information.
In the heart, a ventricle is a heart chamber which collects blood from an atrium (another heart chamber that is smaller than a ventricle) and pumps it out of the heart.
..... Click the link for more information.
Interventricular septum (or ventricular septum, or during development septum inferius) is the stout wall separating the lower chambers (the ventricles) of the heart from one another.
..... Click the link for more information.
The trabeculae carneae (columnae carneae, or fleshy beams), are rounded or irregular muscular columns which project from the whole of the inner surface of the ventricle, with the exception of the conus arteriosus.
..... Click the link for more information.
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.
..... Click the link for more information.


This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus


page counter