HEART PART IN AORTA::
The aorta which is the biggest artery of the body starts from the left ventricle its opening like that of the pulmonary trunk is guarded by the semilunar valve This valve has three curved semilunar cusps which prevent the backward thrust of blood into the left ventricle in the beginning of the ventricular diastole resulting in the second heart sound
Left atrium opens into the left ventricle through an opening called the left atrio-ventricular aperture this aperture is guarded by a valve having two cusps and hence called bicuspid or mitral valve it guards against the back entry of blood into the left atrium at the beginning of the systole The papillary muscles of the left ventricle with its chordae tendinae prevent overdistension of the valve
There is a cord like structure between the arch of the aorta and the pulmonary trunk passing underneath the arch of the aorta This is now a vestigial remnant called Ductus-Arteriosus in the foetal life it works as a vessel link between the two big vessels to bypass the pulmonary circulation After birth the blood changes th
e route and starts circulating through the lungs and therefore the foetal link closes down and gets obsolete and hence it atrophies in rare cases this duct does not close in such cases the deoxygenated blood mixes with the oxygenated blood of the aorta The mixed blood is detrimental to the health it can be corrected only by surgery
e route and starts circulating through the lungs and therefore the foetal link closes down and gets obsolete and hence it atrophies in rare cases this duct does not close in such cases the deoxygenated blood mixes with the oxygenated blood of the aorta The mixed blood is detrimental to the health it can be corrected only by surgery
The two atria are separated by a septum called inter-atrial septum while the two ventricles are separated by the septum called the inter-ventricular septum
Septum Ovale ::There is a crescentic mark on inter-atrial septum representing the closed foramen -ovale which existed in the foetal life That foetal opening was a short circuit in cardiac circulation thus avoiding the blood -entry into the lungs This foramen -ovale closes with the first breath of the baby after birth and this is then called the septum ovale After birth baby"s blood from the right atrium goes to the right ventricle to reach the lungs for purification via pulmonary trunk Rarely in some cases this foramen ovale remains open as a congenital heart defect This defect can be corrected by surgical method
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