Medicine and Health related Information

Development of Interventricular septum-
A muscular diverticulum develops from the floor of the A.V cusion for a short period. It is seperated by a small gap from the atrio-ventricular cusion. It is called “interventricular foramen”. Later the atrio-ventricular cusion develops downwards and fuses with the muscular part thus closing the intra-ventricular foramen.

VENTRICLES-
The ventricles are derived from -
a) The primitive ventricular chamber
b) the proximal part of bulbus cordis.
The conus gives rise to infundibulum of the right ventricle and to aortic vestibule of left ventricle.
AORTIC ARCHES- Each pharyngeal arch has got its own artery, since there are 6 pharyngeal arches the arteries are also 6 pairs. Each artery is embedded in the mesenchyme of the bronchial arches and terminate in the dorsal aorta. Anteriorly they communicate with one another and opens into the aortic sac per 2 horns.
Fate of arteries- The first arch largely disappears and small portion persists to form the maxillar artery.
The second aortic arch soon disappears, the remaining portion of this arch are the hyoid and stapedial arteries. The third arch forms the common carotid artery and the first part of the internal carotid artery. The remainder of the internal carotid artery is formed by the cranial portion of dorsal aorta. The external artery is a sprout of the third aortic arch.
The fourth arch persists on both sides but its ultimate fate is diffrent on the left and right sides.
On the left it forms part of the arch of aorta between the left common carotid and left subclavian artery. On the right it forms the most proximal segment of the right subclavian.