EVERYDAY SCIENCE

Detailed explanation-1: -In reptiles, the gills are fully replaced by lungs. Only III, IV and VI aortic arches are present. With the partial separation of the ventricle into two parts, the distal portion of the conus arteriosus and the entire ventral aorta are split into three vessels, i.e., two aortic or systemic and one pulmonary.

Detailed explanation-2: -The pharyngeal arch arteries (PAAs) in reptiles and birds (sauropsids) and in mammals develop in a craniocaudal sequence as shunts between the aortic sac and the paired dorsal aortae.

Detailed explanation-3: -In most reptiles, the subclavian arteries branch from the dorsal aorta, but in some reptiles, they branch from the systemic arches. These modifications of the aortic arches in reptiles produce one pulmonary circuit and two systemic circuits, each of which arises independently from the heart.

Detailed explanation-4: -The aortic arches are a series of six arches that develop consecutively to connect the aortic sac with the paired dorsal aorta. Cardiac neural crest cells migrate through aortic arches 3, 4, and 6 during weeks 3-4 of human development.

Detailed explanation-5: -The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac.