Basic plan of Aortic arches

In typical vertebrate embryo, major arterial channels:
- Ventral aorta
- Dorsal aorta
- 6 pairs of Aortic Arches: connecting Ventral &
Dorsal aorta
Blood leaves heart through ventral aorta  runs forward,
midventrally, beneath the pharynx  branches
anteriorly into a pair of External Carotid Arteries into
head
In b/w, the Ventral aorta gives off 6 pairs of aortic arches
running through visceral arches
Each aortic arch consists of a
• Ventral Afferent Branchial Artery carrying venous
blood to capillaries in a gill
• Dorsal Efferent Branchial Artery taking arterial blood
from the gill
• All efferent branchial arteries of the same side join
dorsally to form a Lateral Dorsal Aorta/ Radix
• Radix extend into head as Internal Carotid Artery
• The two lateral dorsal aortae unite just behind the
pharynx to form a single Median Dorsal Aorta which
continues behind into tail region as Caudal artery.
• Branches from these main arterial channels supply all
parts of the vertebrate body.