Anatomy of finfish and shellfish

Unit 5 - Circulatory System

5.2.2. Arterial System in Elasmobranchs
Afferent branchial arteries
The ventral aorta arises form the conus arteriosus and veins forwards along the ventral surface of the pharynx right upto the posterior border of the hyoid arch where it bifurcates into two branches each branch divide into first and second afferent branchial arteries. The first afferent branchial artery runs along the posterior border of the first branchial arch and supplied arterial branches to anterior and posterior gill lamellac of the first branchial arch of the third, fourth and fifth afferent branchial arteries arise form the ventral aorta almost equidistant from one another and runs along the outer border of the second third and fourth branchial arches. This supply the blood to the 3rd 4th and 5th gill arches respectively.
Efferent branchial arteries
The blood from the capillaries of gill lamellac is collected by a serious of blood vessel called the efferent branchial arteries. There are nine efferent branchial vessels on each side (may be less depending upon species) of these the first eight join in pairs to form four complete toops around the 1st four gill clefts. The 9th runs along the anterior border of the fifth gill cleft.
The four loop and 5th efferent branchial arteries are joined by short longitudinal connectives running across the inter branchial septa. The efferent branchial subsequently join to form the medium dorsal aorta.
Arteries of the head
The first efferent branchial and a small part from the dorsal aorta supply blood to the head. The first efferent branchial vessel gives rise to three branches the external carotid afferent spiracular and hyoidean.
The afferent spiracular runs forward and gives rise to ophthalmic artery. This artery moves forward joins with external carotid to form cerebral artery.