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Anatomy and Histology of the Cephalic Arterial Coilings in Hammerhead Sharks (Genus Sphyrna )
Author(s) -
MuñozChápuli R.,
Andrés A. V.
Publication year - 1995
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1995.tb01002.x
Subject(s) - anatomy , biology , efferent , connective tissue , artery , medicine , afferent , genetics
Hammerhead sharks (genus Sphyrna) show two large arterial coilings in a posteroventral hollow of the orbitary cavity. The posterior is made up of the hyoid artery which, after giving rise to the stapedial artery, enters the chondrocranium to originate the internal carotid and the cerebral arteries. The efferent pseudobranchial artery forms the anterior coiling, gives rise to the ophthalmic artery, enters the orbitary wall and joins the internal carotid artery. The histological sections of the arterial coilings showed the scarcity of smooth muscle cells in the tunica media as well as an important collagenic and elastic component in the arterial wall. Several venous vessels percolate through the coilings. A large amount of small (mean diameter = 73 μm), spheric corpuscles were observed in the connective tissue around the coilings. These corpuscles were also present in the palate and under the skin of the head of these sharks. They are comprised of spirally‐arranged cells around a bundle of collagen fibres. We hypothesize that their association with the coilings could suggest some kind of involvement in detecting pressure changes in the blood supply to the head.