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Structure of the brain and eye heater tissue in marlins, sailfish, and spearfishes
Author(s) -
Block Barbara A.
Publication year - 1986
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051900203
Subject(s) - anatomy , muscle tissue , tissue fluid , biology , brain tissue , rest (music) , blood supply , skeletal muscle , medicine , surgery
Marlins, sailfish, and spearfishes have a heat‐producing tissue beneath the brain and adjacent to the eyes. This tissue warms the brain and eyes while the rest of the body remains at water temperature. The heater tissue is derived from the superior rectus eye muscle. Only a portion of this eye muscle contains normal skeletal muscle tissue; the rest consists of the modified muscle tissue that is associated with heat production. The heat‐producing portion is supplied with blood through a countercurrent heat exchanger that originates from the carotid artery. The vascular rete prevents the heat being produced by the tissue from being dissipated at the gill. An unusual circulatory supply to the eyes and brain is associated with the presence of the heater tissue in these fishes.