Gross anatomy of the respiratory system of the bowhead whale, Balaena mysticetus

Authors

  • Robert W. Henry,

    1. Department of Veterinary Anatomy and Fine Structure, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408
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  • Dr. Jerrold T. Haldiman,

    Corresponding author
    1. Department of Veterinary Anatomy and Fine Structure, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408
    • Department of Veterinary Anatomy, Louisiana State University, Baton Rouge, Louisiana 70803-8408
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  • Dr. Thomas F. Albert,

    1. Department of Veterinary Science, University of Maryland, College Park, MD 20740
    Current affiliation:
    1. Conservation and Environmental Protection Office, North Slope Borough, P.O. Box 69, Barrow, AK 99723
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  • William G. Henk,

    1. Department of Veterinary Anatomy and Fine Structure, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408
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  • Yahya Z. Abdelbaki,

    1. Department of Veterinary Anatomy and Fine Structure, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408
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  • Dennis W. Duffield

    1. Department of Veterinary Anatomy and Fine Structure, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8408
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Abstract

Components of the respiratory system from seven bowhead whales have been examined. The paired and laterally curved external nares are passively closed by a valve-like mass located in the rostral, lateral, and ventral walls of the nasal vestibules. Nasal septal cartilages are paired smooth plates rostrally changing to accordion-like folds caudally. The epiglottic and arytenoidal protuberances of the larynx are typically cetacean, but blunt. The cricoid cartilage is not a complete ring, but an elongated, inverted, troughshaped structure. The thyroid cartilage is trough-shaped with elongated cranial cornua curving dorsocaudally from each thyroid lamina. A conical mass of skeletal muscle serves as the floor of the short trachea and also surrounds the termination of the laryngeal sac. The trachea is dorsoventrally compressed, lacks a tracheal bronchus, and its width equals its length. The principal bronchi give rise to lobar bronchi at obtuse angles. Large segmental bronchi branch extensively from lobar bronchi near the mediastinal lung surface. The lungs are rectangular and of nearly uniform thickness throughout, without external or internal lobulation.

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