title: Microscopic anatomy of the ringed seal (Phoca hispida) lower respiratory tract.
abstract: The microscopic anatomy of the ringed seal lung exhibits unique features and many features similar to those described in other seal species. Unique features include: Trachealis muscle predominately oriented longitudinally; Large veins within the tracheal wall supported by elastic fibers; Goblet cells and pseudostratified epithelium lining the duct system of bronchial glands of the segmental bronchi; Lamina propria of the segmental bronchus heavily invested with elastic fibers clustered into dense longitudinal bundles; and Capillaries and venules covered with squamous epithelium protruding into bronchiolar lumina. Common features include: Cartilage support of the bronchial tree extending distally into respiratory bronchioles; Smooth muscle enhancements in the distal airways producing sphincter like formations; and Lungs extensively supported with interstitial tissue, which divide lungs into lobules.
authors.affiliation: Department of Comparative Medicine, The University of Tennessee, 2407 River Drive, Room A205 Knoxville, TN 37996-4543, USA.
authors.forename: H
authors.initials: H
authors.lastname: Smodlaka
authors.forename: R B
authors.initials: RB
authors.lastname: Reed
authors.forename: R W
authors.initials: RW
authors.lastname: Henry
mesh_terms: D000818:Animals; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D008168:Lung / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D009130:Muscle, Smooth / Q000033:anatomy & histology / Q000648:ultrastructure; D046049:Phoca / Q000033:anatomy & histology* / Q000502:physiology; D012143:Respiratory Physiological Phenomena; D012137:Respiratory System / Q000033:anatomy & histology* / Q000166:cytology / Q000648:ultrastructure*; D013045:Species Specificity