Browsing by Subject "Marine mammals."
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Item Diving physiology in marine mammals : significant findings in pinniped muscle physiology and trachea morphology.(2014-09-05) Moore, Colby D.; Trumble, Stephen John.; Biology.; Baylor University. Dept. of Biology.The muscular biochemistry and respiratory morphology of diving mammals are closely intertwined through the utilization and allocation of inspired oxygen for metabolism. Marine mammal physiological mechanisms and adaptations are of great intrigue due to the heightened environmental pressures that these animals are routinely subjected. These species also experience varying degrees of ischemia, hypoxemia and gas tissue saturation, which are pathological in terrestrial mammals. Data included in this dissertation suggest a unique skeletal muscle fiber type profile for the deep-diving Northern elephant seal; a profile predominately comprised of enlarged aerobic type I myofibers. In addition, enzymatic data suggest that diving mammals maintain higher levels of aerobic enzymes in primary locomotory muscle and that muscle-based enzymes degrade rapidly and variably with temperature and time. Histological analysis of harbor seal tracheal rings microscopically describes a unique continuity of cartilage that correlates with lung compression, depth at which lungs collapse, as well as maximum dive depth. Cumulatively, biochemical and structural adaptations allow diving mammals to reach extensive depth, while maintaining homeostatic levels of on-board gasses and avoiding dive-related injury. Ultimately, this research highlights the relationship between morphology, physiology and life history of these animals.Item Metabolic lipid regulation during developmental stress : fatty acid dynamics in fasting northern elephant seals.(2014-06-11) Robbins, Kathleen Anne.; Trumble, Stephen John.; Biology.; Baylor University. Dept. of Biology.Long chain fatty acids (LCFA) are important as fuel during exercise in humans, yet have pathological consequences during LCFA overabundance. The northern elephant seal (NES) (Mirounga angustirostris) is a temporally insulin resistant, deep-diving marine mammal reliant on fatty acid oxidation during seasonal fasting. Over the fast, NES females and weaned pups were found to oppositely utilize monounsaturated and saturated fatty acids, while polyunsaturated fatty acids generally increased in both age groups. Fatty acid transporter proteins (FATP) CD36, FATP1, FATP4 and binding protein 3 (FABP3) were detected in adult males, adult females, and pups. This thesis is the first documentation of these FATPs and FABPs in all NES age classes and expands current knowledge of lipid utilization in a mammal accustomed to a LCFA-rich diet.