manatee projects



In the manatee ( Trichechus manatus latirostris), I am working to characterize the morphology and innervation pattern of the diaphragm. The diaphragm in these animals is a huge muscle, running almost the entire length of the body cavity. I am interested in determining if this muscle is "compartmentalized", i.e. having distinct regions that could possibly be recruited individually. If this muscle is "compartmentalized," the manatee would be able to contract distinct portions of its diaphragm, rather than having the entire muscle contract as a unit. Thus, as Rommel and Reynolds (2000) suggest, the manatee would be able to control the amount of air in different areas of its lungs, allowing it to determine its pitch in the water column.

Detailed dissections of the manatee diaphragm have revealed vascular connective tissue (VCT) bundles that may be involved in compartmentalizing this muscle. These elements are spaced approximately one centimeter apart down the length of the diaphragm (cranial to caudal) and extend through the depth of the muscle (abdominal to thoracic). Thus, the VCT bundles separate the muscle of the diaphragm into one centimeter wide blocks. However, the innervation pattern of the manatee diaphragm suggests that the actual compartments are made up of groups of these muscle blocks. Currently, I am working to identify the vascular elements of the VCT bundles using histology, and I am also characterizing the fiber-type profile of the compartments.



 
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