A51 – Summer 2009 VERTEBRATE ANATOMY 1. PHYLUM CHORDATA Four notable characteristics of the phylum: -The presence of pharyngeal gill clefts at some point in development. -The presence of a notochord at some point in development. -The presence of a single, hollow, dorsal nerve cord. -Post anal tail. 2. THE RAT DISSECTION -Use a scissors, not a scapel, to snip the skin and muscles. -Do not plunge the scissors deeply into either the abdominal or thoracic cavities or you will damage the organs underneath. Be especially careful when cutting through the rib cage into the region near the heart. -If you cut the intestines, it may STINK considerably. -Remove ALL pins from the rat when finished. Wrap the rat NEATLY in a plastic bag, secure with 2 strips of tape, and place in the freezer. You should be able to define: dorsal, ventral, medial, distal, proximal, lateral, posterior, anterior. You should be able to identify all of the following structures. External Features:
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Dorsal nerve cord, vena cava Neck Region Salivary Glands