ACB 406.3 Lecture Notes - Lecture 14: Buccal Pumping, Chondrichthyes, Tunicate
30 Oct 2018
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They looked for genes associated w/ gill development (pax1/9 genes) in urochordate and hemichordate gills. Tunicates are a filter-feeders and they have basket-like gills. Water passes through the gills by the action of cilia: cilia also direct food particles. Gills functions in filter feeding and gas exchange gills are used for both eating and breathing. Gills are heavily ciliated and are adjacent to blood channels: gas exchange occurs and food particles are directed into the gut. External gills simple delicate w/ no covering: an elaboration of the skin are extensions of the epithelium, some tadpoles, some adult salamanders. Internal gills covered by a carapace: bony and cartilaginous fish. In vertebrate embryos: endodermal outpouching of the pharynx make contact w/ similar outgrowth of the skin. In lower vertebrates: gills form a variable number of gill slits (amphioxus has 140, fish have 4)
