Mucociliary epithelia are found in the human airways and act as the first line of defence against inhaled foreign agents. Mucus traps potentially damaging particles and the cilia transport the mucus away from the airways to remove the threat. Modelling mucociliary epithelia for research purposes is challenging. This is because the airways are enclosed and are thus difficult to study directly. Instead, tissue is extracted or in vitro techniques are employed. Whilst these systems are useful, there is a need for accessible in vivo models to complement them. In this thesis I assess a new model system for studying mucociliary epithelia. This system is the larval epidermis of the amphibian, Xenopus tropicalis. Its epidermis comprises multi-ciliated cells that beat in a polarised direction reminiscent of those found in the human airways. It is also proposed to have a number of other cell types including mucus-secreting cells, but very little is known about them. The epidermis is open and accessible to manipulation meaning that it has great potential to be used in the study of mucociliary epithelia in live, native conditions. Such a system would be a valuable addition to the current models employed. However, the epidermis has not been thoroughly characterized before so its utility as a model system remains speculative.To develop and evaluate this new model, I fully characterize the epidermis, showing that it has five distinguishable cell types. This includes a population of cells called ionocytes that are shown to be essential for the health and function of the epidermis. I also test for the presence of mucins, the structural component of mucus, secreted from the epidermis in order to evaluate the proposal that mucus-secreting cells are present in the epidermis. A mucin-like protein called otogelin is identified. After characterizing the epidermal cell types, I compare them to the human mucociliary epithelium and consider potential applications and future perspectives for this model.

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