What is the function of the gills in a starfish?

Starfish do not have gills in the traditional sense like many fish; instead, they have structures called papulae or skin gills, which are small projections of the body wall. These structures aid in respiration by allowing gas exchange directly through the thin skin, facilitating the absorption of oxygen and the release of carbon dioxide. Additionally, the papulae help in osmoregulation and the excretion of waste products. Overall, they play a crucial role in the starfish's respiratory and metabolic functions.