GENERAL HISTOLOGY

Detailed explanation-1: -Although they are actually the most abundant of the echinoderms . The small ciliated projections that enable breathing in this animal are called ? Skin gills. You notice that a sea star in an aquarium has one very short arm.

Detailed explanation-2: -Cilia, tiny muscular, hair-like projections on the cells that line the airway, are one of the respiratory system’s defense mechanisms. Cilia propel a liquid layer of mucus that covers the airways.

Detailed explanation-3: -Echinoderms have a unique water vascular system. This network of fluid-filled tubes helps them to breathe, eat, and move. Therefore, they can function without gill slits. Echinoderms also have a very simple digestive system, circulatory system, and nervous system.

Detailed explanation-4: -In sea stars, water enters the system through a sieve-like structure on the upper surface of the animal, called the madreporite.

Detailed explanation-5: -These echinoderms do not have arms, but are hemispherical or flattened with five rows of tube feet that help them in slow movement; tube feet are extruded through pores of a continuous internal shell called a test. Sea lilies and feather stars are examples of Crinoidea. Both of these species are suspension feeders.