Nervous System And Digestive System
Nervous System and digestive system
what type of digestive system has a starfish have?
a simple or complex? and also, what type of nervous system has? none, rudimentary or developed?
Starfish (also called sea stars) are any echinoderms belonging to the class Asteroidea. The names "star sea "and" starfish "are also used in a broader sense to include the closely related brittle stars, which constitute the class Ophiuroide The body cavity also contains the water vascular system that operates the tube feet, and the circulatory system, also called the hemal system. Hemal channels form rings around her mouth (the oral hemal ring), more near the top of the starfish and the entire digestive system (the gastric hemal ring). Part of the body cavity called the axial sinus connects the three rings. Each ray also has hemal channels running next to the gonads. Digestion and excretion of the stars Sea digestion is carried out in two stomachs: the cardiac stomach and pyloric stomach. The cardiac stomach is a sack like stomach located in the center of the body and may be everted body outside the body to engulf and digest food. Some species are able to use their water vascular systems to force open from the shells of bivalve mollusks such as clams and mussels by injecting their stomachs into the shells. With the stomach inserted into the shell, the star sea is able to digest the mollusk in place. The cardiac stomach was brought back into the body, and partially digested food moves pyloric stomach. Besides digestion occurs in the intestine. Waste is either excreted through the anus on the aboral side of the body, or excreted in the mouth if the anus is absent as in brittle stars. Because of this ability to digest food outside their body, the starfish is able to catch prey that are much larger than the mouth otherwise allow, including arthropods, small fish and mollusks. Some echinoderms live several weeks without food under artificial conditions. It is thought that they may receive some nutrients from organic matter dissolved in seawater. Sea stars and other echinoderms have endoskeletons, suggesting that echinoderms are very closely related chordates, animals with a hollow nerve chord that usually have vertebrae. Echinoderms have rather complex nervous systems, but lack a true centralized Brain. All echinoderms have a network of interlacing nerves called a nerve plexus that lies within and below the skin. The esophagus is also surrounded by a series of rings sending nerve radial nerve which are often parallel with the branches of the water vascular system. The nerves and radial nerves coordinate ring of the starfish balance and steering systems. Although the echinoderms do not have many well-defined sensory inputs, sensitive to touch, light, temperature, orientation and state of water around them. The tube feet, spines and pedicellariae is in the starfish are sensitive to touch, while eyespots on the ends of the rays are sensitive light. Hope this helped:)
