Nervous System Of A Mollusca
Like humans the nervous system of a mollusca has its own system of nerve cells and fibers that send sensations to the brain and producing motor impulses to organs and muscles. In this second largest animal kingdom the nervous system of a mollusca is fairly complicated. Where some classes generally have nervous system of a mollusca that include cluster of nerve cells, sensory systems, and nervous systems in a complex manner and some are less complicated at all.
The majority of the molluscan species are marine and the nervous system of a mollusca in this habitats are more complex. Close to the nervous system of a mollusca is a well developed head and sensitive eyes, mouth and then their muscular feet that is used for locomotion. Some other large group of mollusks occupies freshwater and terrestrial domains.
How the circulatory and nervous system of a mollusca function? The blood flows through the gill fibers, where the gaseous exchange occurs (between carbon dioxide and oxygen). The blood and the water flows over the gill surface. The respiratory pigment that is usually present in most mollusks oxygenates the blood and thus turning into a bluish color. On the other way around when the blood is deoxygenated it will turn colorless.
Not all mollusks have hemoglobin in their blood. Hemoglobin is an iron-containing protein in red blood cells that picks up oxygen and delivers or transports it from the lungs to body tissue. The blood circulation varies in each class of mollusks but it is always sorted out by a muscular heart before it is distributed the body tissues. Most mollusks possess well-developed sensory organs and nervous system. Among the classes of mollusca, the class Cephalopoda that consists of squids, octopuses and nautiluses has the highly developed nervous system so far.
They are renowned because of their shells and found in the reefs and beaches but the nervous system of a mollusca is one the complex part in their systems that they were able to live for centuries and being successful among others in the animal kingdom. If you take a look at their body, all you can see is a soft fragile like body but their internal systems works in a complex manner. One of the features of mollusca is their ventral body wall that is used for locomotion and its dorsal body wall that forms a mantle, a flexible body wall cavity that covers the internal organs. Not all have sells that are formed during secretions and considering the octopuses and squids that do not have the shells they are considered as one of the successful in the group.