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1. Endolymphatic Pore 2. Skin 3. Endolymphatic Duct 4. Posterior Vertical Canal 5. Anterior Vertical Canal 6. Horizontal Canal 7. Macula Neglecta 8. Sacculus 9. Utriculus |
A shark's ear is used for hearing and for balance, and is located in it's cartilaginous brain case. Inside the ear there are three fluid filled semi-circular canals, all at right angles to each other. As the shark moves around, the fluid moves over layers of hair cells, which sends nerve impulses to the shark's brain, enabling it to determine it's speed and direction. Attached to these canals are the otolith organs - the sacculus and the utriculus, which are all lined with tiny hair cells called maculae. These maculae have granules of calcium carbonate, known as otoconia, resting upon them, which move with the force of gravity. This sends signals to the sharks brain, telling it the body's gravitational position and the direction of movement. The sharks sense of hearing is very acute, and research suggests that they can hear sounds over several thousands of metres. It is thought that the macula neglecta is used for sound interpretation, and whilst they contain hair cells, these lack otoconia. Pressure from sound waves caused by perhaps a struggling fish, are channeled into this organ, where it is stimulated to send nerve impulses to the brain. |
