Lateral line

A sensory system in aquatic vertebrates for detecting water movements

The lateral line is a sensory system found in aquatic vertebrates, including fish and some amphibians, that enables them to detect movements and vibrations in the surrounding water. This system is crucial for various behaviors such as predator avoidance, prey detection, and schooling behavior.

Structure

The lateral line system consists of a series of mechanoreceptive organs called neuromasts, which are distributed along the sides of the body and head of the animal. These neuromasts can be located on the surface of the skin or embedded within canals beneath the skin.

Neuromasts

Neuromasts are the fundamental sensory units of the lateral line system. Each neuromast contains hair cells similar to those found in the inner ear of terrestrial vertebrates. These hair cells are equipped with hair-like projections called stereocilia and a single kinocilium. When water movement displaces the stereocilia, it causes a change in the electrical potential of the hair cells, which in turn sends signals to the brain via the lateral line nerves.

Canal and Superficial Neuromasts

There are two main types of neuromasts:

• Canal neuromasts: These are located within fluid-filled canals beneath the skin. The canals open to the surface through pores, allowing water to flow through and stimulate the neuromasts.
• Superficial neuromasts: These are located directly on the skin surface and are more sensitive to water currents.

Function

The lateral line system plays a vital role in various behaviors and ecological interactions:

Predator and Prey Detection

Fish use the lateral line to detect the movements of predators and prey. The system is sensitive to low-frequency vibrations, allowing fish to sense the approach of other animals even in murky water or complete darkness.

Schooling

In schooling fish, the lateral line helps maintain the precise spacing and coordination between individuals. It allows fish to detect the movements of their neighbors and adjust their own movements accordingly.

Navigation

The lateral line also aids in navigation by detecting changes in water flow patterns, which can indicate obstacles or changes in the environment.

Evolution

The lateral line system is believed to have evolved early in the history of vertebrates, as it is present in both jawless fish like lampreys and jawed vertebrates. It is considered an ancient sensory system that has been adapted for various ecological niches.

Related pages

• Fish anatomy
• Sensory system
• Mechanoreception
• Amphibian

Lateral_line

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  Lateral line 01

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  Lateral Line Organ

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  Rutilus Rutilus Scales Lateral Line

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  Gasterosteus aculeatus with stained neuromasts

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  Lateral line rate coding

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  Lateral line circuits

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  Electroreceptors in a shark's head

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  Petromyzon marinus

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  White shark (Duane Raver)

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  Coelacanth flipped

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  Chinle fish Arganodus cropped

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  Salamandra salamandra (white background)