What is the function of a squid's siphon?
A squid's siphon is multi-functional. It helps with locomotion in any direction by "spitting" out a stream of water. It helps the squid breathe by getting rid of the "wastewater" from the seawater pumped over the gills in the mantle (head). It also gets rid of other internal waste. , Studying marine biology for over 20 years.
What is a siphon in a mollusc?
The siphon is part of the mantle of the mollusc, and the water flow is directed to (or from) the mantle cavity . A single siphon occurs in some gastropods.
What drives a siphon?
They wrote that: "It is widely believed that the siphon is principally driven by the force of atmospheric pressure. An experiment is described that shows that a siphon can function even under high-vacuum conditions.
What is the root word of siphon?
The word siphon (/ˈsaɪfən/ SY-fən; from Ancient Greek: σίφων "pipe, tube", also spelled syphon) is used to refer to a wide variety of devices that involve the flow of liquids through tubes.
In gastropods
In some (but not all) sea snails, marine gastropod molluscs, the animal has an anterior extension of the mantle called a siphon, or inhalant siphon, through which water is drawn into the mantle cavity and over the gill for respiration.
Paired siphons of bivalves
Drawing of the venerid Venus verrucosa showing paired siphons (upper inhalant and lower exhalant siphon), shell and foot.
Hyponome of cephalopods
Nautilus belauensis seen from the front, showing the opening of the hyponome.
The mantle
The main body of the squid is called the mantle, which fits like a sheath over the internal organs. This colossal squid's mantle is about 2.5 metres long and about 982 millimetres wide, almost the same diameter as a truck tyre.
Gladius, or pen
All molluscs have a shell. The colossal squid has an internal shell called the gladius. The gladius is a rigid internal structure that supports the squid's body and runs through the upper part of the mantle, between the paired tail fin.
Tail fin
The paired tail fin is attached to the upper surface of the mantle and is made up of muscle. The colossal squid swims forward through the water by undulating the fin longitudinally.
Funnel or siphon
The funnel, or siphon, is a muscular structure located on the ventral surface of the mantle. It has several functions, including respiration and discharge of wastes. The colossal squid also uses the funnel to help it move in the water.
History
Egyptian reliefs from 1500 BC depict siphons used to extract liquids from large storage jars.
Theory
A practical siphon, operating at typical atmospheric pressures and tube heights, works because gravity pulling down on the taller column of liquid leaves reduced pressure at the top of the siphon (formally, hydrostatic pressure when the liquid is not moving).
Modern research into the operation of the siphon
In 1948, Malcolm Nokes investigated siphons working in both air pressure and in a partial vacuum, for siphons in vacuum he concluded that: "The gravitational force on the column of liquid in the downtake tube less the gravitational force in the uptake tube causes the liquid to move.
Practical requirements
A plain tube can be used as a siphon. An external pump has to be applied to start the liquid flowing and prime the siphon (in home use this is often done by a person inhaling through the tube until enough of it has filled with liquid; this may pose danger to the user, depending on the liquid that is being siphoned).
Applications and terminology
When certain liquids needs to be purified, siphoning can help prevent either the bottom ( dregs) or the top ( foam and floaties) from being transferred out of one container into a new container. Siphoning is thus useful in the fermentation of wine and beer for this reason, since it can keep unwanted impurities out of the new container.
Devices that are not true siphons
Siphon coffee brewer: when warmed by a heat source (A), vapor pressure increases in the lower chamber (B), forcing the water downwards (C) and through the central pipe into the upper chamber (D) where it is mixed with the coffee grounds. When the heat is removed, the water flows back down.
In nature
The term "siphon" is used for a number of structures in human and animal anatomy, either because flowing liquids are involved or because the structure is shaped like a siphon, but in which no actual siphon effect is occurring: see Siphon (disambiguation) .
Overview
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda (members of these classes include saltwater and freshwater snails, clams, octopus, squid and relatives).
Siphons in molluscs are tube-like structures in which water (or, more rarely, air) flows. The water flow is used for one or more purposes such as locomotion, feeding, respiration, and reproduction. …
In gastropods
In some (but not all) sea snails, marine gastropod molluscs, the animal has an anterior extension of the mantle called a siphon, or inhalant siphon, through which water is drawn into the mantle cavity and over the gill for respiration.
This siphon is a soft fleshy tube-like structure equipped with chemoreceptors which "smell" or "taste" the water, in order to hunt for food. Marine gastropods that have a siphon are either preda…
Paired siphons of bivalves
Those bivalves that have siphons, have two of them. Not all bivalves have siphons however: those that live on or above the substrate, as is the case in scallops, oysters, etc., do not need them. Only those bivalves that burrow in sediment, and live buried in the sediment, need to use these tube-like structures. The function of these siphons is to reach up to the surface of the sediment, so that the animal is able to respire, feed, and excrete, and also to reproduce.
Hyponome of cephalopods
The hyponome or siphon is the organ used by cephalopods to expel water, a function that produces a locomotive force. The hyponome developed from the foot of the molluscan ancestor.
Water enters the mantle cavity around the sides of the funnel, and subsequent contraction of the hyponome expands and then contracts, expelling a jet of water.
In most cephalopods, such as octopus, squid, and cuttlefish, the hyponome is a muscular tube. T…
External links
• Glossary
• Bivalve anatomy
• More bivalve anatomy