<center>https://steemitimages.com/DQmXbR2Ybc5jAL62ZRLEKZw9MNQFC8ZUgCBcSrFTnnRpS4t/jellyfish-690472_1920.jpg</center>

<center>_Welcome my Steemian friends to a new episode of **Myth or Fact?**_</center>

I visited Thailand in February and enjoyed the beautiful scenery. Fantastic beaches, crystal clear water, tropical jungle and much more are awaiting you there. On one day we wanted to visit a quite famous beach called Bottle beach. It was a rather remote place and hard to get there, it took us almost an hour walk to reach the beach. Once we arrived we understood why the beach was named after bottles. Everywhere around the beach you would see bottles, makes sense right?

I asked a local citizen why they had all these fancy bottles around the beach. His answer was quite alarming: there are many jellyfishes in the water and it happens that sometimes people die. In the bottle you will find vinegar.

My stay at the beach was quite short. Right after I heard his story we went immediately back. Wonderful: the hot sun burning on my skin, being exhausted and only wanted to relax I had to walk the hour back!

_Am I exaggerating? Are jellyfish really that deadly? We will find out!_

<center><h1>Jellies </h1></center>

Except the fact that jellyfish are no fish at all, they are invertebrate animals of the phylum Cnidari. Other members of the Cnidari for instance are sea anemones and corals. Jellies consist of 90 to 95% of water and have no brain, blood or heart. In the figure below you will see the diagram of the anatomy of a jellyfish. Jellies are composed of three different layers. Just like us humans jellies have a skin, it's their first layer, the epidermis.  Followed by the second layer which makes most of the gelatinous material. You might call it jelly, gels or scientifically as mesoglea. The third and last layer is the gastrodermis. Some of you might ask yourself now how jellies can interact with their surrounding and even perceive sensations. It's simple, their body has a nervous system so called nerve net. _Don't laugh but their mouth is also their anus._

<center>https://steemitimages.com/DQmesedj2KWqPoxeZLSp8aCDZDLzw9NfCSyHR6sxTAd5fjJ/science-41526_640.png<br>Fig.1 Diagram of a jellyfish [Source](https://pixabay.com/en/science-diagram-cross-drawing-fish-41526/)</center>

Jellies have one big cavity where all the digestive processes happen. In fact the digestion of jellyfish is very fast since they need to stay lightweight. They can absorb nutrients very quickly. 
Because they are carnivores they feed of zooplankton, small fish, little crabs etc. 
Most of the species have tentacles with cnidocytes , which they use for hunt and are important for todays article. 

Jellyfish don't hunt humans or hurt them intentionally. Incidents happen accidentally when humans get in touch with their tentacles and only if these contain cnidocytes. Even if you are underwater and don't see any tentacles it doesn't mean they aren't present. The largest jellyfish, the lions mane jellyfish, has tentacles that reach up to 36.5 meters and are so fine you wont see them.  

<h1><center>Painful cnidocytes</center></h1>

Now that we know a little more about jellies we can talk about their danger. As already mentioned their tentacles contain harmful cells, so called cnidocytes. They use these for hunting or defending against other predators. 
<center>https://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Chironex_fleckeri_nematocysts_01.jpg/448px-Chironex_fleckeri_nematocysts_01.jpg<br>Fig.2 Nematocysts of a sea wasp [Source](https://de.wikipedia.org/wiki/Datei:Chironex_fleckeri_nematocysts_01.jpg)</center>

When a human gets in touch with their tentacles these cells adhere on the human skin. The figure below illustrates how the discharge mechanism works. The cnidocil acts as a trigger. If this trigger is activated, chemically or mechanically, the nematocyst is ejected and will penetrate the skin. In the picture number 2 we see the nematocysts of the sea wasp, one of the most deadly animal on our planet. It's an species of the box jellyfish. Causing terrible pain it can even lead to death within minutes if no medical help is provided immediately. The toxin can stop the heart beat and cause respiratory paralysis.

<center>https://upload.wikimedia.org/wikipedia/commons/b/b0/Nematocyst_discharge.png<br>Fig.3 Discharge mechanism of Nematocysts [Source](https://en.wikipedia.org/wiki/File:Nematocyst_discharge.png)</center>

<h1><center>What to do?</center></h1>
* <center>Try to get out of the water as fast as possible. The next step should be to pour salt water over the area. It's is **very** important to not use fresh water. Since cnidocils act upon chemical changes the freshwater will make even more of the cells inject their venom into your body!</center>
* <center> If you have accesses to vinegar use it instead. It will prevent the nematocysts to pop up and inject toxin into you. After that try to remove the needles with a tweezer. Don't use your hands!</center>
* <center>If you don't have a tweezer use sand. Moisten your skin with water and put sand on it. Now try to wipe off the needles on your skin. Don't use your towel. It will make it worse!</center>
* <center> Call for medical help and wait for rescue </center>

_The local citizen was right and these bottles were to help people that are stung by jellies._

<hr> 
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<hr />

<center>_Thanks for reading this episode of Myth or Fact! If you enjoyed it feel free to resteem and leave a comment! I would love to know what you think about jellyfish!_</center>

Do you love photography? Then take part at my current photography challenge and win great prizes! [MyPictureDay Challenge](https://steemit.com/photography/@timsaid/mypicturesunday-9-london-streetfood-warning-this-post-will-make-you-hungry-mypictureday-round-2) and don't miss tomorrows Crypto Challenge!

<center>Yours,
_Tim_</center>