The Bends
- Thread starter Orleander
- Start date
but why would they look at animals to see if they died when they came up? How would they make that connection unless they were in the water with the animal and saw it come up too quickly.
And I think whales do get the bends, they just tolerate it better than we do.
spidergoat
Valued Senior Member
It first got widespread attention during the building of the Brooklyn Bridge, and was originally called caisson disease, a caisson being the structure designed to hold the water back at great depths. The workers who were down there for hours digging the foundations came up and got sick.
1670: Boyle demonstrated that a reduction in ambient pressure could lead to bubble formation in living tissue. This description of a viper in a vacuum was the first recorded description of decompression sickness.
1769: Giovanni Morgagni described the post mortem findings of air in cerebral circulation and surmised this was the cause of death.
1841: First documented case of decompression sickness, reported by a mining engineer who observed pain and muscle cramps among coal miners working in mine shafts air-pressurized to keep water out.
1870: Bauer published outcomes of 25 paralyzed caisson workers.
From 1870 to 1910 all prominent features were established. Explanations at the time included: cold or exhaustion causing reflex spinal cord damage; electricity cause by friction on compression; or organ congestion and vascular stasis caused by decompression.
1871: The St Louis Eads Bridge employed 352 compressed air workers including Dr. Alphonse Jaminet as the physician in charge. There were 30 seriously injured and 12 fatalities. Dr. Jaminet developed decompression sickness and his personal description was the first such recorded.
1872: The similarity between decompression sickness and iatrogenic air embolism as well as the relationship between inadequate decompression and decompression sickness was noted by Friedburg. He suggested that intravascular gas was released by rapid decompression and recommended: slow compression and decompression; four hour working shifts; limit to maximum depth 44.1 psig (4 ATA); using only healthy workers; and recompression treatment for severe cases.
http://en.wikipedia.org/wiki/Decompression_sickness
1769: Giovanni Morgagni described the post mortem findings of air in cerebral circulation and surmised this was the cause of death.
1841: First documented case of decompression sickness, reported by a mining engineer who observed pain and muscle cramps among coal miners working in mine shafts air-pressurized to keep water out.
1870: Bauer published outcomes of 25 paralyzed caisson workers.
From 1870 to 1910 all prominent features were established. Explanations at the time included: cold or exhaustion causing reflex spinal cord damage; electricity cause by friction on compression; or organ congestion and vascular stasis caused by decompression.
1871: The St Louis Eads Bridge employed 352 compressed air workers including Dr. Alphonse Jaminet as the physician in charge. There were 30 seriously injured and 12 fatalities. Dr. Jaminet developed decompression sickness and his personal description was the first such recorded.
1872: The similarity between decompression sickness and iatrogenic air embolism as well as the relationship between inadequate decompression and decompression sickness was noted by Friedburg. He suggested that intravascular gas was released by rapid decompression and recommended: slow compression and decompression; four hour working shifts; limit to maximum depth 44.1 psig (4 ATA); using only healthy workers; and recompression treatment for severe cases.
http://en.wikipedia.org/wiki/Decompression_sickness
Enmos
Valued Senior Member
There is actually a radiologically induced version of the Bends, it's when the lipids containing nitrogen are excited. Not a particularly pleasant feeling since it's like a sudden increase in Anxiety/Panic, especially for those that don't know where the panic attack has arisen from. Of course it's mild in comparison to compression.
Ohhhhhh, that sounds interesting, does it make one high as well? :shrug:
What mechanism did they evolve?They have another method of dealing with the problem. It's called evolution
I don't think whales have a particualr problem with decomression injuries as they dive with a single lungful of air - so only the nitrogen in that breath will dissolve into their bloodstream - just as human freedivers who dive to well over 100m and surface very fast don't have anything to worry about either.
That said over their lifespans - presumably due to such constant diving activity, there is some evidence of mild DCI damage, but as Enmos said - evolution has taken care of that so for them its nothing particularly life threatening
Two groups of whales, the Humpback Whale and the subspecies of Blue Whale found in the Indian Ocean, are known to produce the repetitious sounds at varying frequencies known as whale song. Marine biologist Philip Clapham describes the song as "probably the most complex in the animal kingdom".[7]
Male Humpback Whales perform these vocalizations only during the mating season, and so it is surmised the purpose of songs is to aid sexual selection. Whether the songs are a competitive behavior between males seeking the same mate, a means of defining territory or a "flirting" behavior from a male to a female is not known and the subject of on-going research. Males have been observed singing while simultaneously acting as an "escort" whale in the immediate vicinity of a female. Singing has also been recorded in competitive groups of whales that are composed of one female and multiple males.
Interest in whale song was aroused by researchers Roger Payne and Scott McVay after the songs were brought to their attention by a Bermudian named Frank Watlington who was working for the US government at the SOFAR station listening for Russian submarines with underwater hydrophones off the coast of the island.
The songs follow a distinct hierarchical structure. The base units of the song (sometimes loosely called the "notes") are single uninterrupted emissions of sound that last up to a few seconds. These sounds vary in frequency from 20 Hz to 10 kHz (the typical human range of hearing is 20 Hz to 20 kHz). The units may be frequency modulated (i.e., the pitch of the sound may go up, down, or stay the same during the note) or amplitude modulated (get louder or quieter). However the adjustment of bandwidth on a spectrogram representation of the song reveals the essentially pulsed nature of the FM sounds.
http://en.wikipedia.org/wiki/Whale_song
Enmos
Valued Senior Member
I admit that I thought it was something else, but:
"Natural selection has in the large part solved the problem by developing dive behaviours that allow the animals to manage the problem," he said.
"Previous research does show that the animals display mid-water stops. At the time it wasn't apparent to anybody why they were stopping - but it fits with this hypothesis."
http://news.bbc.co.uk/2/hi/science/nature/4122119.stm
So apparently they can get the bends, but are using a similar method as we do to avoid it.
Although this article tells a different story (and agrees with what I thought):
"Modern whales of both branches have evolved exquisite adaptations to fight the bends. Some exhale before they dive to clear their lungs of nitrogen gas that could form bubbles, and many whales allow ample time between dives."
"When gas or fat bubbles form in the blood vessels that feed bone cells, the vessels can burst and seal off the oxygen supply to the cells, resulting in tiny lesions that can be detected by X-ray.
"It's a measure of small regular damage and not necessarily something traumatic," Beatty says.
None of the 331 modern whale vertebrae showed signs of decompression syndrome, while a handful of the thousand ancient whale bones contained such marks.
Beatty views the damage as flirtations with the deep ocean, before more modern whales overcame decompression syndrome.
But baleen and toothed whales may have evolved such changes independently. Signs of decompression were found only in very ancient specimens of toothed whales, while more recent baleen whale fossils showed damage, suggesting that baleen whales only evolved their defences much later."
"Some researchers have suggested that military sonar can startle whales into changing their diving behaviour, causing decompression syndrome."
http://www.newscientist.com/article/dn13862-early-whales-got-the-bends.html
I also remember something about them having a specialized form of hemoglobin or myoglobin.
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Interesting - that may explain why so many commercial / deep divers suffer from bone necrosis
So it happens during x-rays???
Enmos
Valued Senior Member
Not really, or they would have to descent really far and come back up very very quickly.
There are mines 2 miles deep. Is that how deep divers go? Don't they ride an elevator up? Elevators aren't that slow.
Enmos
Valued Senior Member
For every ten meters that you dive the pressure increases with 1 atmosphere.
I have no idea what that means