Mailing List Archive Mailing List Archive
From: J Shepherd <jms@fe*.ed*.ac*.uk*>
Subject: Re: Breathing Reflex
To: techdiver@opal.com
Date: Tue, 13 Dec 94 21:12:26 GMT
Yeah, I sort of appreciate that the lungs are being
compressed;
but too a point only.
After the rib cage has bringed as tight as it will get, the lung
volume will be pretty small (I gather that about 2l is the usual 'dead
space'? - my physiology lectures were a few years ago, now). Beyond
that
( a point reached at 50m ) the pressure will stress the ribcage, and
might cause a further (slight) reduction in volume, until the cage
collapses catastophically (ouch) (squish).
So from 50m down, what's happening? Some divers come up
with
blood, implying tearing of the lung tissue or leakage of blood into the
lung airspace. What about the rest?
It used to be believed that the maximum limit for breath hold
diving was set by maximum compression of the ribcage, but this
obviously
is not the case. The limit may then be, the fluid pressure which the
lung tissues can support, before fluid is forced either interstitially,
(say into the plueral sac) or via the pulmonary blood supply directly
into the lung.
Where is it, what's the pressure?
And when some mad fool goes deeper than that, where did
we go
wrong?
:-)
Jason. Hell, it's cheaper than trimix, and it pulls the birds
better.
(JOKE, OK?) Christ....;-)
--
Send mail for the `techdiver' mailing list to `techdiver@opal.com'.
Send subscription/archive requests to `techdiver-request@opal.com'.
What about free divers diving to 200-300 ft (60 - 90 m) ???
marek
\\|//
(0 0)
===========oOO=(-)=OOo===========
Marek Jan Nowicki
Marek@ts*.hs*.us*.ed*
University of Southern California
1840 N. Soto Street, EDM 107,
Los Angeles, California 90032 USA
(213)224-7988, (213) 223-3566 FAX
==================================
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]