lungs at depth/diving Flashcards
what are diving related pulmonary effects mostly due to
- increased gas density
- immersion-related increase in pulmonary blood volume
- higher inspired Po2
why do divers have to work harder to get rid of co2 during dives (8 reasons)
1) Breathing-Gas Density Increases with Depth
2) Physiological Effects of Immersion
3) Altered Regulation of Breathing
4) Increased “Dead Space” During Diving
5) Rebreathing
6) Poor Diving Procedures
7) Gas Contamination
8) CO2 Retainers
why is a divers breathing gas compressed
is compressed by the increased ambient pressure at depth
impact of higher gas density
A volume of gas at depth contains more molecules than the same volume of gas at the surface.
Increased density also increases the viscosity of the gas - means that it is more difficult to breathe the same volume of gas at depth
what happens in immersion
blood that is normally distributed to the limbs moves into the body’s central space
- makes the lungs stiffer, meaning they have reduced elastic recoil and that breathing requires more effort than normal
- the blood also takes up volume - means that the total volume of the lungs would be reduced as a result of the fluid shifts
how does wearing a tight fitted wet suit help with diving
it compounds the redistribution of fluid, shifting additional blood into the central space by compressing the blood vessels in the limbs.
impact of diving in a relatively cold environment
peripheral vasoconstriction contributes to a central fluid shift
what does the exhalation of co2 in gas exchange do while diving
CO2 combines with water in the blood to form carbonic acid (which dissociates as hydrogen and bicarbonate ions).
the change in the pH of the blood is sensed by the brain and serves as the trigger to stimulate breathing.
To maintain the pH balance in the blood, the lungs must be able to “blow off” the CO2 that is produced by the body.
how do the lungs blow off the co2 that is produced by the body
a certain volume of air is used to dilute the CO2 in the alveoli of the lungs by means of inhalation and exhalation
what is dead space
areas in which there is ventilation (i.e., gas movement), but no gas exchange takes place.
examples of gas exchange
since gas exchange happens only in the alveoli, the conducting airways such as the trachea and bronchi are dead space
impact of dead space on diving
diving equipment adds extra dead space
it adds up and leads to elevated breathing volumes
