Diving mammals Flashcards
What is the difference between a voluntary and involuntary dive?
Voluntary would be for things like looking for food and playing, and involuntary would be for escaping from predators
What are the 3 things that need to be considered for determining how long an animal can dive for?
- O2 available for the animal
- Potential of the animal to adjust its cardiovascular physiology
- Potential of the animal to adjust its metabolism to reduce oxygen requirements
How do diving mammals control the oxygen available for diving?
Controlled apnea: suppression of respiratory muscle action and breathing control systems
How are diving mammals able to reduce their lung volume while underwater?
The thorax is highly compressible, so the water pressure at greater depths will shove the thoracic walls in and compress the lungs
What other adaptation do marine mammals have to lower nitrogen buildup in their blood?
Forced alveolar collapse
Where do the gases go when a diving mammal does a forced alveolar collapse?
Away from the respiratory surfaces and into the conducting surfaces
How does the forced alveolar collapse prevent decompression sickness in marine mammals?
By forcing the gases into the conducting airways, the blood isn’t as exposed to the increasing nitrogen pressure in the lungs, which stops it from building up in the blood and tissues
How much of the alveolar collapse occurs in a mammal diving at moderate depths?
Incomplete collapse
How much of the alveolar collapse occurs in a mammal diving at deep depths?
Complete collapse
Why aren’t dolphins affected by decompression sickness when they do repeated dives to moderate depths?
They do have nitrogen buildup in their blood, but they are adapted to the high levels that would be fatal for us
Why are humans susceptible to decompression sickness when diving?
We don’t have the flexible thoracic cavity to allow lung compression, and we can’t do the forced alveolar collapse. The nitrogen just ends up in our blood and will come out in bubbles if we surface too fast
Why do some diving mammals exhale before a long, deep dive?
Avoid lung collapse and decompression sickness
What are the 3 ways oxygen is stored?
Lungs, in the blood attached to Hb, and in myoglobin
Where do we store most of our oxygen while diving?
Lungs
How do diving mammals store oxygen?
Mostly in myoglobin, since they have a lot more muscle than we do. They have a higher O2 carrying capacity and blood volume, so can also store a lot in their blood
