11. Diving Flashcards
(22 cards)
What happens to gases under pressure?
Gases are compressible under pressure
This affects lungs, ears, and other gas-filled spaces.
How does pressure change with depth in water?
Pressure increases by 1 atmosphere every 10 meters of depth
What is the risk associated with gas solubility changes during diving?
Risk of decompression when pressure decreases
Nitrogen is particularly problematic.
How long can sperm whales typically dive?
3+ hours and 2000+ meters
What is the maximum dive time and depth for unassisted humans?
3 minutes and 20 meters
What are some oxygen storage strategies in diving mammals?
- Increased blood volume (3x higher than humans)
- Higher red blood cell count
- Splenic contraction releases additional red blood cells
- Extremely high myoglobin levels in muscles (15-20x higher than humans)
What physiological change occurs in diving mammals to manage circulation?
Diving reflex triggers bradycardia (slowed heart rate)
What is selective vasoconstriction?
Redirection of blood to vital organs, restricting blood flow to non-essential organs
How does the metabolic rate change in diving mammals?
Reduced metabolic rate down to 25% of resting
What type of metabolism do diving mammals shift to during dives?
Anaerobic metabolism
Where does lactic acid accumulate during dives?
In muscles, not blood
What is required for recovery after diving?
Recovery periods needed to clear lactic acid (approximately 1:1 ratio with dive time)
What are some lung adaptations in diving mammals?
- Smaller lungs
- Collapsible chest structures
- Alveolar closure mechanisms to prevent nitrogen absorption
- Some species exhale before diving
What causes decompression sickness?
Nitrogen bubbles forming in tissues as pressure decreases
At what depths is decompression sickness usually a risk?
After prolonged time at depths >20m
What are some prevention methods for decompression sickness?
- Modified breathing gases (helium mixtures)
- Controlled, slow ascent with stops
- Reduced dive time or depth
What is oxygen toxicity?
Toxicity at high partial pressures
What is gas narcosis also known as?
The ‘martini effect’ at extreme depths
What adaptations do professional free divers develop?
- Larger lung capacity
- Reduced CO2 sensitivity
- More efficient swimming techniques
What are the world records for human diving capabilities?
Approximately 11 minutes underwater (static) or 200+ meters depth (with assistance)
How do human physiological adaptations compare to those of marine mammals?
Humans lack many physiological adaptations seen in marine mammals
What is the primary focus of the lecture?
Marine mammals’ remarkable physiological adaptations for deep and long dives
