Diving/Space/Altitude Flashcards
What is the human free dive record?
230 ft
What is the human breath hold record?
6 minutes 30 seconds
How fast does water pressure increase?
1 atmosphere for every 10 meters of depth
What is one issue with the high pressure of water, and how have animals adapted?
It makes it difficult to draw air through a snorkel because it is difficult to expand the chest. Elephants have adapted with fibrous, cartilaginous tissue rather than air in the interpleural space- this helps them to generate higher negative pressures.
When was the first commercial diving/salvage business set up?
1830s
Name three problems associated with human diving
1) The Bends
2) Rapture of the Deep (narcotic effect of gases)
3) Oxygen toxicity
How are the Bends caused?
With increased pressure, more nitrogen dissolves in the blood. When we ascend rapidly, nitrogen comes out of the blood quickly and forms bubbles. Can cause pain, stroke, and death.
At what depth does the Bends become an issue?
20 meters
What is Rapture of the Deep and what causes it? How do we avoid it?
A narcotic effect of gasses. Nitrogen at high pressure has narcotic effects. Use a helium/ oxygen mix
What is oxygen toxicity?
Breathing pure oxygen irritates the lungs (can’t do it for more than a few hours)
What is a nickname for the Bends?
Cassion disease
What are three ways of avoiding the Bends?
1) Ascend slowly (in 20-30 minute stages)
2) Use an inert gas other than nitrogen (could use helium)
3) Breathe liquid?
What are antarctic seals called? Where do they live?
Weddell Seals. the Ross Ice Shelf
Describe the dive characteristics of a Weddell Seal (time and depth)
Most dives last 20-25 min (max 1 hr)
70% of dives are 200m or less, can hit 600m.
What is a seal that can dive deeper than a Weddell Seal? What is its longest and deepest dive?
Elephant Seal. Dives to 1000m, can dive for up to 2 hrs.
Why do most Weddell Seal dives last about 25 mins?
This is their AEROBIC DIVING LIMIT (ADL)
What happens after the aerobic diving limit is passed?
Blood lactate levels rise
What are the two things that we see happen in seals while diving? Be specific about location
Oxygen depletion and lactate accumulation occur in skeletal muscle, but not in the blood!
Do Weddell Seals alter blood flow to the kidney during dives? How can we tell experimentally?
Yes, they reduce blood flow to the kidney, but only on longer dives. We can test by measuring INULIN concentration!
Do Weddell Seals alter blood flow to the liver during dives? How can we tell experimentally?
They reduce blood flow a bit. We can tell by measuring INDOCYANIN GREEN clearance
What is a second way to test blood flow to the kidneys during a dive?
Simulate dive by putting head underwater, image blood flow using a dye.
What happens to a seal’s heart beat during a dive? What do we call this?
It slows down.
BRADYCARDIA
What happens to blood co2 content and blood o2 content during a dive?
The co2 content rises, while the o2 content falls
What can we say about where oxygen is stored in diving animals (lungs, blood, muscle)
Roughly similar amount stored in lungs. Much more oxygen stored in blood and muscle though!
What are three cardiovascular adaptations common to diving animals?
1) large blood volume (2-7x greater)
2) high hematocrit (55-60%)
3) lots of myoglobin
What happens to the lungs at great depths?
The lungs and alveoli actually collapse, forcing air into the dead spaces, and making gas exchange negligible!
What do seals have to prevent heat loss?
An insulating layer of BLUBBER
What are two adaptations to the seals head area?
They are located on the top of the head, so that the seal can easily see the ice above.
Also, have protruding teeth to open diving holes in the winter!
What two organs do the seals maintain blood flow to? What three organs do they reduce blood flow to?
Heart and brain
Kidney, liver and muscles
Why do the seals reduce blood flow to the muscles?
To prevent lactate buildup in blood until post-dive
Name three ways in which seals avoid the Bends
1) EXHALE before diving
2) Lung collapse at 25-30 meters
3) Very little blood to lungs during dive
Name a large diving penguin. How long/deep can it dive
Emperor Penguin: 23 minutes, 500 meters deep
Name four adaptations that allow birds to dive
1) high HEMATOCRIT
2) high MYOGLOBIN concentration
3) diving BRADYCARDIA
4) limited blood flow to skeletal muscle (to avoid lactate buildup in blood)