Chapter 3: Anatomy and physiology Flashcards
what are the challenges of living in an aquatic habitat? (4 main)
-H20 800x denser + 60x more viscous than air
(buoyancy + drag)
-Hydrostatic pressure and oxygen shortage
-thermal conductivity 24x greater than in air. difficult to keep warm
-high salinity. maintain homeostasis.
4 ways to overcome drag
- streamlined bodies and enlarged propulsive appendages
- submerged movement (less drag deeper)
- absence of prolonged recovery phase during stroke cycle
- different swim movements
what are the average sprint speeds of m.mammals?
5(narwhal)-11(dolphin/orca)m/sec
How do Otariids swim?
By flapping their forelimbs
How do Odobenids swim?
hind leg rotation
How do Cetaceans swim? Sirenians?
Cetaceans: tail thrust, flipper thrust (humpback)
Sirenians - slow flipper thrust.
What are the four main problems of diving physiology?
- limited availability of oxygen
- accumulation of CO2
- accumulation of lactic acid
- water pressure (toxicology of O2 & N)
How have the lungs changed?
Open system in air, closes system underwater.
- Otter: larger lung volume. (anatomical float)
- M.Mammals: Collapsed lung dives >10-35m. Flexible rib cage.
- progressive lung collapse as hydrostatic pressure increases.
why collapse a lung?
-enables the animals to avoid the buildup of N2 and ‘the bends’.
How is oxygen stored in M.Mammals?
Lungs, blood, muscles.
Seals: blood>muscles
Whales: muscles>blood
87% of oxygen in blood and muscles of deep divers
how is oxygen capacity enhanced in blood storage?
- blood volume
- # of circulating red blood cells
- haemoglobin concentration
- increased blood volume
- increased blood vessels (rete mirabilia)
- increased hemoglobin & myoglobin concentration
- lowered metabolic rates.
What is the Anaerobic Dive?
- limits dependence on O2 storage and exercise/metabolic rate
- Switch to anaerobic metabolism
- lactic acid in tissue and blood
- tissue and blood acid tolerant
- need for longer surface recovery periods
How are toxins removed during dives?
- muscle and myoglobin have higher buffering capacity
- brain and heart tolerate hypoxia
- reopened blood circulation removes lactate from tissue and is expelled through lungs
- lungs expand rapidly and air is expelled.
- 90% O2 removal from air in a single breath (humans 20%)
Diving response: Living under pressure
- reduced heart rate
- collapsed lungs
- reduce blood circulation
- reduce metabolic rates
- aerobic dive limit->anaerobic dive
- reduce body temp
- restore everything quickly when at surface
Insulation
- increased metabolic rates: otters
- water insulated fur
- large bod size= small body surface
- blubber: insulator/streamliner/buoyancy/energy store 30% of body weigh
