Phys Eco Exam 2 Section 10: Arousal, Hibernation Energetics & PUFAs

What is the most energetically expensive part of the hibernation cycle?

Arousal.

What is used first during arousal?

Brown adipose tissue and non-shivering thermogenesis.

What follows non-shivering thermogenesis during arousal?

Shivering.

How does muscle blood flow change during arousal?

It can reach 16 times that of a non-hibernator.

What happens to critical body parts during arousal?

They are warmed.

Why do hibernators periodically arouse?

Not fully understood, but there is evidence of a role in maintaining immune function.

What is the main benefit of hibernation?

Significant energy savings.

How can social hibernation and synchronized arousal conserve energy?

Animals use one another's body heat while maintaining effective hibernation body temperatures.

What are PUFAs?

Polyunsaturated fatty acids containing more than one double bond.

How do double bonds affect membrane fluidity?

More double bonds make membranes more fluid.

Why are PUFAs important to hibernators?

They help maintain membrane fluidity at low body temperatures.

How does daily torpor differ from true hibernation?

It occurs on a 24-hour cycle and is more plastic rather than hardwired.

What triggers daily torpor?

Night temperature and food shortage.

What is the major benefit of daily torpor?

Significant energy savings.

How does winter lethargy differ from true hibernation?

Body temperature does not decrease as much.

Why doesn't body temperature decrease as much during winter lethargy?

Rewarming from a much lower temperature would take too long.