BIO 461 - Exam 1 - Thermoregulation PowerPoint Flashcards
What are the 3 different ways we exchange heat.
∙ Radiation Heat: like we get from the sun; it does not transfer until it hits something. Everything around us (including us) radiates heat.
∙ Conduction Heat: direct heat transfer from surface to surface – laying on a rock. Conduction can go both ways, moving from a warm object to a cold object.
∙ Convective Heat: two static objects exchanging heat until they are even on both sides. This is where you have air flow going across – when a breeze is blowing, you feel cooler than when there is not a breeze.
The only way an animals can cool off when the outside temperature is warmer than it is, through ______.
evaporation
Slide 3
Why thermoregulate?
To survive and maximize performance.
What are the traits affecting heat transfer?
- amount of heat you are gaining from the environment
- amount of heat you are losing to the environment
- how much energy you need to expend to maintain that temperature.
Slide 6 - insulation
Why don’t reptiles have surface insulation?
Ectotherms need to gain heat quickly in the morning and warm up fast. They rely on heat transfer.
Heat in a shark is produced locally by?
red muscle contractions (tuna lamnid sharks)
o functional heat production
o keeps swimming muscles warm
o expands thermal niche, increases swimming speed, & increases exercise recovery rate
Heat retained locally through?
∙ having red muscle internalized – muscles are deeper and surrounded by other tissues to insulate.
∙ counter-current heat exchange – located in the gills, where water flows one way over the respiratory membrane and the blood flows the other direction. This optimizes the transfer of oxygen from the water to the blood. In this case, we are moving heat. The artery and vein are going next to each other. The muscles are producing the heat, warm the blood – as the blood goes off to the rest of the body, the gills are in close contact with the water, and the temperature of the blood is going to drop. If you want to keep your muscles warm, you want to keep the heat where the muscles are. When the warm vein leaves the muscle, there is a cooler artery coming from the gills. There is a lot of contact between a warm vein and a cool artery. Heat is then going to move from the warm thing to the cool thing. Helps keep the heat centralized.
How do bears arouse?
White fat – release lipids into the bloodstream for other tissues to use as energy.
Brown fat – heavily packed with mitochondria – where cellular respiration occurs. Great potential to produce ATP and heat; are stimulated when they want to be aroused, burn the lipids in the cell, and generate a lot of heat. As a human baby, you had a lot of brown tissue – not a lot of hair and not a lot of movement.
Traits affecting heat transfer
B
E
I
M
Sh
Si
1) Insulation: minimize heat transfer. It does not matter which way.
∙ Repels water, reflects radiant heat, & traps air – still air is an excellent insulator (i.e., poor conductor).
∙ Water has 4X heat capacity (specific heat) of air.
2) Evaporative water loss (latent heat of vaporization) – one means by which a body can lose heat, even if the outside environment is warmer than it is.
3) Blood perfusion
4) Mucosal (± panting)
5) Size (surface to volume ratio): the bigger you are (more total surface area) but you have less relative to your volume.
∙ Thermal inertia: resistance to change in temperature. Temperature is independent of mass. It is the amount of heat that needed to be added or removed from something to alter that temperature. Larger animals have a less chance of cooling off quickly in a cold environment (and vice versa).
6) Shape (also affects S: V & thus heat transfer): Long and skinny animals have a lot more surface area than if you are a sphere (tortoise vs snake). Shape can be adjustable to reduce surface area – ducks sleep by tucking their bills and feathers on a cold night, and snakes coil up.
