Behavioral Neuroscience XI
How we Control our Body Temperature?
Homeostasis: How we keep our internal environment stable
Homeostasis is the active process of maintain a relatively stable, balanced, internal environment. The reason why this is important is that many internal processes require a very specific setting to work properly. For example, chemical reactions run faster at higher temperatures. So if you’re body were to decrease by just 10 degrees, chemical reactions would happen 2 – 3 times slower than usual (Called Q10). This would completely destroy the flow of most of your chemical processes.
Homeostasis works on negative feedback. Negative Feedback works by having a stronger response the farther the current state is away from a set point, or optimal value. Think of a thermostat—the farther away from the set point it’s supposed to be at, the colder/warmer it will make it’s output to help push room temperature to the correct value. In humans, this set point is whatever is optimal for our body, for example 98.6*F, and our body works harder to move towards this set point the farther away the outside temperature is to this value. The three most common set points our body fixates on is salt concentration, water volume, and temperature. While all three use negative feedback, we are going to talk more in-depth about temperature.
Temperature Homeostasis
Endotherms are animals (mammals and birds) that can regulate their body temperature by generating heat internally. Ectotherms (like snakes) don’t do this, instead relying on external heat like sun to maintain body temperature.
Most chemical energy used by muscles—around 80%— is actually lost as heat. While this may seem like a waste, this excess energy is used to increase our body temperature, and is the reason why we get hotter as we exercise, or why we shiver when we are cold—increasing muscular activity increases our body temperature. 1 calorie of food can raise the temperature of 1L of water by 1*C.
Smaller things have a larger surface-to-volume ratio, meaning that there is a lot more surface area in comparison to how much volume the object has. Since heat is dissipated across the body surface, small things lose heat more quickly than large things, and therefore need to eat more food-per-body-weight than larger animals. This means that canaries have to eat much more per body weight than humans, despite being much smaller and with energy output being held equal.
Recap:
- Our bodies regulates important metrics like temperature, water volume, and salt concentration through negative feedback