Is it our blood going through the heart, but in that case wouldn’t that mean our heart is a furnace?
In: Biology
So a few things actually. The primary way is sweat and blood flow. When you are hot you will sweat. The evaporation of the water will cool the body down. When cold your body constricts blood flow to the surface of the skin so you loose less heat. Heat in the body is produced by biological activity. This largely takes place in the muscles and digestion. This is why you shiver when cold. It increases the activity in the muscles thus producing heat. On a technical level the heart does produce heat as well, it is a muscle after all, but the amount is little compared to the other muscles in the body especially those in the legs and back. There are other factors that impact body temp such as heat exchange when breathing but these are less notable.
>Is it our blood going through the heart, but in that case wouldn’t that mean our heart is a furnace?
Heat energy is released as a by-product of your cells’ metabolism. It just needs to be gotten rid off to a smaller or larger degree, depending on your immediate environmental conditions.
Your body temperature is therefore regulated by your skin and your blood vessels. The less constricted your small vessels are (so the more blood flows through your peripheral body parts) and the more sweat your skin produces the more your body cools down via evaporative cooling.
Homeostasis. Body targets our temp to a certain range (35 ish to 37.6 ish) like a thermostat.
When it’s cold, the body regulates temperature( of the blood for example) via several mechanisms ( ie, constrict vessels to minimize heat loss; shivering to expens energy and in turn creating warmth)
When it’s hot, body creates sweat (evaporation done by using excess heat) etc.
The bit missing from other explanations is how heat is generated.
In mammals the nutrients we eat and the oxygen we inhale are used by the mitochondria that are present in every cell of our bodies to generate energy in the form of heat. This is *endothermic* (internal energy) and is unique to modern animals (mammals and, I think, some birds – can’t remember off the top of my head).
All other animals are exothermic (external energy), so can only warm themselves using external sources – eg basking in the sun or staying in warm water.
All of the other mechanisms described in this thread are designed to stop the internal heat becoming excessive (ie becoming a dangerous fever). However, when you are ill allowing the body temperature to rise is one (not terribly reliable) method the body has for combatting infections.
tl;dr: You are less likely to be eaten by a crocodile (exothermic) at the crack of dawn (no overnight heat) than at noon (nice and toasty), but a lion (endothermic) will happily hunt whenever food is around, day or night.
Latest Answers