what makes the blood in your body heat up?

The human body has developed a number of very complex reactions and responses in order to maintain homeostasis. Since we are a 'warm-blooded' animal, we must maintain our body temperature in order for the necessary chemical reactions to take place at their optimum condition. One of the quicker ways to increase body temperature is through shivering. When we are cold, we shiver and the heat generated from the large scale muscular contraction is utilized to increase body temperature. If we are too hot we sweat, the evaporation of liquid from the skin leads to cooling and capillaries in the skin help to express this cooling effect throughout the body. As was mentioned in one of the previous answers, the hypothalamus is a key regulatory site for maintaining body temperature, sending signals to dilate or constrict blood vessels, increase blood flow and change any of a number of different physiologic responses. The bottom line is that the heat that we need to maintain our temperature comes largely from muscular contraction, ranging from skeletal muscle to smooth muscle, but there are contributions from a number of other sources within the body.

Kudos for your grandfathers curiosity. And for you, to ask the question!

The way I was taught, your "chemical" body heat is generated from your mitochondria.

Those are the little "powerhouses" within each cell (there are hundreds of them, maybe even thousands per cell), that convert the chemical energy (from food sources) into ATP.

As they do this conversion, the molecule of ATP is formed (along with some chemicals needed to reduce some free ionizing molecules).

The ATP is (classically) understood to be used for energy. As it gets converted to ADP (and I think also AMP), heat is generated.

What is happening chemically: the phosphate molecules are being shuffled around to new molecules. Adenosine Tri-phosphate loses a phosphate and converts to Adenosine Di-phosphate, etc.

Sorry I can't tell you specifically where the phosphate molecule goes. I forget right now. And surely it would depend on the cell type.

I will say that phosphate molecules seem to be extremely important in other activities within the cell (heat generating or not).

I also will say this, (just briefly, again, because it is not my specialty), that a phosphate is required to for the actin:myosin group (which makes a muscle move) to perform its function.

Heat is lost after muscles move. So after the phosphate is transferred from the ATP, it leaves the mitochondria and finds an actin:myosin complex in need of its services.

This would only happen in a specialized cell containing actin:myosin complexes.

[Not to be a smart-***, but]... these specialized cells are pretty much found only within muscles.

These are the two places I can recall in my studies that really make a difference in heat generation and maintenance of homeostatic regulation of temperature.

I think there is also a feedback system in the brain (maybe the hypothalamus?), that will indirectly get involved with temperature regulation if it senses something is amiss.

I can bet there is some other systems I am forgetting, along with some other internal regulations science has yet to discover.

I had fun thinking about the answer to your question, and I hope it helped some.

Don't forget to pass on the good Karma!!

......For me?

...Salma Hayek or Uma Thurman heat my blood up.

*wink*

...but seriously...I believe the process is called HOMEOSTASIS.

...from wikipedia..."Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms. The term was coined in 1932 by Michael Ohanian from the Greek homoios (same, like, resembling) and stasis (to stand, posture)."

BIOLOGICAL HOMEOSTASIS

Homeostasis is one of the fundamental characteristics of living things. It is the maintenance of the internal environment within tolerable limits.

The internal environment of a living organism's body features body fluids in multicellular animals. The body fluids include blood plasma, tissue fluid and intracellular fluid. The maintenance of a steady state in these fluids is essential to living things as the lack of it harms the genetic material.

With regard to any parameter, an organism may be a conformer or a regulator. Regulators try to maintain the parameter at a constant level, regardless of what is happening in its environment. Conformers allow the environment to determine the parameter. For instance, endothermic animals maintain a constant body temperature, while ectothermic animals exhibit wide variation in body temperature.

This is not to say that conformers may not have behavioral adaptations that allow them to exert some control over the parameter in question. For instance, reptiles often sit on sun-heated rocks in the morning to raise their body temperatures.

An advantage of homeostatic regulation is that it allows the organism to function more effectively. For instance, ectotherms tend to become sluggish at low temperatures, whereas endotherms are as active as always. On the other hand, regulation requires energy. One reason snakes are able to eat just once a week is that they use much less energy for maintaining homeostasis.

***

well i assume that if your blood is heating up thn you are unhealth because the body is always trying to maintin homeostasis (a constant environment). The part of the brain which regulates temperature is called the hypothalmus, so that would have omethig to do wit it

Waste heat from chemical reactions. Although it's not really 'waste' heat in mammals, since it's used to maintain a constant body temperature.