how does human body produce heat ?

and what is the mechanism or chemical reaction (metabolism) involved and how much heat the human body produces this is the questions that flashed in my brain with the recent drop in temperature in Bangalore and when i felt body heat of my little nephew when i held him in my arms, then thought of googling to find the answers and googling helped me to find all my answers but could not able to fully understand the process and medical jargons :) ... so below are few things which i understood and sharing with you, if any medical pro reading correct me if i have understood it in a wrong way...

so how body produces heat?
interestingly i came across a thread started by a person who put across the same question in discussion form and found a convincing answer given by R. James Swanson, med faculty of old dominion university, by putting it in laymen terms below is the process what i understood :-

--> Food we eat is physically and chemically broken-down into smaller particles until absorbed by the walls of intestine as individual molecules

--> Then These Molecules are absorbed by blood and are distributed throughout the body and taken up by cells that need :
(1) carbohydrate molecules for the energy ,
(2) amino acid molecules for building proteins, or
(3) lipid molecules (fat) for building membranes, certain of the hormones and other things or just store this concentrated form of potential energy in form of fats

--> carbohydrate will be absorbed as glucose or another closely related monosaccharide molecule

--> Chemical reaction or metabolism converts glucose to Adenosine Triphosphate (ATP),ATP is like the fuel or wood to produce heat

--> Now this ATP can be used by any cell for reaction that require energy in an easily usable form.

--> Now answering to the point CELLS produces heat while "burning" the glucose and while using ATP just like a fuel.

Now who controls or limits the amount of heat produced in the body?
Now we know that cells produces heat using ATP a molecule produced by a metabolism of Glucose and oxygen and this generation of heat or thermal process is controlled by a hormone from thyroid gland, the basal metabolic rate (BMR) is a term used to refer to a overall metabolism process of human body and this keep the temperature of human body approximately at 37 degree centigrade throughout our life, body temperature at or above 40 °C (104 °F) is considered as life threatening and is a medical emergency, so guys had you ever had same question in your mind?