What happens in our body on a daily basis? We present some of the functions of our body that typically is not consciously controlled by ourselves, rather they function automatically.

Transferring Energy

The laws of thermodynamics are major pillars of how physics and chemistry are understood. The first law of thermodynamics states the energy can neither be created nor destroyed; it can only change form.

The most basic function of our body is to take part in a continuous flow of energy. We take in energy in the form of matter – eating the bodies of other organisms. The energy stored in the chemical substances of that matter is used to fuel the processes of metabolism and homeostasis (see below).

Metabolism – Building and Breaking

The word metabolism describes the chemical reactions that happen in the body. These reactions are of two kinds – anabolic reactions create and catabolic reactions destroy. The body performs both anabolic and catabolic reactions at the same time, around the clock, to keep the organism alive and functioning. Even when we sleep, the cells are busy.

The cells in our body are like tiny factories, converting raw materials to useful molecules such as proteins. The raw materials, nutrients, come from food that we eat and the cells use the nutrients in metabolic reactions. During these reactions some of the energy from catabolized nutrients is used to generate a compound called adenosine triphosphate (ATP). When ATP is catabolized it releases energy that a cell can use.

Homeostasis – Staying Within Boundaries

Chemical reactions in the body are not random events. A reaction takes place only when all conditions are right for it. Homeostasis is the term for the subset of metabolic reactions that keep the internal environment of the body in a state conducive to the chemical reactions that maintain our life.

There are a number of important variables that homeostasis keeps in range:

• Constant temperature, thermoregulation. There are a number of ways that the body keeps the temperature – sweating, blood circulation, muscle contraction and insulation.
• Fluid balance. A watery environment is a requirement for a large proportion of the metabolic reactions. Thirst and later drinking is a way to keep the water in balance.
• Adjusting fuel supply. Glucose is the fuel of all cellular processes and is distributed dissolved in blood. The amount of glucose in the blood is controlled by the intestines and by the hormone insulin.