Human Survival Needs

Human Survival Needs

Terms and Nomenclature

Survival Needs: Factors that the human body and the environment need to have inorder to sustain life. They include nutrients, oxygen, water, and appropriate temperature and atmospheric pressure.

Nutrients: These are taken via the diet and contain chemical substances used for energy and cell building. Most plant-derived foods are rich in carbohydrates, vitamins and minerals, whereas most animal foods are richer in protein and fats. 

               Carbohydrates: major energy fuel source for body cells.

               Proteins (and fats): essential sources for building cell structures.

               Fats: provide reserve of energy-rich fuel.

               Minerals and Vitamins: required in chemical interactions that go on in cells and 

               for oxygen transport in the blood.   

Oxygen: Required in all nutrients. Because the chemical reactions that release energy from foods are oxidative reactions that require oxygen, human cells can survive for only a few minutes without oxygen. 20% of air is made up of Oxygen.

Water: Accounts for 60-80% of human body weight and is the single most abundant chemical substance in the body. Provides necessary environment for chemical reactions and fluid base for body secretions and excretions.

Normal Body Temperature: Required temperature to sustain life-sustaining chemical reactions. Usually 37 Celsius and 98.6 F. The lower the temperature, the slower the metabolic reactions. The higher the temperature, the higher the metabolic reactions (causing proteins to lose shape and functions). 

Appropriate Atmospheric Pressure: force that air exerts on the surface of the body. Breathing and gas exchange in the lungs depend on appropriate atmospheric pressure. At high altitudes, where atmospheric pressure is lower and the air is thin, gas exchange may be inadequate to support cellular metabolism.