Human health and diseases
According to the World Health Organisation (WHO), health is defined as:
Health is a state of complete physical, mental, and social well being and not merely absence of disease or infirmity.
Good health of an individual is important in order to ensure happiness and our ability to work. There are many factors which affect our health. Some of these factors like balanced diet, clean water and clean environment have a positive impact on health while others such as disease causing organisms and unhygienic conditions have a negative effect on our health.
Balanced diet, personal hygiene and regular exercise are very important to maintain good health. Yoga has been practiced since time immemorial to achieve physical and mental health. Awareness about diseases and their effect on different bodily functions, vaccination (immunization) against infectious diseases, proper disposal of wastes, control of vectors and maintenance of hygienic food and water resources are necessary for achieving good health.
Disease :Disease is a malfunctioning process related to a certain part of the whole body in which normal functions are disturbed or damaged. Disease literally means not at ease
Disease may be the sickness of the body or the mind. A disease can be as mild as a sore throat, common cold, and stomach upset or as serious as cancer. Disease can strike almost any part of the body and anybody at some stage or the other. They can also affect a person‘s mental and emotional health.
Deficiency diseases :The diseases which occur due to deficiency of one or more nutrients (proteins,carbohydrates, vitamins and minerals) in our diet are called deficiency diseases.
The overall ability of the host to fight the disease-causing organisms, conferred by the immune system is called immunity. Immunity is of two types: (i) Innate immunity and (ii) Acquired immunity.
Innate Immunity :-Innate immunity is non-specific type of defence that is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body.
Acquired immunity, on the other hand, is pathogen specific. It is characterized by memory. This means that our body when it encounters a pathogen for the first time produces a response called primary response which is of low intensity.