Theory:

The effect of chronic diseases on health:
The acute and chronic diseases have different effects on the health of an individual. The diseases that cause low functioning of particular body parts causes a significant impact on health because all the functions of the body play a significant role in health.

The acute diseases do not cause a significant impact on health because it gets over very soon. The common cold and cough is an example of this as most of us are affected by these from time to time and also get recovered within a week. These acute diseases have no harmful effects on health. There is no weight loss, occurrence of short breath, feeling of tiredness.
 
Unlike acute diseases, chronic diseases cause major effects as they last for a long time. The chronic diseases like tuberculosis cause various ill effects on health as follows:
  • They hinder growth.
  • Causes tiredness all the time.
  • Leads to an increase or decrease in weight.
  • Effects the day to day activities and the ability to learn new things.
Also, prolonged treatment is given when a person is affected with chronic disease. This treatment affects the organs of the body leading to more severe complications. Thus, when compared to acute diseases, chronic diseases have a very drastic long-term effects on the health of the individual.
Causes of diseases:
Diseases are caused by various factors, which can be classified as internal factors and external factors. These factors are as follows:

1. Internal factors:
 
These are the factors found inside the body, such as an imbalance of hormones, allergic reactions, genetic disorders and malfunctioning of the body organs.
 
2. Malfunctioning of body organs:
 
This is the improper functioning of a body organ. Non-communicable diseases such as diabetes and heart diseases are caused by the malfunctioning of the pancreas and heart, respectively.
 
3. Genetic factors:
 
These are factors that are present from the birth of an individual. Diseases like haemophilia are caused due to genetic factors.
 
4. External factors:
 
These include the various factors that are found outside the body, such as an unhealthy diet, infections by microorganisms, unhealthy lifestyle and polluted environment.
 
5. Infections by microorganisms and worms:
 
These include bacteria, viruses, fungi, protozoans which cause communicable diseases. This mode causes diseases such as HIV, hepatitis.
 
6. Unhealthy diet:
 
An unhealthy diet leads to the deficiency of one or more nutrients, causing a disease. Diseases such as goitre, marasmus and kwashiorkor are caused due to this.
 
7. Polluted environment:
 
This is the lack of a proper hygienic environment. The lack of clean water and other public services causes diseases such as diarrhoea.