Page 4 - 2- Lesson Notes- Health and its failure; Disease and its causes

There are many factors that can cause infection or spread diseases. There can be

different factors responsible for uneasiness.
a) Extrinsic factors

These are the external factors which affect the normal functioning of the body. They
are categorised as -

i. Disease causing microorganisms

ii. Inadequate diet
iii. Environmental pollutants

iv. Tobacco, alcohol, Narcotic drugs, etc.
b) Intrinsic factors

These are those factors that are within the human body and are non-infectious.

They are categorized as -
i. Malfunctioning or improper functioning of any body part

ii. Genetic disorder
iii. Hypo or hyper secretions of hormones

iv. Malfunctioning of body’s immune system
Immediate Causes and Contributory Causes

Immediate Causes

These are the real or primary causes that are responsible for a disease. These
causes can be infectious as well as non-infectious. Such immediate causes are

termed as First-level causes.

Contributory Causes

These are not the direct causes but factors that contribute in causing a disease
The susceptibility may be due to poor health of a person as a result of

undernourishment. Thus, contributory causes are also called as Second-level
causes.

Types of diseases

1. Acute and Chronic diseases

Acute Diseases Chronic Diseases