Human Health And Disease PDF Free Download
Chapter 8: Human Health and Disease
Health, for a long time, was considered as a state of body and mind where there was a balance of certain ‘humor’.
This is what early Greeks like Hippocrates as well as the Indian Ayurveda system of medicine asserted. It was thought that persons with ‘black bile’ belonged to hot personalities and would have fevers.
This idea was arrived at by pure reflective thought. The discovery of blood circulation by William Harvey using the experimental method and the demonstration of normal body temperature in persons with black bile using a thermometer disproved the ‘good humor’ hypothesis of health.
In later years, biology stated that the mind influences, through the neural system and endocrine system, our immune system and that our immune system maintains our health.
Hence, the mind and mental state can affect our health. Of course, health is affected by –
(i) genetic disorders – deficiencies with which a child is born and deficiencies/defects which the child inherits from parents from birth;
(ii) infections and
(iii) lifestyle including food and water we take, rest and the exercise we give to our bodies, habits that we have or lack, etc
The term health is very frequently used by everybody. How do we define it? Health does not simply mean ‘absence of disease’ or ‘physical fitness. It could be defined as a state of complete physical, mental and social well-being.
When people are healthy, they are more efficient at work. This increases productivity and brings economic prosperity.
Health also increases the longevity of people and reduces infant and maternal mortality.
A 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.
When the functioning of one or more organs or systems of the body is adversely affected, characterized by various signs and symptoms, we say that we are not healthy, i.e., we have a disease. Diseases can be broadly grouped into infectious and non-infectious.
Diseases that are easily transmitted from one person to another, are called infectious diseases.
Infectious diseases are very common and every one of us suffers from these at some time or other.
Some infectious diseases like AIDS are fatal. Among non-infectious diseases, cancer is the major cause of death. Drug and alcohol abuse also affect our health adversely.
8.1 Common Diseases In Humans
A wide range of organisms belonging to bacteria, viruses, fungi, protozoans, helminths, etc., could cause diseases in man.
Such disease-causing organisms are called pathogens. Most parasites are therefore pathogens as they cause harm to the host by living in (or on) them.
The pathogens can enter our body by various means, multiply and interfere with normal vital activities, resulting in morphological and functional damage.
Pathogens have to adapt to life within the environment of the host.
For example, the pathogens that enter the gut must know a way of surviving in the stomach at low pH and resisting the various digestive enzymes.
A few representative members from different groups of pathogenic organisms are discussed here along with the diseases caused by them.
Preventive and control measures against these diseases, in general, are also briefly described.
| Author | – |
| Language | English |
| No. of Pages | 22 |
| PDF Size | 2.9 MB |
| Category | Biology |
| Source/Credits | – |
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