Lesson 1 of 13 · 6 min

Health and disease

NCERT §7 (chapter introduction)

On Monday morning the waiting hall is full. Dr Leela asks Nikhil a simple question before the first patient: the man who jogs every day but has not slept for a week, is he healthy?

The story this chapter follows: A monsoon week at the hospital

Nikhil, a Class 12 student in Kozhikode, spends one monsoon week shadowing his aunt, Dr Leela, at the district hospital. Each day takes him to a different corner: the fever ward, the immunisation clinic, the allergy clinic, the blood bank, the cancer ward and the de-addiction centre. Every patient he meets becomes one part of this chapter.

The lesson in notes

In short

Early Greeks such as Hippocrates, and the Indian Ayurveda system, pictured health as a balance of body 'humors'; a person with excess 'black bile' was supposed to be hot-tempered and feverish. This idea came from reflection alone, not from experiment.

The humor idea fell when William Harvey showed blood circulation by experiment, and when a thermometer found normal body temperature in so-called black-bile people.

Later biology showed that the mind acts on the immune system through the neural and endocrine systems, and the immune system keeps us healthy, so mental state can affect health.

Health is affected by genetic disorders (defects present at birth or inherited from parents), by infections, and by life style: food and water, rest and exercise, and habits.

Health is not just the absence of disease or plain physical fitness; it means being completely well in body, in mind and in social life.

Healthy people work more efficiently, which raises productivity and prosperity; health also lengthens life and lowers infant and maternal mortality.

Good health rests on a balanced diet, personal hygiene, regular exercise and yoga, together with awareness of diseases, vaccination, proper waste disposal, vector control and clean food and water.

A disease is present when one or more organs or systems work badly and signs and symptoms appear. Infectious diseases pass easily from person to person, and some, like AIDS, kill; of the non-infectious diseases, cancer causes the most deaths.