Class 9 Why do we fall ill?

CHAPTER - 13

WHY DO WE FALL ILL

1. Health is defined as a state of physical, mental, social, economic, emotional and spiritual well-being of a person.
2. To be healthy good economic conditions and jobs, social equality and harmony are therefore necessary for individual health.
3. Disease simply means discomfort or disturbed ease.
4. A disease can be diagnosed by its symptoms.
5. When there is a disease, either the functioning of the appearance of one or more systems of the body will change for the worse. These changes give rise to symptoms and signs of the disease.

SYMPTOMS

Symptoms of disease are the things we feel as being 'wrong'. So we have a headache, we have cough, we have loose motions, we have wound with pus; these are all symptoms. These indicate that there may be a disease, but they don't indicate what the disease is.

For example, a headache may mean just examination stress or, very rarely.

SIGNS

Signs of the disease are what physician will look for on the basis of the symptoms. Signs will give a little more definite indication of the presence of a particular disease. Physicians will get laboratory tests done to pinpoint the disease further.

DISEASE

1. ACUTE DISEASE

The disease which lasts for a short duration are known as acute diseases.

Examples: - Viral fever, common cold

2. CHRONIC DISEASE

The disease which lasts for a long duration of time are known as chronic disease

Examples: - TB, AIDS, Polio

Any disease that causes poor functioning of some part of the body will affect our general health as well. An acute disease, will not affect our general health but chronic disease do so.

Note:

1. Congenital diseases are the diseases that are present since birth.

REASONS

1. Defective development of embryo

2. Acquired diseases are those that are picked up after birth. 3. Malnutrition

3. INFECTIOUS DISEASES

Infectious diseases are those which can spread from one person to another. These can be caused by microbes and other pathogens such as bacteria, fungi, viruses, protozoan, worms etc. Means of spread are air, water, food etc.

4. NON – INFECTIOUS DISEASES

Non – infectious diseases are those which do not spread from one person to another. These can be caused due to nutritional deficiency, from infected mother to the baby through her milk, sexual contact with an infected person.

CAUSES OF DISEASES

1. Pathogens
2. Lack of nutrition
3. Lack of public health services

INFECTIOUS AGENTS

1. Bacteria
2. Viruses
3. Protozoan
4. Helminthes

The infectious agents may attack the same organ where they have entered or they may enter some other organ. In most of the cases the infected organ or tissue depends upon the portal of entry. Some of the common effects of infectious diseases are fever, weakness, loose motions, body pain.

PRINCIPLES OF TREATMENT

1. Reducing the effects of the disease.
2. Killing the microbe.

ANTIBIOTICS

Antibiotics commonly block the biochemical pathways important for bacteria. Many bacteria make a cell wall to protect themselves. The antibiotics commonly block this process. As a result the bacteria become weak and die easily. They therefore are used in the treatment of diseases. They do not work against viruses as they do not produce cell walls.

WAYS TO PREVENT INFECTIONS

1. Proper habits
2. Relaxation
3. Immunisation
4. Vaccination
5. Nutrition
6. Exercise

VACCINES

Vaccines are weak germs which when injected in our body creates a particular memory in our body of that organism and formulates the formation of antibodies which kill those intruders and when they enter again they are ready with that way used by them to kill those intruders. They are available for many diseases.

Jaundice, are transmitted through water for this vaccine HEPATITIS A is used.

DISEASES AND THEIR PATHOGENS

DISEASE	PATHOGEN
Common cold	Virus
Measles	Virus
Chicken pox	Virus
Diphtheria	Bacteria
Tetanus	Bacteria
Malaria	Protozoa
Skin infections	Fungi
SARS	SARS virus
Staphylococci	Bacteria causing acne
Trypanosome	Protozoa causing sleeping sickness
Leismania	Protozoa causing Kala - Azar