Immune System - 2

Genetic disorders result from errors in the DNA of our body cells. Hormonal disorders (for e.g. excessive growth, appearance of facial hair in females, etc) are the results of imbalanced secretion of hormones produced within the body. Similarly, if any body organ malfunctions, i.e. it does not function in proper order, then it is an internal cause. But if there is malnutrition, then the cause is purely external and not within our body. We should remember that cause may be external or internal, but the effect is seen on the general health of our body.

During any accident, wounds occur and they are exposed to air and soil. The air and soil may contain tetanus-causing microbes. Hence, the person is immediately given anti-tetanus injection. 

A defective gene that leads to a defect is a factor which is present inside the body cells of an organism. Hence, it is an internal factor.
Extrinsic factors are those which are outside of the body and they include causative agents, diet, community, social system, etc.

The second time, our immune system has memory cells which quickly identify the problem and counter it and thus, eliminate it. This is called immunisation. Immunisation is a method of prevention of disease or infection and it also helps to avoid the spreading of a disease.

AIDS is a viral disease caused by HIV. The human body cannot develop immunity against it. The antibodies that human immune system makes to fight HIV are not effective. HIV actually targets, invades and then destroys some of the most important cells in the immune system itself. So, no vaccine is effective in preventing AIDS.
 

Hepatitis is the swelling and inflammation of the liver, most commonly caused by a viral infection. It may lead to liver damage, liver failure or even liver cancer.

“Health” refers to physical and mental well-being. If a person has psychological tension, his mental stability is disturbed. In this situation, we may say that he is unhealthy. Being wise or wealthy has no relation (under scientific logic) with health. Unhealthy people can also be rich and wise.

AIDS stands for Acquired Immuno Deficiency Syndrome. It is a disease in which a person’s immune system becomes weak and he/she is unable to fight infections. Hence, the concerned person finally dies due to other infections like common cold, soar throat, flu, etc. At the last stage, the person suffers from physical trauma due to infection and the inability to treat it.

Infectious diseases spread through all of the above given ways.

Immunisation is a specific way to prevent a disease as it helps to provide immunity against diseases.

Headache and unconsciousness are the ailments related to nervous system, i.e. they are related to brain. Also, the brain has a part called medulla which controls the stimuli for vomiting. 

Small pox has been completely eradicated from the world by the use of vaccination.