Active and Passive Immunity

Q: What is immunisation?

Explanation:Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine.Vaccines stimulate the body's own immune system to protect the person against subsequent infection or disease.

Q: Explain the principle of immunization.

Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease.This happens because when the immune system first sees an infectious microbe, it responds against it and then remembers it specifically. So the next time that particular microbe, or its close relatives enter the body, the immune system responds with even greater vigor. This eliminates the infection even more quickly than the first time around. This is the basis of the principle of immunisation.

Q: What are the immunisation programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?

At the nearest health centre in our locality, the following immunisation programmes are available:(i) For preventing polio.(ii) For preventing tetanus, diphtheria, and whooping cough(iii) For preventing tuberculosis(iv) For preventing measles.Occasionally, children suffer from measles in our area.

Q: Which of the following is not an autoimmune disease ?

Psoriasis, Vitiligo and Rheumatoid arthritis are autoimmune diseases. An illness that occurs when the body tissues are attacked by its own immune system is known as autoimmune disease. Alzheimer's is caused by brain cell death. It is a neurodegenerative disease. There is progressive brain cell death that happens over time. Thus the correct answer is option A.

Q: Write short note on vaccination.

Vaccination is a process of development of immunity without infection. In this case, weakened pathogens are injected in the body to produce immunity against the particular pathogen. This pathogen stimulates the body to form anti-bodies. In this way, vaccinated person develops immunity against the pathogen. These days vaccination is used for T.B., mumps, polio, small pox, typhoid etc.

Q: Which of the following is not a lymphoid tissue

Lymphoid tissue is a cylinder of loosely organized cells surrounding the arteries. It is rich in lymphocytes and includes lymph nodes, spleen, tonsils, bone marrow and thymus. An appendix is a lymphoid organ which helps the body to stave diseases.So, the correct option is 'Appendix'.

Q: Identify the wrong statement with reference to immunity.

Active immunity develops in an organism when exposed to a specific antigen, that is, the organism produces antibodies in response to a foreign antigen. However, the antibody production may not be quick but is long lasting.So, the correct answer is 'Active immunity is quick and gives full response.'

Q: Why do we often sneeze when we inhale a lot of dust-laden air?

Answer-We often sneeze when we inhale a lot of dust-laden air to expel out these foreign particles. These particles get past the hair in the nasal cavity and irritate the lining of the cavity which triggers a message to the brain. The brain instructs the nasal chamber to initiate sneezing. This is a method to remove unwanted dust particles from the nostrils. Sneezing is a type of defence mechanism used by our body.

Q: State the functions of primary and secondary lymphoid organs in humans.

The primary lymphoid organs are the bone marrow and the thymus. The act as the site for the production , clonal selection and maturation of the B and T cells. The secondary lymphoid organs are the spleen and the lymph nodes. They act as sites for maintaining the mature naive lymphocytes and are also the site where lymphocyte binding to antigen and hence their activation occurs.

Q: MALT constitutes about ............ percent of the lymphoid tissue in the human body.

MALT stands for mucosa-associated lymphoid tissue. It consists of T cells, B cells, and macrophages. It is distributed in association with mucosal tissue. It consists of 50% of the lymphoid tissue in the human body.So, the correct answer is option B.

Biology

definition

Active immunity and passive immunity

The difference between active and passive immunity are as follows:

Active immunity	Passive immunity
1. Produced by one's own body.	1. Received from outside.
2. It is developed by an individual's own cells in response to an infection or a vaccine.	2. It is developed when ready-made antibodies are inoculated from outside.
3. It provides effective and long lasting protection.	3. The protection is less effective and short lived.
4. It has no side effects.	4. It may cause reactions.
5. Time is required for the effectiveness of the immunity.	5. Immediately effective.