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Question
Which of the following is a secondary lymphoid organ that is also considered as vestigial organ in human beings?
Which of the following is a secondary lymphoid organ that is also considered as vestigial organ in human beings?
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Solution
The correct option is C Appendix
Lymphoid organs are specialised organs in the body that provide the ideal environment for the production, maturation and proliferation of lymphocytes (white blood cells which have a non-granular cytoplasm and can provide immunity against specific foreign substances in the body). They are of two types, primary and secondary lymphoid organs.
Primary lymphoid organs like the bone marrow (soft spongy tissue of the long bones) and the thymus (lobed organ located near the heart and beneath the breastbone) are the sites of origin and maturation of the lymphocytes. The thymus acts as the site of maturation of a specific type of lymphocyte known as the T- lymphocyte (T stands for thymus).
The secondary lymphoid organs are the sites where the lymphocytes migrate after maturation, interact with antigens (foreign substances that trigger the immune responses in the body) and proliferate (multiply by cell division and differentiate into various cell types). These include the spleen, tonsils, lymph nodes, Peyer’s patches in small intestine, appendix, mucous membranes of the respiratory, digestive and urogenital tracts (mucosa-associated lymphoid tissue or MALT).
The spleen is the largest lymphoid organ, it also acts as a reservoir for erythrocytes in the body and helps to filter blood by trapping foreign substances. It is also the site for destruction of worn-out erythrocytes in the body.
Vestigial organs are those organs present in an organism that have lost all or most of their original form and function, in the course of evolution, but were fully functional in the ancestors.
The vermiform appendix, is a small worm-like blind ended tube that is attached to the caecum (pouch-like structure at the junction of the small and large intestine). Its function in human ancestors was to help in the digestion of complex carbohydrates that were a major part of their raw plant-based diet. But gradually humans started consuming cooked and easily digestible food and the appendix eventually lost its function. Thus, the appendix is a vestigial organ in humans and merely acts as a reservoir for some beneficial ‘good bacteria’.
It contains aggregates of lymphoid tissues and is considered a secondary lymphoid organ. The immunological function of the appendix is redundant as removal of the appendix does not have any massive effect on the immunological responses.
Tonsils are secondary lymphoid organs situated near the entrance of the digestive and respiratory tracts. They have an important role in trapping foreign substances that enter the body through the nose or the mouth and eliminate them with the help of the lymphocytes.
Lymphoid organs are specialised organs in the body that provide the ideal environment for the production, maturation and proliferation of lymphocytes (white blood cells which have a non-granular cytoplasm and can provide immunity against specific foreign substances in the body). They are of two types, primary and secondary lymphoid organs.
Primary lymphoid organs like the bone marrow (soft spongy tissue of the long bones) and the thymus (lobed organ located near the heart and beneath the breastbone) are the sites of origin and maturation of the lymphocytes. The thymus acts as the site of maturation of a specific type of lymphocyte known as the T- lymphocyte (T stands for thymus).
The secondary lymphoid organs are the sites where the lymphocytes migrate after maturation, interact with antigens (foreign substances that trigger the immune responses in the body) and proliferate (multiply by cell division and differentiate into various cell types). These include the spleen, tonsils, lymph nodes, Peyer’s patches in small intestine, appendix, mucous membranes of the respiratory, digestive and urogenital tracts (mucosa-associated lymphoid tissue or MALT).
The spleen is the largest lymphoid organ, it also acts as a reservoir for erythrocytes in the body and helps to filter blood by trapping foreign substances. It is also the site for destruction of worn-out erythrocytes in the body.
Vestigial organs are those organs present in an organism that have lost all or most of their original form and function, in the course of evolution, but were fully functional in the ancestors.
The vermiform appendix, is a small worm-like blind ended tube that is attached to the caecum (pouch-like structure at the junction of the small and large intestine). Its function in human ancestors was to help in the digestion of complex carbohydrates that were a major part of their raw plant-based diet. But gradually humans started consuming cooked and easily digestible food and the appendix eventually lost its function. Thus, the appendix is a vestigial organ in humans and merely acts as a reservoir for some beneficial ‘good bacteria’.
It contains aggregates of lymphoid tissues and is considered a secondary lymphoid organ. The immunological function of the appendix is redundant as removal of the appendix does not have any massive effect on the immunological responses.
Tonsils are secondary lymphoid organs situated near the entrance of the digestive and respiratory tracts. They have an important role in trapping foreign substances that enter the body through the nose or the mouth and eliminate them with the help of the lymphocytes.
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