Which of the following is largest lymphoid organ?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Applied Anatomy

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Explanation

The spleen is the largest secondary lymphoid organ in the body, weighing approximately 150 grams in adults.
It is crucial for mounting immune responses against antigens circulating in the blood.
The spleen's white pulp is rich in lymphocytes (B and T cells), making it a major site of immune activity.
Its red pulp acts as a filter to remove old and damaged red blood cells and platelets from circulation.

Option A: The thymus is a primary lymphoid organ, but it is largest during childhood and puberty, after which it progressively shrinks (atrophies) and is replaced by fat tissue. In adults, it is much smaller than the spleen.
Option B: The liver is the largest internal organ and the largest gland in the body, but it is not a lymphoid organ. Its primary functions are metabolic, digestive, and detoxification.
Option D: Tonsils are small masses of lymphoid tissue located in the pharynx. They are part of the Mucosa-Associated Lymphoid Tissue (MALT) and are significantly smaller than the spleen.

Clinical Relevance

Nursing practice connection: Knowing Identification of the largest lymphoid organ in the human body helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
An enlarged spleen, or splenomegaly, is a key diagnostic sign. It can indicate various underlying diseases, including infections (like mononucleosis), liver disease (cirrhosis), blood cancers (leukemia, lymphoma), and certain anemias.
Nurses may be required to palpate for an enlarged spleen, which is typically not palpable unless it is two to three times its normal size. Palpation should be gentle to avoid rupturing an enlarged, fragile spleen.
What if a patient undergoes splenectomy (spleen removal)? The patient becomes significantly immunocompromised and has a lifelong risk of overwhelming post-splenectomy infection (OPSI), especially from encapsulated bacteria like Streptococcus pneumoniae. This necessitates patient education on infection risks and adherence to a specific vaccination schedule.

How to Approach the Question

First, identify the keywords in the question: 'largest' and 'lymphoid organ'. This is a factual recall question about anatomy.
Next, evaluate each option based on whether it is a lymphoid organ. The liver is primarily a metabolic/digestive organ, so it can be eliminated.
Then, compare the sizes of the remaining lymphoid organs: thymus, spleen, and tonsils.
Recall that tonsils are small clusters of tissue and the thymus gland is largest in puberty and shrinks significantly in adulthood.
Remember that the spleen is a substantial organ that persists in size throughout adulthood.
Conclude that the spleen is the largest lymphoid organ among the given choices.

Concept Tested & Keywords

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