Skip to main content
Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues
Hoehn - Marieb Human Anatomy & Physiology, 12th edition
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
Chapter 20, Problem 8

The lymphoid organ that functions primarily during youth and then begins to atrophy is:
a. Spleen
b. Thymus
c. Palatine tonsils
d. Bone marrow

Verified step by step guidance
1
Understand the function and lifespan of each lymphoid organ listed: the spleen, thymus, palatine tonsils, and bone marrow.
Recall that the thymus is most active during childhood and adolescence, playing a crucial role in the development of T lymphocytes (T cells) for the immune system.
Recognize that after puberty, the thymus begins to shrink or atrophy, a process called involution, which reduces its size and functional tissue.
Contrast this with the spleen, palatine tonsils, and bone marrow, which do not primarily atrophy after youth but continue to function throughout life.
Conclude that the lymphoid organ that functions primarily during youth and then begins to atrophy is the thymus.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Thymus Function and Development

The thymus is a primary lymphoid organ responsible for the maturation of T lymphocytes during early life. It is most active during childhood and adolescence, after which it gradually shrinks or atrophies, reducing its functional capacity in adulthood.
Recommended video:
4:48
Introduction to Human Development

Lymphoid Organs and Their Roles

Lymphoid organs include primary organs like the thymus and bone marrow, where lymphocytes develop, and secondary organs like the spleen and tonsils, which filter lymph and blood and facilitate immune responses. Each organ has distinct functions and activity timelines.
Recommended video:
4:34
Primary & Secondary Lymphoid Organs

Atrophy in Lymphoid Organs

Atrophy refers to the reduction in size and function of an organ over time. In the immune system, the thymus undergoes physiological atrophy after puberty, unlike other lymphoid organs such as the spleen or tonsils, which remain active throughout life.
Recommended video:
2:07
Primary Lymphoid Organs Example 1