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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which of the pharyngeal pouch contributes to the thymus?
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The correct answer is  The elongate ventral poions of the third pair of pharyngeal pouches migrate medially and fuse to form the primordium of the thymus gland. Development of the thymus is not complete at bih; it contains to grow and reaches its greatest size at pubey, after which it gradually shrinks and its functional tissue is replaced by a fatty tissue. Ref: Ochs H.D., Notarangelo L.D. (2010). Chapter 82. Immunodeficiency Diseases. In J.T. Prchal, K. Kaushansky, M.A. Lichtman, T.J. Kipps, U. Seligsohn (Eds),Williams Hematology, 8e.