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thymus

[Greek, thymos = excrescence, sweetbread] Function: - role in immunological function throughout life. - produces hormones, including thymosine that can continue to influence T-cells after they have left the gland Structure: - a bilobed mass of pinkish gray lymphoid tissue located deep to the sternum, in the anterior region of the mediastinum. - the thymus is covered by a connective tissue capsule that separates it into smaller lobules. - each lobule has an outer cortex & an inner medulla. - cortex composed of densely packed lymphocytes - medulla composed of lymphocytes; also has thymic corpuscles Arterial supply: - inferior thyroid artery & internal thoracic artery Innervation: - derived from the vagus & sympathetic nerves Development: - it increases in size during fetal life & early childhood. - after puberty, it undergoes gradual involution & is largely replaced by adipose tissue. Pathology: - in some newborn infants, the thymus may also extend superiorly through the superior thoracic aperature into the neck & compress the trachea Biochemistry: Transcription factors implicated in thymic development & function: - FoxN1 - HoxA3 - Pax-1 - Pax-9 - Eya-1 - Six-1

Related

thymic neoplasm

General

organ

References

  1. Clinically Oriented Anatomy, 4th edition, KL Moore & AF Dalley (eds), Lippincott Williams & Wilkins, Philadelphia, PA 1999.
  2. Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999.
  3. Human Anatomy and Physiology, Alexander P Spence & Elliot B. Mason, The Benjamin/Cummings Publishing Company, Inc, 1979.
  4. Introduction to Human Anatomy and Physiology, Eldra P. Solomon. W.B. Saunders Company, Philadelphia, PA 1992.
  5. Anderson & Jenkinson. Nature Reviews Immunology 1:31-40, 2001
  6. Blackburn & Manley. Nature Reviews Immunology 4:278-289, 2004

Component-of

lymphatic system thorax

Components

thymic corpuscles (Hassall bodies, Hassall concentric corpuscles, Virchow-Hassall bodies, Hassall's corpuscles)

Images

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