Thymus gland Flashcards
what type of organ is the thymus gland?
The thymus gland is a pink, lobulated lymphoid organ
where is the thymus gland located?
located in the thoracic cavity and neck
what is the function of the thymus gland in adolescent?
it is involved the development of the immune system
what happens to the thymus gland after puberty?
it decreases in size and is slowly replaced by fat
Embryologically, where is the thymus gland is derived from?
the third pharyngeal pouch
what type of shape & structure is the thymus gland?
The thymus gland has an asymmetrical flat shape, with a lobular structure
what are the lobules comprised of?
The lobules are comprised of a series of follicles, which have a medullary and cortical component
where is the cortical portion of the lobules located?
Located peripherally within each follicle
what is the cortical portion of the lobules composed of?
It is largely composed of lymphocytes, supported epithelial reticular cells
where is the medullary portion of each lobule located?
Located centrally within each follicle
What does the medullary portion of each lobule contain?
contains fewer lymphocytes than the cortex, and an increased number of epithelial cells
what else is present within the medullary portion of each lobule?
Hassall’s corpuscles are also present
what are Hassall’s corpuscles?
these are concentric arrangements of epithelial reticular cells. Their function is unclear
where is the thymus gland mainly located?
within the thoracic superior mediastinum, posterior to the manubrium of the sternum
where can the thymus gland extend to in some individuals?
it can extend superiorly into the neck (reaching the thyroid gland), and inferiorly into the anterior mediastinum (lying in front of the fibrous pericardium)
what is the arterial supply to the thymus gland via?
via the anterior intercostal arteries and small branches from the internal thoracic arteries
where does venous blood drains into from the thymus gland?
Venous blood drains into the left brachiocephalic and internal thoracic veins
what is DiGeorge syndrome?
a genetic syndrome caused by the deletion of part of chromosome 22. The clinical findings vary greatly between individuals
how can the most common features of the syndrome can be memorised?
using the mnemonic ‘CATCH’
what does ‘CATCH’ stand for in DiGeorge syndrome?
Congenital heart defects Abnormal facies Thymic aplasia Cleft palate Hypoparathyroidism
what are individuals with an absent or asplastic thymus are susceptible to? why?
recurrent infections due to an underdeveloped immune system
