Stroma

The thyroid gland is invested by a thin fibrous capsule of connective tissue, which projects(forming a connective-tissue framework called the stroma) into its substance (the parenchyma) and imperfectly divides it into masses of irregular form and size (the lobules), . When the organ is cut into, it is of a brownish-red color, and is seen to be made up of a number of closed vesicles, containing a yellow glairy fluid, and separated from each other by intermediate connective tissue.