Each of the four or more rounded or ovoid bodies has a fine CT capsule and delicate, incomplete septa. These septa carry vessels, nerves and many fat cells. More oxyphil cells are seen in older individuals. 2 Composite of medullary and cortical tissues , linked by blood supply, but embryologically and functionally distinct. 5 Mature adrenal has a thick CT capsule , bringing arteries to serve radial capillaries draining down towards the venules and central vein of the medulla.
Arterioles also penetrate the cortex to serve a medullary capillary bed.
The medulla is a long, thin strip of basophilic cells, which can be made outstanding by the chromaffin reaction - a darkening produced by dichromate ions. The supporting element throughout is the reticular fibre . 2 Cortex l Polyhedral glandular cells, in cords usually two cells wide, run roughly radially, along with sinusoidal capillaries. 2 Release is controlled by a direct, 'preganglionic', sympathetic innervation , terminating synaptically on the glandular cells. The granules form in relation to the Golgi body, but a dense GER is not required.