Lab 22 Endocrine System: 1) Index 2) Introduction 3) Things to Identify 4) Pituitary Gland 5)Thyroid Gland 6) Parathyroid Gland 7) Adrenal Cortex 8) Adrenal Medulla 9) Pineal Gland 10) Practical

 

Adrenal Gland (Medulla)

 

# 221 - Adrenal gland, rabbit, H&E, 1.5mm

# 162 - Adrenal gland, cat, medulla and cortex, H&E

 

The adrenal medulla is the loosely arranged central portion of the gland consisting primarily of unmyelinated nerve fibers and large, ovoid cells.

The secretory cells of the adrenal medulla may contain granules which are the precursors to the catecholamine hormones, norepinephrine and epinephrine. However, special stains are needed to distinguish these substances. Since these cells react with chromic acid, they are known as pheochromocytes or chromaffin cells ("chrome-affinity").

Clinical note: Tumors of these cells called pheochromocytomas cause severe hypertension accompanied by sweating, headaches, palpitation, tremor, pallor and other sympathetic nervous system effects caused by the unregulated secretion of these vasoconstricting hormones / neurotransmitters.)

Scattered among these secretory cells are the cell bodies of postganglionic sympathetic ganglion cells. Although both the ganglion cells and chromaffin cells have large nuclei, you may be able to identify ganglion cells occurring singly or in small clusters. Branches of the large medullary vein may be seen in your specimens.

REFERENCE: Ross, p. 632 - 635 Gartner, p. 210-213Wheater, pp. 313 - 318, Fig. 17.11 - 17.18 DiFiore, pp. 272 - 273

 

This is an image taken from the border between Cortex (red arrow) and the Medulla (blue arrow). The red arrow is also covering the zona reticulosa. Notice how the composition of the section changes. That is because of the difference in the type of cells. In the medulla you now get Chromaffin cells and Postganglionic Sympathetic cells.

Red arrow - Adrenal Gland Cortex

Blue arrow - Adrenal Gland Medulla

 

 

 

This is a high power image look at the Adrenal Gland Medulla. The yellow arrows are pointing to the specialized Chromaffin cells, which are responsible for making Norepinephrine & Epinephrine. The darker stained cells which appear far less numerous and appear in bunches that the red arrows are pointing to are the Postganglionic Sympathetic Ganglion Cells.

Yellow arrows - Chromaffin cells

Red arrows - Postganglionic Sympathetic Ganglion cells

 

Adrenal Gland (border of cortex and medulla)

Chromafiin Cells