The adrenal medulla is present completely surrounded by the adrenal cortex and accounts for a small portion of the adrenal gland.The region mostly produces glucocorticoids, but some species might produce the sex steroids called androgens. The zona reticularis is the innermost layer composed of polyhedral cells arranged in linear or round nests or clumps.It is composed of columns of secretory cells surrounded by multiple capillaries. Zona fasciculata is the middle and thickest zone of the cortex.Zona glomerulosa of the adrenal cortex produces the hormone aldosterone. The zona glomerulosa is the outermost zone that is composed of a thin layer of columnar cells arranged in an arched pattern.It consists of three distinct zones zona glomerulosa, zona fasciculate and zona reticularis.The adrenal cortex is the more important part of the adrenal gland that is composed of glandular epithelium.

The glands are enclosed in a fibrous capsule and a cushion of fat that serves to protect the gland from internal shocks. The glands are pyramid-shaped, but the exact shape might differ in different people with age and their physiological condition. There are two adrenal glands that occur atop each kidney which is why these are also called suprarenal glands. The adrenal cortex is essential for life, whereas the adrenal medulla is not essential for survival.The adrenal cortex arises from the embryonic mesoderm, whereas the adrenal medulla arises from the nervous tissue of the embryo. The embryonic origin of the two parts of the adrenal gland is different.The hormones of the adrenal gland are important for metabolism as well as reproduction, and the normal functioning of the body.The adrenal gland secretes metabolically important hormones like mineralocorticoids and glucocorticoids, as well as steroid hormones like androgens.The adrenal cortex and adrenal medulla are so different that it has been suggested that these should be considered different glands. The adrenal gland is defined by its two parts and their embryological, functional, and structural differences.It is an endocrine gland and thus releases its hormones into the bloodstream, which then transports them to their target cells or organs.Adrenal glands have been a topic of interest in biology over the years due to their heterogeneous structure, complex neural connections, multiple physiological functions, and the number of hormones produced.Adrenal glands consist of two distinct structures the adrenal cortex and adrenal medulla, both of which are different in structure as well as functions.The adrenal glands, also called suprarenal glands, are a pair of glands occurring on the top of kidneys and produce different steroid hormones. What is Adrenal Gland? Definition of Adrenal Gland

Adrenal cortex adrenal medulla