Difference Between Adrenal Cortex and Adrenal Medulla

Main Difference

The main difference between the Adrenal Cortex and the Adrenal Medulla is that Adrenal Cortex is the outermost covering of the adrenal gland whereas Adrenal Medulla is the inner or middle part of the adrenal gland.

Adrenal Cortex vs. Adrenal Medulla

Adrenal glands are the paired structures that are located on the top of the kidneys. Each adrenal gland consists of two parts, i.e., the external adrenal cortex and the inner adrenal medulla. If we know our anatomy, then there is really no problem in describing these two regions. There are basically two endocrine organs which are present in the adrenal gland, in which one surrounds the other. The names of these two particular regions tell about their location. The adrenal cortex is the outermost portion of the adrenal gland, whereas, the adrenal medulla of the adrenal gland is the inner or middle layer of it. Both of them release or secrete different types of hormones. The outer adrenal cortex releases three types of hormones, i.e., the mineralocorticoids, the glucocorticoids, and the androgens. The inner adrenal medulla, on the other hand, releases two major hormones which include the adrenaline (epinephrine) and the noradrenaline (norepinephrine). The hormones of the outer adrenal cortex are released by virtue of ACTH and are stimulated by the anterior pituitary gland. The hormones of the inner adrenal medulla, on the flip side, are released because of the several nerve signals for the stress reaction (response).

Comparison Chart

Adrenal CortexAdrenal Medulla
The outermost covering of the adrenal gland is called adrenal cortex.The inner or middle part of the adrenal gland is called adrenal medulla.
Type
It is the outer rigid portion of the adrenal gland.It is the central soft part of the adrenal gland.
% of Construction
It constructs about 75% of the adrenal gland.It constructs about 25% of the adrenal gland.
Covering
It is covered by a fibrous capsule.Fibrous capsule does not cover the adrenal medulla.
Development
The adrenal cortex is developed from the mesodermal layer.The adrenal medulla is developed from the ectodermal layer.
Zones or Regions
The adrenal cortex contains three zones or regions.The adrenal medulla is not differentiated into zones or regions. It is composed of chromaffin cells.
Necessary
It is very necessary for life. Its destruction results in death.It is not so necessary for life. Its destruction does not result in death.
Stimulation
The ACTH of the anterior lobe of the pituitary gland is responsible for the stimulation of adrenal cortex to release its hormones.The nerve impulses which are reaching through the sympathetic nerve fibers are responsible for stimulating the adrenal medulla to release its hormones.
Hormones
It releases three types of hormones which include the mineralocorticoids, the glucocorticoids, and the androgens.It releases two major hormones, which include the adrenaline (epinephrine) and the noradrenaline (norepinephrine).
Cooperation with SNS
Adrenal cortex has no cooperation with the sympathetic nervous system.The sympathetic nervous system functions with the adrenal medulla as an integrated system which is called as the sympatheticoadrenal system.

What is Adrenal Cortex?

The adrenal cortex is the outermost portion of the adrenal gland. As it is an outer layer, therefore, it surrounds the entire medulla. It contains three types of hormones which are the androgens, the glucocorticoids, and the mineralocorticoids. The group androgens contains the male sex hormone, which is called testosterone. The glucocorticoids is that group of hormones which consists of the stress hormone (cortisol). Aldosterone is an example of the hormone mineralocorticoid, which is the chief hormone for the regulation of blood pressure and water reabsorption. The production and release of these hormones are all controlled by the pituitary gland (the master gland) mainly with the help of adrenocorticotrophic hormone (ACTH).

What is Adrenal Medulla?

The adrenal medulla is the inner or middle part of the adrenal gland. It has a clump of neurons that show a main role in the autonomic nervous system. It releases two types of hormones, i.e., the adrenaline (epinephrine) and the noradrenaline (norepinephrine). The effect of these two hormones on the body includes blood diversion from the skin (integument) to the inner organs like brain and liver. They also cause an increase in overall metabolism, bronchial and pupil dilation, decreased clotting time, piloerection (skin or hair ‘stands’ like goose flesh or goosebumps), and an increased release of ACTH from the anterior pituitary gland. These effects are more or less similar to the effect of adrenal cortex hormones.

Key Differences

  1. The outermost portion of the adrenal gland is called adrenal cortex, whereas, the inner or middle part of the adrenal gland is called adrenal medulla.
  2. The adrenal cortex is the outer rigid part of the adrenal gland, while, the adrenal medulla is the central soft part of the adrenal gland.
  3. Adrenal cortex constructs about 75% of the adrenal gland, on the other hand, adrenal medulla constructs about 25% of the adrenal gland.
  4. A fibrous capsule surrounds the adrenal cortex. Conversely, the adrenal medulla is not covered by a fibrous capsule.
  5. The adrenal cortex is developed from the mesoderm, on the flip side, the adrenal medulla is developed from the ectoderm.
  6. The adrenal cortex contains three zones or regions; on the other side, the adrenal medulla is not differentiated into zones or regions. It is composed of chromaffin cells.
  7. The adrenal cortex is very necessary for life. Its destruction results into the death, while, the adrenal medulla is not so necessary for life. Its destruction does not result in death.
  8. The ACTH of the anterior lobe of the pituitary gland is responsible for the stimulation of adrenal cortex to release its hormones, on the other hand, the nerve impulses which are reaching through the sympathetic nerve fibers are responsible for stimulating the adrenal medulla to release its hormones.
  9. The adrenal cortex releases three types of hormones which include the mineralocorticoids, the glucocorticoids, and the androgens, whereas, adrenal medulla releases two major hormones which include the adrenaline (epinephrine) and the noradrenaline (norepinephrine).
  10. Adrenal cortex has no cooperation with the sympathetic nervous system, on the flip side, the sympathetic nervous system functions with the adrenal medulla as an integrated system which is called as the sympatheticoadrenal system.

Conclusion

All of the above discussion summarizes that adrenal cortex is the outermost part of the adrenal gland that surrounds the adrenal medulla which is the central portion of the adrenal gland. The former releases hormones like androgens, glucocorticoids, and mineralocorticoid, while the latter releases hormones like epinephrine and norepinephrine.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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