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The Suprarenal Gland | Anatomy Snippets

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These small acorn-sized glands located on the top of each kidney are arguably two of the most important glands in the human body. These glands are involved in the production of several hormones that maintain the normal body function.

The suprarenal gland has two main parts: the outer cortex and the inner medulla.

The two main parts of the suprarenal gland, labelled in Complete Anatomy
The suprarenal gland microanatomy model in Complete Anatomy

The Suprarenal Cortex is responsible for the production of steroid hormones. It is arranged in 3 distinct functional parts or zones and these zones produce specific hormones. The zones are called:

  1. Zona Glomerulosa: This is the outermost part and through a series of chemical reactions releases a mineralocorticoid known Aldosterone, which acts on the kidneys to maintain electrolyte-water balance. This regulates body fluid volume, osmotic pressure and blood pressure.
  2. Zona Fasciculata: This is the middle layer of cells and it secretes the glucocorticoid known as Cortisol A huge percentage of body cells have cortisol receptors, so this hormone has a generalized functionality. It is a stress hormone that maintains glucose balance, suppresses the immune system and engages in the metabolism of carbohydrates, fat and protein. It also participates in bone modeling and the maintenance of the skeletal structure.
  3. Zona Reticularis: This is the inner layer of cells which is responsible for production of gonadocorticoids, also known as the sex hormones. The male sex hormones are known as androgens, while in the female they are known as oestrogens and they play a role in development of sexual traits and characteristics.

The Suprarenal Medulla is the deepest part of the suprarenal gland. The cells here are functionally different from the cortex and are closely related to the cells of the sympathetic part of the autonomic nervous system which regulates the ‘fight or flight’ responses of the body system.

A gland as small as a grape is responsible for the control of the majority of the body’s general function, imagine that!

The suprarenal gland is one of 14 microanatomy models available in Complete Anatomy. Discover a whole new world of detailed anatomy with Complete Anatomy 2020.