The suprarenal glands or adrenal glands’ anatomy is vital in the body’s fight-or-flight response. These glands are an essential component of the endocrine system.
They produce stress hormones, which trigger physiological adjustments required to cope with changes in the climate. These glands also release several important hormones which help to strengthen the immune system metabolic and water and salt balance in the body.
These triangular-shaped structures are roughly 5 cm by 2 cm and weigh 4 to 5 gms each. They are located on the top of each kidney.
Structure and Purpose of Adrenal Gland
The adrenal glands’ anatomy is present on each kidney. We can find them in the perirenal area inside the superior renal fascia.
The adrenal glands are around one-third the length of the kidney during birth. But they are to one-thirtieth the length of the kidney as an individual matures.
The apex of the kidney, opposing the 11th intercostal end of the spinal gap and the 12th rib, contains the adrenal glands. The right suprarenal gland has a triangular shape, whereas the left is crescentic in form. Each gland is 50 mm tall, 30 mm wide, and 10 mm thick. Every gland is around 5 grams in weight.
Anatomical Relations
The right adrenal gland anatomy is beneath the liver, anterior toward the diaphragm and posterior towards the inferior vena cava.
The left adrenal gland is located anterior towards the diaphragm, medial towards the spleen (and the splenic artery and vein), superior towards the splenic artery and vein, and laterally to the abdominal aorta.
Internal Structure
Its outer cortex and the inner medulla are two different tissues that make up the adrenal gland. The fatter the adrenal cortex is, the much more yellow it appears. The hue of the adrenal medulla is much more reddish-brown. The whole adrenal gland anatomy is encased in a thick layer of connective tissue.
Zona Glomerulosa (Outer Layer)
The zona glomerulosa synthesises mineralocorticoids. Aldosterone is the most significant mineralocorticosteroid. The hormone is vital for electrolyte balance & blood pressure management.
Zona Fasciculata (Middle Layer)
The zona fasciculata secretes glucocorticoids. The most important glucocorticosteroid is cortisone. Through gluconeogenesis, these hormone aids in blood sugar management.
Cortisol affects the immune system and lipid, protein, and glucose metabolism. The adrenocorticotropic hormone, secreted from the pituitary gland, regulates cortisol production.
GFR is mnemonic for glomerulosa, fasciculata, and reticularis that will help you recall the names of these zones.
The adrenal medulla produces catecholamines. The process combines the dopamine precursor with tyrosine to produce norepinephrine. The enzyme phenylethanolamine N-methyltransferase (PNMT), also found in the adrenal medulla, methylates this norepinephrine.
What is the Role of the Adrenal Gland in Kidney Function?
The adrenal gland secretes many hormones that serve to control your vital activities such as:
- Metabolism
- Immunological system
- Heart rate
- Stress reaction
The Adrenal Gland’s Functional Anatomy
The two adrenal glands are usually wrapped in a connective tissue capsule and generally partially hidden inside a fat area just anterior to the kidneys.
These adrenal glands, like the kidneys, are placed beneath the peritoneum. The approximate placement of an adrenal gland about the kidney and its form varies per species.
When we dissect the mammalian adrenal gland, it displays two different zones:
- The inner medulla produces catecholamines, i.e., epinephrine and norepinephrine. A chromaffin cell is by far the most common form observed. The medulla is a sympathetic nerve extension that is often affected by preganglionic sympathetic fibres.
- An outer cortex that produces and secrete steroid hormones in various forms. A histological study of the cortex describes three concentric regions of cells that secrete different steroid hormones.
The medulla and brain are separate endocrine structures with diverse embryological origins, notwithstanding their arrangement into such a single gland. The medulla comprises the ectoderm (nervous crest), whereas the cortex consists of the mesoderm.
It is unclear what benefit, if any, putting them all in one organ would provide. Some animals, such as amphibians and certain fishes, possess two distinct organs.
Conclusion
Climate changes might produce conditions that the brain sees as threatening or unpleasant. The adrenal glands produce hormones that prepare the organism to deal with such changes.
These yellow, asymmetrical structures, positioned suprarenal & bilaterally there in the rear abdominal cavity, secrete stress hormones. These hormones drive physiological responses to attenuate changes in the environment. The adrenal gland seems to be almost one-third the kidney size in newborns and babies.