Escuche esta historia
--:--
7:01
Clinical importance of the adrenal gland
Also known as the adrenal gland, these are endocrine glands that are located in the upper pole of both kidneys. Likewise, among its functions, the synthesis of hormones and catecholamines stands out.
Embryological origin of the adrenal gland
The adrenal gland is made up of a cortex and a medulla, structures that have a different embryological origin.
On the one hand, the cortex of the adrenal gland originates from the embryological mesoderm layer, while the medulla comes from the neural crest, that is, from the ectoderm.
This is how it interferes with the sympathetic autonomic nervous system, through the synthesis of catecholamines.
Basic anatomy of the adrenal gland
There are two adrenal glands in the body, one left and one right. In addition, they can weigh up to 12 grams and their dimensions are between 3 cm long by 1 cm high approximately.
Besides, the shape of both glands is slightly different. The right gland is more triangular, but the left is cap-shaped.
Also, the face that is applied on the surface of the kidney is concave. On the other hand, the color of the gland is in yellow tones.
In addition to this, the blood supply of the gland is in charge of the superior, middle and inferior adrenal arteries.
Within its internal configuration, two different structures can be described, the cortex and the medulla.
What is the adrenal cortex, and what is its function?
The cortex of the gland represents 80% of it, which is distributed in the peripheral part of the gland.
An interesting fact is that three different histological zones can be distinguished in the cortex. In turn, these areas have specific functions, that of producing steroid hormones. In this sense, the zones are.
Glomerular zone
Fascicular zone
Reticular zone
Glomerular zone
This area has that name assigned, because its characteristics in terms of shape is similar to the glomerulus of the kidney. The glomerular zone covers 15% of the cortex.
Now, the function is to produce mineralocorticoids, that is, aldosterone.
Aldosterone release is stimulated by the presence of angiotensin II, a resulting product of the renin-angiotensin-aldosterone system.
Basically, aldosterone helps maintain extracellular fluid volume.
Fascicular zone
It represents 75% of the cortex, in the fascicular zone the synthesis of glucocorticoids is carried out, mainly, the hormone cortisol.
Cortisol has many functions, but one of the most important is to serve as a counter-regulating hormone for insulin.
Reticular zone
It only covers 10% of the cortex and male sex hormones are produced in this area.
What stimulates the adrenal gland?
Of course, since it is a gland, it has an axis that regulates the synthesis and release of the hormones that are produced in it.
In the case of the adrenal gland, the axis is led by the hypothalamus, which synthesizes the corticotropin-releasing hormone.
Subsequently, the corticotropin-releasing hormone exerts its effects on the anterior pituitary, allowing the release of the corticotropin hormone.
This last hormone is transported by the bloodstream to the adrenal gland to stimulate the synthesis of cortisol.
Then, when blood cortisol levels are elevated, the release of hypothalamic and pituitary hormones is automatically inhibited.
How are steroid hormones formed?
The composition of these hormones is cholesterol. In this way, cholesterol reaches the adrenal gland via lipoproteins.
At the same time, the corticotropin hormone arrives, which activates a series of mechanisms in the three areas of the cortex.
What happens is that an enzyme called desmolase will transform cholesterol into prenegnolone.
From this process, a series of reactions begins to result in aldosterone, cortisol, and testosterone.
So, if an interference occurs at some point in the reaction, it can condition clinical pathological entities.
What are the functions of cortisol?
Cortisol is a very versatile hormone, since it intervenes in metabolism, has a function in different tissues and in inflammatory processes. Some of its functions are.
It is a hormone that counteracts the function of insulin, thus inducing hyperglycemia, this means high blood sugar.
Stimulates the breakdown of lipids.
Increases constriction of blood vessels.
It does not allow a good healing of the skin.
It is an anti-inflammatory hormone.
Lymphopoiesis decreases.
Diseases related to the adrenal gland
The clinical importance of the radial adrenal gland in how to apply all the basic knowledge to understand the alterations that may occur. In this way, some pathologies are.
Cushing's syndrome
It is a syndrome characterized by chronic elevation of glucocorticoids, regardless of the cause.
However, there is another term, Cushing's disease, which refers to the fact that the cause of the syndrome is due to a tumor in the pituitary gland.
Likewise, the syndrome can be categorized as corticotropin-dependent, corticotropin-independent, or iatrogenic.
From this it can be deduced that the most frequent is corticotropin-dependent in 90%, its predominant cause being the pituitary tumor.
In relation to the iatrogenic cause, it is given by an abusive administration of glucocorticoids to alleviate the symptoms of inflammatory diseases.
Addison's disease
It is an insufficiency of the adrenal gland to produce hormones, which is why it cannot meet the demands that the body has on these hormones.
In general, this process occurs due to a destruction of the adrenal cortex. Although the main causes are.
Autoimmune adrenalitis
Infectious diseases such as tuberculosis, HIV, among others.
Tumor metastasis
Some of the clinical manifestations that can occur when the destruction of the cortex is already 90% are.
Hypotension
Weightloss
Muscular weakness
Vomiting
Diarrhea
Hair darkening
Pheochromocytoma
They are not so frequent tumors, whose composition is chromaffin cells, which release catecholamines in the medulla of the gland.
What tumors can generate is severe hypertension, sweating, anxiety, nausea, chest pain, abdominal pain, palpitations, among others.
Congenital adrenal hyperplasia
It is the deficiency of an enzyme that does not allow the synthesis of cortisol or aldosterone, but that of male sex hormones.
It is a disease with a genetic basis and that affects both males and females.
Also, clinical variants of the disease are known, with the worst prognosis being the one that manifests itself in the neonatal stage, since the mortality rate is high.
