Few people know that on the top of the kidneys there is an "attached" organ called the adrenal gland. The adrenal gland secretes a number of hormones into the bloodstream (adrenaline, norepinephrine, cortisol, aldosterone, sex hormones). Therefore, in case of problems with the level of certain hormones, first of all, attention is paid to the adrenal glands. With tumor or cystic neoplasms of the adrenal gland, it is examined histologically. We will talk about it in this article.
Where the organ is located
The organ is located on top of the kidneys. Since there are two kidneys, there are also two adrenal glands. The adrenal gland is shaped like a pyramid, three-dimensional with rounded edges and small in size. The right adrenal gland from above and in front is in contact with the liver (with its visceral surface), and behind - with the diaphragm. The left adrenal gland is in contact with the pancreas from above and in front, and behind the left adrenal gland is the diaphragm.
Synthesizes a number of fundamentally important hormones for the body, such as cortisol, adrenaline, norepinephrine, dopamine, gluco- and mineralocorticoids, as well as sex hormones.
Structure and function of the adrenal glands, histology
In order to understand what histology is (as a diagnostic method), you need to have an idea of what a histological preparation is and how it is prepared.
A piece of the organ is taken, a slice is cut off from it (a very thin fragment, which is several microns in thickness). Then this slice is stained with special dyes, after which the preparation is ready. And he is being examined under a microscope.
Analysis of the histology of the adrenal gland occurs in several stages:
- Examination of the fatty, periorbital capsule.
- Examination of the stroma of the organ.
- Examination of the parenchyma.
- Examination of the medulla.
Perio-organ capsule
Examining the near-organ capsule, you can see that it consists mainly of adipose tissue, which is colored yellowish-white on the preparation. Large rounded formations are visible in the capsule. In the middle of these formations there are many oval-shaped cells. To view these cells in more detail, you need to switch to a large increase.
By switching to a large magnification, you can see the nervous tissue. Cell nuclei are large and light. The nucleus itself in the cell is located eccentrically. Since the cells are stained in light colors, it can be argued that they contain euchromatin. Betweencells are many small cells - microglia. Nearby is a nerve fiber, which consists of elongated cells - olemocytes (Schwan cells).
Based on the above, we can draw the following conclusion: rounded large formations in the periorgan capsule are the parasympathetic periorgan ganglion and the nerve itself.
It is worth noting that in addition to nerve fibers in the periorgan capsule, there are many adipocytes - adipose tissue cells. In the thickness of adipose tissue there are many veins and arteries. Between themselves, they differ in a layer of muscle tissue. In the artery, it is significantly larger.
Organ stroma
Before moving on to the stroma, I would like to say: the adrenal gland is a typical parenchymal organ, which consists of stroma and parenchyma.
The elements of the stroma include:
- Connective tissue capsule. It consists of two layers. From a layer of fibers, which are dense unformed connective tissue. And from the cell layer, from which the formation of the parenchyma of the organ begins.
- Layers of loose connective tissue that extend to the medulla.
Organ parenchyma
Presented in three layers. The top layer is glomerular. Between the so-called glomeruli are gaps that are painted white. These gaps are called sinusoidal capillaries.
Since the epithelial strands change somewhat and become more ordered as they go deeper into the organ, they begin to resemble bundles. Therefore, the second layer of the cortexadrenal gland is called fascicular.
The third layer of the cortex on the histology of the adrenal gland is reticular. Why is it called that? Because the epithelial cords in this layer intertwine and form the so-called networks.
Under the reticular layer of the adrenal cortex is a thin layer. This layer consists of loose fibrous tissue. Separates the cortex from the medulla.
Adrenal medulla
On the histology of the adrenal gland, its medulla is no longer represented by epithelial strands, but by endocrine cells - chromophinocytes. These are cells of a nervous nature. Since the histology of the development of the adrenal glands showed that these cells are formed from the nervous tissue (neuroectoderm). There are many spaces in the medulla - these are all the same sinusoidal capillaries.
It is worth noting that the medulla secretes hormones much more actively and therefore is much more permeated with blood vessels. Vessels show endothelial lining.
Where what hormones are produced
On the adrenal histology slide, you can see where the disruption of hormone production occurs, but you need to know the corresponding areas. In the glomerular zone of the adrenal cortex are produced:
- Aldosterone - normalizes the balance of sodium and potassium in the body. When it is synthesized, sodium reabsorption increases and potassium decreases.
- Corticosterone - has negligible mineralocorticoid activity.
The beam zone generates suchhormones like cortisone and cortisol. They increase the excitability of the nervous tissue, activate lipolysis to glucose. In addition, they play an important role in inflammatory processes, inhibiting them. Participate in immune responses and allergic reactions.
The reticular zone produces androgens, sex hormones. These hormones affect secondary sex characteristics.
The medulla is catecholamines such as epinephrine and norepinephrine. They affect the metabolic rate, the speed of nerve impulses. The hormone adrenaline is the main activator of the body in stressful situations.
