Adrenal gland

You have small parts in your body.

They sit on top of your kidneys. These parts help you stay well. They help your body react to stress. They also help you use food. They work hard for you. The parts have an outer layer and an inner part.

The outer layer makes many things. The inner part makes a part that helps you react fast. These parts are yellow. They are very small. They help you every day.

You have two small glands in your body.

They sit on top of your kidneys. These glands are yellowish in color. They are quite small. One gland is shaped like a triangle. The other is shaped like a crescent moon. Each gland has two main parts.

The outer part is the adrenal cortex. The inner part is the medulla.

The cortex has three layers. These layers make steroid hormones. One layer makes aldosterone. This hormone helps control blood pressure. Another layer makes cortisol. This hormone helps your body use food for power. The last layer makes androgens. These help make sex hormones later. The way the cortex makes these is called steroidogenesis. It starts with cholesterol.

Enzymes change the cholesterol into different hormones.

The medulla is in the center. It makes catecholamines. These include adrenaline. This hormone helps your body react fast to stress. The glands have a lot of blood. Up to 60 small arteries enter each gland. This helps them send hormones into your blood quickly.

{ "text": "Your body has two small, yellowish glands called the adrenal glands.

They sit right above your kidneys on both sides of your body. In humans, the right gland looks like a triangle or pyramid. The left gland is a bit larger and shaped like a crescent moon. These tiny organs are very important for keeping you healthy. They help control everything from your blood pressure to how you react to stress. Together, the two glands weigh only about 7 to 10 grams in an adult.

\n\nEach gland is made of two main parts with different jobs. The outer part is called the adrenal cortex. The inner part is called the adrenal medulla. The cortex is the largest part and is divided into three layers. The first layer is the zona glomerulosa, which makes aldosterone to help manage blood pressure. The middle layer is the zona fasciculata, which makes up 80% of the cortex. This layer produces cortisol to help manage metabolism and the immune system. The third layer is the zona reticularis, which makes androgens.

\n\nMaking these hormones

The adrenal glands are essential endocrine glands located in the retroperitoneum.

They sit on both sides of the body, directly above and slightly medial to the kidneys. These yellowish organs are vital because they produce hormones that regulate many bodily functions. These hormones manage blood pressure, metabolism, and the body's response to stress. In an adult human, the combined weight of both glands is only 7 to 10 grams.

While small, they are highly active and receive a massive blood supply. Up to 60 small arteries may enter each single gland.

Each adrenal gland consists of two distinct functional regions: the adrenal cortex and the adrenal medulla. The adrenal cortex is the outer region and represents the largest part of the gland. It is further divided into three specific layers called zones. The outermost layer is the zona glomerulosa. The middle layer is the zona fasciculata, which makes up nearly 80% of the cortical volume. The innermost cortical layer is the zona reticularis.

Each of these zones uses specific enzymes to produce different types of steroid hormones.

The zona glomerulosa is located immediately beneath the gland's fibrous capsule. Its cells form oval groups separated by thin strands of connective tissue. This layer is the primary site for producing aldosterone. Aldosterone is a mineralocorticoid, which is a type of steroid hormone. This hormone is crucial for the long-term regulation of blood pressure. It works by helping the kidneys reabsorb sodium and excrete potassium and hydrogen ions. By managing sodium retention, aldosterone helps regulate blood volume and pressure.

The middle layer, the zona fasciculata, is situated between the other two cortical zones. The cells here are arranged in columns that point toward the medulla. This layer contains many lipid droplets, mitochondria, and a complex smooth endoplasmic reticulum. The zona fasciculata produces glucocorticoids, with cortisol being the main hormone in humans. Cortisol helps regulate metabolism by increasing circulating glucose levels. It does this by mobilizing amino acids from protein and stimulating glucose synthesis in the liver. Cortisol also helps suppress the immune system and provides anti-inflammatory effects.

The innermost layer of the cortex is the zona reticularis. This layer lies directly next to the adrenal medulla. Its small cells form irregular cords and clusters. The zona reticularis produces androgens, which are hormones like dehydroepiandrosterone (DHEA). These androgens are later converted into functional sex hormones in other organs, such as the gonads.

The production of these steroid hormones is a complex process called steroidogenesis. This process begins with the uptake or synthesis of cholesterol.

Steroidogenesis starts when cells acquire cholesterol from the blood or build it themselves. The first enzymatic step involves the enzyme P450scc, also known as cholesterol desmolase. This enzyme cleaves the cholesterol side chain to create a product called pregnenolone. From there, different enzymes in each layer modify the molecule into specific hormones. At the center of the gland lies the adrenal medulla. The medulla contains chromaffin cells that produce catecholamines, such as adrenaline and noradrenaline. These hormones allow the body to have a rapid response during stress. The medulla is driven by the sympathetic nervous system through nerve fibers from the spinal cord.

Because the adrenal glands are so important, malfunctions can lead to serious medical conditions. Overproduction of the hormone cortisol can cause Cushing's syndrome. Conversely, if the gland does not produce enough cortisol, it is associated with Addison's disease.

There is also a genetic disease called congenital adrenal hyperplasia, which is caused by the dysregulation of endocrine control. Additionally, various tumors can arise from adrenal tissue. These tumors are often discovered during medical imaging when doctors are looking for other diseases.

Understanding these glands helps scientists understand how the body maintains balance and reacts to the world.