TLDR: The adrenal glands are small glands located above the kidneys that produce hormones like adrenaline and cortisol. They have two main parts: the outer cortex, which produces steroid hormones, and the inner medulla, which produces adrenaline. These hormones play important roles in regulating blood pressure, metabolism, and the body's response to stress.

The adrenal glands are endocrine glands that produce hormones. They are located above the kidneys and have a unique structure with an outer cortex and an inner medulla. The cortex is divided into three zones, each responsible for producing different types of steroid hormones. These hormones include mineralocorticoids, which help regulate blood pressure and electrolyte balance, glucocorticoids, which regulate metabolism and suppress the immune system, and androgens, which are converted into sex hormones in other parts of the body.

The medulla, on the other hand, produces adrenaline and noradrenaline, which are responsible for the body's fight-or-flight response in stressful situations. These hormones increase heart rate, blood pressure, and energy levels, preparing the body to respond to a perceived threat.

The adrenal glands can be affected by various diseases, such as Cushing's syndrome, Addison's disease, and congenital adrenal hyperplasia. These conditions can result in an overproduction or underproduction of certain hormones, leading to a range of symptoms and health problems.

The development of the adrenal glands begins in the early stages of fetal development and continues throughout childhood. The glands undergo changes during puberty, leading to increased production of androgens, which are responsible for the development of secondary sexual characteristics like pubic and axillary hair.

In summary, the adrenal glands are small glands located above the kidneys that produce hormones essential for regulating various bodily functions. They consist of an outer cortex that produces steroid hormones and an inner medulla that produces adrenaline. These hormones play important roles in maintaining blood pressure, metabolism, and the body's response to stress.