The thyroid gland is located in the neck under the larynx and consists of two lobes connected by an isthmus, adjacent to the trachea. It produces the hormones thyroxine (T4) and triiodothyronine (T3), which regulate metabolism by affecting how quickly cells use energy, body temperature, and metabolic processes. These hormones are also critically important for growth and development, especially the nervous system in children. Interesting fact: Weighing only about 20 grams, it has a tremendous impact on nearly all aspects of human health. The thyroid gland is the only organ in the human body capable of absorbing and utilizing iodine, making this micronutrient vital for our health.

The thymus, located behind the sternum in the upper part of the chest, is active during childhood and adolescence but decreases in size with age. This organ is critical for the development of the immune system, providing maturation and selection of T-lymphocytes (T-cells) necessary for recognizing and destroying infected or cancerous cells. The thymus also participates in the process of immune tolerance, removing T-cells that could attack the body's own tissues. Interesting fact: By the age of 75, the thymus is almost completely involuted in most people, which reduces its ability to train T-lymphocytes important for the adaptive immune response. This process makes elderly individuals more susceptible to infections and can affect the effectiveness of vaccinations.

Paired glands located above the kidneys, consisting of the cortex and medulla. They perform key functions: the cortex produces corticosteroids, such as cortisol, regulating metabolism and stress response, while the medulla produces adrenaline and norepinephrine, involved in the 'fight or flight' response and increasing heart rate and blood pressure. The adrenal glands also regulate water-salt balance through mineralocorticoids, for example, aldosterone. Interesting fact: Although very small, about the size of a grape, the adrenal glands play a huge role in the body's response to stress. The hormones they produce, including adrenaline and cortisol, can dramatically alter body functions within seconds.

This small organ contains both exocrine and endocrine cells. The endocrine part of the pancreas consists of cell groups known as the islets of Langerhans. These are distributed throughout the gland and contain several types of cells, including alpha cells, beta cells, delta cells, and others, each producing different hormones. Interesting fact: The pancreas has no pain receptors, so the early stages of its diseases can proceed without symptoms.

Paired female reproductive organs located in the pelvic area, performing crucial functions. They produce eggs for reproduction and secrete sex hormones such as estrogens and progesterone. These hormones regulate the menstrual cycle, prepare the body for pregnancy, and maintain it, as well as affect overall reproductive health and the condition of the skin, bone density, and cardiovascular system. Interesting fact: They not only produce eggs and secrete female sex hormones but also play a role in selecting an egg for ovulation each month. Not all eggs in the ovaries reach maturity; in fact, most undergo a process known as atresia, where the eggs naturally die and are absorbed by the body. This means that of the more than 1 million potential eggs each woman is born with, only about 400 eggs can actually ovulate during her reproductive life.