Along with the nervous system , the endocrine system coordinates all of our body’s functions. The hypothalamus, a group of nerve cells located at the base of the brain, integrates these two systems.
Glands of the Endocrine System
Endocrine glands are located in different parts of the body: pituitary , thyroid and parathyroid , thymus , adrenal glands , pancreas and the sex glands .
Pituitary gland
The pituitary gland is located in the center of the head, just below the brain. It produces several hormones, including growth hormone.
It is considered the master gland of our body, as it stimulates the functioning of other glands, such as the thyroid and sexual glands.
Excess production of this hormone causes gigantism (excessive growth) and a lack causes dwarfism.
Another hormone produced by the pituitary gland is the antidiuretic ( ADH ), a substance that allows the body to save water during excretion (urine formation).
Thyroid
The thyroid is located in the neck and produces thyroxine , a hormone that controls the speed of cellular metabolism, maintaining weight and body heat, growth and heart rate.
Hyperthyroidism, an overactive thyroid, speeds up the entire metabolism: the heart beats faster, the body temperature is higher than normal, and the person loses weight by using more energy.
This condition favors the onset of heart and vascular diseases, as the blood circulates with more pressure. If left untreated, it can cause the appearance of goiter (swelling in the neck) and also exophthalmos (bulging eyes).
Hypothyroidism is when the thyroid gland works less and produces less thyroxine. As a result, the metabolism slows down, some areas of the body become swollen, the heart beats more slowly, blood circulates more slowly, the person uses less energy, tends to gain weight and physical and mental responses become slower and, if left untreated, goiter can occur.
Parathyroids
The parathyroids are four small glands, located behind the thyroid, that produce parathyroid hormone , a hormone that regulates the amount of calcium and phosphorus in the blood.
The decrease in this hormone reduces the amount of calcium in the blood and causes the muscles to contract violently.
This symptom is called tetany , as it is similar to what occurs in people with tetanus. In turn, the increased production of this hormone transfers part of the calcium to the blood, weakening the bones and making them brittle.
Timo
The thymus gland is located between the lungs. It produces a hormone that acts to defend the newborn’s body against infections.
At this stage, it presents a marked volume, growing normally until adolescence, when it begins to atrophy. In adulthood, it decreases in size, as its functions are reduced.
Adrenals
The adrenal glands are located above the kidneys and produce adrenaline , a hormone that prepares the body for action. The effects of adrenaline on the body are:
- Tachycardia: the heart races and pumps more blood to the legs and arms, increasing the ability to run or get excited in tense situations;
- Increased respiratory rate and blood glucose levels, releasing more energy for cells;
- Contraction of the blood vessels in the skin, so that the body sends more blood to the skeletal muscles and, as a result, we become “pale with fright” and also “cold with fear”.
Pancreas
The pancreas is a mixed gland because in addition to hormones (insulin and glucagon), it also produces pancreatic juice, which is released into the small intestine and plays an important role in digestion.
Insulin controls the entry of glucose into cells (where it will be used to release energy) and storage in the liver , in the form of glycogen.
Lack of or low production of insulin causes diabetes , a disease characterized by excess glucose in the blood ( hyperglycemia ).
Glucagon works in the opposite way to insulin. When the body goes many hours without eating, blood sugar levels drop significantly and the person may experience hypoglycemia , which causes a feeling of weakness, dizziness, and in many cases, even fainting.
In this case, the pancreas produces glucagon, which acts on the liver, stimulating the “breakdown” of glycogen into glucose molecules. Finally, the glucose is sent to the blood, normalizing hypoglycemia.
Sex glands
The sexual glands are the ovaries and testicles , which are part of the female reproductive system and the male reproductive system respectively.
The ovaries and testicles are stimulated by hormones produced by the pituitary gland . Thus, while the ovaries produce estrogen and progesterone , the testicles produce several hormones, including testosterone , which is responsible for the appearance of male secondary sexual characteristics: beard, deep voice, broad shoulders, etc.
