It consists of endocrine glands whose products are released into the blood in order to maintain homeostasis, It also comprises endocrine cells arranged diffusely in certain tissues, Blood transports hormones to the target cells, where they induce biochemical and physiological alterations

They are transported by blood to the target cells where they perform their function (biochemical and physiological alterations), Some of the hormones facilitate water and sodium retention in the body, They increase or decrease the level of blood glucose (the hormones secreted by the islets of Langerhans)

According to their chemical composition they are steroid hormones (steroids) and non-steroid hormones (non- steroids), Cortisol, oestrogens and aldosterone are cholesterol-derived hormones, Non-steroid hormones include protein hormones (consisting of amino acid chains, interconnected by peptide bonds)

Peptide hormones are represented by ADH and oxytocin, while protein hormones by insulin, STH and prolactin, Some non-steroid hormones (noradrenalin and adrenalin) contain amine groups in their structure

They cross easily the cell membrane, dissolving in phospholipids, They combine with proteins in the cytoplasm of target cells, resulting a complex which stimulates the activity of certain genes that encode specific types of messenger RNA molecules

They consist of amino acid chains, They have peptide molecules between their constituent molecules

They are membrane-phospholipid soluble, They have a lipid structure, Inside the cell, they combine with proteins resulting a complex that stimulates genes which encode messenger RNA molecules (mRNA)

Cellular division, Alteration of membrane permeability, Activation of certain enzymes

It is situated in the lower part of the encephalon, It is situated right behind the optic chiasm, Also called pituitary gland, it consists of two lobes (anterior and posterior)

Represents the posterior lobe of the hypophysis, It temporarily stores the neurohormones synthesized in the hypothalamus, It releases hormones as a response to stimuli coming from the hypothalamic neurons

It is controlled by the hypothalamus which secretes stimulating and inhibiting hormones, It secretes tropic hormones which control other endocrine glands, It is considered the „conductor” gland of the endocrine system

Adenohypophysis – protein hormones – human growth hormone (HGH), prolactin, Neurohypophysis – posterior lobe of hypophysis – releases the antidiuretic hormone

It stimulated protein synthesis, by introducing amino acids into cells, It ensures fat mobilisation from the adipose tissue, By stimulating protein synthesis, it accelerates body growth

The synthesis and release of thyroid hormones take place under the action of adenohypophyseal TSH, It is a tropic hormone produced by the anterior lobe of the hypophysis, TSH stimulates iodine capture by the thyroid gland

It stimulates water reabsorption by acting on the kidney tubules, Induces the increase of the blood volume, It induces vasoconstriction, thus increasing blood pressure

It is located in the neck’s soft tissues, It is situated anterior to the larynx, It consists of two lateral lobes, interconnected by a thin band of tissue called isthmus

T3 is also called thriiodothyronine, T4 is also called thyroxine

Stimulation of enzyme activity associated with glucose metabolism, Increased basal metabolic rate, Increase of cellular oxygen uptake and of the quantity of heat released by them

Goitre develops (enlargement of the thyroid), The thyroid cannot produce T3 and T4

They consist of four small masses of glandular tissue located on the posterior face of the thyroid, Each of them is about the size of a pea

It stimulates osteoclast activity, It increases bone calcium resorption

They can also be caused by a parathyroid tumour, Its characteristic signs are represented by bone deformity, Its characteristic signs are represented by low bone density

It is a large, flattened, glandular organ, It lies in the abdominal cavity, posterior to the stomach and peritoneum, It has a double function, digestive and endocrine

It is secreted by the β (beta) cells in the islets of Langerhans, It is secreted after food ingestion, It is a protein hormone with the molecule consisting in 51 amino acids arranged in two chains