Epithelial tissues are tissues characterized by having cells juxtaposed with little or no intercellular substance. This tissue is characterized by being avascular, with nutrients and oxygen being diffused from capillaries of adjacent connective tissues.
This tissue can be classified according to its function in lining and glandular epithelia. The lining epithelia are involved with the protection and lining of the body and organ cavity. The glandular epithelia, which form the glands, are those responsible for producing substances.
We can classify glands into three types: exocrine, endocrine and mixed. we call endocrine glands those that release their secretions directly into the bloodstream or lymph vessels. They differ from exocrine glands in that they do not have channels through which secretions exit. The substances produced by the endocrine glands are called hormones.
Among the main endocrine glands of the human body, we can mention the pituitary gland, thyroid gland, parathyroid gland, adrenal glands and pancreas.
THE hypophysis it is a small gland located at the base of the brain. This gland is divided into the adenohypophysis and the neurohypophysis. The neurohypophysis is responsible for the production of oxytocin and antidiuretic hormone. The adenohypophysis is responsible for the production of somatotrophin, prolactin, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone and thyrotrophic hormone.
THE thyroid gland it is responsible for the production of two main hormones: triiodothyronine and thyroxine. At parathyroid glands are responsible for the production of parathyroid hormone. The adrenal glands are responsible for producing adrenaline and noradrenaline in the adrenal medulla, as well as glucocorticoids and mineralocorticoids in the adrenal cortex. The pancreas is a mixed gland and its endocrine part produces insulin and glucagon.
A deficiency or excess in the production of hormones can cause various illnesses. Low insulin production, for example, can cause type 1 diabetes. The large production of thyroid gland hormones can cause the so-called hyperthyroidism.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-glandula-endocrina.htm
