Part I

• The endocrine system consists of glands that secrete hormones into the bloodstream.
• Hormones are chemical messengers that regulate various bodily functions.
• The endocrine system plays a crucial role in maintaining homeostasis.
• The endocrine system consists of the pituitary gland, hypothalamus, thyroid gland, parathyroid gland, adrenal gland, and pancreas.
• The pituitary gland is located at the base of the brain and is responsible for regulating various bodily functions.
• The hypothalamus is located in the brain and is responsible for regulating the pituitary gland.
• The thyroid gland is located in the neck and is responsible for regulating metabolism.
• The parathyroid gland is located in the neck and is responsible for regulating calcium levels.
• The adrenal gland is located in the abdomen and is responsible for regulating the body's response to stress.
• The pancreas is located in the abdomen and is responsible for regulating blood sugar levels.
• Hypophysis consists of two main parts with different embryonic development and morphology: Adenohypophysis (Pars lateralis, Pars intermedia, Pars tuberalis) and Neurohypophysis (lobus neuralis, infundibulum, eminentia mediana).
• Hypophysis is an impair, spherical body, flattened anterior-posteriorly, with a weight of about 0.5 g (after pregnancy to 1g), situated in the hypophysialis (sella turcica ossis sphenoidale), above the diaphragma sellae (dura mater) and the infundibulum of the hypothalamus pass through.
• Hypophysis, also known as pituitaria glandula, is the central organ of the endocrine system and part of the hypothalamus-hypophysis axis.
• Neurohypophysis, or lobus neuralis, is built from neuroglia cells, spindle-shaped with long processes (pituicytes, contacts between them and the blood sinusoids).
• Adenohypophysis, or Pars lateralis, constitutes 75% of the organ, with Pars intermedia as a cellular plate between Adenohypophysis and Neurohypophysis, and Pars tuberalis as a cellular plate on the infundibulum.
• The cytoplasm of the pinealocytes contain well developed organelles for protein synthesis, granules, lysosomes and lipid droplets.
• The neurohypophysis is a microscopic structure with the axon collected in bundles and their terminal endings bodies of Hering where neurohormones are accumulated.
• The pineal body or epiphysis cerebri attains its maximum development by about 7 years of age and thereafter shows regressive changes which involves mainly the supporting elements.
• Acervuli (brain sand or corpora arenacea) appear mainly in the capsule and septa.
• The neuroglia cells (astrocytes and microglia) serve as supporting elements.
• The hypothalamus has a neurohypophysis axis.
• The adenohypophysis is connected with the mediobasal part of the hypothalamus.
• The adenohypophysis is supplied with blood by the hypophysial arteries (a.carotis interna) and receives venous return from the sinus cavernosus.
• The pineal body or epiphysis cerebri is a small cone-shaped body attached by the roof of the third ventricle, covered by the pia mater and forming a thin capsule which sends septa into the organ.
• Neuroendocrine cells in the nucleus arcuatus, tuber cinereum, and nucleus ventromedialis produce releasing factors.
• Neuroendocrine cells in the anterior hypothalamus (nucleus supraopticus et paraventricularis) produce vasopressin and oxytocin.
• The axons of these cells reach the eminentia mediana, forming synapses with the sinusoids of the adenohypophysis.
• Neurohormones in the bodies of Hering make synapses with the blood sinusoids, releasing of the hormones in the blood stream.
• The pinealocytes are irregularly shaped cells with long, branching processes which terminate in bulbous endings.
• The parenchyma of the pineal body or epiphysis cerebri is divided into lobules, composed of epithelial cells or pinealocytes and neuroglia.