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The anterior pituitary (also called the adenohypophysis or pars anterior) is a major organ of the endocrine system.The anterior pituitary is the glandular, anterior lobe that together with the (posterior pituitary, or the neurohypophysis) makes up the pituitary gland (hypophysis) which, in humans, is located at the base of the brain, protruding off the bottom of the hypothalamus.
The anterior pituitary is typically divided into two regions, a more anterior rostral portion and a posterior proximal portion, but the boundary between the two is often not clearly marked. In elasmobranchs, there is an additional, ventral lobe beneath the anterior pituitary proper. [27]
The pouch eventually loses its connection with the pharynx giving rise to the anterior pituitary. The anterior wall of Rathke's pouch proliferates, filling most of the pouch to form pars distalis and pars tuberalis. The posterior wall forms pars intermedia. In some organisms, the proliferating anterior wall does not fully occupy Rathke's pouch ...
The mouth is developed partly from the stomodeum, and partly from the floor of the anterior portion of the fore-gut.. By the growth of the head end of the embryo, and the formation of the cephalic flexure, the pericardial area and the buccopharyngeal membrane come to lie on the ventral surface of the embryo.
The cells of the anterior pituitary express specific G protein-coupled receptors that bind to the neuropeptides, activating intracellular second messenger cascades that produce the release of anterior pituitary hormones. [4] The following is a list of hormones that rely on the hypophyseal portal system to indirectly mediate their function by ...
A Rathke's cleft cyst is a benign growth on the pituitary gland in the brain, specifically a mucin-filled [1] cyst in the posterior portion of the anterior pituitary gland. [2] [3] It occurs when the Rathke's pouch does not develop properly and ranges in size from 2 to 40 mm in diameter.
The pars intermedia is one of the three parts of the anterior pituitary. It is a section of tissue sometimes called a middle or intermediate lobe, between the pars distalis, and the posterior pituitary. [1] It is a small region that is largely without blood supply. [2] The cells in the pars intermedia are large and pale.
These cells are stimulated by corticotropin releasing hormone (CRH) and make up 15–20% of the cells in the anterior pituitary. [1] The release of ACTH from the corticotropic cells is controlled by CRH, which is formed in the cell bodies of parvocellular neurosecretory cells within the paraventricular nucleus of the hypothalamus and passes to ...