anterior pituitary

Examples of anterior pituitary in the following topics:

• Control of the Pituitary Gland by the Hypothalamus

  • The pituitary gland consists of the anterior pituitary and the posterior pituitary.
  • The pituitary gland consists of two components: the anterior pituitary and the posterior pituitary, and is functionally linked to the hypothalamus by the pituitary stalk (also named the infundibular stem, or simply the infundibulum).
  • The anterior lobe of the pituitary receives hypothalamic-releasing hormones from the hypothalamus that bind with receptors on endocrine cells in the anterior pituitary that regulate the release of adrenal hormones into the circulatory system.
  • Hormones from the hypothalamus are rapidly degraded in the anterior pituitary, which prevents them from entering the circulatory system.
  • The anterior and posterior lobes of the pituitary (hypophysis) gland are shown.

• The Anterior Pituitary

  • A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis) is the glandular, anterior lobe of the pituitary gland.
  • The fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary.
  • The anterior pituitary is composed of multiple parts:
  • The anterior pituitary, in yellow, is linked to the hypothalamus by a portal system.
  • Identify the location and the hormones produced by the anterior pituitary

• Hypothalamic-Pituitary Axis

  • The hypothalamus, an endocrine organ, regulates the anterior pituitary gland and transports hormones along the posterior pituitary gland.
  • The pituitary has two distinct regions: the anterior pituitary and the posterior pituitary.
  • The anterior pituitary gland, or adenohypophysis, is surrounded by a capillary network that extends from the hypothalamus, down along the infundibulum, and to the anterior pituitary.
  • This capillary network is a part of the hypophyseal portal system which carries substances from the hypothalamus to the anterior pituitary and hormones from the anterior pituitary into the circulatory system.
  • The posterior pituitary is significantly different in structure from the anterior pituitary.

• Control of Thyroid Hormone Release

  • The production of thyroxine and triiodothyronine is regulated by thyroid-stimulating hormone (TSH) that is released from the anterior pituitary.
  • The production of thyroxine (T4) and triiodothyronine (T3) is primarily regulated by thyroid-stimulating hormone (TSH) that is released from the anterior pituitary gland.
  • Thyroid hormones also provide negative feedback to the hypothalamus and anterior pituitary gland.
  • Thyroid hormones are produced from the thyroid under the influence of thyroid-stimulating hormone (TSH) from the anterior pituitary gland, which is itself under the control of thyroptropin-releasing hormone (TRH) secreted by the hypothalamus.

• Overview of Endocrine Glands

  • The pituitary gland consists of two major regions, the anterior pituitary gland (adenohypophysis) and the posterior pituitary gland (neurohypophysis).
  • The anterior pituitary is involved in sending hormones that control all other hormones of the body.
  • These hormones are released into a capillary network that supplies the anterior pituitary.
  • The hormones then diffuse from this secondary plexus into the anterior pituitary, where they initiate the production of specific hormones by the anterior pituitary.
  • Differentiate among the types of endocrine glands (pituitary [posterior pituitary, anterior pituitary], thyroid, parathyroid, adrenal, and pancreas) in the endocrine system

• Overview of the Pituitary Gland

  • The pituitary gland, or hypophysis, is an endocrine gland about the size of a pea.
  • The pituitary is functionally connected to the hypothalamus by a small tube called the infundibular stem, or, pituitary stalk.
  • The pituitary gland secretes hormones that regulate homeostasis.
  • The pituitary gland is divided into two parts, the anterior pituitary and the posterior pituitary.
  • The anterior pituitary receives signaling molecules from the hypothalamus, and in response, synthesizes and secretes seven important hormones including thyroid-stimulating hormone and growth hormone.

• Humoral, Hormonal, and Neural Stimuli

  • For example, the hypothalamus produces hormones that stimulate the anterior portion of the pituitary gland.
  • The anterior pituitary, in turn, releases hormones that regulate hormone production by other endocrine glands.
  • The anterior pituitary releases the thyroid-stimulating hormone (TSH), which then stimulates the thyroid gland to produce the hormones T3 and T4 .
  • As blood concentrations of T3 and T4 rise, they inhibit both the pituitary and the hypothalamus in a negative feedback loop.
  • The hypothalamus stimulates the anterior pituitary gland, via hormones, to release thyroid-stimulating hormone (TSH).

• The Posterior Pituitary

  • The posterior pituitary (or neurohypophysis) comprises the posterior lobe of the pituitary gland and is part of the endocrine system.
  • Despite its name, the posterior pituitary gland is not a gland; rather, it is largely a collection of axonal projections from the hypothalamus that terminate behind the anterior pituitary gland.
  • The posterior pituitary is derived from the hypothalamus and is distinct from the more fleshy, vascularized anterior lobe.
  • The posterior pituitary is composed of two parts:
  • Identify the location of the posterior pituitary and the hormones associated with it

• The Stress Response

  • The body's stress response is mediated by the sympathetic nervous system and the hypothalmic-pituitary-adrenal (HPA) axis.
  • The body's stress response is mediated by the interplay between the sympathetic nervous system (SNS) and the hypothalmic-pituitary-adrenal (HPA) axis.
  • A complex interaction of direct influences and indirect feedback mechanisms among the SNS, the hypothalmus, the pituitary gland and the adrenal glands contributes to the neuroendocrine regulation involved in reactions to stress.
  • These two hormones regulate the anterior lobe of the pituitary gland and stimulate the release of adrenocorticotropic hormone (ACTH), also known as corticotropin.
  • CRH gets transported to the anterior pituitary through the circulatory system and vasopressin is transported by axonal transport to the anterior pituitary.

• Pituitary Gland Disorders

  • The pituitary is a "small, pea-sized gland" located at the base of the brain .
  • Most of the hormones in the anterior pituitary are each part of an axis that is regulated by the hypothalamus.
  • The hypothalamus secretes a number of hormones, often according to a circadian rhythm, into blood vessels that supply the anterior pituitary; most of these are stimulatory (thyrotropin-releasing hormone, corticotropin-releasing hormone, gonadotropin-releasing hormone and growth hormone-releasing hormone), apart from dopamine, which suppresses prolactin production.
  • In response to the releasing hormone rate, the anterior pituitary produces its hormones (TSH, ACTH, LH, FSH, GH) that stimulate effector hormone glands in the body, although prolactin acts directly on the breast gland.
  • There are multiple ways of treating pituitary adenomas.