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").
  • Whilst the pituitary gland is known as the 'master' endocrine gland, both of the lobes are under the control of the hypothalamus; the anterior pituitary receives its signals from the parvocellular neurons and the posterior pituitary receives its signals from magnocellular neurons.
  • The anterior lobe of the pituitary receives hypothalamic releasing hormones from the hypothalamus which bind with receptors on endocrine cells in the anterior pituitary regulating the release of adrenal hormones into the systemic circulation.
  • Hormones from the hypothalamus are rapidly degraded in the anterior pituitary preventing them entering the systemic circulation.

• 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

• Control of Thyroid Hormone Release

  • The production of thyroxine and triiodothyronine is regulated by thyroid-stimulating hormone (TSH), released by the anterior pituitary.
  • The production of thyroxine (T4) and triiodothyronine (T3) is primarily regulated by thyroid-stimulating hormone (TSH), released by 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 homoeostasis.
  • The pituitary gland is divided into two parts, the anterior pituitary and the posterior pituitary .
  • The anterior pituitary receives signalling molecules from the hypothalamus, and in response, synthesizes and secretes seven important hormones including thyroid-stimulating hormone and growth hormone.

• 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 so is distinct from the more fleshy vascularised anterior lobe.
  • The posterior pituitary is composed of two parts:
  • Identify the location of the posterior pituitary and the hormones associated with it

• Hormonal Regulation of the Male Reproductive System

  • However, it is known that initiation of spermatogenesis occurs at puberty due to the interaction of the hypothalamus, pituitary gland, and Leydig cells.
  • If the pituitary gland is removed, spermatogenesis can still be initiated by follicle-stimulating hormone (FSH) and testosterone.
  • Gonadotropin Releasing Hormone (GnRH) is mainly made in the preoptic area of the hypothalamus from where it travels to the pituitary gland.
  • Follicle Stimulating Hormone is released by the anterior pituitary gland.
  • Luteinizing Hormone is released by the anterior pituitary gland.

• 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 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 contribute to the neuroendocrine regulation involved in reactions to stress.
  • These two hormones regulate the anterior lobe of the pituitary gland, stimulating 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.

• Hormonal Abnormalities and Height

  • Abnormal production of growth hormone due to tumors on the pituitary or other genetic causes can cause pathological changes in growth.
  • Children who out of the norm in their growth, either much shorter or taller than average, should be analyzed for pituitary tumors.
  • Acromegaly is a syndrome that results when the anterior pituitary gland produces excess growth hormone (GH) after epiphyseal plate closure at puberty.
  • When these non-pituitary tumors are surgically removed, GH levels fall and the symptoms of acromegaly improve.
  • The goals of treatment are to reduce GH production to normal levels, to relieve the pressure that the growing pituitary tumor exerts on the surrounding brain areas, to preserve normal pituitary function, and to reverse or ameliorate the symptoms of acromegaly.