Physiology 2 Week 2: Hypothalamus & Pituitary Gland Review Sheet FA2022 PDF

Physiology 2 I. Week 2: Hypothalamus & Pituitary Gland - Review Sheet FA2022 Hypothalamus & Pituitary Functionally, the hypothalamus regulates the pituitary gland by both neural and hormonal mechanisms. Describe the anatomic relationship of the hypothalamus and the pituitary gland. Identify these tw...

Physiology 2 I. Week 2: Hypothalamus & Pituitary Gland - Review Sheet FA2022 Hypothalamus & Pituitary Functionally, the hypothalamus regulates the pituitary gland by both neural and hormonal mechanisms. Describe the anatomic relationship of the hypothalamus and the pituitary gland. Identify these two different pathways used for hypothalamic–pituitary interactions. Describe the routes of transport of hypothalamic neuropeptides to the posterior and anterior pituitary. A. Hypothalamic–Pituitary Axis - Describe the role of negative feedback in the functional relationship between the hypothalamus and anterior pituitary gland. What are the two forms of regulatory hormones secreted by the hypothalamus? Identify the appropriate hypothalamic releasing and inhibitory factors controlling the secretion of each of the anterior pituitary hormones. B. Hypophysiotropic Neurohormones (Releasing And Inhibiting Hormones) The hypothalamus synthesizes the hypophysiotropic neurohormones which control secretion of the anterior pituitary hormones. Thyrotropin-releasing hormone (TRH) Gonadotropin-releasing hormone (GnRH) Corticotropin-releasing hormone (CRH) Growth hormone–releasing hormone (GHRH) Growth hormone–inhibiting hormone (somatostatin) Prolactin-inhibiting hormone (PIH) C. Neural Integration and The Hypothalamus The hypothalamus receives neural inputs from many areas of the brain. This information, related to the well-being of the body, is integrated in the hypothalamus. Some of this input is receives from “emotional centers” of the brain as well as the cerebral cortex. (This becomes quite relevant during the lecture on the adrenal gland and the stress response) D. Posterior Pituitary - Posterior Pituitary - a neural structure (neurohypophysis) What is the anatomic connection between the hypothalamus and the posterior pituitary? Identify the hormones of the posterior pituitary, identify their target & functions. Describe how the hypothalamus controls the release of these hormones. Magnocellular Neurons: Hormones are not formed in the posterior pituitary; rather they are “released”. Explain the anatomical/physiological reason for this distinction. Magnocellular Neurons – These are neuroendocrine neurons, Located in the hypothalamus, these neurons produce & secrete the two hormones of the posterior pituitary Supraoptic nuclei (SON) of the hypothalamus - produce anti-diuretic hormone (ADH) Paraventricular nuclei (PVN) of the hypothalamus - produce oxytocin What blood vessels serves as the primary blood supply to the neurohypophysis? ( ADH and oxytocin are released into this capillary plexus) How does the hypothalamus control the release of ADH from the posterior pituitary? E. Anterior Pituitary - an epithelial component (adenohypophysis) Identify the hormones of the anterior pituitary, identify their target & functions. Describe the physiologic & anatomic relationships between the hypothalamus and the anterior pituitary. What blood vessels directly link the hypothalamus and anterior pituitary? Hypothalamic-Hypophysial Portal Vessels: The hypophyseal portal system connects the hypothalamus with the anterior pituitary. Its main function is to quickly transport and exchange hormones between the hypothalamus anterior pituitary gland. The hypothalamic hormones do not appear in the systemic circulation in high concentrations F. Anterior Pituitary Hormones Identify the six primary hormones released from the anterior pituitary. How is the release of each of these hormones regulated by the hypothalamus? Growth hormone (GH) - Somatotrophs Prolactin (PRL) - Lactotrophs Follicle-stimulating hormone (FSH) - Gonadotrophs Luteinizing hormone (LH) - Gonadotrophs Adrenocorticotropic hormone (ACTH) - Corticotrophs Thyroid-stimulating hormone (TSH) – Thyrotrophs Each of the anterior pituitary hormones is a peptide or polypeptide. (Protein based hormone) Explain how the hypothalamus controls the release of hormones from the anterior pituitary and describe the general function/ actions of each anterior pituitary hormone on its respective target organs. (e.g. TSH stimulates production of Thyroid hormones; Prolactin stimulates milk breast milk production in the mammary glands) *Be prepared to predict the changes in secretory rates of hypothalamic anterior pituitary and target gland hormones caused by oversecretion or undersecretion of any of these pituitary hormones ( i.e. Lab 5 : TSH & hyper/hypothyroidism)