MPharm Programme Normal Systems PDF

WEEK 15 MPharm Programme Normal Systems The Endocrine System 1 Dr G Boachie-Ansah [email protected] Dale 113 ext. 2617 MPharm PHA112 The Endocrine System WEEK Outline of Lecture 15 General principles of endocrine function Types of hormones & signalling pathways or mech...

WEEK 15 MPharm Programme Normal Systems The Endocrine System 1 Dr G Boachie-Ansah [email protected] Dale 113 ext. 2617 MPharm PHA112 The Endocrine System WEEK Outline of Lecture 15 General principles of endocrine function Types of hormones & signalling pathways or mechanisms Broad divisions of the endocrine system The Central Endocrine Glands & their hormones The Peripheral Endocrine Glands & their hormones Slide 2 of 85 MPharm PHA112 The Endocrine System Learning Outcomes WEEK 15 At the end of this lecture, you should be able to: Give a general description of the basic principles of endocrine signalling Describe the major divisions of the endocrine system Give a detailed account of the major hormones of the central endocrine glands & their actions Give a detailed account of the major hormones of the peripheral endocrine glands & their actions Predict what might happen during over- or undersecretion of the major hormones Slide 3 of 85 MPharm PHA112 The Endocrine System WEEK 15 General Principles of Endocrine Function Slide 4 of 85 MPharm PHA112 The Endocrine System The Endocrine System WEEK 15 Consists of specialised ductless glands (and neurosecretory cells) scattered throughout body Glands/cells secrete biologically active chemical messengers (hormones) into the blood stream The hormones are carried in the blood stream to interact with distant target cells Interaction leads to specific target cell response in terms of metabolism, growth or reproduction Slide 5 of 85 MPharm PHA112 The Endocrine System WEEK 15 Slide 6 of 85 The Endocrine System MPharm PHA112 The Endocrine System WEEK 15 Slide 7 of 85 The Endocrine System MPharm PHA112 The Endocrine System WEEK 15 Functions of the Endocrine System One of the body’s two major regulatory systems Regulates, integrates, coordinates & controls important cellular, organ & body functions Cellular metabolism, and water & electrolyte balance Cell growth, development and reproduction Adaptive changes to help the body cope with stressful situations Control & integration of the circulatory & digestive systems Slide 8 of 85 MPharm PHA112 The Endocrine System WEEK The Endocrine System 15 Chemical Classification of Hormones Amines & Amino Acid derivatives NA, AD, DA, melatonin, T3 & T4 Polypeptides, Proteins & Glycoproteins TRH, ADH, GH, FSH, insulin Steroids – derived from cholesterol Cortisol, testosterone, estradiol, progesterone Hydrophilic vs Lipophilic hormones Slide 9 of 85 MPharm PHA112 The Endocrine System WEEK 15 Synthesis & Transport of Hormones Synthesis Vesicle-mediated pathway Synthesised in rER & packaged in secretory vesicles polypeptide / protein hormones Non-vesicle-mediated pathway Synthesised in sER & directly released steroid hormones Transport Free & unbound – peptide hormones & amines Carrier protein-bound – steroid & thyroid hormones Slide 10 of 85 MPharm PHA112 The Endocrine System WEEK 15 Synthesis & Transport of Hormones Slide 11 of 85 MPharm PHA112 The Endocrine System WEEK 15 Control of Hormonal Secretion Timing/Pattern of secretion Pulsatile or cyclical Diurnal or circadian rhythm Negative-feedback control End-product inhibition Slide 12 of 85 MPharm PHA112 The Endocrine System WEEK Hormonal Signalling 15 Hormones produce their effects on target cells by interacting with specific receptors Target cell receptors are linked to specific effector systems in the cell Two broad types of hormonal receptors: Cell surface receptors Receptor-ion channels G-protein coupled receptors Tyrosine kinase-linked receptors Intracellular or nuclear receptors Slide 13 of 85 MPharm PHA112 The Endocrine System Endocrine Disorders WEEK 15 May result from: Hyposecretion Endocrine gland secretes too little of its hormone Primary, Secondary or Tertiary Hypersecretion Endocrine gland secretes too much of its hormone Primary, Secondary or Tertiary Abnormal Target Cell Responsiveness Receptor down-regulation Receptor up-regulation Slide 14 of 85 MPharm PHA112 The Endocrine System The Endocrine System WEEK 15 Two broad anatomical divisions The Central Endocrine Glands Hypothalamus Pituitary Gland Pineal Gland The Peripheral Endocrine Glands Thyroid glands Adrenal glands Endocrine pancreas Parathyroid glands The Gonads (ovaries & testes) Slide 15 of 85 MPharm PHA112 The Endocrine System WEEK 15 The Central Endocrine Glands Slide 16 of 85 MPharm PHA112 The Endocrine System WEEK 15 The Hypothalamus & Pituitary Gland Both located in the diencephalon Function cooperatively as ‘master regulators’ of the endocrine system  control of critical homeostatic & metabolic functions Both structures connected by blood flow via the hypophyseal portal system (hypothalamus  anterior pituitary) via the hypothalamo-hypophyseal nerve tract (hypothalamus  posterior pituitary) Slide 17 of 85 MPharm PHA112 The Endocrine System WEEK 15 The Hypothalamus & Pituitary Gland Slide 18 of 85 MPharm PHA112 The Endocrine System WEEK 15 The Hypothalamus & Pituitary Gland Slide 19 of 85 MPharm PHA112 The Endocrine System WEEK The Hypothalamus 15 18 Brain’s coordinating centre for endocrine, behavioural & autonomic nervous system function Acts as neuroendocrine transducer or bridge receives & integrates multiple brain signals converts the electrical signals into chemical messages releases chemical messengers (hormones) to control secretion of pituitary hormones pituitary hormones control the of peripheral MPharm MPH116 Normal Systems - Theactivity Endocrine System endocrine glands Slide 20 of 85 MPharm PHA112 The Endocrine System WEEK Hypothalamic Hormones 15 Hormones That Regulate Anterior Pituitary Secretions Stimulatory Growth hormone-releasing hormone (GHRH) Thyrotropin-releasing hormone (TRH) Corticotropin-releasing hormone (CRH) Gonadotropin-releasing hormone (GnRH) Inhibitory Somatostatin (Growth hormone-inhibiting hormone; GHIH) Dopamine (Prolactin-inhibiting hormone; PIH) Slide 21 of 85 MPharm PHA112 The Endocrine System WEEK 15 Hypothalamic Releasing Hormones Hypothalamus makes releasing hormones They are sent to the anterior pituitary The anterior pituitary releases its stored tropic hormones into the systemic circulation They tell other endocrine organs in the body to grow & secrete their hormones Slide 22 of 85 MPharm PHA112 The Endocrine System WEEK 15 The Major Hypothalamic Hormones Slide 23 of 85 MPharm PHA112 The Endocrine System WEEK Hypothalamic Hormones 15 Hormones That Are Transported & Stored in The Posterior Pituitary Vasopressin or Antidiuretic hormone (ADH) Oxytocin Slide 24 of 85 MPharm PHA112 The Endocrine System WEEK The Pituitary Gland 15 Hypophysis – located in diencephalon The ‘Master Gland’ – secretes hormones that control the function of many target glands & cells Consists of two anatomically & functionally distinct lobes Anterior pituitary (Adenohypophysis) Secretes & releases 6 major hormones Posterior pituitary (Neurohypophysis) Stores & releases 2 hormones Slide 25 of 85 MPharm PHA112 The Endocrine System WEEK 15 Slide 26 of 85 The Pituitary Gland MPharm PHA112 The Endocrine System WEEK 15 Slide 27 of 85 The Pituitary Gland MPharm PHA112 The Endocrine System WEEK 15 Anterior Pituitary Hormones Growth hormone (GH, somatotropin) Primary hormone for regulation of overall body growth Stimulates growth of soft tissues & bone Stimulates cell division & protein synthesis  tissue hyperplasia & hypertrophy Promotes cartilage & bone growth (in length & thickness) Growth-promoting effects are mediated via stimulated release of insulin-like growth factors (IGFs) or somatomedins by the liver Slide 28 of 85 MPharm PHA112 The Endocrine System WEEK 15 Anterior Pituitary Hormones Growth hormone (cont’d) Important role in intermediary metabolism Exerts largely anti-insulin effects Increases lipolysis   free fatty acid (FFA) mobilization & use as fuel Inhibits peripheral cellular glucose uptake   blood glucose levels and  use of glucose as fuel Secretion modulated by GHRH & somatostatin from hypothalamus Ghrelin from gastric fundus Slide 29 of 85 MPharm PHA112 The Endocrine System WEEK 15 Functions of Growth Hormone Slide 30 of 85 MPharm PHA112 The Endocrine System WEEK 15 Slide 31 of 85 GH – Control of Release & Functions MPharm PHA112 The Endocrine System