Hormones and Endocrine System PDF

Hormones and Endocrine System Hormones and Endocrine System Vikram Sharma Hormones and Endocrine System FMD002 Credits: Dr. Michael Thom 1  Lecture outline – Compare the nervous and endocrine...

Hormones and Endocrine System Hormones and Endocrine System Vikram Sharma Hormones and Endocrine System FMD002 Credits: Dr. Michael Thom 1  Lecture outline – Compare the nervous and endocrine communication systems – Identify and compare three basic types of hormones – Recognize the different modes of action between water and lipid soluble hormones – Outline the mechanisms that control the release of hormones – Describe the basic control of the pituitary gland FMD002 Hormones and Endocrine System 2  Communication systems in animals Animals respond to changes in their environments External e.g. – changes in temperature – response to danger Internal e.g. – changes in blood glucose levels – changes in osmotic pressure FMD002 Hormones and Endocrine System 3  Communication systems in animals Communication systems – detect changes – generate appropriate responses Nervous and endocrine systems – work together in a coordinated and complimentary manner to achieve this FMD002 Hormones and Endocrine System 4  Hormonal vs nervous communication System Hormonal Nervous Speed Slow Fast – almost instantaneous (seconds – minutes) (100Ms-1 - over 200mph) Duration Longer lasting Short lived Action Widespread Localised FMD002 Hormones and Endocrine System 5  The intercellular language is chemical Hormone from an endocrine cell Hormone from a neurosecretory cell Neurotransmitter FMD002 Hormones and Endocrine System 6  The major endocrine glands in humans FMD002 Hormones and Endocrine System 7  Hormones Regulate energy use, metabolism, and growth Maintain homeostasis Are secreted by endocrine (ductless) glands – directly into the bloodstream Reach all parts of the body – react with specific receptors on target cells Minute quantities produce significant effects FMD002 Hormones and Endocrine System 8  One hormone can have different effects FMD002 Hormones and Endocrine System 9  Hormones Three main types Proteins (water soluble) – e.g. insulin, glucagon Amines (either water or lipid soluble) – synthesized from amino acids (usually tyrosine) – e.g. adrenaline Steroids (lipid soluble) – e.g. cortisol, oestrogen and progesterone FMD002 Hormones and Endocrine System 10  Lipid-soluble hormones Pass through the target cell membrane Bind to an intracellular receptor Hormone-receptor complex binds to DNA – turns specific genes on or off – E.g. new protein is synthesised FMD002 Hormones and Endocrine System 11  Water-soluble hormones Bind to receptors – cell membrane target cell Receptor protein – activates a signal-transduction pathway Series of relay molecules – transmits the signal Cell response occurs FMD002 Hormones and Endocrine System 12  Adrenaline causes the release of glucose FMD002 Hormones and Endocrine System 13  Control of glucose Insulin and glucagon are antagonistic Negative feedback In the pancreas Alpha cells – release glucagon Beta cells – release insulin ↑ Blood Glucose, release of insulin – triggers glucose uptake from blood  Blood glucose, release of glucagon, releases glucose into blood FMD002 Hormones and Endocrine System 14  Steroid hormones regulate gene expression Receptors in cytosol Hormone receptor complex Conformational change Nuclear translocation Activates gene transcription Production of protein FMD002 Hormones and Endocrine System 15 Mechanisms controlling the release of hormones Specific metabolite in the blood e.g. glucose Another hormone in the blood e.g. (TSH) thyroid stimulating hormone Stimulation of neurons – Autonomic nervous system e.g. Adrenaline FMD002 Hormones and Endocrine System 16  The pituitary gland and hypothalamus FMD002 Hormones and Endocrine System 17  The posterior pituitary Hormones made in hypothalamus Hormonal storage and transport in vesicles Release into bloodstream Also called vasopressin FMD002 Hormones and Endocrine System 18  The posterior pituitary FMD002 Hormones and Endocrine System 19  The anterior pituitary Special network blood vessels Hypothalamus – stimulatory or inhibitory hormones Act on the anterior pituitary Stimulate release of hormones FMD002 Hormones and Endocrine System 20  The thyroid Thyroid gland secretes thyroid hormone (Actually 2 hormones, T3 and T4 or thyroxine) Regulates: Heart rate Muscle tone Bioenergetics Digestive and reproductive functions FMD002 Hormones and Endocrine System 21  Control of thyroxine secretion FMD002 Hormones and Endocrine System 22  Hypothyroidism can lead to goitre No inhibition Hypothalamus TRH Anterior pituitary TSH No iodine Insufficient T4 and T3 Thyroid produced Thyroid grows to form goitre Weight gain, lethargy, cold intolerance FMD002 Hormones and Endocrine System 23  Hyperthyroidism – Graves’ disease Hypothalamus TRH Anterior pituitary Constant activation TSH Thyroid Excessive thyroxine produced Weight-loss, tremor, sweating, hyperactivity, Graves’ opthamology FMD002 Hormones and Endocrine System 24  Summary Two communications systems: nervous and endocrine Endocrine effects are slower, more widespread and longer lasting Main types of hormone: steroid and non-steroid – With different modes of action Hormones only exert their effects in cells that have receptors for those hormones Hormone levels are controlled by negative feedback The hypothalamus controls the secretions of the pituitary gland using nervous and hormonal control FMD002 Hormones and Endocrine System 25  Classification of Diabetes Type 1 Diabetes AUTOIMMUNE ATTACK MANAGED WITH INSULIN RISK: MAINLY GENETIC Type 2 Diabetes METABOLIC DISORDER PHARMACOLOGICAL THERAPY RISK: LIFE STYLE AND GENETIC Gestational Diabetes SPECIAL CASE OF TYPE 2 DIABETES TRANSIENT No current cure – diabetes attracts much research interest 26 Diabetes – an enormous healthcare burden 3.3 mln UK citizens diagnosed with diabetes (5 mln by 2025) [AN ESTIMATED 590,000 PEOPLE REMAIN UNDIAGNOSED] 10% of the total NHS budget is spent on diabetes [£1 MLN PER HOUR] Diabetic complications further burden the healthcare budget [2014: £24 BLN PREDICTED 2035: £40 BLN] heart, kidney, eye, nerve, bladder disease; amputation; depression  The Metabolic Syndrome Insulin Hyperglycaemia Obesity resistance (β-cell failure) A cluster of medical disorders that collectively increase the risk of developing type 2 diabetes and cardiovascular disease 28 28 Cardiovascular Disease Research in SoBS  SysVasc Consortium ( 2014-2017) https://www.youtube.com/watch?v=8fuvtMiZfao#action=share International ( & Serious) Effort! Type 2 diabetes is a multifactorial disease Multiple Multiple Multiple risk factors symptoms organs Aetiology of T2D is incompletely understood 32 32 T2D in context of the Metabolic Syndrome 33 33  Insulin sensitivity of skeletal muscle ANABOLIC STIMULATION Insulin Signal Transduction 34 Link between Diabetes, Obesity and Figure 1 Cancer The Lancet Diabetes & Endocrinology 2018 6, 95-104DOI: (10.1016/S2213-8587(17)30366-2) Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license Terms and Conditions The Lancet Diabetes & Endocrinology 2018 6, 95-104DOI: (10.1016/S2213-8587(17)30366-2)  ? 11/16/2020 36