Introduction to the Endocrine System PDF

Introduction to the endocrine system 1 Learning Objectives 1. Be able to define a hormone and compare endocrine signaling with other types of cell-to-cell signaling. 2. Know the 3 main types of hormones and understand how the type of hormone affects synthesis, secretio...

Introduction to the endocrine system 1 Learning Objectives 1. Be able to define a hormone and compare endocrine signaling with other types of cell-to-cell signaling. 2. Know the 3 main types of hormones and understand how the type of hormone affects synthesis, secretion, and transport. Protein Steroid Amine 3. Define what a receptor is and discuss the major types of hormone receptors. 4. Be able to identify the hypothalamus and pituitary and explain their role in the endocrine system. 2 Hormones Low concentration 1 picogram (0.000000000001 g) in 1 ml Steps of Hormone Action 1. Production/Secretion 2. Transport Through Blood 3. Binds to Receptors on Target Cells 3 Types of Hormones Can classify of hormones based on their function or the type of molecule 1. System/Organ 2. Type of Molecules Protein/peptide Steroid Amine testosterone cortisol aldosterone 4  Protein Hormones synthesize like any other protein (e.g. insulin) Very controlled synthesis Hydrophilic/Lipophobic Cannot pass through plasma membrane Stored by cell until secreted Do not need transport proteins Bind to transmembrane receptor 5 Protein Hormones - Transport Enter blood vessel at capillary beds Hydrophilic does not need carrier protein Exit blood vessel at capillary beds 6  Protein Hormones - Receptors Cannot get into cells Bind to transmembrane receptors Activate a cascade of events inside the cell that change cell function Outside Cell Inside Cell 7 Amine Hormones Small/ hydrophilic Stored/actively secreted e.g. thyroid hormones, adrenergic hormones Triiodothyronine (T3) epinephrine 8 Amine Hormone Synthesis Thyroid hormone synthesis Thyroglobulin is broken down Thyroglobulin is taken into thyroid cell into thyroid hormones 9 Amine Hormone Synthesis 10  Amine Hormone Receptors Thyroid hormones -> enter cells and bind to intracellular (nuclear) receptors Catecholamines ->bind to transmembrane receptor Thyroid Hormones Catecholamines 11  Steroid Hormones Lipophilic Different types Cannot be stored in cells Glucocorticoids Needs carrier protein in Mineralocorticoids blood Cholesterol Sex steroids estradiol cortisol 12 Steroid Hormones- Transport corticosteroid-binding globulin (CBG)- binds cortisol and progesterone Sex hormone binding globulin- testosterone and estrogen Transcortin- binds to aldosterone Albumin- binds all steroids with low affinity Transport Protein Free Hormone and hormone ~95% of hormone ~5% of hormone 13  Hormone Receptors No receptor -> no (direct) effect Cells integrate signaling from many hormones at once Cellular Response Hormone Receptor 14  Types of Hormone Receptors Intracellular Receptors Transmembrane Receptors Aka nuclear receptor Pass through cell membrane Present inside the cell Intracellular and extracellular parts Require hormones to get Response in seconds to minutes into cell Response in hours to days 15  Intracellular (Nuclear) Receptors Steroid Bound to Receptors for Steroids and Thyroid Hormones Carrier Proteins Thyroid Hormone Free Steroid nucleus Regulation of Transcription mRNA 16 Transmembrane Receptors Initiate cascade of events Hormone Hormone inside cells: Outside Cell Regulate protein activity Inside Cell Make more protein Biological Effects 17 Hypothalamus & Pituitary Hypothalamus Pituitary 18 The Pituitary Anterior Posterior 19 Circumventricular Organs Circumventricular Organs Median Eminence Posterior Pituitary 20 Posterior Pituitary (aka Neurohypophysis) Made of Neural Tissue (part of brain) circumventricular organ Hormones Secreted Oxytocin Antidiuretic Hormone (ADH) oxytocin Antidiuretic Hormone (ADH) 21 Anterior Pituitary (aka Adenohypophysis) Hypothalamus median eminence (circumventricular organ) Anterior Pituitary Made of glandular tissue (NOT part of brain) Connected to hypothalamus via a portal system 22 Portal Systems hypothalamus Anterior Pituitary 23 Anterior Pituitary Hormones produced by Anterior Pituitary Growth Hormone (GH) Thyroid Stimulating Hormone (TSH) Adrenocorticotropic hormone (ACTH) Prolactin Follicle Stimulating Hormone (FSH) Luteinizing Hormone (LH) 24 In Summary Endocrine system releases hormones into blood that affect distant cells Classify hormones by system they regulate or by how they are made Receptors bind to specific hormones Nuclear receptors- regulation mRNA transcription Transmembrane receptors- activate intracellular signaling pathways Posterior Pituitary – secretes hormones made in hypothalamus Anterior Pituitary- secretes hormones in response to hypothalamic hormones 25 Study Aids https://thecrashcourse.com/courses/endocrine-system-part-1- glands-hormones-crash-course-ap-23/ https://www.youtube.com/watch?v=eWHH9je2zG4 https://www.youtube.com/watch?v=ER49EweKwW8 https://www.youtube.com/watch?v=8uxTTucIb48 https://www.youtube.com/watch?v=7rWPKHFMqEU 26