Endocrine System PDF Study Guide

The Endocrine System Chapters 7 and 23 ✓ HORMONES ✓ CLASSIFICATION ✓ REGULATION ✓ INTERACTION...

The Endocrine System Chapters 7 and 23 ✓ HORMONES ✓ CLASSIFICATION ✓ REGULATION ✓ INTERACTION Learning Objectives Describe the different classifications of hormones and how they are different Describe the different hormones are metabolized Understand how endocrine systems are regulated A Tale of Three Hormones… TYROXINE (T4) & INSULIN CORTISOL Triiodothyronine (T3) TYPE: Peptide Steroid hormone Amino Acid Derivative ORIGIN: Beta cells of pancreas Adrenal cortex Thyroid gland Metabolism of fats & Glucose; immune response; Basal metabolic rate; Protein REGULATES: carbohydrates fat, protein & carbohydrate synthesis; Growth; Neural metabolism maturation REGULATED BY: Glucose levels Stress Metabolic demand METABOLIZED IN: Liver & Kidney Liver Liver & Kidney  TYROXINE (T4) & INSULIN CORTISOL Triiodothyronine (T3) STRUCTURE: Hydrophobic; soluble Hydrophobic; soluble TRANSPORT: Water soluble; blood binding protein binding protein Body tissues that use glucose (e.g. Adipocytes; TARGET TISSUE (receptor Body tissues that use location) Hepatocytes; Skeletal All body tissues glucose muscle) Plasma membrane Plasma membrane & SIGNAL TRANSDUCTION: Intracellular receptors receptors Nuclear receptors FEEDBACK REGULATION: Negative Feedback Negative Feedback Negative Feedback Hypothalamic-Pituitary Axis Hypothalamic-Pituitary Axis Learning Objectives Describe the relationship between the hypothalamus and the anterior & posterior pituitary Name the primary hormones of the anterior pituitary and their target tissues Give examples of regulatory feedback loop for anterior pituitary hormones  Endocrine System Hypothalamic-Pituitary Axis neurohypophysis adenohypophysis Figure 7-11 Endocrine System Hypothalamic-Posterior Pituitary Axis Figure 7-12 Endocrine System Hypothalamic-Posterior Pituitary Axis Hypothalamus Synthesis Supraoptic nuclei Paraventricular nuclei Posterior Pituitary secretion e.g. Oxytocin Vasopression (antidiuretic hormone=ADH)  Endocrine System Hypothalamic-Anterior Pituitary Figure 7-15 Regulating Hormone Action: trophic hormones Example: Hypothalamic-Pituitary Feedback Loop Hormones themselves may serve as feedback signals. Figure 7-11 Endocrine System Hypothalamic-Anterior Pituitary Figure 7-17  Endocrine System Cortisol Secretion Figure 7-15 Endocrine System Cortisol Secretion Figure 23-3 Figure 7.11b (2 of 2) Control Pathway for Cortisol Secretion Cortisol is a steroid hormone secreted by the adrenal cortex. ACTH = corticotropin or adrenocorticotropic hormone; CRH = corticotropin-releasing hormone. Hypothalamus CRH Long-loop negative feedback Anterior pituitary ACTH Adrenal cortex Cortisol Target To target tissue tissue FIGURE QUESTION Response Draw in the short-loop negative feedback for this pathway.  Exogenous hormone has the same negative feedback effect as endogenous hormone. CRH (Hypothalamus) ACTH (Anterior pituitary) Exogenous Cortisol (Adrenal cortex) cortisol Target tissue Response Figure 7.14 Primary and secondary hypersecretion of cortisol Primary Hypersecretion Due to Secondary Hypersecretion Secondary Hypersecretion Due Problem with Adrenal Cortex Due to Pituitary Problem to Hypothalamic Problem Hypothalamus CRH Hypothalamus CRH HYPERSECRETING TUMOR IN CRH HYPOTHALAMUS Anterior PATHOLOGY Anterior pituitary ACTH IN ANTERIOR ACTH pituitary ACTH PITUITARY PATHOLOGY Adrenal IN ADRENAL Cortisol Adrenal Cortisol cortex Cortisol CORTEX cortex Negative feedback fails Symptoms Symptoms Symptoms of excess of excess of excess CRH levels – low CRH levels – low CRH levels – high ACTH levels – low ACTH levels – high ACTH levels – high Cortisol levels – high Cortisol levels – high Cortisol levels – high Endocrine Disorders Draw arrows for the following situations:  Endocrine System Anterior Pituitary Hormones and Targets Figure 7-13 The Endocrine System The hypothalamic-pituitary-thyroid axis controls thyroid THYROID REGULATION gland function through negative feedback regulation. The hypothalamic-pituitary-adrenal axis controls adrenal ADRENAL REGULATION gland function through negative feedback regulation. Fuel storage versus mobilization in adipose tissue, liver, and skeletal muscle is regulated by the pancreas through the METABOLISM insulin-to-glucagon ratio. Parathyroid Hormone and Vitamin D regulate calcium and CALCIUM AND PHOSPHATE BALANCE phosphate homeostasis among the gut tube, kidneys, and bone. The hypothalamus and pituitary control body growth GROWTH HORMONES mediated by growth hormone, insulin, and androgens. Adrenal Glands  Learning Objectives Understand the anatomy of the adrenal gland Describe the role of cortisol in non stressful situations and under stress Describe the regulatory feedback loop of cortisol Understand how how disrupted regulation may lead to pathology ADRENAL GLANDS AND STRESS Cortisol secretion – Stress response Noxious stimuli – Hypothalamic-Pituitary system. Control of secretion STRESS Any event that increases cortisol Noxious or potentially noxious stimuli – Environmental – Infection – Shock – Sleep deprivation – Pain – Fright – The next exam  STRESS Hypothalamus Sympathetic Pituitary Chronic Adrenal Adrenal medulla Sudden Cortex Acute epinephrine cortisol STRESS Hypothalamus CRH Anterior Pituitary ACTH Vasopression Cytokines Adrenal Cortex cortisol Physiological Functions of Cortisol in Stressful Situations Mobilize fuels – Gluconeogenesis – Breakdown of skeletal muscle protein – Enhances lipolysis Vascular smooth muscle tone Anti-inflammatory, anti-immune function Negative Ca++ balance (net loss of Ca++ from the body) Brain function – Memory – Mood  Other Stress Hormones Aldosterone Vasopressin Growth hormone Glucagon Beta endorphin Others Physiological Functions of Cortisol in Non-Stressful Situations Normal blood pressure – Smooth muscle tone Epinephrine, norepinephrine Metabolic homeostasis – Hepatic glucose production Maintaining blood glucose levels Anti-inflammatory, anti-immune function – Brake for immune function Decreased cortisol = Autoimmune reaction? Fetal and neonatal development – Gland, organ development Table 23-1 Physiological Functions of Cortisol: Circadian Rhythm Figure 23-4  Regulating Hormone Action: permissiveness & synergy Synergy: sum is greater than the individual effects Permissive: presence of one hormone allows another to have its full effect: Thyroid hormone has a permissive effect on reproductive hormones Cortisol has a permissive effect on Growth Hormone, also on Insulin and glucogenesis Figure 7-18 Psychological Stress and Disease mind body connection – Effect on immune system Repeated sympathetic stimulation – Hypertension – atherosclerosis THE THYROID GLAND  Thyroid Gland Learning Objectives Describe the synthesis of thyroid hormone Understand the regulation of thyroid hormone Understand the role of thyroid hormone in maintaining homeostasis, metabolism and growth and development Endocrine System Thyroid Gland Figure 23-7 Thyroid Hormone Synthesis Figure 23-9  Endocrine System Thyroid Hormone Regulation Figure 23-12 Endocrine System Thyroid Hormone Regulation Figure 23-14 Endocrine System Thyroid ? Hormone Regulation ? ? ? Feedback ? ? Feedback ? ? ? ? ? ? ?  Actions of Thyroid Hormones Thyroid hormone receptor – Wide distribution – 3 types of functional receptors 1 with unknown function Thyroid hormones – Induce transcription and protein synthesis – Calorigenic effects: increase metabolism Carbohydrate absorption Fatty acid release stimulate Na+/K+ ATPase activity – Permissive effects Up-regulation of beta-adenergic receptors epinephrine, norepinephrine – development of the nervous system – growth. Thyroid hormones Calorigenic effect + Thyroid Na+/K+ ATPase stimulation Hormone ATP + Low intracellular stores glycolysis ATP production heat Thyroid hormones Permissive effect + Thyroid Beta-adenergic receptors (catecholamine receptors) Hormone Increased Sympathetic Activity Anxiety Nervousness Increased heart rate Thyroid hormones Growth Nervous system Thyroid Growth hormone Hormone Fetal Iodine deficiency X cretinism CNS development (fetal) Nerve terminals Synapse formation Dendrite connections Myelin Adult maintenance Nerve/muscle reflexes Cognition Regulation of Growth Endocrine factors Genetic factors Environmental factors – nutrition Regulation of Growth Learning Objectives Understand how bone is added and lost Understand the hormones and environmental factors that affect growth and development Describe and understand the regulation of calcium balance in the body  Endocrine System Regulation of Growth Chondrocytes Osteoblasts epiphyseal growth plate – linear bone growth. – rapid bone growth First two years of life puberty. Endocrine System Regulation of Growth Figure 23-19 Endocrine System Regulation of Growth  Endocrine System Regulation of Growth Figure 23-16 Environmental Factors Influencing Growth nutrition – prenatal – postnatal disease environmental Hormonal Influences on Growth Hormones regulating to human growth (+/-) – Growth hormone Post-natal growth, protein synthesis – Insulin like growth factors I & II stimulates cell division – Thyroid hormones Fetal and Post-natal growth, protein synthesis – Insulin Permissive for GH and CNS development – Testosterone Growth at puberty, epiphysis closure, protein synthesis (male) – Estrogens Growth at puberty, epiphysis closure – Cortisol Inhibits growth, stimulates protein catabolism – Peptide growth factors  Hormonal Influences on Growth mitogen = stimulating cell division – 60 known growth factors and growth inhibiting factors – paracrine or autocrine regulation. Cancer – Oncogenes – Abnormal/uncontrolled growth Control of growth hormone secretion – Dependent on developmental stage Effect of Growth Hormone on Post-natal growth Anterior Pituitary Protein synthesis (Muscle) GH Post-natal growth liver Insulin-like Fetal Growth factor I development (IGF-1: somatomedin C) IGF-II mitogen Effect of Growth Hormone on Post-natal growth Anterior Pituitary GH Post-natal growth liver X Insulin-like Growth factor I (IGF-1: somatomedin C) mitogen nutrition  Compensatory Growth Compensatory growth – Regenerative growth – Organs Liver Compensation for loss of kidney Angiogenesis – Growth of blood vessels to increase flow Calcium & Calcium Balance Figure 23-22 Endocrine System Calcium and Calcium Balance Figure 23-21  Endocrine System Calcium and Calcium Balance Figure 23-22 Endocrine System Calcium and Calcium Balance Figure 23-22