A&P_CH16_ENDOCRINE_SYSTEM_FINAL sc.pptx PDF

16: Endocrine System Anatomy and Physiology in Context Chapter 16 Objective Chapter 16 Endocrine System 16.1Anatomy Overview 16.2 Patterns of Organization 16.3Regulation of Endocrine Tissues: Hypothalamus and Pituitary 16.4Endocrine Tissue : Hormone Activate Signaling Ca...

16: Endocrine System Anatomy and Physiology in Context Chapter 16 Objective Chapter 16 Endocrine System 16.1Anatomy Overview 16.2 Patterns of Organization 16.3Regulation of Endocrine Tissues: Hypothalamus and Pituitary 16.4Endocrine Tissue : Hormone Activate Signaling Cascades that Regulate Many Physiological Processes 16.5Effects of Aging on the Endocrine System 16.1 Anatomy Overview Chapter 16: Endocrine System  16.1.1 Endocrine Tissues are Diverse and Decentralized Releasing and inhibitory hormones (hypothalamus), Melatonin systemic hormones (pituitary) Thyroxine (thyroid), Leptin parathyroid and calcitonin (parathyroid) Atrial natriuretic Gastrin factor Erythropoietin, IGF Insulin, glucagon Steroids, Calcitriol, angiotensin II catecholamine Estrogen, inhibin Secretin Testosterone, inhibin 16.2 Patterns of Organization Chapter 16: Endocrine System  16.2.1 General Definition of Endocrine Cells ENDOCRINE CELL: Releases chemical messengers (hormones) into the bloodstream Only cells with receptors for that particular hormone will respond  16.2.2 Properties of Hormones GENERAL TYPES OF PROPERTIES Regulation of physiological HORMONES processes Variety in chemical structure Released in very low quantities Movement through diffusion or plasma Bind to receptors on target cells Released in response to changes in homeostasis Autocrine – same cell Lipophilic – lipid; can penetrate membranes, receptor in cell Paracrine – neighboring cell Hydrophilic – water loving; receptor in membrane  Hormone Regulation Negative Feedback Loop Mechanism There is also a Positive Feedback Loop, but not as common 16.2.3 Hormones Regulate the Receptor Levels of Other Hormones Upregulation: increasing receptor levels on target cells Downregulation: decreasing receptor levels on target cells Permissiveness: the process of hormones regulating the receptor levels of other hormones 16.2.4 Hormone Release Is Amplitude- Modulated Three Types of Hormones 1. Peptide - most common 2. Steroids - lipophilic 3. Amino Acid Derived NEUROTRANSMITTERS: Release is “all or nothing” Vary in frequency HORMONES: Levels never approach zero Fluctuate between high  16.2.5 Peptide and Protein Hormones Are Synthesized in an Inactive Form Encoded by genes Multiple peptide hormones can be encoded by one gene Signal peptide: directs hormone to correct intracellular organelle for processing Other Peptide Hormnes preprohormone prohormone Pro-opiomelanocortin (POMC) ACTH – release corticol Lipotropin – promotes release of fat reserves Endorphin – cause analgesic effect MSH – associated with skin pigmentation, sleep activity and appetite Other Peptide Hormnes Insulin (c) Proinsulin Insulin C-peptide marker 16.2.6 Synthesis of Amino Acid Derivative Hormones Biochemically synthesized from amino acids Stored within vesicles E.g., epinephrine (catecholamine)  16.2.7 Processes That Influence Hormone Secretion Changes in a critical physiological factor (e.g., ions) Direct input from the nervous system through neurohormone release Actions of other hormones (e.g., hypothalamic regulation of pituitary gland) Mechanical stresses or cellular metabolism to consider about each hormone : s of hormone secretion, the chemical type, gland or cell, transport, target cell, response and reg 16.2.8 Hormones Are Transported Through the Blood  16.2.9 Hormones Are Excreted in the Urine or Digestive Tract WATER-SOLUBLE, FREE HORMONES: Smaller than kidney filtration barrier Excreted in urine LIPID-SOLUBLE HORMONES: Some excreted in urine (if chemically modified to be more water-soluble) Otherwise excreted in GI tract HALF LIFE: time required to 16.2.10 Metabolism Can Change Hormone Levels or Activity EXAMPLE: sulfation or glucuronidation 16.2.11 VIDEO: Mechanism of Hormone Action Please insert the following video: https://www.youtube.com/watch? 16.2.12 Hormone Receptors (1): G- protein Coupled Receptors (GPCRs) FEATURES OF GPCRs: Integral membrane proteins Extracellular region binds hormone Intracellular region interacts with G- proteins  16.2.13 Downstream Effectors of GPCRs SUBUNITS OF G- EFFECTS OF cAMP Gɑ Activates adenylate cyclase PROTEINS Activates Protein Kinase A S (AC) (PKA) Converts ATP to cAMP Degraded by Gɑi Inhibits adenylate cyclase phosphodiesterase (PDE) (AC) EFFECTS OF DAG AND Blocks production of cAMP IP3IP3 causes Ca2+ release Gɑ Activates phospholipase C from ER q (PLC) DAG activates Protein Breaks down PIP2 into IP3 and Kinase C (PKC) DAG 16.2.14 Hormone Receptors (2): One- Transmembrane Spanning Receptors (1- TMS) FEATURES OF 1-TMS: Integral membrane proteins Extracellular region binds hormone Intracellular region contains a kinase domain; directly activates enzymes without G- proteins 16.2.15 Hormone Receptors (3): Nuclear Receptors FEATURES OF NUCLEAR RECEPTORS: Found inside the cell Act as transcription factors Generally cytoplasmic proteins complexed with heat shock proteins (HSPs) Hormone binding leads to dissociation of HSPs, dimerization to a second bound receptor, and translocation to the nucleus  16.2.16 FOCUS ON DISEASE: Diseases Caused by Mutations in Hormone Receptors RECEPTOR DISEASE CAUSED BY MUTATION Thyroid stimulating hormone Grave’s disease (hyperthyroidism) receptor Parathyroid hormone receptor Jansen’s metaphyseal chondrodysplasia Follicle-stimulating hormone Ovarian dysgenesis type I receptor Melanocortin/adrenocorticotropic Familial glucocorticoid deficiency hormone receptor Luteinizing hormone receptor Familial male precocious puberty Antidiuretic hormone receptor Familial hypocalciuric hypercalcemia  16.3 Endocrine Tissues: Hypothalamus and Pituitary Chapter 16: Endocrine System 16.3.1 Anatomy of the Hypothalamus ANATOMY FEATURES Located inferior to the thalamus; part of the limbic system Contains many distinct nuclei that produce and release unique hormones Is sexually dimorphic (different between men and women) Hypophyseal portal system connects hypothalamus and The Pituitary Gland Anatomy neurohypophysis adenohypophysis Copyright © 2009 Pearson Education, Inc. Figure 7-11 The Pituitary Gland: Posterior Neurohormone HYPOTHALAMUS Posterior pituitary 1 Hormone is made and Vasopressin packaged in cell body of neuron. Oxytocin 2 Vesicles are transported down the cell. 3 Vesicles containing hormone are stored in posterior pituitary. POSTERIOR PITUITARY Vein 4 Hormones are released Note: water retension, milk and uterus, autism into blood. Copyright © 2009 Pearson Education, Inc. Figure 7-12 The Pituitary Gland : Anterior HYPOTHALAMUS 1 Neurons synthesizing Tropic Hormones trophic hormones release them into capillaries of the portal system. Capillary bed Artery 2 Portal vessels carry the trophic hormones directly to the anterior pituitary. POSTERIOR PITUITARY 3 Endocrine cells release their hormones into the Capillary bed second set of capillaries for distribution to the rest of the body. ANTERIOR PITUITARY Veins TO TARGET ORGANS Prolactin Gonadotropins (LH & FSH) GH TSH ACTH Ovary Testis Mammary glands Musculoskeletal system Thyroid gland Adrenal cortex Gonads Copyright © 2009 Pearson Education, Inc. Figure 7-16 16.3.2 Functions of Hormones Produced by the Hypothalamus Hypothalamus releases hormones that act on the pituitary gland. Chapter 16 Endocrine System 16.1Anatomy Overview 16.2 Patterns of Organization 16.3 Regulation of Endocrine Tissues: Hypothalamus and Pituitary 16.4 Endocrine Tissue : Hormone Activate Signaling Cascades that Regulate Many Physiological Processes 16.5 Effects of Aging on the Endocrine System  16.3 Endocrine Tissues: Hypothalamus and Pituitary Chapter 16: Endocrine System 16.3.1 Anatomy of the Hypothalamus ANATOMY FEATURES Located inferior to the thalamus; part of the limbic system Contains many distinct nuclei that produce and release unique hormones Is sexually dimorphic (different between men and women) Hypophyseal portal system connects hypothalamus and The Pituitary Gland Anatomy Copyright © 2009 Pearson Education, Inc. Figure 7-11 The Pituitary Gland: Posterior Neurohormone HYPOTHALAMUS Posterior pituitary 1 Hormone is made and Vasopressin packaged in cell body of neuron. Oxytocin 2 Vesicles are transported down the cell. 3 Vesicles containing hormone are stored in posterior pituitary. POSTERIOR PITUITARY Vein 4 Hormones are released Note: water retension, milk and uterus, autism into blood. Copyright © 2009 Pearson Education, Inc. Figure 7-12 The Pituitary Gland : Anterior HYPOTHALAMUS 1 Neurons synthesizing trophic hormones release them into capillaries of the portal system. Capillary bed Artery 2 Portal vessels carry the trophic hormones directly to the anterior pituitary. POSTERIOR PITUITARY 3 Endocrine cells release their hormones into the Capillary bed second set of capillaries for distribution to the rest of the body. ANTERIOR PITUITARY Veins TO TARGET ORGANS Prolactin Gonadotropins (LH & FSH) GH TSH ACTH Ovary Testis Mammary glands Musculoskeletal system Thyroid gland Adrenal cortex Gonads Copyright © 2009 Pearson Education, Inc. Figure 7-16 16.3.2 Functions of Hormones Produced by the Hypothalamus Hypothalamus releases hormones that act on the pituitary gland. 16.3.3 Anatomy of the Pituitary Gland ANATOMY FEATURES Located inferior to the hypothalamus Composed of anterior, intermediate and posterior lobes Anterior lobe: subdivided into pars tuberalis and pars distalis Two pituitary areas do not regulate each other  16.3.4 Hormones Secreted by the Posterior Pituitary Gland OXYTOCIN ANTIDIURETIC HORMONE Structur e Movement of mammary Renal system: increased milk into subareolar sinuses expression of aquaporin (milk ejection/ letdown) channels (increased water Stimulation of uterine absorption); increased Functio contraction during interstitial osmolarity ns pregnancy (increased water, Na+ Social behavior: feelings of reabsorption) contentment, reduced Cardiovascular system: anxiety, calmness vasoconstriction CNS: aggression, blood Hypothalamic Anterior Pituitary Portal System stimulus Hypothalamus  Glad or Anterior Pituitary Cell  Target Tissue Efferent Pathway Tropic Hormone Hormone Feedback response Pathophysiologies Copyright © 2009 Pearson Education, Inc. Figure 7-11 The Pituitary Gland: Anterior HYPOTHALAMIC HORMONES Neurons in hypothalamus secreting trophic hormones Dopamine* tropic PRFs TRH CRH GHRH* GnRH Somatostatin Portal system Anterior pituitary ANTERIOR PITUITARY HORMONES Prolactin TSH ACTH GH FSH LH Endocrine (Gonadotropins) cells To target ENDOCRINE TARGETS tissues AND THE HORMONES Endocrine cells THEY SECRETE Thyroid Adrenal Liver of the gonads gland cortex Thyroid Estrogens, Cortisol IGFs Androgens hormones progesterone NONENDOCRINE TARGETS Many Germ cells Breast of the gonads tissues Copyright © 2009 Pearson Education, Inc. Figure 7-13  16.3.5 Hormones of the Anterior Pituitary Gland (1): Growth Hormone hypoglycemia stress diurnal rhythm 16.3.6 Hormones of the Anterior Pituitary Gland (2): Thyroid Hormone diurnal rhythm highest level at night 16.3.7 Hormones of the Anterior Pituitary Gland (3): Prolactin 16.3.8 Hormones of the Anterior Pituitary Gland (4): Adrenocorticotropin Hormone (ACTH) Adrenal Gland Cortex  16.3.9 FOCUS ON DISEASE: Pituitary Adenoma Types of pituitary Norm adenoma: Benign (65% of the time) al Invasive (0.1%) Carcinoma (35%) Symptoms: Over-secretion of one or two hormones Eye disorders (compression of optic Cance nerve) r Severe headaches Under-secretion of some hormones 16.4 Endocrine Tissues Chapter 16: Endocrine System 16.4.1 Anatomy of the Thyroid Gland ANATOMY FEATURES Found lateral to the upper trachea Made up of two lobes connected by highly vascularized band of tissues called isthmus Contains follicles that store thyroglobulin, the substrate for thyroxine Image courtesy of Nephron under CC BY-SA 3.0. Parafollicular cells are 16.4.2 Thyroxine Synthesis in the Thyroid Gland 1. Iodide ions transported into 2. follicular cells TG synthesis and TSH stimulates storage within follicles 3. Iodide is oxidized to iodine by thyroid peroxidase; diffuses to 4. follicle lumen are covalently Iodine atoms attached to tyrosine residues on thyroglobulin, forming MIT or DIT 5. Two DIT molecules join to form T4, or one MIT and one DIT join to 6. form T3 cells take up iodinated Follicular thyroglobulin by endocytosis. Within endosomes, proteolytic enzymes release thyroxine from 7. TG Thyroxine is released into blood bound to proteins (e.g., TBG or 16.4.3 Effects of Thyroxine Throughout the Body Hypothalamus/ Pituitary Thyroid/Parathyroid Glands LUNG: increased ventilation LIVER: increased MUSCLE: increased basal metabolic rate protein catabolism HEART: increased heart ADIPOSE: increased rate, increased force of lipolysis contraction, increased cardiac output  16.4.4 Anatomy of the Parathyroid Gland ANATOMY FEATURES Four parathyroid glands (2 embedded in each thyroid gland) Densely-packed with chief and oxyphil cells Mainly secretes parathyroid hormone (PTH) Image courtesy of Nephron under CC BY-SA 3.0. 16.4.5 Effects of Parathyroid Hormone Throughout the Body Thyroid/Parathyroid Glands BONE: increased resorption KIDNEY: increased calcitriol INTESTINE: increased calcium reabsorption  16.4.6 Anatomy of the Adrenal Glands ANATOMY FEATURES Embedded in adipose tissue in the superior regions of the kidney Composed of endocrine and nervous tissue Organized into zones which are structurally and functionally distinct  16.4.7 Hormones Produced by the Adrenal Gland Zone of adrenal Hormone Features gland Zona glomerulosa Mineralocorticoi Aldosterone: increases Na+ ds, e.g., resorption (urine, sweat aldosterone glands, salivary glands, colon), Zona fasciculata Glucocorticoids Hyperglycemia, increased renal K+ excretion immunosuppression, increase lipolysis, decreased glucose uptake into skeletal muscle, increased gluconeogenesis, increased protein degradation Zona reticularis Androgen Converted to androgens; direct precursors effects on testes and ovaries, bone-protective effects, increased neuron survival  16.4.8 Anatomy of Adipose Tissue ANATOMY FEATURES Found under skin, around organs, in bone marrow, within muscle and breast tissue Composed predominantly of adipocytes along with fibroblasts, macrophages and endothelial cells Releases hormones (leptin, adiponectin, resistin) Main hormone functions: regulating body metabolism,  16.4.9 Anatomy of the Pancreas ANATOMY FEATURES Lies beneath the greater curvature of the stomach and small intestine Bulk of mass is exocrine tissue/ducts  Produces pancreatic juice and secretes it into the small intestine for digestion Clusters of endocrine cells are scattered throughout; produce insulin and glucagon 16.4.10 Types of Endocrine Cells in the Islets of Langerhans a cells (20%): secrete glucagon b cells (75%): secrete insulin and amylin (satiety) δ cells (3-10%): secrete somatostatin PP cells (3-5%): secrete pancreatic polypeptide Image courtesy of Polarlys under ε cells (1%): secrete ghrelin CC BY 2.5. (huger hormone -  food intake) 16.4.11 Structure and Functions of Insulin STRUCTURE: a and b chains held together by disulfide bonds FUNCTIONS: Secreted in response to increased blood glucose concentrations Insulin facilitates glucose entry into muscle, adipose and other tissues, through GLUT4 Increases glucose in liver through multiple mechanisms 16.4.12 Structure and Functions of Glucagon STRUCTURE: Synthesized as pro-glucagon in pancreatic a cells Proteolytically processed to yield glucagon FUNCTIONS: Secreted in response to low blood glucose concentrations Mainly affects the liver to increase blood glucose levels Stimulates breakdown of liver glycogen and stimulates gluconeogenesis  16.4.13 Other Endocrine Tissues Tissue Hormones/Functions Heart Atrial natriuretic peptides Maintain total blood volume, blood Na+ levels and arterial blood pressure Pineal gland Melatonin and arginine vasotocin Melatonin: secreted in response to light versus dark; inhibits GnRH release and reproductive functions through decreased blood LH and FSH Gastrointestin Digestive tract hormones al tract Regulation of food digestion and absorption Immune Cytokines system Regulation of cell differentiation/growth and immune response Placenta Pregnancy hormones Regulate energy metabolism, fetal development in mother and fetus 16.5 Aging and the Endocrine System Chapter 16: Endocrine System  16.5.1 Aging in the Endocrine System Age-related endocrine Associated physiological changes: Decrease in GH release changes: Decrease in body mass (especially in those who exercise less) Decrease in TSH and the T3/T4 Loss of TSH-regulated functions ratio Over-secretion of PTH Loss of bone mass Decrease in renal renin Decreased ability to regulate release arterial blood pressure Decrease in reproductive Reduced production of sperm hormones (men), menopause (women) Decrease in thymus cytokines Fewer mature, functional lymphocytes  Review Chapter 16: Endocrine System 16.2.12 Hormone Receptors (1): G- protein Coupled Receptors (GPCRs) FEATURES OF GPCRs: Integral membrane proteins Extracellular region binds hormone Intracellular region interacts with G- proteins  16.2.13 Downstream Effectors of GPCRs SUBUNITS OF G- EFFECTS OF cAMP Gɑ Activates adenylate cyclase PROTEINS Activates Protein Kinase A S (AC) (PKA) Converts ATP to cAMP Degraded by Gɑi Inhibits adenylate cyclase phosphodiesterase (PDE) (AC) EFFECTS OF DAG AND Blocks production of cAMP IP3IP3 causes Ca2+ release Gɑ Activates phospholipase C from ER q (PLC) DAG activates Protein Breaks down PIP2 into IP3 and Kinase C (PKC) DAG 16.2.14 Hormone Receptors (2): One- Transmembrane Spanning Receptors (1- TMS) FEATURES OF 1-TMS: Integral membrane proteins Extracellular region binds hormone Intracellular region contains a kinase domain; directly activates enzymes without G- proteins 16.2.15 Hormone Receptors (3): Nuclear Receptors FEATURES OF NUCLEAR RECEPTORS: Found inside the cell Act as transcription factors Generally cytoplasmic proteins complexed with heat shock proteins (HSPs) Hormone binding leads to dissociation of HSPs, dimerization to a second bound receptor, and translocation to the nucleus