Chapter 6 Endocrine Glands and Hormone Actions.pdf

PowerPoint® Lecture Presentation CHAPTER 6 The Endocrine System: Endocrine Glands and Hormone Actions © 2017 Pearson Education, Inc. Chapter Outline 6.1 6.2 6.3 6.4 6.5 Primary Endocrine Organs Secondary Endocrine Organs Hormone Actions at the Target Cell Abnormal Secretion of Hormones Hormone...

PowerPoint® Lecture Presentation CHAPTER 6 The Endocrine System: Endocrine Glands and Hormone Actions © 2017 Pearson Education, Inc. Chapter Outline 6.1 6.2 6.3 6.4 6.5 Primary Endocrine Organs Secondary Endocrine Organs Hormone Actions at the Target Cell Abnormal Secretion of Hormones Hormone Interactions © 2017 Pearson Education, Inc. Endocrine Glands • Derived from epithelial tissue • Primary endocrine organs • Secondary endocrine organs © 2017 Pearson Education, Inc. 6.1 Primary Endocrine Organs • • • • • • • Hypothalamus and pituitary gland Pineal gland Thyroid gland and parathyroid glands Thymus Adrenal glands Pancreas Gonads © 2017 Pearson Education, Inc. Figure 6.1 Endocrine organs. Primary Endocrine Organs Secondary Endocrine Organs Pineal gland Hypothalamus Pituitary gland Thyroid gland Parathyroid glands Thymus Heart Stomach Adrenal gland Pancreas Liver Kidney Ovaries (female) Small intestine Testes (male) Placenta (not shown, pregnant female only) © 2017 Pearson Education, Inc. Skin Hypothalamus and Pituitary Gland • Hypothalamus: Located in the brain • Pituitary gland • Anterior lobe • Posterior lobe • Infundibulum © 2017 Pearson Education, Inc. Figure 6.2a Hypothalamus and pituitary gland. Pineal gland Brain Hypothalamus Pituitary gland Spinal cord © 2017 Pearson Education, Inc. Figure 6.2b Hypothalamus and pituitary gland. Hypothalamus Anterior pituitary Infundibulum Posterior pituitary © 2017 Pearson Education, Inc. Figure 6.3 Connection between the hypothalamus and the posterior pituitary gland. Supraoptic nucleus (cells secrete oxytocin) Neurosecretory cells Paraventricular nucleus (cells secrete ADH) Hypothalamus Artery Inflow of blood Infundibulum Axon terminals (release hormones to capillaries) Anterior pituitary Capillary bed Posterior pituitary Vein © 2017 Pearson Education, Inc. Outflow of blood Hormones of Posterior Pituitary • Antidiuretic hormone (also called ADH or vasopressin) • Paraventricular nucleus • Water balance and osmolarity • Oxytocin • Supraoptic nucleus • Milk ejection © 2017 Pearson Education, Inc. Hypothalamic-Pituitary Portal System • Portal system • Links two capillary beds • Exchange between blood and tissue occurs in the capillaries © 2017 Pearson Education, Inc. Figure 6.4 The hypothalamic-pituitary portal system. Neurosecretory cells Median eminence Inflow of blood Capillary bed Hormones Artery Portal vein Capillary bed Posterior pituitary Anterior pituitary Endocrine cell Vein © 2017 Pearson Education, Inc. Outflow of blood Hypothalamic-Pituitary Portal System • The hypothalamus secretes releasing or inhibiting hormone into the primary capillary bed • Blood with tropic hormones enters the portal vein • Hypothalamic tropic hormones access the anterior pituitary secretory cells through the secondary capillary bed • Anterior pituitary tropic hormones enter the bloodstream in the same secondary capillary bed • They travel to the distant endocrine gland to trigger release of the hormone © 2017 Pearson Education, Inc. Figure 6.5 Hypothalamic and anterior pituitary tropic hormones. Neurosecretory cells Hypothalamus Hypothalamic tropic hormone PRH Hypothalamicpituitary portal vein + PIH (dopamine) – TRH CRH + + GHRH – + Prolactin Breasts © 2017 Pearson Education, Inc. + Endocrine cells Anterior pituitary Anterior pituitary tropic hormones Systemic circulation GnRH GHIH (somatostatin) TSH ACTH Thyroid gland Adrenal cortex TH Cortisol GH Liver LH Cells throughout body Insulin-like growth factors FSH Gonads Male Female Estrogens, progesterone Androgens Control of Hypothalamic Tropic Hormone Release • Neural input • Hormonal • Negative feedback • Circadian rhythm • Suprachiasmatic nucleus of the hypothalamus © 2017 Pearson Education, Inc. Figure 6.6 Negative feedback loops affecting hypothalamic and anterior pituitary tropic hormones. Hypothalamus Tropic hormone 1 secretion Long loop negative feedback Anterior pituitary Tropic hormone 2 secretion Endocrine gland Hormone 3 secretion Target cell response Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Short loop negative feedback Figure 6.7 Regulation of cortisol release. Hypothalamus Corticotropin releasing hormone (CRH) secretion Anterior pituitary Adrenocorticotropic hormone (ACTH) secretion Long loop negative feedback Adrenal gland Cortisol secretion Target cell response Initial stimulus Physiological response © 2017 Pearson Education, Inc. Result Pineal Gland • Glandular tissue in the brain • Secretes melatonin • May be involved in circadian rhythms • Plays an important role in the timing of seasonal processes in mammals © 2017 Pearson Education, Inc. Figure 6.2a Hypothalamus and pituitary gland. Pineal gland Brain Hypothalamus Pituitary gland Spinal cord © 2017 Pearson Education, Inc. Hormones of the Thyroid Gland • Two thyroid hormones • T4: Tetraiodothyronine (thyroxin) • T3: Triiodothyronine • Regulate metabolism • Calcitonin • Regulates calcium levels in the blood © 2017 Pearson Education, Inc. Figure 6.8a Locations of the thyroid and parathyroid glands. Larynx Thyroid gland Carotid artery Ventral view © 2017 Pearson Education, Inc. Trachea Parathyroid Hormone (PTH) • Regulates calcium levels in the blood © 2017 Pearson Education, Inc. Figure 6.8b Locations of the thyroid and parathyroid glands. Pharynx Parathyroid glands Esophagus Trachea Dorsal view © 2017 Pearson Education, Inc. Thyroid gland Carotid artery Thymus • Secretes thymosin • Regulates T-cell function Pineal gland Hypothalamus Pituitary gland Thyroid gland Parathyroid glands Thymus © 2017 Pearson Education, Inc. Figure 6.9a Anatomy of the adrenal gland. Adrenal cortex Adrenal medulla Adrenal gland Kidney © 2017 Pearson Education, Inc. Figure 6.9b Anatomy of the adrenal gland. Capsule Zona glomerulosa Cortex Zona fasciculata Zona reticularis Medulla Adrenal medulla © 2017 Pearson Education, Inc. Hormones of the Adrenal Gland: Adrenocorticoids • Mineralocorticoids (aldosterone) • Secreted from zona glomerulosa • Regulates sodium and potassium levels • Glucocorticoids (cortisol) • Secreted from zona fasciculata and zona reticularis • Regulates the body's response to stress • Regulates metabolism • Sex hormones (androgens) • Secreted from zona fasciculata and zona reticularis • Regulate reproductive function © 2017 Pearson Education, Inc. Adrenal Medulla • Secretory cells = chromaffin cells • 80% epinephrine • 20% norepinephrine • <1% dopamine • Under neural control © 2017 Pearson Education, Inc. Figure 6.10a Anatomy of the pancreas. Stomach Pancreas © 2017 Pearson Education, Inc. Pancreas Figure 6.10b Anatomy of the pancreas. Alpha cell (secretes glucagon) Beta cell (secretes insulin) Delta cell (secretes somatostatin) © 2017 Pearson Education, Inc. Exocrine pancreas (acinar cells and duct cells) F cell (secretes pancreatic polypeptide) Figure 6.10c Anatomy of the pancreas. Islet of Langerhans Exocrine pancreas Acinar cells Endocrine cells Duct cells © 2017 Pearson Education, Inc. Exocrine Pancreas • Acinar and duct cells • Secrete fluid and enzymes • Secretions enter the digestive tract via the pancreatic duct © 2017 Pearson Education, Inc. Endocrine Pancreas • Islets of Langerhans • • • • Alpha cells: glucagon Beta cells: Insulin Delta cells: Somatostatin F cells: Pancreatic polypeptide © 2017 Pearson Education, Inc. © 2017 Pearson Education, Inc. © 2017 Pearson Education, Inc. 6.2 Secondary Endocrine Organs • Heart: Atrial natriuretic peptide • Kidneys: Erythropoietin • GI tract: Several hormones released • Cholecystokinin • Secretin • Gastrin • Liver: Insulin-like growth factors (somatomedins) • Skin and kidneys: 1,25-Dihydroxy vitamin D3 • Fat: Leptin © 2017 Pearson Education, Inc. Control of Hormone Levels in Blood • Rate of hormone secretion • Amount of hormone bound to plasma proteins • Rate of hormone metabolism © 2017 Pearson Education, Inc. Figure 6.11 Neural control of hormone release from the hypothalamus. Stress Neural signals Hypothalamus Corticotropin releasing hormone (CRH) secretion Anterior pituitary Adrenocorticotropic hormone (ACTH) secretion Adrenal cortex Cortisol secretion Initial stimulus © 2017 Pearson Education, Inc. Physiological response Figure 6.12 Examples of humoral control of hormone release. Blood glucose Beta cells of pancreas Insulin secretion Cells throughout body Negative feedback Glucose uptake Blood glucose Regulation of blood glucose levels Blood K+ Adrenal cortex Aldosterone secretion Kidneys Negative feedback K+ excretion Blood K+ Regulation of blood potassium levels Initial stimulus Physiological response © 2017 Pearson Education, Inc. Result Transport of Hormones • Hydrophilic hormones • Peptides, catecholamines • Dissolved in plasma • Hydrophobic hormones • • • • • Steroids, thyroid hormones Bound to carrier proteins Only free hormone can bind to receptors Only free hormone can be metabolized Longer half-life © 2017 Pearson Education, Inc. Rate of Hormone Metabolism • Sites of hormone metabolism • Target cell • Blood • Liver • Lipophilic hormones can be stored in adipose tissue © 2017 Pearson Education, Inc. 6.4 Abnormal Secretion of Hormones • Hormone levels must be kept in balance • Pathologies • Hyposecretion: Too little • Diabetes mellitus type 1 • Hypersecretion: Too much • Acromegaly • Abnormal tissue responsiveness • Normal hormone levels • Tissue responds inappropriately © 2017 Pearson Education, Inc. Primary Versus Secondary Secretion Disorders • Primary • Abnormality in the endocrine organ secreting the hormone • Secondary • Abnormality in tropic hormone • Hypothalamic tropic hormone • Anterior pituitary tropic hormone © 2017 Pearson Education, Inc. Figure 6.13a Abnormal secretion of cortisol. Slide 1 Hypothalamus Corticotropin releasing hormone (CRH) secretion Anterior pituitary Adrenocorticotropic hormone (ACTH) secretion Regulation inadequate START HERE Abnormal adrenal gland Excess cortisol secretion Primary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Negative feedback Figure 6.13a Abnormal secretion of cortisol. START HERE Slide 2 Abnormal adrenal gland Primary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13a Abnormal secretion of cortisol. START HERE Slide 3 Abnormal adrenal gland Excess cortisol secretion Primary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13a Abnormal secretion of cortisol. Slide 4 Hypothalamus Corticotropin releasing hormone (CRH) secretion Anterior pituitary Adrenocorticotropic hormone (ACTH) secretion Negative feedback START HERE Abnormal adrenal gland Excess cortisol secretion Primary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13a Abnormal secretion of cortisol. Slide 5 Hypothalamus Corticotropin releasing hormone (CRH) secretion Anterior pituitary Adrenocorticotropic hormone (ACTH) secretion Regulation inadequate START HERE Abnormal adrenal gland Excess cortisol secretion Primary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Negative feedback Figure 6.13b Abnormal secretion of cortisol. Slide 1 Hypothalamus Corticotropin releasing hormone (CRH) secretion Regulation inadequate START HERE Regulation inadequate Abnormal anterior pituitary Excess Adrenocorticotropic hormone (ACTH) secretion Negative feedback Adrenal gland Excess cortisol secretion Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13b Abnormal secretion of cortisol. START HERE Abnormal anterior pituitary Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Slide 2 Figure 6.13b Abnormal secretion of cortisol. START HERE Slide 3 Abnormal anterior pituitary Excess Adrenocorticotropic hormone (ACTH) secretion Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13b Abnormal secretion of cortisol. START HERE Slide 4 Abnormal anterior pituitary Excess Adrenocorticotropic hormone (ACTH) secretion Adrenal gland Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13b Abnormal secretion of cortisol. START HERE Slide 5 Abnormal anterior pituitary Excess Adrenocorticotropic hormone (ACTH) secretion Adrenal gland Excess cortisol secretion Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13b Abnormal secretion of cortisol. Slide 6 Hypothalamus Corticotropin releasing hormone (CRH) secretion Regulation inadequate START HERE Abnormal anterior pituitary Excess Adrenocorticotropic hormone (ACTH) secretion Negative feedback Adrenal gland Excess cortisol secretion Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Figure 6.13b Abnormal secretion of cortisol. Slide 7 Hypothalamus Corticotropin releasing hormone (CRH) secretion Regulation inadequate START HERE Regulation inadequate Abnormal anterior pituitary Excess Adrenocorticotropic hormone (ACTH) secretion Negative feedback Adrenal gland Excess cortisol secretion Secondary hypersecretion of cortisol Initial stimulus Physiological response Result © 2017 Pearson Education, Inc. Hormone Interactions • The effects of combined actions • • • • Antagonism Additive Synergistic Permissiveness © 2017 Pearson Education, Inc. Antagonism • Effects of hormones oppose each other • Example: Glucagon versus insulin • Glucagon increases blood glucose levels • Insulin decreases blood glucose levels © 2017 Pearson Education, Inc. Additive Effect • Net effect equals the sum of the individual effects © 2017 Pearson Education, Inc. Synergism • Synergism: Effects of two hormones favor each other but the net effect exceeds the sum of individual effects • Example: The effects of glucagon, cortisol, and epinephrine on blood glucose © 2017 Pearson Education, Inc. Permissiveness • One hormone is needed for another to exert its effects • Examples: • Thyroid hormones cause expression of β adrenergic receptors in bronchiolar smooth muscle • Estrogen causes expression of progesterone receptors in the uterus © 2017 Pearson Education, Inc.