Ja Ch 18 Endocrine System PDF

Ch. 18 :The Endocrine System Jessy Abraham 2-5 Slides – chapter notes  Ch. 18 The Endocrine System 1. Pituitary gland is located in sella turcica of sphenoid and is divided into anterior lobe and posterior lobe a...

Ch. 18 :The Endocrine System Jessy Abraham 2-5 Slides – chapter notes  Ch. 18 The Endocrine System 1. Pituitary gland is located in sella turcica of sphenoid and is divided into anterior lobe and posterior lobe a. Anterior lobe i. Human growth hormone is most plentiful hormone of anterior lobe, it acts indirectly on tissues by promoting synthesis and secretion of small protein hormones called insulin-like growth factors 1. Insulin-like growth factors stimulate general body growth and regulate various aspects of metabolism ii. Thyroid-stimulating hormone stimulates production of thyroid hormones iii.Follicle stimulating hormone 1. In females initiates follicle development and secretion of estrogens in ovaries 2. In males, stimulates sperm production in testes iv. Luteinizing hormone 1. In females stimulates secretion of estrogen by ovarian cells to result in ovulation and stimulates formation of corpus luteum and secretion of progesterone 2. In males stimulates interstitial cells of the testes to secrete testosterone v. Prolactin initiates and maintains milk secretion by mammary glands vi. Adrenocorticotrophic hormone controls production and secretion of hormone called glucocorticoids by cortex of adrenal gland vii.Melanocyte-stimulating hormone increases skin pigmentation a. Posterior lobe i. Oxytocin stimulates contraction of uterus and ejection of milk from breasts ii. Antidiuretic hormone stimulates water reabsorption by kidneys, it decreases urine volume and conserve body water iii.Both hormones are made by hypothalamus and stored in posterior lobe b. Thyroid gland i. Thyroid hormones regulate oxygen use and basal metabolic rate, cellular metabolism and growth and development ii. Calcitonin inhibit osteoclast activity, lowers blood level of calcium. Secretion is controlled by calcium levels in the blood c. Parathyroid glands are embedded on posterior surfaces of lateral lobes i. Produce parathyroid hormone, regulate homeostasis of calcium and phosphate by increasing blood calcium level and decreasing blood phosphate level ii. Parathyroid hormone increases number and activity of osteoclasts, increases rate of calcium and magnesium from reabsorption from urine therefore more is secreted in urine iii.Calcitriol ( from kidney) increase absorption of calcium and magnesium from the gastrointestinal system. a. Adrenal gland i. Mineralcorticoids, aldosterone, increases sodium and water reabsorption and decrease potassium reabsorption, helping to regulate sodium and potassium levels in body ii. Secretion is controlled by renin-angiotensin pathway and blood level of potassium iii.Glucocorticoids, cortisol promote breakdown of proteins, formation of glucose, lipolysis, resistance to stress, anti-inflammatory effects, and depression of immune response b. Pancreas i. Cell call Pancreatic Islets produce hormones 1. Alpha cells secrete the hormone glucagon, which increases blood glucose levels 2. Beta cells secrete the hormone insulin, which decreases blood glucose levels 3. Pancreatic polypeptide cells secrete pancreatic polypeptide, which regulates release of pancreatic digestive enzymes a. Pineal gland i. Attach to roof of third ventricle of brain ii. Pineal secretes melatonin in diurnal rhythm linked to dark-light cycle iii.Seasonal affective disorder (SAD) type of depression that arises during winter months when day length is short, thought to be due to over- production of melatonin b. Thymus gland i. Secretes several hormones related to immunity, promote proliferation and maturation of T cells, type of white blood cell involved in immunity c. Ovaries i. Produce estrogens and progesterone, related to development and maintenance of female sexual characteristics, reproductive cycle, pregnancy, lactation and normal reproductive functions d. Testes i. Produce sex hormones, primarily testosterone, related to development and maintenance of male sexual characteristics and normal reproductive functions  Organs with Secondary 7 Endocrine Functions Heart Atrial natriuretic peptide (ANP) Thyroid Gland Brain natriuretic peptide (BNP) Thyroxine (T4) Triiodothyronine (T 3) Thymus (undergoes atrophy Calcitonin (CT) during adulthood) Thymosins Adrenal Glands Adipose Tissue Medulla Leptin Epinephrine (E) Norepinephrine (NE) Digestive Tract Cortex Secretes numerous hormones Cortisol, corticosterone, involved in the coordination of cortisone, aldosterone, system functions, glucose androgens metabolism, and appetite Pancreas Kidneys (Pancreatic Islets) Erythropoietin (EPO) Calcitriol Insulin, glucagon Gonads KEY TO PITUITARY HORMONES Testes (male) Androgens (especially testosterone) ACTH Adrenocorticotropic hormone Testis Inhibin TSH Thyroid-stimulating hormone GH Growth hormone Ovaries (female) PRL Prolactin Estrogens FSH Follicle-stimulating hormone Ovary Progesterone LH Luteinizing hormone Inhibin MSH Melanocyte-stimulating hormone Endocrine Glands /Organs 1:Pituitary gland (hypophysis)  Lies within sella turcica  The master gland of the body Pituitary gland (hypophysis)  Secretes 9 major hormones  Attached to the hypothalamus by an infundibulum  Two Basic division of pituitary gland  Anterior Lobe (adenohypophysis)  Posterior lobe ( Neurohypophysis)  Hormones of anterior lobe  1.Thyroid-stimulating hormone (TSH) : stimulates production of thyroid hormones  2.Adrenocorticotropic hormone (ACTH)  3.Prolactin (PRL)  4.Growth hormone (GH), or somatotropin  Gonadotropins  5.Follicle-stimulating hormone (FSH)  6.Luteinizing hormone (LH)  In females, it induces ovulation and stimulates secretion of estrogens and progesterone  In males, it stimulates production of androgens  Production of FSH and LH is stimulated by gonadotropin- releasing hormone (GnRH)  Hypogonadism  Caused by low production of gonadotropins  7. melanocyte-stimulating hormone (MSH)  Hypothalamus KEY TO PITUITARY HORMONES: Direct Control Indirect Control through Release ACTH Adrenocorticotropic hormone by Nervous of Regulatory Hormones TSH Thyroid-stimulating hormone System 13 Regulatory hormones are released GH Growth hormone into the hypophyseal portal system PRL Prolactin for delivery to the anterior lobe of the FSH Follicle-stimulating hormone pituitary gland LH Luteinizing hormone MSH Melanocyte-stimulating hormone ADH Antidiuretic hormone OXT Oxytocin Anterior lobe of Adrenal pituitary gland medulla Adrenal ACTH gland Adrenal GH cortex TSH Epinephrine and Liver MSH Thyroid norepinephrine PRL FSH LH gland Somatomedins Glucocorticoids (cortisol, Melanocytes (uncertain corticosterone) significance in healthy adults) Bone, muscle, Ovaries Testes of female other tissues Mammary of male glands Thyroid hormones (T3, T 4) Inhibin Testosterone Estrogen Progesterone Inhibin  MSH is virtually nonfunctional in adults except in  Pregnant women  Those with certain diseases  Posterior lobe of the pituitary gland  Also called neurohypophysis  8.Antidiuretic hormone (ADH)  stimulates water reabsorption by kidneys, it decreases urine volume and conserve body water  9.Oxytocin (OXT)  Stimulates contraction of uterus during labor  Promotes ejection of milk after delivery  Both hormones are made by hypothalamus and stored in posterior lobe  Hypothalamus KEY TO PITUITARY HORMONES: Direct Release ACTH Adrenocorticotropic hormone 16 of Hormones TSH Thyroid-stimulating hormone Sensory Osmoreceptor GH Growth hormone stimulation stimulation PRL Prolactin FSH Follicle-stimulating hormone LH Luteinizing hormone MSH Melanocyte-stimulating hormone ADH Antidiuretic hormone OXT Oxytocin Posterior lobe of pituitary gland ADH Kidneys OXT Males: Smooth muscle in ductus deferens and prostate gland Females: Uterine smooth muscle and mammary glands  Hypothalamus KEY TO PITUITARY HORMONES: Direct Control Indirect Control through Release Direct Release ACTH Adrenocorticotropic hormone 17 by Nervous of Regulatory Hormones of Hormones TSH Thyroid-stimulating hormone System GH Growth hormone Regulatory hormones are released Sensory Osmoreceptor into the hypophyseal portal system stimulation stimulation PRL Prolactin for delivery to the anterior lobe of the FSH Follicle-stimulating hormone pituitary gland LH Luteinizing hormone MSH Melanocyte-stimulating hormone ADH Antidiuretic hormone OXT Oxytocin Posterior lobe Anterior lobe of of pituitary gland Adrenal pituitary gland medulla ADH Adrenal ACTH gland Adrenal TSH GH Kidneys cortex OXT Males: Smooth Epinephrine and Liver MSH muscle in ductus Thyroid norepinephrine PRL FSH LH deferens and gland Somatomedins prostate gland Females: Uterine smooth muscle and mammary glands Glucocorticoids (cortisol, Melanocytes (uncertain corticosterone) significance in healthy adults) Bone, muscle, Ovaries Testes of female other tissues Mammary of male glands Thyroid hormones (T3, T4) Inhibin Testosterone Estrogen Progesterone Inhibin 2:Thyroid Gland  Located in anterior neck  Largest pure endocrine glands  Thyroid hormones affects many target cells around the body  Thyroid hormones  Thyroxine (T4), or tetraiodothyronine  Contains four iodine atoms  Triidothyronine (T3), or tetraiodothyronine  Contains three iodine atoms  calcitonin (CT)  Helps regulate concentrations of Ca2+ in body fluids  Stimulates Ca2+ excretion by kidneys  Prevents Ca2+ absorption by digestive tract  Helps to reduce blood calcium level  Mostly active during childhood when skeleton grows quickly 3:Parathyroid Gland  Two pairs  Embedded in posterior surface of thyroid gland parathyroid hormones  Increases blood calcium level  Opposite effects of calcitonin i. Parathyroid hormone increases number and activity of osteoclasts, ii. increases rate of calcium and magnesium from reabsorption from urine therefore more is secreted in urine iii.Calcitriol increase absorption of calcium and magnesium from the gastrointestinal system 4:Suprarenal Gland  Lie along superior border of each kidney  Superficial adrenal cortex  Manufactures steroid hormones (corticosteroids)  Inner adrenal medulla  Produces epinephrine and norepinephrine (catecholamines) Adrenal cortex  Produces mineralocorticoids (e.g., aldosterone)  Aldosterone  Stimulates conservation of sodium ions and elimination of potassium ions  Increases sensitivity of salt receptors in taste buds  Secreted in response to  Drop in blood Na +, blood volume, or blood pressure  Rise in blood K+ concentration   Produces glucocorticoids  Example: cortisol, corticosterone, and cortisone  Secretion is regulated by negative feedback  Effects of glucocorticoids  Helps body deal with a stressful situation  Accelerate glucose synthesis and glycogen formation, especially in liver  Keeps higher level of sugar in the blood for brain function  Have anti-inflammatory effects ( large quantity of cortisol )  Used as a strong anti-inflammatory medication eg- prednisone, cortisone, etc  Produces small quantities of androgens under stimulation by ACTH Adrenal medulla  Contains two types of secretory cells  One produces epinephrine (E)  75–80 percent of medullary secretion  The other produces norepinephrine (NE)  20–25 percent of medullary secretion  Enhance fight or flight response  5:Pineal gland  Lies in posterior portion of roof of third ventricle ( epithalamus )  Synthesize hormone melatonin  Functions of melatonin  Influence circadian rhythms  6:Pancreas  Large gland  Contains exocrine and endocrine cells  Exocrine pancreas  Gland and duct cells secrete alkaline, enzyme-rich fluid, pancreatic digestive enzymes  Passes through a network of ducts to lumen of digestive tract  Endocrine pancreas  Consists of cells that form clusters known as pancreatic islets (islets of Langerhans)  Alpha (α) cells produce glucagon  Beta (β) cells produce insulin  When blood glucose level increases  Beta cells secrete insulin  Stimulating transport of glucose into target cells  Promotes storage of glucose as glycogen in liver  It lower blood sugar level  When blood glucose level decreases  Alpha cells secrete glucagon  Stimulating glycogen breakdown and glucose release by liver  It raises blood sugar level  Hyperglycemia  Abnormally high glucose levels in the blood  Diabetes mellitus  Characterized by high glucose concentrations  Glucose appears in urine  Polyuria  Urine volume becomes excessive  Type 1 diabetes mellitus  Characterized by inadequate insulin production by pancreatic beta cells  Patients require daily injections or continuous infusion of insulin  Usually develops in children and young adults  Type 2 diabetes mellitus  Most common form  Usually, normal amounts of insulin are produced, at least initially  Tissues do not respond properly (insulin resistance)  Associated with obesity  Weight loss can be an effective treatment  Complications of untreated or poorly managed diabetes mellitus include  Kidney degeneration  Retinal damage (diabetic retinopathy)  May lead to blindness  Early heart attacks (3–5 times more likely)  Peripheral nerve problems (diabetic neuropathies)  Peripheral tissue damage due to reduced blood flow  Tissue death, ulceration, infection, and amputation Secondary Endocrine Function Glands 7:Thymus Gland  Thymus  Located in lower neck and anterior thorax  Important immune organ  Site at which T lymphocyte matures.  Produces thymosin (blend of several hormones)  Promotes development and maturation of lymphocytes  Very developed in younger age, and small in adult 8: Gonads  Testes  Interstitial endocrine cells produce androgens  Testosterone is an important androgen  Nurse cells (Sertoli cells)  Secrete inhibin for negative feedback  Ovaries  Produce estrogens  After ovulation, follicle cells  Reorganize into corpus luteum  Release estrogens and progesterone  Other Endocrine Cells  9 :Heart  Produces natriuretic peptides (ANP and BNP)  When blood volume becomes excessive  Actions opposes those of angiotensin II  Resulting in reduction in blood volume and blood pressure  10: GI tract  Cells secretes gastrin which stimulates acid release in the stomach  11:Placenta  sustain fetus with steroid hormones  12:Kidney  Secretes hormones to increase blood pressure and make RBC’s  erythropoietin, renin, and calcitriol.  13:Skin  Hormone precursor for Vit D Common Disorders of the Endocrine System  Disorders of the Endocrine System Pituitary Disorders  Gigantism : hypersecretion of growth hormones ( GH)  Pituitary Dwarfism : hyposecretion of GH  Diabetes Insipidus: post pituitary does not release enough antidiuretic hormones ( ADH), Kidney do not take up enough water , increased urination ( polyuria), increased thirst ( polydipsia )dilute /watery urine and concentrated blood.  Pancreatic Disorders  Diabetes Mellitus  Type 1 : Young : Autoimmune destruction of Beta cells – can’t produce insulin  Type II : Adult :cells have lower sensitivity to insulin ( resistance )  Thyroid Disorders Graves’ Disease  Hyperthyroidism & Hypothyroidism  Graves’ Disease Most common type of hyperthyroidism =increased thyroid hormones ( TH)  Symptoms , nervousness, sweating and rapid heart rate  Myxedema: adult hypothyroidism = decreases thyroid hormones( TH)  Symptoms :low metabolic rate and weight gain  Adrenal Disorders  Cushing syndrome :hypersecretion of glucocorticoid hormones ( cortisol )  Symptoms : swollen face , high bp , depression of immune and inflammatory response  Addison's Disease : severe hyposecretion of corticosteroid hormones ( aldosterone )  Symptoms : blood sugar level and sodium drop, severe dehydration , low blood pressure , fatigue