Anatomy and Physiology, Sixth Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Chapter 18 Lecture Outline* *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 18 Endocrine Glands

Endocrine System Functions Metabolism and tissue maturation Ion regulation Water balance Immune system regulation Heart rate and blood pressure regulation Control of blood glucose and other nutrients Control of reproductive functions Uterine contractions and milk release

Pituitary Gland and Hypothalamus Where nervous and endocrine systems interact Pituitary gland/hypophysis Secretes 9 major hormones Hypothalamus Regulates secretory activity of pituitary gland through neurohormones and action potentials Posterior pituitary is an extension of

Pituitary Gland Structure Posterior or neurohypophysis Continuous with the brain Secretes neurohormones Anterior or adenohypophysis Consists of three areas with indistinct boundaries: pars distalis, pars intermedia, pars tuberalis

Relationship of Pituitary to Brain

Hypothalamus, Anterior Pituitary and Target Tissues

Pituitary Gland Hormones Posterior Antidiuretic hormone (ADH) Oxytocin Anterior Growth hormone (GH) or somatotropin Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Melanocyte-stimulating hormone (MSH) Luteinizing hormone (LH) Follicle-stimulating hormone (FSH) Prolactin

Antidiuretic Hormone Also called vasopressin Promotes water retention by kidneys Secretion rate changes in response to alterations in blood osmolality and blood volume Lack of ADH secretion is a cause of diabetes insipidus

Oxytocin Promotes uterine contractions during delivery Causes milk ejection in lactating women

Growth Hormone (GH) Stimulates uptake of amino acids and conversion into proteins Stimulates breakdown of fats and glycogen Promotes bone and cartilage growth Increased secretion in response to increase amino acids, low blood glucose, or stress Regulated by GHRH and GHIH or somatostatin

TSH, ACTH, MSH ACTH TSH or thyrotropin MSH Stimulates cortisol secretion from adrenal cortex MSH Increases skin pigmentation TSH or thyrotropin Causes release of thyroid hormones from thyroid gland

LH, FSH, Prolactin Prolactin LH and FSH Both hormones regulate production of gametes and reproductive hormones Testosterone in males Estrogen and progesterone in females GnRH from hypothalamus stimulates LH and FSH secretion Prolactin Stimulates milk production in lactating females

Thyroid Gland One of largest endocrine glands Highly vascular Histology Composed of follicles Parafollicular cells Secrete calcitonin which reduces calcium concentration in body fluids when levels elevated

Biosynthesis of Thyroid Hormones

Thyroid Hormones Include Transported in blood Triiodothryronine or T3 Tetraiodothyronine or T4 or thyroxine Transported in blood Bind with intracellular receptor molecules and initiate new protein synthesis Increase rate of glucose, fat, protein metabolism in many tissues thus increasing body temperature Normal growth of many tissues dependent on

Regulation of T3 and T4 Secretion

Thyroid Hormone Hyposecretion and Hypersecretion Hypothyroidism Decreased metabolic rate Weight gain, reduced appetite Dry and cold skin Weak, flabby skeletal muscles, sluggish Myxedema Apathetic, somnolent Coarse hair, rough dry skin Decreased iodide uptake Possible goiter Hyperthyroidism Increased metabolic rate Weight loss, increased appetite Warm flushed skin Weak muscles that exhibit tremors Exophthalmos Hyperactivity, insomnia Soft smooth hair and skin Increased iodide uptake Almost always develops goiter

Parathyroid Glands Embedded in thyroid Secrete PTH Increases blood calcium levels Stimulates osteoclasts Promotes calcium reabsorption by kidneys

Regulation of PTH Secretion

Adrenal Glands Functions as part of sympathetic nervous system Composed of medulla and cortex (3 layers) Hormones Medulla secretes epinephrine and norepinephrine Cortex secretes mineralocorticoids, glucocorticoids, androgens

Hormones of Adrenal Cortex Mineralocorticoids Zona glomerulosa Aldosterone produced in greatest amounts Increases rate of sodium reabsorption by kidneys increasing sodium blood levels Glucocorticoids Zona fasciculata Cortisol is major hormone Increases fat and protein breakdown, increases glucose synthesis, decreases inflammatory response Androgens Zona reticularis Converted to androgen and testosterone

Pancreas Located along small intestine and stomach Exocrine gland Produces pancreatic digestive juices Endocrine gland Consists of pancreatic islets Composed of Alpha cells secrete glucagon Beta cells secrete insulin Delta cells secrete somatostatin

Insulin and Glucagon Insulin Target tissues: liver, adipose tissue, muscle, and satiety center of hypothalamus Increases uptake of glucose and amino acids by cells Glucagon Target tissue is liver Causes breakdown of glycogen and fats for energy

Regulation of Insulin Secretion

Regulation of Blood Nutrient Levels After a Meal

Regulation of Blood Nutrient Levels During Exercise

Hormones of the Reproductive System Female: Ovaries Estrogen and Progesterone Uterine and mammary gland development and function, external genitalia structure, secondary sex characteristics, menstrual cycle Inhibin Inhibits FSH secretion Relaxin Increases flexibility of symphysis pubis Male: Testes Testosterone Regulates production of sperm cells and development and maintenance of male reproductive organs and secondary sex characteristics Inhibin Inhibits FSH secretion

Pineal Body In epithalamus Produces Melatonin Arginine vasotocin Enhances sleep Arginine vasotocin Regulates function of reproductive system in some animals

Effects of Aging on Endocrine System Gradual decrease in secretory activity of some glands GH as people age Melatonin Thyroid hormones Kidneys secrete less renin Familial tendency to develop type II diabetes

Diabetes Mellitus Results from inadequate secretion of insulin or inability of tissues to respond to insulin Types Type I or IDDM (Insulin-dependent) Develops in young people Type II or NIDDM (Non-insulin dependent) Develops in people older than 40-45 More common