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Memmler’s The Human Body in Health and Disease 11th edition Chapter 12 The Endocrine System: Glands and Hormones Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Endocrine System •Consists of a group of glands that produce hormones •Works with nervous system to control and coordinate all other body systems •Affects body systems by chemical stimuli Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones •Chemical messengers with regulatory effects on cells or organs •Hormones from endocrine glands are released directly into tissue fluids; not through ducts •Some affect many tissues – Growth hormone – Thyroid hormone – Insulin •Some affect a specific tissue (target tissue). Receptors on the cells of the target tissue interpret the hormone message. – Thyroid-stimulating hormone (TSH) - acts on Thyroid gland – Adrenocorticotropic hormone (ACTH) - acts on Adrenal glands Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormone Chemistry •Amino acid compounds – Proteins or related compounds – All hormones except steroids •Lipids – Made of fatty acids – Most are steroids, derived from the steroid cholesterol – Produced in adrenal cortex and sex glands – Prostaglandins are also lipids – Steroid hormones can be recognized by the suffix -one. Testosterone and progesterone Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-1: What are hormones and what are some effects of hormones? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: Hormones from the sex glands are made up of: a. amino acid compounds b. lipids c. proteins Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: b. lipids Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormone Regulation •Negative feedback (most common) – Endocrine gland over secretes hormone – Tissue becomes too active – Tissue negatively affects gland to decrease secretion •Positive feedback – Hormone response produces more hormone •Rhythmic pattern Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-2: Hormone levels are normally kept within a specific range. What is the most common method used to regulate secretion of hormones? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Endocrine Glands and Their Hormones Tissues other than endocrine glands also secrete hormones •Brain •Digestive organs •Kidney Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The endocrine glands. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Pituitary Pituitary (hypophysis) gland •Master gland •Size of a cherry •Releases hormones that affect working of other glands •Controlled by hypothalamus •Consists of 2 lobes - Anterior Pituitary Lobe and the Posterior Pituitary Lobe Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The hypothalamus, pituitary gland, and target tissues. Arrows indicate the hormones’ target issues and feedback pathways. ZOOMING IN • What two structures does the infundibulum connect? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Control of the Pituitary Hypothalamus •Sends releasing hormones (RH) and inhibiting hormones (IH) – Hormones stimulate (RH) and suppress (IH) anterior pituitary secretions – Nerve impulses stimulate secretions – RH and IH are sent from the Hypothalamus to the Anterior Pituitary lobe. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-3: What part of the brain controls the pituitary? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones of the Anterior Lobe •Growth hormone (GH) or somatotropin - promotes growth of all body tissue •Thyroid-stimulating hormone (TSH) or thyrotropin promotes thyroid hormone production •Adrenocorticotropic hormone (ACTH) - promotes adrenal cortex hormone production Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones of the Anterior Lobe •Prolactin (PRL) - promotes lactation •Gonadotropins - acts on male and female reproductive systems. – Follicle-stimulating hormone (FSH) - promotes the development of egg (ovaries) and sperm (testes) – Luteinizing hormone (LH) - promotes ovulation and sex hormone secretion in males and females Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones of the Posterior Lobe •Hormones are produced by the Hypothalamus •They are stored in the Posterior Pituitary lobe •Antidiuretic hormone (ADH) - promotes water reabsorption in the kidneys therefore preventing water loss – Too much ADH will raise blood pressure – Not enough ADH will cause excessive water loss •Diabetes insipidus •Oxytocin - promotes uterine contractions and lactation Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-4: What are the hormones from the anterior pituitary? Checkpoint 12-5: What hormones are released from the posterior pituitary? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tumors of the Pituitary •Excessive number of tumor growth hormone (GH) cells in childhood – Gigantism •Overactive GH-producing tumor cells in adulthood – Acromegaly •Tumors that destroy secreting tissues – Underactivity Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Thyroid Gland •Largest endocrine gland •Lateral lobes on either side of larynx •Connecting band (isthmus) - center •Enclosed by connective tissue capsule •Functions with iodine Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones of the Thyroid Gland •Thyroxine (T4) – Principle hormone – Increases energy and protein metabolism rate •Triiodothyronine (T3) – Increases energy and protein metabolism rate •Calcitonin – Regulates calcium metabolism – Lowers the amount of calcium in blood ,depositing it in bone tissue – Works with parathyroid hormone and vitamin D Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Disorders of the Thyroid Gland •Goiter is enlargement of thyroid gland – Simple goiter – Adenomatous or nodular goiter - tumor formation •Hypothyroidism - underactive thyroid – Infantile hypothyroidism (cretinism) - failure of thyroid to form in utero, lack of physical and mental development – Myxedema - thyroid atrophy - can be treated •Hyperthyroidism - overactive thyroid – – Graves disease - goiter, bulging eyes, intense nervousness, rapid pules Thyroid storm - develops quickly and will likely cause death •Thyroiditis - thyroid inflammation – Hashimoto disease - autoimmune disorder Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-6: What is the effect of thyroid hormones on cells? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Parathyroid Glands •Four glands in posterior capsule of thyroid •Secrete parathyroid hormone (PTH) – Works with calcitonin to regulate calcium metabolism Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Calcium Metabolism Calcium balance requires •Calcitriol (dihydroxycholecalciferol) – AKA - Vitamin D – Produced by modifying vitamin D in liver and then in kidney •Parathyroid hormone •Calcitonin Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Disorders of the Parathyroid Glands •Tetany - muscle spasms – Inadequate production of parathyroid hormone (PTH) •Fragile bones and kidney stones – Excess production of parathyroid hormone (PTH) Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: Which gland secretes triiodothyronine to help increase the metabolic rate in cells? a. parathyroid b. thyroid c. adrenal Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer b. thyroid Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-7: What mineral is regulated by calcitonin and parathyroid hormone (PTH)? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Adrenal Glands •Two small glands on top of kidneys •Each gland has two parts that act as separate glands – Medulla - inner area – Cortex - outer portion Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones from the Adrenal Medulla Fight-or-flight hormones •Epinephrine (adrenaline) •Norepinephrine (noradrenalin) Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-8: The main hormone from the adrenal medulla also functions as a neurotransmitter in the sympathetic nervous system. What is the name of this hormone? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones from the Adrenal Cortex •Glucocorticoids - maintains the body’s carbohydrate reserve. – Cortisol or hydrocortisone - released in times of stress, increases carbohydrates in blood •Mineralocorticoids - regulates electrolyte balance – Aldosterone - controls sodium and potassium levels by influencing water volume •Sex hormones Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Disorders of the Adrenal Cortex •Addison disease – Hypofunction of adrenal cortex – Muscle atrophy, weakness, and inadequate water and salt balance. •Cushing syndrome – Hypersecretion of cortisol – Obesity, round (moon) face, thin skin, easily bruised, bone loss, and elevated blood sugar •Aldosteronism – Hyperfunction of adrenal cortex resulting in excess secretion of aldosterone Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-9: What three categories of hormones are released by the adrenal cortex? Checkpoint 12-10: What effect does cortisol have on glucose levels in the blood? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Pancreas and Its Hormones Islets of Langerhans are specialized pancreas cells that secrete hormones and are part of the Endocrine system •Insulin – Lowers blood sugar level – Stimulates manufacture of amino acids into protein – Produced by beta cells of the Pancreas •Glucagon – Increases blood sugar – Produced by alpha cells of the Pancreas Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-11: What two hormones produced by the islets of the pancreas act to regulate glucose levels in the blood? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Diabetes Mellitus •Insulin-dependent diabetes mellitus (IDDM) – Type 1 diabetes – Less common but more severe – Results in the destruction of Pancreatic beta cells - not enough insulin •Non—insulin-dependent diabetes (NIDDM) – Type 2 diabetes – Body cells cannot respond to insulin - Obesity •Gestational diabetes – Usually disappears after childbirth Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Metabolic Syndrome •Also called syndrome X or insulin-resistance syndrome •Related to type 2 diabetes •High state of hyperglycemia and obesity •Caused by insulin resistance in combination with high plasma glyceride levels, low HDL levels, and hypertension •Treated with weight loss, diet, exercise; drugs to lower blood pressure and cholesterol; drugs to lower insulin resistance Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-12: What hormone is low or ineffective in cases of diabetes mellitus? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Sex Glands Ovaries and testes produce hormones to •Develop sexual characteristics - secondary sex characteristics •Maintain reproductive organs Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones of the Sex Glands •Male sex hormone – Testosterone •Female sex hormones – Estrogen - stimulates ovulation, menstruation – Progesterone - maintains pregnancy Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-13: In addition to controlling reproduction, sex hormones confer certain features associated with male and female gender. What are these features called as a group? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: What is the name for the male sex glands? a. gonads b. pituitaries c. testes Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: c. testes Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Thymus Gland •Mass of lymphoid tissue in upper chest superior to heart •Important in development of immunity •Produces thymosin – Assists in maturity of T lymphocytes – T lymphocytes circulate in the lymph Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Pineal Gland •Cone-shaped structure posterior to midbrain •Produces melatonin – Influences sleep–wake cycles – Stimulated by light intensity – Appears to delay onset of puberty Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Other Hormone-Producing Tissues Substances that regulate body actions are also produced by •Stomach •Small intestine •Kidneys •Brain •Atria of heart •Placenta Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: Which endocrine gland is also called the hypophysis and is known as the “master gland”? a. the pituitary gland b. the thyroid c. the pancreas Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: a. the pituitary gland Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Prostaglandins Group of hormones made by most body tissues •Produced, act, and rapidly inactivated in or close to origin •Constrict structures - blood vessels, bronchi, and intestines •Dilate structures - blood vessels, bronchi, and intestines •Promote inflammation – Anti inflammatory drugs block prostaglandin production. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-14: What are some organs other than the endocrine glands that produce hormones? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones and Treatment Hormones are extracted from animal tissue, manufactured in the lab, or genetically engineered •Growth hormone •Insulin •Adrenal steroids •Epinephrine (adrenaline) •Thyroid hormones •Oxytocin •Androgens •Estrogen and progesterone Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question: Which hormone is used medically to treat a severe allergic reaction (anaphylactic shock)? a. oxytocin b. insulin c. epinephrine Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer: c. epinephrine Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hormones and Stress Stress response involves both nervous and endocrine system •Hormones released during stress help body cope - ACTH, Insulin, Sex hormones, and Thyroid hormones •Unchecked levels of hormones can harm body – High blood pressure – Heart disease – Headaches – Insomnia Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Checkpoint 12-15: What are some hormones released in time of stress? Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Aging and the Endocrine System •Pancreas – Adult-onset diabetes mellitus - Type 2 •Thyroid – Decreased hormone secretion •Pituitary – Decreased bone mass Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins End of Presentation Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins