ENDOCRINE SYSTEM Chapter 11

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. FUNCTION OF THE ENDOCRINE SYSTEM

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. FUNCTION OF THE ENDOCRINE SYSTEM Secretion of hormones or chemical messengers that coordinate and direct activities of target cells and organs Major glands of endocrine system –pituitary- thyroid- thymus –pineal- parathyroid- adrenals –pancreas- gonads

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. HORMONAL CONTROL Negative feedback –occurs when there is a drop in the level of a hormone –triggers a chain reaction of responses to increase hormones in the blood

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PITUITARY GLAND Located at the base of the brain and connected to the hypothalamus Divided into anterior and posterior lobes Known as the master gland because of its major influence in body’s activities

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. HORMONES OF THE PITUITARY GLAND Divided into two lobes –anterior pituitary lobe is larger and produces seven hormones –posterior pituitary lobe is smaller and consists primarily of nerve fibers and neuroglial cells

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. THYROID AND PARATHYROID GLANDS Thyroid glands –Located in the anterior part of neck –Secretes 3 hormones: Thyroxine Triiodthyronine Calcitonin

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. THYROID AND PARATHYROID GLANDS Parathyroid glands –Four glands attached to posterior surface of thyroid –Stimulate an increase in number and size of osteoclasts (specialized bone cells)

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. THYMUS GLAND The thymus gland is both an endocrine gland and lymphatic organ The thymus secretes a large number of hormones

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. ADRENAL GLANDS Two adrenal glands located on top of each kidney; each has two parts –Cortex - secretes 3 groups corticoids Mineralocorticoids Glucocorticoids Sex hormones –Medulla - secretes epinephrine norepinephrine

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. GONADS Gonads - sex organs –Ovaries - female sex organ ova estrogen and progesterone –Testes - male sex organ sperm testosterone

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PANCREAS Located behind stomach Functions as: –Exocrine gland Secretes pancreatic juices into small intestine to become digestive juices –Endocrine gland Produces insulin and glucagon

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PINEAL GLAND Attached to the third ventricle of the brain Produces the hormone melatonin –Amount of light affects the amount of melatonin secreted –Causes body temperature to drop

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. OTHER HORMONES PRODUCED IN THE BODY There are many hormones produced throughout the body originating from many different glands and organs Prostaglandins are hormones secreted in various tissues throughout the body

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. DISORDERS OF THE ENDOCRINE SYSTEM Endocrine gland disturbances may be caused by: –Disease –Infection –Hyperactivity –Hypoactivity

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PITUITARY DISORDERS Hyperfunction of Pituitary –Gigantism –Acromegaly Hypofunction of Pituitary –Dwarfism Diabetes Insipidus –Caused by posterior lobe dysfunction

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. THYROID DISORDERS Blood tests are done to diagnose –Hyperthyroidism Due to overactivity of thyroid gland Hypersecretion of thyroxin –Hypothyroidism Due to inflammation of thyroid gland Thyroid isn’t able to secrete enough thyroxin

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PARATHYROID DISORDERS The parathyroid glands regulate the use of calcium and phosphorus Hyperfunctioning –Kidney stones –Calcium taken from bones Hypofunctioning –Tetany - low levels of calcium affects the nerves

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. ADRENAL DISORDERS Hyperfunction of the Adrenal –Cushing’s syndrome Hypofunction of Adrenal Cortex –Addison’s disease

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. STEROID ABUSE IN SPORTS Effects of steroid abuse: –Liver changes –Decreased spleen production –Atrophy of testicles –Breast enlargement –Cardiovascular disease

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PANCREATIC DISORDERS Diabetes mellitus –Ineffective secretion or use of insulin –Type I - juvenile diabetes –Type II - adult diabetes Treatment –Glucose monitoring- Diet –Weight reduction - Medication

© 2004 Delmar Learning, a Division of Thomson Learning, Inc. PANCREATIC DISORDERS Tests for Diabetes Mellitus –Urine samples –Blood samples glucometer (glucose monitor) glycosylated hemoglobin (HbA1c)