Endocrine System

Structure of the Endocrine System A network of Endocrine glands A network of Endocrine glands –Ductless (tubeless) organs or groups of cells that secrete hormones directly into the blood stream –Hormones – chemical substances that are produced in glands and help regulate many of your body’s functions Hormones are secreted by the endocrine glands and carried by the blood to their destinations Hormones are secreted by the endocrine glands and carried by the blood to their destinations

Glands of the Endocrine System Thyroid – produces hormones that regulate metabolism, body heat, and bone growth Thyroid – produces hormones that regulate metabolism, body heat, and bone growth Parathyroid glands – produce a hormone that regulates the body’s calcium and phosphorus balance Parathyroid glands – produce a hormone that regulates the body’s calcium and phosphorus balance Testes – male reproductive glands produce testosterone Testes – male reproductive glands produce testosterone Ovaries – female reproductive glands estrogen & progesteron Ovaries – female reproductive glands estrogen & progesteron

Glands of the Endocrine System Hypothalamus Hypothalamus –Links the endocrine system with the nervous system –Stimulates the pituitary gland Pineal gland – regulates sleep cycles Pineal gland – regulates sleep cycles Thymus gland – regulates the development of the immune system Thymus gland – regulates the development of the immune system Pancreas – a gland that serves both the digestive and the endocrine systems Pancreas – a gland that serves both the digestive and the endocrine systems –Regulates the level of glucose in the blood (glucagon and insulin)

Pituitary Gland Regulates and controls the activities of all other endocrine glands Regulates and controls the activities of all other endocrine glands “master gland” “master gland” Has 3 lobes (sections) Has 3 lobes (sections) –Anterior lobe –Intermediate lobe –Posterior lobe

Anterior Lobe Produces 6 hormones Produces 6 hormones –Somatotropic – stimulates normal body growth –Thyroid-stimulating hormone (TSH) – stimulates thyroid –Adrenocorticotropic hormone (ACTH) – stimulates production of hormones in the adrenal glands –2 hormones stimulate all other sex hormones –Follicle-stimulating hormone (FSH) and Lutenizing hormone (LH) control the growth, development and functions of the gonads Gonads – ovaries and testes Gonads – ovaries and testes In females In females –FSH – stimulates cells in ovaries to produce estrogen –LH – responsible for ovulation and stimulates ovaries to produce progesterone In males In males –LH – stimulates cells in testes to produce testosterone –FSH – controls the production of sperm

Intermediate lobe Secretes melanocyte-stimulating hormone (MSH) Secretes melanocyte-stimulating hormone (MSH) –Controls darkening of the skin – stimulates skin pigments

Posterior lobe Secretes antidiuretic homone (ADH) Secretes antidiuretic homone (ADH) –Regulates the balance of water in the body –Produces Oxytocin Stimulates uterine contractions during the birthing process Stimulates uterine contractions during the birthing process

Adrenal Glands Glands that help the body recover from stress and respond to emergencies Glands that help the body recover from stress and respond to emergencies Each gland has 2 parts Each gland has 2 parts –Adrenal cortex Secretes a hormone that inhibits the amount of sodium excreted in urine and maintains blood volume and pressure Secretes a hormone that inhibits the amount of sodium excreted in urine and maintains blood volume and pressure Secretes a hormone that aids in the metabolism Secretes a hormone that aids in the metabolism –Adrenal medulla Controlled by the hypothalamus and the autonomic nervous system Controlled by the hypothalamus and the autonomic nervous system –Secretes epinephrine and nor-epinephrine

Problems of the Endocrine System Diabetes – the pancreas secretes little or no insulin Diabetes – the pancreas secretes little or no insulin Graves disease – hyperthyroidism – overactive or enlarged thyroid Graves disease – hyperthyroidism – overactive or enlarged thyroid –Symptoms – nervousness, weight loss, increases thirst, rapid heartbeat, and intolerance for heat Cushing’s disease – overproduction of adrenal hormones Cushing’s disease – overproduction of adrenal hormones –Symptoms – round face, humped upper back, thin and easily bruised skin, and fragile bones Goiter – enlarged thyroid – caused by a lack of iodine in the diet Goiter – enlarged thyroid – caused by a lack of iodine in the diet Growth disorders – abnormal amounts of growth hormone Growth disorders – abnormal amounts of growth hormone

Care of the Endocrine System Eat nutritious meals Eat nutritious meals Get enough sleep Get enough sleep Avoid stress Avoid stress