39-2 Human Endocrine Glands Copyright Pearson Prentice Hall
39-2 Human Endocrine Glands Endocrine glands are scattered throughout the body. The human endocrine system regulates a variety of activities. Any improper functioning of an endocrine gland may result in a disease or a disorder. Copyright Pearson Prentice Hall
39-2 Human Endocrine Glands The major glands of the endocrine system include: the pituitary gland the hypothalamus the thyroid gland the parathyroid glands the adrenal glands the pancreas the reproductive glands Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pituitary Gland The pituitary gland secretes nine hormones that directly regulate many body functions and controls the actions of several other endocrine glands. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pituitary Gland The pituitary gland is a structure at the base of the skull. The gland is divided into two parts: the anterior pituitary and the posterior pituitary. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pituitary Gland The Pituitary Gland Hypothalamus The pituitary gland, which controls many other endocrine glands, is located below the hypothalamus in the brain. The pituitary gland has two lobes: an anterior lobe and a posterior lobe. Anterior pituitary Posterior pituitary Pituitary gland Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pituitary Gland Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pituitary Gland Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pituitary Gland Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Hypothalamus The hypothalamus is the part of the brain attached to the posterior pituitary. The hypothalamus controls the secretions of the pituitary gland. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Hypothalamus Hypothalamus The pituitary gland, which controls many other endocrine glands, is located below the hypothalamus in the brain. Pituitary gland Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Hypothalamus The hypothalamus: - is influenced by hormone levels in the blood and by sensory information. coordinates interactions between the nervous system and the endocrine system Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Thyroid Gland Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Thyroid Gland The thyroid gland is located at the base of the neck and wraps around the upper part of the trachea. It: produces thyroxine. thyroxine regulates the metabolic rate of cells. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Thyroid Gland Thyroid Gland Larynx Thyroid gland Esophagus Hormones produced by the thyroid gland and the parathyroid glands maintain the level of calcium in the blood. The thyroid gland wraps around the trachea. Trachea Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Thyroid Gland Thyroid Disorders Hyperthyroidism: the body produces too much thyroxine. It is characterized by elevated temperature and metabolic rate, increased blood pressure, and weight loss. Hypothyroidism: the body produces too little thyroxine. It is characterized by lower temperature and metabolic rate, lack of energy, and weight gain. Goiter: enlargement of thyroid gland. Caused by an iodine deficiency. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Parathyroid Glands The four parathyroid glands are found on the back surface of the thyroid gland. Hormones from the thyroid gland and the parathyroid glands act to maintain homeostasis of calcium levels in the blood. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Parathyroid Glands Parathyroid glands: secrete parathyroid hormone (PTH). PTH regulates calcium levels in the blood by increasing reabsorption of calcium in the kidneys and by increasing uptake of calcium from the digestive system. PTH affects other organ systems, promoting proper nerve and muscle function and bone structure. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Parathyroid Gland Parathyroid Glands Thyroid gland Parathyroid glands Hormones produced by the thyroid gland and the parathyroid glands maintain the level of calcium in the blood. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Adrenal Glands The adrenal glands are two pyramid-shaped structures that sit on top of the kidneys, one gland on each kidney. The adrenal glands release hormones that help the body prepare for and deal with stress. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Adrenal Glands Adrenal gland Kidney The adrenal glands release hormones that help the body prepare for and deal with stress. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Adrenal Glands An adrenal gland has an outer part called the adrenal cortex and an inner part called the adrenal medulla. Adrenal cortex Adrenal medulla Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Adrenal Glands Adrenal Cortex produces over 24 steroid hormones. the hormone aldosterone regulates reabsorption of sodium ions and the excretion of potassium ions by the kidneys. the hormone cortisol controls the rate of metabolism of carbohydrates, fats, and proteins. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Adrenal Glands Adrenal Medulla: prepares the body for energy-intense activities. releases epinephrine and norepinephrine. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Adrenal Glands Epinephrine and norepinephrine: increase heart rate, blood pressure, and blood flow to the muscles. cause air passageways to open wider, allowing for an increased intake of oxygen. stimulate the release of extra glucose into the blood to help produce a sudden burst of energy. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas The pancreas has both exocrine and endocrine functions. It is a digestive gland whose secretions break down food. It also produces the hormones insulin and glucagon. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas Insulin and glucagon help to keep the level of glucose in the blood stable. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas Insulin stimulates cells in the liver and muscles to remove sugar from the blood and store it as glycogen or fat. Glucagon stimulates the liver to break down glycogen and release glucose back into the blood. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas Maintaining Blood Sugar Levels When glucose levels rise, the pancreas releases insulin. Insulin stimulates cells to take glucose out of the bloodstream. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas Glucose taken out of circulation is stored as glycogen in the liver (about one day’s worth of energy) and skeletal muscles. In fat tissue, glucose is converted to lipids. When blood glucose level drops, glucagon is released from the pancreas. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas Glucagon stimulates liver cells and skeletal muscles to break down glycogen and increase glucose levels. It causes fat cells to break down fats for production of carbohydrates. This makes more chemical energy available and helps raise the blood glucose level back to normal. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Pancreas Diabetes Mellitus When the pancreas fails to produce or properly use insulin, diabetes mellitus occurs. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Reproductive Glands The gonads are the body’s reproductive glands. The gonads serve two important functions: the production of gametes, and the secretion of sex hormones. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Reproductive Glands The female gonads, ovaries, produce the female sex hormones estrogen and progesterone. Progesterone prepares the uterus for the arrival of a developing embryo. Estrogen is needed for the development of eggs and for the formation of physical characteristics of the female body. Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall Reproductive Glands The male gonads, testes, produce testosterone, which is needed for normal sperm production and development of male physical characteristics. Copyright Pearson Prentice Hall