13_Endocrine System.pptx

Endocrine System Chapter 15, Human Anatomy (LibreTexts) "The Endocrine System" by OpenStax is licensed under CC BY 3.0 Functions of Endocrine System • Regulate a wide range of body functions through production and secretion of hormones into the bloodstream. • Hormones are molecules that have an e...

Endocrine System Chapter 15, Human Anatomy (LibreTexts) "The Endocrine System" by OpenStax is licensed under CC BY 3.0 Functions of Endocrine System • Regulate a wide range of body functions through production and secretion of hormones into the bloodstream. • Hormones are molecules that have an effect only on specific cells called target cells which have receptors for that hormone. The organs that contain target cells are called target organs. • Body functions regulated by endocrine system: • • • • • • • • metabolism growth and development sexual function and reproduction heart rate blood pressure appetite sleeping and waking cycles body temperature Organs of Endocrine System Endocrine glands: • • • • • Pituitary gland Thyroid gland Parathyroid gland Adrenal glands (Pineal gland) Organs containing endocrine cells: • • • • • Hypothalamus Thymus Pancreas Testes and Ovaries (GI Tract, Kidneys, Heart) "The Endocrine System" by OpenStax is licensed under CC BY 3.0 Hypothalamus • Master control center of the endocrine system • Controls secretory activity of anterior pituitary gland • Oversees stimulation and hormone secretion of adrenal medulla • Produces hormones to be released by the posterior pituitary gland: • Regulatory hormones i.e. Prolactin-releasing hormone • Antidiuretic hormone (ADH) • Oxytocin (OT) Pituitary Gland • Pituitary is also called the hypophysis • Located just inferior to the hypothalamus – connected by infundibulum (stalk) • Housed in sella turcica of sphenoid bone • Divided into anterior and posterior lobes "Hypothalamus-Pituitary Complex" by OpenStax is licensed under CC BY 3.0 Pituitary Gland - Hormones • Secretes hormones that regulate other organs. • Anterior Pituitary hormones: • • • • • • • Follicle-stimulating Hormone (FSH) Luteinizing Hormone (LH) Adrenocorticotropic Hormone (ACTH) Thyroid-Stimulating Hormone (TSH) Prolactin (PRL) (Ignore) Growth Hormone (GH) • Posterior Pituitary releases Regulatory Hormones, Antidiuretic hormone (ADH) and Oxytocin (OT) which are produced by hypothalamus Thyroid Gland • Thyroid is largest gland entirely devoted to endocrine activities • Located inferior to thyroid cartilage and anterior to the trachea • Butterfly shape • Secretes hormones important for metabolism and calcium balance: • Thyroid hormone (TH) increases metabolic rate (iodine is needed to produce TH) • Calcitonin reduces blood calcium "The Thyroid Gland" by OpenStax is licensed under CC BY 3.0 / Micrograph provided by the Regents of University of Michigan Medical School © 2012 Parathyroid Glands • Essential endocrine gland • Four small nodules located on the posterior surface of the thyroid gland • Secretes hormones important for calcium balance • Parathyroid hormone (PTH) increases blood calcium levels "Posterior Thyroid" by OpenStax is licensed under CC BY-SA 3.0 Adrenal Glands • Paired adrenal glands sit on superior borders of the kidneys • Each gland has an outer adrenal cortex and an inner adrenal medulla, with each region secreting different hormones • Controlled by anterior pituitary hormones • Adrenal cortex secretes corticosteroid hormones that regulate salt, sugar and reproduction • Adrenal medulla is a modified sympathetic ganglion that secretes epinephrine (adrenaline) and norepinephrine involved with fight-or-flight response Adrenal Glands - Image "The Adrenal Glands" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work / Micrograph provided by the Regents of University of Michigan Medical School © 2012 Thymus • The thymus is located just superior to the heart and just deep to the sternum • Larger in infants and children than in adults • Functions in association with lymphatic system to regulate body immunity Pancreas • Elongated organ situated posterior to the stomach • Exocrine cells secrete alkaline pancreatic juice in small intestine • Endocrine cells secrete hormones important for blood glucose levels: • Insulin decreases blood glucose levels • Glucagon increases blood glucose levels • Somatostatin slows down absorption of nutrients Pancreas - Image "Exocrine and Endocrine Pancreas" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work in (a) and the original work in (b) Gonads • Secrete sex hormones starting at puberty and under control of the hypothalamus and anterior pituitary gland (LH and FSH): • Testes secrete Androgens (primarily testosterone) that stimulate male reproductive organ development, production of sperm • Ovaries secrete Estrogen and Progesterone that stimulate development of female reproductive organs and regulate menstrual cycle Clinical Anatomy: Pituitary Dwarfism and Gigantism • Pituitary Dwarfism: Caused by growth hormone deficiency due to hypothalamic or pituitary problem. Proportionate dwarfism: arms, legs and head are smaller than normal. Injections of growth hormone helps but slightly. • Pituitary Gigantism: Over-secretion of growth hormone during childhood due to tumor in the pituitary gland. Abnormally high levels of growth hormone are dangerous because they can cause heart failure, diabetes, high blood pressure and may increase the risk of colon cancer. "A giant and a dwarf, London, 1927 Wellcome L0014197" by Wellcome Images is licensed under CC BY 4.0 Clinical Anatomy: Hyperthyroidism • Excessive production of thyroid hormone • Consequences: Increased metabolic rate, weight loss, hyperactivity, heat intolerance, exophthalmos (bulging eyes) • Cause: Most common cause is Graves disease • Treatment: Initial treatment for hyperthyroidism usually is anti-thyroid medicine or radioactive iodine therapy. Clinical Anatomy: Hypothyroidism • Decreased production of thyroid hormone • Symptoms: Low metabolic rate, lethargy, being cold, weight gain, photophobia. It can lead to goiter which is the enlargement of the thyroid gland. • Causes: Caused by lack of iodine which leads to deficiency of Thyroid hormone • Treatment: oral thyroid hormones; surgically removal for goiter "Goiter" by Almazi is licensed under CC BY 4.0