Chapter_18review_sheet.docx

Chapter 18: The Endocrine System and Development Hormones circulate throughout the body until they reach target cells Circulating hormones – travel long distances Local hormones – affect cells close by Autocrine Paracrine Define endocrine glands. Are made up of secretory cells that release their pro...

Chapter 18: The Endocrine System and Development Hormones circulate throughout the body until they reach target cells Circulating hormones – travel long distances Local hormones – affect cells close by Autocrine Paracrine Define endocrine glands. Are made up of secretory cells that release their products called hormones directly into blood or tissue fluid What is the purpose of target cells? Target cells respond to the hormone, influencing growth, development, metabolism, and behavior What is the main function of the endocrine system? Main function of the endocrine system is to coordinate body systems and maintain homeostasis What are the five major endocrine glands? Pituitary – Thyroid – Parathyroid – Adrenals – Pineal – Name five organs with some endocrine tissue. Hypothalamus – Thymus – Pancreas – Ovaries – Testes – Explain the difference between how steroid hormones and non-steroid hormones work. Steroid Hormone – are lipid-soluble Can pass directly through the phospholipid bilayer of cell membranes Steroid hormones pass directly through cell and nuclear membranes of their target Steroid hormones are lipid-soluble and can readily diffuse across the phospholipid bilayer of the target cell After crossing the cell membrane, steroid hormones can bind to their specific receptors in the cytoplasm or nucleoplasm The receptor-hormone complexes then either act to increase or decrease the production of specific proteins These newly made proteins in turn alter the activities of the target cell Non-steroid hormone – are not lipid-soluble Cannot pass through the cell membrane Non-steroid hormones are water-soluble and cannot diffuse across the phospholipid bilayer Hormone binds to a receptor on the cell membrane which activates adenylate cyclase Adenylate cyclase activates cyclic AMP (cAMP) cAMP in turn activates protein kinases, that phosphorylate proteins inside the cell Phosphorylated proteins make changes in the cell very quickly The main difference between these classes is solubility Hypothalamus and pituitary glands – both are master endocrine glands because they release hormones that affect other glands in the body Hypothalamus – secretes hormones called releasing factors that control the anterior pituitary Produces ADH and Oxytocin that are released through the posterior pituitary Oxytocin – causes uterine contraction to occur during birth After birth oxytocin causes release of milk from the mammary glands Antidiuretic Hormone – ADH, vasopressin Acts on kidney tubules causing them to conserve water in the body Name the six hormones released by anterior pituitary. Thyroid-stimulating Hormone– TSH, stimulates the thyroid gland to produce the thyroid hormone Luteinizing Hormone – LH, in females LH stimulates ovulation LH stimulate testosterone production in males Follicle-stimulating Hormone – FSH, stimulates egg development in the follicle of the ovary Stimulate sperm production in the testes Adrenocorticotropic Hormone – ACTH, stimulates cells of the adrenal cortex that produce cortisol Growth Hormone – hGH, controls the growth of all body tissues including bone Hypersecretion – too much during childhood = giantism Too much GH in adult = acromegaly, thickening of the hands, feet, skull, and skin Melanocyte-stimulating Hormone – MSH, Prolactin – PRL, stimulates milk production in females What are two GH disorders? Define ACTH. Name 2 hormones made by the thyroid gland. What are their functions? Butterfly shaped gland located on top of the trachea, it produces: Thyroid hormone – T3,T4, control metabolism in the body Calcitonin – removes calcium from the blood into bone tissue What removes calcium from the blood into bone tissue? Calcitonin Differentiate between cretinism and myxedema. Cretinism – Too little TH during fetal development or infancy Characterized by dwarfism and delayed mental and sexual development Myxedema – Too little Th in adulthood Causes a condition in which fluid accumulates in facial tissues and a decrease in alertness, body temperature, and heart rate Goiter – enlarged Thyroid gland may be associated with hypothyroidism or hyperthyroidism Grave’s Disease – too much thyroid hormone Weight loss, nervousness, tremor and exophthalmos Exophthalmos – edema behind eyes 4 peasized glands found on back of thyroid gland Release parathyroid hormone Parathyroid hormone – moves calcium from the skeleton into the blood Which gland releases parathormone? Where are the adrenal glands located? What are the 2 main parts? Located on top of the kidneys Adrenal Cortex – releases hormones Release Aldosterone – hold salt in the body Cortisol – reduces inflammation; help regulate metabolism by increasing rate of protein and lipid break down Androgens – male hormone, same effect as testosterone; in females it can be change to estrogen Adrenal medulla – releases hormones Epinephrine – is commonly called adrenalin; both hormones increase heart rate and blood pressure Cushing’s syndrome – over production of cortisol Symptoms Moon face, buffalo hump on back, hanging abdomen What is epinephrine commonly called? Adrenaline Define norepinephrine. ?????? Where is the pineal gland located? What does it promote? Located near diencephalon Melatonin – responsible for controlling the biological clock and onset of puberty Promotes sleepiness Define thymus gland. Which hormone does it produce? Decreases in size with age Produces the hormone Thymosin which causes T cells to mature Pancreas – The islets of Langerhans contain three kind of secreting cells Alpha cells – secrete glucagon to raise blood glucose Glucagon – Stimulates liver and muscle cells to break down glycogen into glucose, thus increasing blood glucose levels Glycogen – long chains of bonded glucose molecules Beta cells – secrete insulin to lower blood glucose Insulin – Stimulates liver, muscle , and fat cells to take up glucose from the blood, thus lowering blood glucose levels Delta cells – secrete somatostatin Somatostatin – Inhibits the production of insulin, glucagon, human growth hormone Diseases of pancreas? Type I Diabetes – Used to be called “juvenile diabetes” because of its early onset Usually appear before age 25 When pancreas suddenly stops making functional insulin An autoimmune disease – Imunne system destroys its own cells within the islet of Langerhans With insulin production Treatment involves monitoring blood glucose levels and injecting insulin when glucose levels are high Insulin stimulates liver, muscle, fat cells to take up glucose from the blood Thus lowering blood glucose levels Type II Diabetes – Used to be called “adult-onset diabetes because it appears during adulthood Even though the blood contains abnormally high levels of insulin Basically – the cells cannot absorb glucose properly Leaving high levels of blood glucose Strongly associated with a famyl history of diabeted, older age, obesity, and lack of exercise More common in women Especially those with a history of gestational diabetes, during pregnancy Also common among Hispanic, Native American, and African American popultions Erythropoietin – Hormone released by the kidneys Stimulates production of red blood cells by the red bone marrow. Regulation of blood glucose levels Rising blood glucose levels stimulate the production and secretion of insulin As insulin circulates in blood It prompts cells to absorb Thus lowering blood glucose When blood glucose levels are lowered, glucagon is secreted and insulin secretion stops Glucagon triggers glucose release from glycogen stores Thus increasing blood glucose What is estrogen? Progesterone? Estrogen – development of the female reproductive organs and female secondary sex characteristics Progesterone – help estrogen build up uterine lining for inplantation Inhibin secretion of FSH Define testes and what it controls. Produce testosterone Testosterone controls development of male reproductive system and secondary sex characteristics in males Inhibin – shuts of the secretin of FSH by anterior pituitary