- Action of Thyroid hormone
- -almost all organs in body are target of thyroid hormone; it increases protein synthesis and cell respiration; thus increasing metabolic rate (by stimulating the synthesis of uncoupling proteins; these dissociate electron transport and ATP synthesis; lead
- Activation of Adrenal medulla
- -adrenal gland innervated by sympathetic neurons so its activated when sympathetic ns is activated (during fight/flight)
- Addison's Disease
- -hyposecretion (too little) of corticosteroids and mineralocorticoids; leads to low blood glucose; Na and K imbalance; and weakness
- Adrenal Cortex
- -cells here secrete 3 different kinds of sterooid hormones
-collectively called corticosteroids or corticoids - Adrenal Medulla
- -secretes epinephrine and norephinephrine; similar to effect of sympathetic nervous system activation but lasts longer (increase heart rate, resp rate, blood glucose, etc)
- glucocorticoids
- -steroid hormone secreted by adrenal cortex
-involved in regulation of metabolism
-ex: cortisol; regulated by release of ACTH from anterior pituitary
-cortisol raises level of glucose and other energy rich molecules in blood
-cortisol results in
- Location of Adrenal Glands
- Paired organs that cap superior borders of kidneys
- Melatonin and Circadian Rhythm
- -circadian rhythm (24 hour patterned period)
-night-> activity of SCN rises (more melatonin secreted) - Mineralocorticoids
- -steroid hormone secreted by adrenal cortex
-regulate amt of Na and K in body
-ex: aldosterone acts on kidneys
-causes kidneys to retain Na and water and loose K in urine
-affects circulatory system
*increases blood pressure and volume; regulates - pineal gland
- -found in brain; secretes hormone called melatonin; secretion of melatonin shows a circadian rhythm
- Role of pineal gland in regulation of emotional state
- -SAD-seasonal affective disorder
-depression when days get shorter, improved by light exposure
-SAD affects 20% of pop of Alaska; only 2.5% in Florida
-melatonin level is high in SAD patients (but reduced by light exposure) - Role of Pineal Gland in sexual development
- -inhibits GnRH secretion
- sex steroids
- -steroid hormone secreted by adrenal cortex
-supplemental source in addition to the gonads - Stress response of adrenal gland
- -ALARM: adrenal medulla is activated (prepares body for fight/flight)
-RESISTANCE: adrenal cortex is active (-cortisol release-> breakdown of fat; -cortisol inhibits protein synthesis->immune system is suppressed)
-EXHAUSTION: adrenal cortex becomes ina - Structure of Adrenal Glands
- -outer cortex and inner cortex
-have different functions
-origin of cells of medulla made from the same tissue that makes sympathetic neurons
-so cells of medulla and sympathetic neurons are very similar - T3 and T4 Travel Methods
- -travel to target cells in blood attached to carrier proteins; once free of carrier T4 can enter cells; in cells T4 is converted to T3 (the active form)
- thyroid glands
- -secrete thyroid hormone (molecules T3 and T4 collectively; thyroid follicles take iodide from blood and secrete it into the interior of the thyroid gland; it is used to make hormones called T3 and T4; release of T3 and T4 triggered by stimulation by TSH
- thyroid goiter
- -effect of change in secretion of thyroid hormone; too little iodine in diet; abnormal growth of thyroid gland; symptoms include low bmr and large thyroid gland
- Transport of thyroid hormone
- -lipid soluble; diffuses across cell membrane and acts in nucleus of target cells where it regulates gene transcription; like a steroid hormone, thyroid hormone acts via nucleus
- Treatment of Addison's Disease
- -use of glucocortisoids and mineralocorticoids; test for hormone that regulates adrenal cortex
- Tumor of Adrenal Medulla
- -result of hypersecretion (too much) of epinephrine and norepinephrine; symptoms are hypertension and high blood glucose
