BIOL 460 1nd Edition Lecture 8 Outline of Last Lecture I Mechanisms of Hormone action a Lipophilic b Steroid hormone family c Thyroid hormone family II Glands Outline of Current Lecture I Pituitary Gland a Embryology b Hormones i Adenohypophysis ii Neurohypophysis II Adrenal Gland Current Lecture Pituitary Gland Continued 1 Embryology a Notochord skeletal support for embryo b Also called primary inducer produces growth factors c Very anterior end of notochord secretes GFs or inducers that trigger floor of diencephalon to evaginate d Also evagination in embryonic mouth stomadeum Rathke s pouch These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute e Rathke s pouch forms adenohypophysis evagination from hypothalamus forms neurohypophysis 2 Pituitary Hormones a Hormones of adenohypophysis i Trophic hormones ii Means to feed iii High concentration of trophic hormones cause target glands to hypotrophy iv Low concentration atrophy v Growth hormone GH somatotrophin promotes tissue and organ growth vi Thyroid stimulation hormone TSH thyrotropin produce and secrete thyroid hormones vii Adrenocorticotrophic hormone ACTH corticotrophin 1 Triggers adrenal cortex growth 2 Trigger corticosteroid release viii Follicle stimulating hormone FSH Folliculotropin 1 Stimulate follicles in ovary to mature 2 Stimulate seminiferous tubules to produce sperm ix Luteinizing hormone LH luteotropin 1 Stimulate corpus luteum formed from remnants of follicle after ovulation endocrine gland producing progesterone 2 Causes interstitial cells to secrete testosterone in males x Prolactin stimulates milk production after childbirth b Hormones of neurohypophysis i Neurohypophysis storage organ ii Hormones secreted are produced by nuclei of hypothalamus paraventricular nucleus and supraoptic nucleus iii Hormones are 1 Antidiuretic Hormone a Diuretic makes you urinate b ADH kidneys reabsorb water less urine produced 2 Oxytocin a Contraction of the uterus in childbirth b Responsible for milk ejection reflex iv Neurons produce these hormones in their cell bodies v Axons extend into neurohypophysis causing exocytosis of the hormone vi ADH and oxytocin have similar structures 2 nucleotides are different polypeptide NTM vii Hypothalamic control of neurohypophysis secretion 1 Controlled via a tract 2 Hypothalamic neurohypophyseal tract 3 Group of parallel axons viii Neuroendocrine reflexes 1 Osmoreceptors relay info to nuclei in hypothalamus 2 This relays to neurohypophysis 3 Results in release of ADH ix Adenohypophyseal control 1 Hypothalamus secretes hormones that control adenohypophyseal hormone release 2 Transported via adenohypophyseal portal system 3 Hypothalamic hormones adenohypophyseal hormones a Thyrotropin RH TSH b Corticotrophin RH ACTH c Gonadotropin releasing hormones FSH LH d GH RH growth hormone somatotrophin e Somatostatin inhibits GH somatotrophin f Prolacting inhibiting hormone prolactin 4 Works via negative feedback a More T3 and T4 inhibits hypothalamus from releasing TSH RH b Also make adenohypophysis less sensitive to TSH RH 5 Relationship between hypophysis pituitary and target organ is called axis Adrenal Glands 1 Composed of medulla and cortex 2 Medulla 85 epinephrine 15 norepinephrine 3 Cortex corticosteroids a Formed from mesoderm
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