PHIS 206 1st Edition Lecture 32 Outline of Last Lecture I Location Anatomy of Pituitary II Blood Supply in Anterior Pituitary Gland III Mammals except humans IV 2 Kinds of Hormones of Posterior Pituitary V Anterior Lobe VI Secretions of Anterior Pituitary VII Hormones of Anterior Lobe VIII Growth Hormone Outline of Current Lecture I Thyroid Gland II 2 Thyroid Hormones III Follicular Cells IV T4 v T3 V Major Effect of Thyroid Hormone VI Anabolic Processes VII Fat Mobilizing VIII Thyroid Hormone IX TSH Thyroid Stimulating Hormone X TRH XI Causes of Hypothyroidism XII Symptoms of Hypothyroidism XIII Causes of Hyperthyroidism XIV Symptoms Effects of Grave s Disease XV Another Cause of Hyperthyroidism XVI Goiter Current Lecture I II Thyroid Gland consists of 2 bulbs connected by a narrow connective tissue cells have sacs surrounded by a one layer with liquid in the inside Follicle cell outside colloid like glue inside of follicle cell 2 Thyroid Hormones T4 Tetraiodothyronine T3 Triiodothyronine 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 III Major effect increase basal metabolic rate increase rate at which cells use oxygen Follicular Cells vigorous active systems that allow them to take up tyrosine and iodide from plasma tyrosine amino acid some tyrosine material to synthesize thyroglobin o on ribosomes E R golgi body etc thyroglobin is synthesized in tyrosine cells but secreted into colloids iodide diffuses into colloid loads of thyroglobin high concentration of iodide in follicular cells you can iodinate proteins easily tyrosines which thyroglobin is loaded with wind up with iodide ions attached 1 I monoiodotyrosine 2 I diiodotyrosine iodinated tyrosines spontaneously react with one another and attach 2 I 2 I tetraiodotyrosine 2 I 1 I triiodotyrosince 1 I 1I diiodotyrosine no endocrine property of thyroid o diiodotyrosine more reactive than monoiodotyrosine o all occurs when thyroglobin is in colloids endocytosis drink and lysozomes break thyroglobin into amino acids derivatives are T4 and T3 fat soluble NOT PEPTIDES OR STEROIDS behave as steroids diffuse out before synthesis bind to proteins IV T4 v T3 90 of what is released T4 5 times more potent gives response T3 T4 converted to T3 when passing kidneys and liver 90 95 response comes from T3 V Major Effect of Thyroid Hormone increase basal metabolic rate oxidation of substrates generates heat calorigenic effect VI Anabolic Processes protein process that will not proceed in the absence of the thyroid hormone normal physiological catabolic needs to break down increases metabolism decreases fat glycogen protein result reduce muscle mass VII Fat Mobilizing thyroid hormone increases receptors of norepinephrine makes cells more sensitive to stimuli responses are exaggerated sympathomimetic dramatic effect that the thyroid hormone has other effects of high levels of thyroidism increase cardiac output increase blood pressure VIII Thyroid Hormone essential to growth essential to normal function of CNS IX TSH Thyroid Stimulating Hormone stimulated to take up more tyrosine and iodide and make thyroglobin TSH increases thyroid hormone TSH deficiency thyroid gland doesn t make much thyroglobin so bulk of follicle cells have atrophy TSH excess hypertrophy of thyroid gland follicles bigger thyroid gland bigger X TRH from hypothalamus stimulates TSH negative feedback in which thyroid hormone inhibits TRH TRH decreases TSH stimulation XI Causes of Hypothyroidism defect in follicular cells reduced pathological secretion of TRH anterior pituitary disorder iodide deficiency XII Symptoms of Hypothyroidism basal metabolic rate decreases person gains weight intolerance to cold fatigue easily low blood pressure reflexes low slow thinking sluggish myxedema accumulation of fluid subcutaneously ADULTS edema means swelling myxedema swelling of ankles cretinism retarded growth profoundly retarded NEWBORNS no survival chance as dwarf XIII Causes of Hyperthyroidism Grave s Disease production of abnormal antibody that fools thyroid gland into thinking it is TSH stimulates follicular cells into doing job but NOT subject to negative feedback increased circulating levels of thyroid hormone XIV Symptoms Effects of Grave s Disease weight loss muscle weakness heart rate increases blood pressure increases cardiac output increases Central Nervous System hyperactivity reduced emotional control irritable paranoia anxiety exophtalmos bulgy eyes dues to accumulation of fluid behind eyes XV Another Cause of Hyperthyroidism Thyroid Stimulating Tumor XVI Goiter enlarged thyroid cannot tell by looking whether it is hypo or hyper thyroidism does not enlarge thyroid under stimulated hyperthyroidism o no goiter o iodine deficiency goiter with hyperthyroid
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