Physiology 206 1STedition Lecture 31 Outline of Last Lecture I Endocrine disorders II Hypothalamus III Pituitary IV Hormones Outline of Current Lecture I Colloid II Thyroid Hormone Regulation Current Lecture 4 11 14 Colloid consists of solution with high protein solution in which they produce Thyroglobulin Follicular cells produce two types of hormone 1 Thyroxine T4 90 2 Triiodothyronine T3 5 times as powerful many years before they were known as 2 difference things so are referred to as thyroid hormone but actually consists set 2 hormones Elicit some effects but one more potent Major Effect Increase metabolic rate Follicular Cells are good at 1 Remove Iodine concentration of cell is so big that it diffuses into colloid 2 Remove Tyrosine use some of this in the synthesis of thyroglobulin which has high amounts of tyrosine because they were made on ribosomes of which the tyrosine was taken in Iodine spontaneously attaches itself to Tyrosine some tyrosine have iodine attached Monoiodotyrosine some have 2 iodine Diiodotyrosine this happens to tyrosine even when they are in thyroglobulin Diiodotyrosine is much more reactive than monoidotyrosine when these things react you usually get two tied together you get Thyrosine When a dio and mono react you get triidothyronine 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 all this happens when stimulates part of protein structure next step is follicular cell takes up thyroglobulin lysosomes digest thyroglobulin you have these compounds in free state these hormones are fat soluble diffuse out of cell get carried off when it receives secretory stimulus it increases most of its activities about 90 or what gets synthesized is T4 T3 is 5 times more powerful Liver and kidneys convert T4 to T3 so after short time majority in blood stream majority of effects response is due to T3 Most important thing T4 does is to be a source for T4 Almost all of these things are bound to protein One called thyroxine binding protein protein that binds the most binds T3 and T4 Thyroid Hormone Regulation Calorigenic Effect burns calories Sympathomimetic effect mimics sympathetic nervous system Increase blood pressure and heart rate reason it is no longer used for weight loss Necessary for normal growth Essential for development of nervous system Essential for proper function of the nervous system in adults Major regulator is TSH from Pituitary When there are deficiencies of TSH thyroid gland atrophies When there is too much TSH thyroid gland hypertrophies Control of TSH secretion comes from feedback in Thyroid and stimulation by Hypothalamus TRH Hypothalamus controlled by many aspects of the Nervous System Hypothyroidism can have many different causes Salt is iodized so that there isn t a deficiency in dietary aid Thyroid deficiences are easy and cheap to treat
View Full Document
Unlocking...