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93 Cards in this Set
- Front
- Back
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What cells produce calcitonin?
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C Cells (parafollicular cells)
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What type of cells produce thyroid hormone?
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Follicular cells
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How many iodides in Thyroxine?
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4
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Triiodothyronine is made how?
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T3 is made from the break down of T4
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What does colloid consist of?
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Thyroglobulin
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What makes the thyroid gland unique?
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Composed of many follicles
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What is the typical U.S. diet intake of iodide?
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300-400ug/day
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Where is iodide ABSORBED?
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In the intestine
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What is the minimum daily requirement of iodide?
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75 ug/day
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What type of transport is iodide brought into the cells in the thyroid?
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Active Transport. The concentration within cells can be higher than in the blood.
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Iodide is enzymatically attached to tyrosine residues within what?
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Thyroglobulin
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What is thyroglobulin?
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Large glycoprotein that transports iodide
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Monoiodide consists of? Diiodotyrosine?
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1 Iodide attached to tyrosine forms monoiodotyrosine. 2 Iodide attached to tyrosine.
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What occurs within the thyroglobulin between 2 diiodotyrosines?
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Coupling to make T4, or T3
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Where is thyroglobulin stored?
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Colloid
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Organification is the process of what?
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The iodide enzymatically attached to tyrosine residues within thyroglobulin
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Goitrogens do what?
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Block iodide uptake as well as organification (iodidde enzymatically attached to tyrosine residues within thyroglobulin) and coupling (2 iodotyrosines coupling to make T4 or a di and mon to make T3)
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Examples of Goitrogens
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Thiocyantes and Perchlorate (in CO high levels in ground water b/c by product of rocket fuel)
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How do Thioureas like Propylthiouracil and Methimazole cause Hypothyroidism?
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By blocking organification and coupling. They are found in naturally occuring substances such as cabbage, effecting Hippies that live in the mountains of California
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How are T3 and T4 released into circulation?
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Cells surrounding the colloid endocytos it partially.
Lysosomes with hydrolytic enzymes fuse with colloid particle. Thyroglobulin broken down amino acids + MIT and DIT (deiodinated enzymatically>iodotyrosine dehalogenase) |
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What is the intermediate enzyme in between Thyroglobulin + Iodide to become MIT and CIT to make T3 and T4?
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Thyroid Peroxidase
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Which is secreted in higher amounts, T3 or T4?
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T4
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Where does T3 predominantly come from?
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T4 converted to T3 in peripheral tissues
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What is the consequence of non-covalently bonded T3 and T4 to Thyroxine binding globulin (TBG), Thyroxine binding prealbumin (TBPA) and Albumin?
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Allow large buffer capacity for them to exist and maintain concentration at a steady level.
TH+BP<>TH-BP |
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Polyurea is?
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Higher osmolarity of urine due to glucose drawing in water
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Glycosurea is?
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When the capacity of the kidney to reabsorb glucose is exceeded. Diabetes Mellitis, sweet urine
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When the glucose uptake by many tissues of the body is decreased?
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Hyperglycemia
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Elevated levels of plasma glucose is a sign of?
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Hyperglycemia
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What type of test is given to determine Hyperglycemia?
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Glucose tolerance test
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What effect does exercise have upon glucose uptake?
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Increases it
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In Hyperglycemic case of a Mellitus Diabetic, what is the purpose of protein break down?
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Protein catabolism increased so amino acids can be used in the gluconeogenic pathway in the liver. Insulin is used to get glucose into the cell, without the cells are starving without glucose uptake and protein break down participates in gluconeogenic pathway
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Type II Diabetes onsets when?
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After the age of 40
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Which type of diabetes can be controlled by exercise and diet?
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Type II
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Non-insulin dependent diabetic is which type?
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Type II
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What effect does elevated insulin levels have on insulin receptors?
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Decreases sensitivity to insulin
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What can cause insulin receptor insensitivity?
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Increased insulin production
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What type of diabetes has a juvenile onset?
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Type I
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Insulin dependent diabetics are which type?
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Type I
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Insulin dependent says what about their insulin production in Type I Diabetics?
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They have loss of insulin from destruction of Beta cells in the Pancreas
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Diabetes Mellitus is due to what levels of insulin?
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Deficiency in insulin
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Insulin is formed how?
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2 chains connected by disulfide bridges, synthesized as a larger preprohormone, converted to prohormone (proinsulin). Proinsulin's C peptide connects the Alpha and Beta chains, then cleaved to make INSULIN
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What hormone contains and alpha and beta chain connected by disulfide bonds?
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Insulin
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What is secreted by the cells in the mucosa in the gastrointestinal tract?
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Glucagon, Somatostatin, and Pancreatic Polypeptide
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F cells secrete what?
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Pancreatic Polypeptide Enzymes
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Delta cells secrete what?
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Somatostatin which causes halt in production of what it is acting upon. It is made by hypothalamus, ie GH growth hormone release inhibiting hormone.
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Beta cells of the Islets of Langerhans in the Pancreas secrete what?
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Insulin, which increases the storage of glucose, fatty acids and amino acids
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60% of cells are what kind in the pancreas?
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Beta cells
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25% of cells are what kind in the pancreas?
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Alpha cells, which secrete GLUCAGON
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Glucagon does what?
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It mobilizes glucose, fatty acids and amino acids because it is CATABOLIC
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The pancreas is what kind of gland?
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Exocrine and Endocrine
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What is the endocrine function of the pancreas?
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Islets of Langerhans, the 1-2% of the pancreas
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Graves Disease causes what kind of thyrodism
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Hyperthyroidism
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Hyperthyroidism is manifested how in patients?
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Enlarged thyroid, Exopthalamus (bug eyes), Autoimmune disease and Tunors
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Adenomas and Graves Disease are examples of what type of thyroidism?
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Hyperthyroidism
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In Graves Diseases, what are the levels of Thyroid Hormone, Thyroid Stimulating Hormone, and Goiter potential?
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High TH, Low TSH and yes to goiter
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In the case of a thyroid adenoma, could a patient present with a goiter?
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No because TSH levels are low
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Thyroid adenoma patients has what levels of TH, TSH and Goiter?
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High TH, Low TSH, and NO goiter
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In a hypothyroid patient, what are their TH, TSH and goiter levels?
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Low TH, High TSH and yes to goiter
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What are the signs of a hyperthyroid patient?
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Heat intolerance, nervousness and increased BMR
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Does a child that suffers from Hypothyroidism, suffer from mental retardation?
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Yes
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Is cretinism in children with hypothyroidism reversible?
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Yes by giving them thyroid replacement therapy
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Cretinism signs are?
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Dwarfism and mental retardation
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What is tested in a newborn to check for hypothyroidism?
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TSH levels are checked
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Are TSH levels high or low in Hypothyroidism?
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TSH levels are high due to loss of feedback inhibition resulting in a goiter.
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Hypothyroid patients symptoms consist of?
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Poor toleration of cold, coarse hair, husky voice and slow mental porcessing
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What are the physiological effects of low levels of thyroid hormones?
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Cause accumulation in skin of proteins combined with polysaccharides, hyaluronic acid and chondroitin sulfate
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High or Low levels of thyroid hormones cause water retention and puffiness of skin? Also increase in Cardiac Output, increasing sensitivity of heart to catecholamines?
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Low levels, aka Myxedema
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Which thyroidism suffers from bradychardia?
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Hypo
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Which thyrodism suffers from tachycardia?
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Hyper
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Increase catecholamines leads to which thyroidism?
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Hyper
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Decrease in catecholamines results in which type of thyrodism?
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Hypo
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Growth Hormone does what?
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Promotes growth
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Physiologically, does thyroid hormones increase O2 consumption by almost all body tissues?
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Yes, called Calorigenic effect
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Calorigenic Effect is what?
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Thyroid hormone effect on increase in O2 consumption by all tissues
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Effect of Thyroid hormone on Protein synthesis, if high, if low?
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High thyroid hormones, cause net protein breakdown (Catabolism)
Low thyroid hormones, cause increase protein synthesis (Anabolism) |
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LATS stands for?
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Long Acting Thyroid Stimulator which is an antibody
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Long Acting Thyroid Stimulator does what?
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Stimulates thyroid hormones formation in same way as TSH when TSH levels are low
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What cases is LATS found?
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Graves Disease cases, most common form of Hyperthyroidism
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Which Antibody + Thyroid causes increase in thyroid hormone?
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LATS, Long Acting Thyroid Stimulator
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Increase in iodide causes what effect that effects TSH?
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Decreased responsiveness to TSH
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Decreased iodide causes what type of reponsiveness to TSH?
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Increase in responsiveness
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Increase iodide, what TSH responsiveness?
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Decreased
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Decrease iodide, what TSH responsivenss?
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Increased
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What acts back on Anterior Pituitary inhibiting TSH release?
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T3 and T4
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Absence of what leads to elevated TSH levels?
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T3 and T4, its absense leads to growth of the thyroid gland aka goiter
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What is TRH?
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Thyrotropin Releasing Hormone
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Where does TRH come from?
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The hypothalamus
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What is the function of TRH?
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Stimulate Thyroid Stimulating Hormone (TSH) release from the Anterior Pituitary
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What 3 amino acids make up TRH?
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Pyroglutamate-Histidine-Proline Amide
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Where is TSH synthesized?
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Anterior Pituitary
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What is TSH?
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Thyroid Stimulating Hormone that leads to the production/synthesis of Thyroid Hormone and its release
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What processes does TSH stimulate?
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Iodide uptake
Organification Coupling Thyroglobulin Breakdown |
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Goitrogens has what effect on TSH?
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Blocking formation by a goitrogen causes loss of feedback inhibition on TSH release, therefore leads to TSH elevation releasing in excess TH with an enlarged Thyroid Gland that can become a goiter
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