Term
| what are the parts of the thyroid |
|
Definition
| two lobes, isthmus, maybe pyrmidal |
|
|
Term
| where is the thyroid located |
|
Definition
| anterior nect below thyroid cardilage of the larynx |
|
|
Term
| what directly surrounds the thyroid, what is its function |
|
Definition
| thin connective tissue covering, sends trabeculae into the thyroid partitioning it |
|
|
Term
| what are the functional units of the thyroid |
|
Definition
|
|
Term
| when does the thyroid begin to develop |
|
Definition
|
|
Term
| what does the thyroid originate as |
|
Definition
| endodermal thickening of floor of primitive pharynx |
|
|
Term
| what is the remnent of the thyroid origin |
|
Definition
|
|
Term
| what is the first thing to form after the thyroid begins as an endodermal thickening |
|
Definition
| duct like invatingation called thyroglossal duct |
|
|
Term
| describe the movement of the thyroglosseal duct |
|
Definition
| descends throug the neck to its final destination in front of the trachea where it divides into two lobes |
|
|
Term
| what happens to the thyroglosseal duct during its migration |
|
Definition
| it atrophies, leaving remnant called pyrmidal lobe |
|
|
Term
| what happens to the thyroid in week 9 of gestation |
|
Definition
| endodermal cells differentiate into plates of follicular cells that become arranged into follicles |
|
|
Term
| what happens to the thyroid in week 14 |
|
Definition
| well developed follicles contain colloid |
|
|
Term
| what happens to the thyroid in week 7 |
|
Definition
| ultimobranchial bodies start migrating to the developing thyroid from the fifth pouch and become incorporated into the lateral loves |
|
|
Term
|
Definition
| invagination from the fourth pharyngeal pouch |
|
|
Term
| what are ultimobranchial bodies |
|
Definition
| epithalial cells that become part of the lobes of the thyroid |
|
|
Term
| what do ultimobranchial bodies ultametly give rise to |
|
Definition
|
|
Term
| what type of tissue are thyroid follicles |
|
Definition
| simple cuboidal or low columnar |
|
|
Term
| what do thyroid follicles contain |
|
Definition
|
|
Term
| where is colloid in a thyroid follicle |
|
Definition
|
|
Term
| where is the basal surface of a thyroid follicle cells located |
|
Definition
|
|
Term
| what are the principal cells of the thyroid follicle |
|
Definition
|
|
Term
| what produces thyroid hormones T3 and T4 |
|
Definition
|
|
Term
| what surrounds thyroid follicles |
|
Definition
|
|
Term
| at what point is a thyroid follicle makiing or secreting hormones |
|
Definition
| they can both happen at the same time or alone |
|
|
Term
| what is the general function of thyroid hormones |
|
Definition
| normalize metabolism, homeostasis, regulate cell and tissue basal metabolism, influence growth and development, heat production |
|
|
Term
| what are the thyroid hormones |
|
Definition
| thyroxine (T4), triiodothyronine (T3) |
|
|
Term
| what are the thyroid hormones derivatives of, how in general are they altered |
|
Definition
| they are iodinated tyrosine derivates |
|
|
Term
| what is the release of thyroid hormones regulated by |
|
Definition
| TSH from the anterior pituirary |
|
|
Term
| what is the major component of colloid |
|
Definition
|
|
Term
|
Definition
| thyroglobulin, 120 residues of tyrosine, PAS |
|
|
Term
| what is the inactive form of thyroid horomones |
|
Definition
|
|
Term
| what makes thyroid hormone storage unique |
|
Definition
| it is in the extracellular area of the thyroid |
|
|
Term
| what is the role of thyroid hormones in fetal growth |
|
Definition
| they are essential and can cross the placenta, early brain development, |
|
|
Term
| what happens to mom's thyroid hormone contribution when baby develops their own thyroid, when does this happen |
|
Definition
| in week 14, both contribute to the babys thyroid hormone needs |
|
|
Term
| what occurs when there is a thyroid deficiencey in fetal development |
|
Definition
| irreversible damage to the CNS, reduced neurons, defective myelination, mental retardation, stunted growth |
|
|
Term
| what happens when there is a thyroid deficiency in development before the baby's thyroid develops |
|
Definition
| severe mental retardation |
|
|
Term
| why does thyroid hormone have a role in growth, how does it do this |
|
Definition
| it stimulates gene expression of GH in the somatotropes of the anterior pituitary |
|
|
Term
| what is congenital hypothyroidism |
|
Definition
| CNS and stunted growth abnormalities combined (cretinism) |
|
|
Term
| what is another name for parafollicular cells |
|
Definition
|
|
Term
| where are parafollocular cells located |
|
Definition
| in peripherial follicular epitheliym of the thyroid gland |
|
|
Term
| what do parafollocular cells fo |
|
Definition
| synthesize and secrete calcitonin |
|
|
Term
|
Definition
| parafollocular cells and the thyroid gland |
|
|
Term
| how does the hypothalamus / pituitary unit regulate parafollocular cells |
|
Definition
|
|
Term
| what is the antagonist of parathyroid hormone |
|
Definition
|
|
Term
| what type of molecule is calcitonin, how big |
|
Definition
|
|
Term
| how does calcitonin do its job |
|
Definition
| supresses resorptive action of osteoclases, promoting calcium deposition in bones by increasing rate of osteoid calcification |
|
|
Term
| what regulates calcitonin rellease |
|
Definition
| increase in blood Ca increases secretion, decrease inhibits secretion |
|
|
Term
| how many parathyroid glands are there |
|
Definition
| usually 4 but there can be move located in the thymus |
|
|
Term
| what are parathyroid glands covered by |
|
Definition
|
|
Term
| how do the parathyroid glands change as one gets older |
|
Definition
| more connective tissue with fat |
|
|
Term
| what do the parathyroid glands develop from |
|
Definition
| third and fourth pharyngela pouches |
|
|
Term
| what are the inferior parathyroid glands and thymus developed from |
|
Definition
|
|
Term
| what are the superior parathyroid glands derived from |
|
Definition
|
|
Term
| when do the principal cells of the parathyroid differentiate |
|
Definition
| durine embryonic development and are function active in regulating fetal calcium metabolism |
|
|
Term
| when do oxyphil cells differentiate |
|
Definition
|
|
Term
| what are they types of cells in the parathyroid |
|
Definition
| principal (chief) cells, oxyphil cells |
|
|
Term
| what are the most numerous cells of the parathyroid |
|
Definition
|
|
Term
| what is the function of the principal cells of the parathyroid |
|
Definition
|
|
Term
|
Definition
| small dense membrane bound vesicles in the cytoplasm of principal cells of the parathyroid |
|
|
Term
| which parathyroid cell is the largest |
|
Definition
|
|
Term
|
Definition
| donno but they dont secrete |
|
|
Term
| what does the parathyroid hormone regulate |
|
Definition
| calcium and phosphate levels in the blood |
|
|
Term
| what type of molecule is PTH, how big |
|
Definition
|
|
Term
| is parathyroid hormone essential for life |
|
Definition
|
|
Term
| what happens if the parathyroid gland is totally removed |
|
Definition
| death mecause muscles, including laryyngeal go into tetanic contraction as blood calcium falls |
|
|
Term
|
Definition
| reabsorption, activates osteolysis by osteoclasrs, releases Ca and P into the blood |
|
|
Term
| what does PTH do in the kidney |
|
Definition
| excretion of Ca is decreased during tubular reabsorption, conserving Ca, phosphate secretion is increased, converts 25-OH vitamin D to active 1,25-OH2 |
|
|
Term
| what does PTH do in the intestines |
|
Definition
|
|
Term
| what secretes parathyroid hormone KNOW ME |
|
Definition
|
|
Term
| what hormone is essential for life KNOW ME |
|
Definition
|
|
Term
| what cells secrete calcitonon KNOW ME |
|
Definition
|
|
Term
| what influences for calcitonin to be released KNOW ME |
|
Definition
| nothing, just its own influence |
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