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Cards In This Set
| Front | Back |
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Nuclear Receptor action in the absence of E2
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Binds to Nuclear response element without E2 present
Corepressor complex: histone deacetylases (HDACs) close chromatin, repressing transcription |
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What happens when E2 (ligand) bind to the nuclear receptor?
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 ATP is used to remodel chromatin -Coactivators recruite histone acetyltransferases (HATs), which open chromatin for transcription |
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How common is breast cancer?
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-Second most common cancer
-most prevalent cancer in women world wide -25% of all cancers in women and in 2012 there were 1.7 million new cases. |
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In humans, _____ and ____ decrease the risk for cancer
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Earlier and multiple pregnancies
-wonmen >35 yrs of age at first pregnancy or have no pregnancies are at greater risk -multiple birthing rats and mice are also highly protected against carcinogen - induced breast cancer |
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What happens to Estriol secretion in urine during pregnancy?
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Increases by 1,000 fold & plasma estradiol levels rise from 40-180 pg/ml to 15.000 - 22,000 pg/ml - Supra physiological levels
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Estrogen is essential for
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Growth and function of normal breast
-plays a pivitol role in Breast Carcinogenesis, however, mechanism is unclear -pregnancy levels of estrogen may be linked to the mechanism for the protective effect of pregnancy against breast cancer. |
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Very high levels of both _____ and ____ are secreted during pregnancy
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Estrogen and progesterone
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Supraphysiological levels of estrogen may ___?
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Selectively induce cell death in ER+ breast cancer cells while promoting normal breast growth
--> may be part of mechanism of protection against breast cancer from pregnancy |
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Mammogenesis
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Descrives the development of the mammary gland
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What is unique about mammary glands?
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-one of few tissues in mammals which can repeatedly undergo growth, functional differentiation and regression
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Characteristics of mammary glands
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-modified and highly specialized type of apocrine sweat glands
--consists of parenchyma which is formed from ducts and connective tissue stroma - from surface e |
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Parenchyma derives embryonically from ____
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Surface ectoderm
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Stroma arises from
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Mesenchyme (surrounds surface ectoderm?)
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Describe the development of mammary glands
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 -Each primary bud gives rise to several secondary mammary buds that develop into lactiferous ducts and their branches |
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Canalization of mammary buds is induced by ___
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-placental sex hormones, entering the fetal circulation. this process continues into late gestation, and by term , 15-19 lactiferous ducts are formed
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