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16 Cards in this Set
- Front
- Back
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In all mammels, the CL in the ovary at the time of fertilization fails to regress and instead enlarges in response to stimulation by gonadotropic hormones secreted by the placenta. TRUE/FALSE
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TRUE.
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What is the placental gonadotropin in humans called?
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Human chorionic gonadotropin(hCG).
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The enlarged CL of pregnancy secretes what?
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Estrogens, progesterone and relaxin. The relaxin helps maintain pregnancy by inhibiting myometrial contractions.
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In most species, removal of the ovaries at any time during pregnancy precipitates abortion. TRUE/FALSE
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TRUE.
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Ovariectomy before the sixth week leads to abortion, but ovariectomy thereafter has no effect on pregnancy. TRUE/FALSE
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TRUE. The function of the CL begins to decline after 8 weeks of pregnancy, but it persists throughout pregnancy.
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What is hCG?
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It is a glycoprotein that contains galactose and hexosamine. It is produced by the syncytioblast. It is made up of alpha and Beta subunits.
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How can hCG be measured?
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By radioimmunoassay and detected in the blood as early as 6 days after conception.
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hCG acts on which receptor?
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It appears to act on the receptor as LH. hCG is not specific for pregnancy. Small amounts are secreted by a variety of gastrointestinal and other tumors in both sexes, and hCG has been measured in individuals with suspected tumors as a tumor marker.
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What is hCS?
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The syncytioblast also secretes large amounts of a protein hormone that is lactogenic, and has a small amount of growth stimulating activity. This is referred to as human chorionic somatomammotropin (hCS).
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Large quantities of hCS are found where?
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In maternal blood, but very little reaches the fetus.
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What are the very basic functions of hSC?
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It possesses most of the actions of growth hormones and apparantly functions as a maternal growth hormone of pregnancy to bring about the nitrogen, potassium and calcium retention, lipolysis and decreased glucose utilization seen in this state. Glucose is diverted to the fetus as well.
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How much hCS is normally secreted?
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Secretion is proportionate to the size of the placenta, which normally weighs about one sixth of the fetus, and low hCS levels are a sign of placental insufficiency.
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About 35% of carcinomas of the breast in womwn of childbearing age are estrogen dependent. TRUE/FALSE
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TRUE.Their continued growth depends on the presence of estrogens in the circulation.
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Are these tumors cured by decreasing estrogen secretion?
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No, but symptoms are dramatically relieved and the tumor regresses for months or years before recurring.
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Womaen with estrogen dependent tumors often have a remission when their ovaries are removed. TRUE/FALSE
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TRUE. Inhibition of the action of estrogens with Tamoxifen also produces remissions, and inhibition of estrogen formation with drugs that inhibit aromatase is even more effective.
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Some carcinomas of the prostate are androgen dependent. TRUE/FALSE
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TRUE. Some will regress temporarily after the removal of the testes or treatments with GnRH agonists in doses that are sufficient to produce down regulation of the GnRH receptors on gonadotropes and decrease LH secretion.
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