Term
| How does increased estrogen om the late follicular phase promote sperm transport to the ovum during ovulation? |
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Definition
| Estrogen stimulates increased growth and activity of oviduct cilia, oviduct smooth muscle contraction, isthmus smooth muscle contraction, myometrium contraction, glycogen (for lactic acid fermentation, which will drop pH in the vagina), and decreased viscosity of cervical mucus |
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Term
| How does a rise in progesterone after ovulation promote the arrival and implantation of the blastocyst? |
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Definition
| increased progesterone causes increased progesterone receptor expression on oviduct and uterine smooth muscle, differentiation and secretion of uterine milk by endometrium, viscosity of cervical mucus, and decreased myometrium contraction |
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Term
| How do prostaglandins help with sperm transport to the fallopian tubes? How does oxytocin assist? |
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Definition
1. they stimulate smooth muscle contraction of the myometrium, causing a sort of reverse peristalsis
2. same way |
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Term
| What is the window of opportunity for fertilization of an ovum? |
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Definition
| depending, it could be 6 hours to 5 days after ovulation |
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Term
| How long does an embryo spend in the fallopian tube before implantation in the uterus? What is the cell cluster stage called? Where does nourishment for the embryo come from initially? |
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Definition
1. 3-5 days
2. blastocyst
3. "uterine milk" (fluid in the oviducts) and from the trophoblastic digestion of the endometrium itself until the placenta forms |
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Term
| What is hCG? Where does it come from? What is its effect? |
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Definition
1. human chorionic gondaotropin
2. it is made in the placenta tissue
3. it has the same effect as LH and maintains the corpus luteum, allowing a persisting high secretion of progesterone |
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Term
| What is the function of trophoblasts after fertilization? |
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Definition
| trophoblasts digest the endometrium to provide nutrients for the embryo, resulting blood pools in the sinuses and are drained by veins; trophoblasts eventually differentiate into placental villi |
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Term
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Definition
| it is often used to describe change undergone due to progesterone, IL-1, IGF-1, or post-fertilization; the lining of the uterus dies and becomes phagocytized by trophoblasts to provide nutrients for the embryo |
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Term
| What happens to syncytial trophoblasts when the placenta is developed? |
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Definition
| they become hormone producers and main tissue transporters |
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Term
| How is a baby able to get sufficient oxygen when the mother already has to supply her own body with oxygen? |
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Definition
1. fetal hemoglobin is better at binding to oxygen than adult hemoglobin, so it will bind to available oxygen even faster than the mother's own hemoglobin
2. fetuses have high Hb concentrations (generally)
3. the Bohr effect allows for the release of a large amount of oxygen from the mother when the venous blood from the baby is low in oxygen; the placenta would always count as metabolically active tissue, so a lot of oxygen will be released there |
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Term
| What is the pattern of hCG secretion throughout pregnancy? Progesterone? Estrogen? |
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Definition
1. zero until the placenta is developed, after which it increases enormously for the first trimester, after which it slowly decreases during the second trimester and plateau's during the third trimesters
2. gradually increases until the end of pregnancy; it is the primary hormone (over estrogen) until the third trimester
3. it gradually increases until the end of pregnancy; it remains lower than progesterone until the third trimester, when it surpasses progesterone |
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Term
| What endocrinological and circulatory parameters increase during pregnancy? |
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Definition
| blood volume, adrenalcorticoid secretion, T4, cardiac output, BMR, renal Na+ and H2O absorption, maternal respiration, PTH secretion, TRH, and CRH |
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Term
| What is the effect of placental CRH on the fetus's adrenals? |
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Definition
| placental CRH establishes a positive feedback loop with the fetal adrenals and the fetal pituitary; CRH stimulates the pituitary to release ACTH and ACTH and CRH stimulate the adrenals to release cortisol and DHEA; the cortisol further stimulates the placental CRH and develops the fetal lungs and guts, but does have negative feedback for the pituitary (though CRH still stimulates the pituitary) |
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Term
| Amount how much amniotic fluid build up in the course of pregnancy? How is it formed? What is its function? |
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Definition
1. usually 0.5 L to 1 L
2. fetal metabolism and renal recretion
3. it is the medium that cycles through the fetus and substances exchanged across the placenta, including cycling water every 3 hours and electrolytes every 15 hours |
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Term
| How does progesterone prevent further entry of sperm into the uterus after fertilization? How might it help with preventing early birth? |
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Definition
1. progesterone causes a mucus plug to form in the cervix, preventing the entry of more sperm
2. progesterone inhibits prostaglandins and uterine contractions during early stages of pregnancy |
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Term
| How are contractions prior to term prevented? How are they probably initiated when the baby comes to term? |
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Definition
1. progesterone, which is release more than estrogen for the first to trimesters and even for the 7th month sometimes, prevents uterine contraction
2. later in the pregnancy, estrogen levels increase; as the estrogen:progesterone ratio increases, uterine contractions become less inhibited by progesterone and more stimulated by estrogen; when the ratio rises enough, contractions to push the baby to the cervix are probably initiated, activating the oxytocin positive feedback loop |
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Term
| Besides estrogen, what are other possible initiators/helpers with contractions for birth? |
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Definition
| the release of fetal oxytocin and fetal cortisol; the stimulus of the cervix (which releases large amounts of maternal oxytocin, which causes uterine contractions), and the fetal release by fetal membranes (possibly when they are ruptured) of prostaglandins, which can intensify the uterine contractions |
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Term
| Why does the uterus continue to contract post partum? |
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Definition
| due to the release of so many hormones that stimulate contraction, contraction many not cease for 10-45 minutes; also, the placenta must be delivered in addition to the baby |
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Term
| What is hCS? Where is it released? What is its function? |
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Definition
1. human chorionic somatomammotropin
2. secreted by the placenta at about week 5 (secretion is in proportion to placenta weight and far exceeds other hormones)
3. hCS seems to help develop the breasts for future lactation, but it also has effects similar to hGH, stimulating protein deposition in the embryo and decreasing sensitivity of the mother to insulin; the thought is that decreased insulin sensitivity increases the availability of glucose for the fetus for growth while the mother begins to rely more on fat |
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Term
| Describe the morphology of fetal adrenal glands |
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Definition
| 1. thin outer region is the cortex and becomes the glomerulosa; the transitional zone become the reticularis and fasiculata; th thick inner cortical zone is called the fetal zone and secretes DHEA, though it regresses after birth; |
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Term
| What hormones contribute to mammary gland development and how? |
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Definition
1. hCS seems to help develop the breasts but the mechanism and exact development is unsure
2. estrogen stimulates proliferation of lobules and alveoli in breasts, increasing fat deposition and ductal branching
3. hGH, PRL, insulin, and glucocorticoids contribute to ductal growth and are necessary to have FFAs, aa's, glucose, and calcium in the milk
4. progesterone promotes growth and maturation, especially secretory features |
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Term
| If both estrogen and progesterone are involved in mammary gland development, why doesn't milk secretion occur until after birth? |
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Definition
| estrogen and progesterone develop the mammary gland, but also inhibit milk secretion; prolactin stimulates breast development and milk secretion, but it must compete with estrogen and progesterone for the latter function; after birth, progesterone and estrogen secretions drop and prolactin (which as been secreted more since week 5 of pregnancy) will start the secretion of milk |
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Term
| What stimulates to ejection of milk from the nipple? What is the mechanism? |
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Definition
1. oxytocin
2. suckling causes a nervous signal to be transmitted to the pituitary to cause a prolactin surge (to secrete more milk) and oxytocin release, which stimulates ejection of milk |
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Term
| What is special about the first ejection of milk? |
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Definition
| it contains no fat, but has IgG and gut microbes to prepare the infant's stomach |
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Term
| When is milk no longer secreted in the mammary glands? |
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Definition
| When milk ejection has been stimulate bu not all the milk is sucked out or pumped out of the mammary glands, the glands will cease to secrete milk |
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Term
| How can milk ejection be inhibited? How can milk ejection be stimulated without suckling? |
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Definition
1. SNS stimulation
2. sometimes the sound of an infant crying or simply stress can cause lactation |
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Term
| How does human milk compare to cow milk? |
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Definition
| they are fairly similar, though human milk has significantly more lactose and cow milk has much more ash (a substance containing calcium and other minerals) |
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Term
| How do hormones change from pregnancy to post-pregnancy? |
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Definition
| estrogen, progesterone, and prolactin levels all drop incredibly, though prolactin is stimulated periodically during nursing |
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