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141 Cards in this Set
- Front
- Back
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what three steps of reproduction occur within the female reproductive tract?
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internal insemination, internal fertilization and internal gestation
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What is the placenta composed of?
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chorion (extraembryonic membranes of the fetus) and decidua (endometrial tissue form mom)
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what three endocrine systems are interacting during pregnancy?
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maternal, fetal and placental
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what is the purpose of vaginal tenting?
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to draw cervix away from vagina to create a local reservoir for sperm.
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what is capacitation? where does it occur?
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transient event that must occur before sperm can fertilize the egg. Occurs in oviduct.
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where do uncapacitated sperm bind? what is the purpose of this?
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bind epithelium of oviduct; it increases the lifespan of the sperm.
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what are the 4 ways in which capacitation modifies spermatozoa?
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1) alters membrane fluidity by removal of cholesterol from membrane.
2) removes proteins and/or carbs that may block binding sites for egg 3) changes membrane potential that may assist Ca to enter sperm and facilitate acroosmal rxn 4) protein phosphorylation. |
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What three layers must sperm pass thru?
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cumulus, zona pellucida and fusion of sperm and plasma membrane of egg.
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what is the cumulus composed of? how does the sperm get thru this?
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hyaluronic acid. Sperm has membrane bound hyalurnidase to eat thru that layer.
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what is the zona pellucida composed of? what does sperm bind to in this layer? what does that cause?
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glycoprotein: ZP1, ZP2, ZP3
sperm binds to ZP3 which triggers an acrosome reaction and enzymes are released that digest the zona pellucida. |
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why does sperm bind ZP2?
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to be held in place while the zona is digested.
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T/F
the egg is metabolically active before and after sperm egg fusion. |
FALSE
the egg is metabolically quiesent until sperm egg fusion. |
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how is polyspermy prevented?
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the egg is metabolically quiesent until sperm egg fusion, so the same egg cannot be activated by multiple sperm
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when is the egg finally haploid?
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when the sperm egg fusion occurs because that triggers the completion of meiosis.
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what triggers the egg "wakes up" events?
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Ca release
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what layer hardens preventing polyspermy?
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zona pellucida
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increased Ca stimulates the recruitment of _______ within the egg that will synthesize _____ needed for early embryonic development.
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stored maternal mRNA; proteins
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what layer of cells separates and forms the chorionic villi that indigitates with the endometrium? what two hormones are important for this process?
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the trophoblasts; prostaglandins and histamine
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what does the blastocyst secrete? why?
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secretes immunosuppressive agents to avoid rejection by the maternal immune system.
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during implantation, what sustains the corpus luteum even though LH is rapidly declining? what does it act as? what does it promote?
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human chorionic gonadotropin (hCG). Acts as an immunosuppresive agent. Promotes trophoblast growth and placental development.
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during week one, what encapsulates the embryo?
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zona pellucida
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what is present at day 3 of fertilzation and development?
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16 cell morula.
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what is formed at days 4-5?
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blastocyst cavity.
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what are the two cell types of the blastocyst?
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eccentric inner cell mass and outer, epithelial-like layer of trophoblasts.
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what is the embryonic pole?
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trophoblasts cells that are adjacent to inner cell mass.
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what are the three stages of implantation?
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apposition, adhesion and invasion
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what is required before implantation occurs?
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hatching- degeneration of the zona pellucida
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where does apposition occur? why does it occur there?
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at a site where the zona pellucida is ruptred or lysed so it is possible for the cell membranes of the trophoblast to make direct contact with cell membranes of the endometrium.
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what is the correct orientation in apposition?
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the inner cell mass points towards the endometrium.
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on the intracellular site, what do the receptor ligands interact with?
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cytoskeletal elements
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on the extracellular side, what type of receptors are located? (adhesion)
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receptors for matrix proteins (collagen, laminin and fibronectin).
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what happens during the invasion phase of implantation?
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trophoblasts differentiate into two layers: syncytiotrophoblasts and cytotrophoblast.
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what is the syncytiotrophoblast?
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the outerlayer of the trophoblast. It is multinucleated without cellular boundaries. It has long protrusions that extend between uterine epithelial cells(decidual lining).
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what is eventually penetrated by syncytiotrophoblast?
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the basement membrane of uterine epithelial cells.
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what happens to the decidual cells in the region of the invading syncytiotrophoblast? what is released?
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the decidual cells degenerate; lipids and glycogen are released to provide nutrients to the embryo.
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what is the cytotrophoblast layer?
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the inner layer of the trophoblast. It initially provides a layer of continuously dividing cells.
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what begins secreting hCG at implantation?
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syncytiotrophoblasts
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when does endocrine function begin?
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at implantation
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what is the first detectable sign of pregnancy?
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plasma level of hCG
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at ten weeks, what do the syncytiotrophoblasts start producing? why?
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they start making progesterone independent of the corpus luteum because they have become steriodogenic
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syncytiotrophoblasts take on the function of what three activities?
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gas transfer, facilitated transport, and pinocytosis / transcytosis.
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what is decidualization?
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enlargment and engorgement of stromal cells as they fill with lipid and glycogen
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what is the function of the decidua?
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to form an epithelial sheet with adhesive junctions to inhibit migration of implanting embryo.
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what does the decidua secrete? what is the function of the secreted substances?
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factors that moderate activity of syncytiotrophoblastic-derived hydrolytic enzymes. This regulates invasion of the embryo and placenta so it never reaches the myometrium.
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what are the four layers of the chorionic membrane?
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syncytiotrophoblasts, cytotrophoblasts, mesenchyme and fetal blood vessels.
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where is maternal blood trapped?
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in the intervillous space, between th decidua capsularis (mom side) and the villi (fetal).
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what types of arteries, in the mature placenta, empty directly into the intervillous space? what drains these arteries?
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spiral arteries; maternal veins
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what does the original uterine endometrium become?
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decidua pareetalis
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early nutrition for the placenta is from what? what is early absorption from?
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nutrition: trophoblastic digestion
absorption: nutrients form the endometrium |
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what supplies nutrition for the placental later on in the pregnancy?
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diffusion through placental membrane.
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near the end of pregnancy, what is the mean PO2 of maternal blood in placental sinus? what is the mean PO2 of fetus after oxygenation?
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~50 mmHg; 30 mmHG
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T/F
Fetal Hb has higher O2 affinity than adult Hb. |
True
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what kind of shift is caused by the fetus's demand for O2?
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double bohr shift
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what are the 5 endocrine functions of the placenta?
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1) maintain pregnant state of uterus
2) stimulate lobuloalveolar growth and function of breast 3) adapt maternal metabolism and physiology to support a growing fetus 4) regulate portions of fetal development 5) regulate timing and progression of partuition. |
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what types of hormones are secreted by syncytial trophoblasts?
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gonadotropin like homrones (LH and FSH); hCG and hCS
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how many days does it take for hCG to appear in serum?
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at most 9 days
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What are the two subunits that hCG consists of? what is the difference between the two?
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alpha and beta. Alpha is identical for FSH, LH and TSH and the B subunit has only an 80% homology to B subunit of LH
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how is hCG secreted in regards to the SCT layer?
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The CT layer stimlates the LHRH which then stimulate sthe SCT to secrete hCG via paracrine action.
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what is responsible for morning sickness in some people?
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rapid rise in hCG
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T/F
no hCG enters fetal circulation. |
FALSE
a very small amount enters 1%-10% |
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what does hCG stimulate in male fetuses?
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leydig cells to produce the testosterone critical for sexual differentiation.
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what is detected at 5 weeks and continues to rise throughout pregnancy in proportion to the weight of the placenta?
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human chorionic somatomammotropin.
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what is hCS? what does it cause?
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a protein hormone with similar functions as prolactin and GH; causes decrease insulin sensitivity and decreased glucose utilization in the mother; directs larger flow of glucose to the fetus. also stimulates the development of mammary glands.
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what does relaxin do?
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relaxes pubis and helps dilate cervix
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what enzyme do SCT cells lack?
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17 alpha hydroxylase
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what kind of receptors do SCT cells have?
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LDL receptors
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what is required to maintain q quiescent myometrium and pregnant uterus?
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progesterone
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T/F
progesterone production by the placenta is completely independent of the fetus and is regulated. |
FALSE
it is not regulated |
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how does progesterone quiet uterine contractions?
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by inhibiting prostaglandins
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what affect does progesterone have on the mother?
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increases capacity of alveolar pouches to hold milk
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what role does progesterone play in regards to the respiratory center of the fetus?
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stimulates respiratory center to get rid of excess CO2 produced by fetus.
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what produces estrogen during pregnancy?
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SCT cells
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where do androgens come from?
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fetal adrenal cortex
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T/F
The fetal zone expresses little or no 3B-HSD |
true
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what is released from the fetal zone of the adrenal gland during gestation?
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androgen DHEA-S
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what is the production of DHEA in the fetus is dependent on?
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release of ACTH from fetal pituitary
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what converts DHEA to estriol?
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placenta
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what can be used to assess fetal well being?
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estriol
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what affect does estrogen have on placental blood flow, LDL receptors and partuition?
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increase placental blood flow, increase LDL receptor in SCT layer and induce factors involved in partuition.
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What is estrogen's role in the uterus?
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stimulates growth of uterine muscle, softens pelvis along with relaxin and causes enlargement of external genitalia
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T/F
estrogen inhibits Progesterone synthesis. |
FALSE
augments |
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what conversion does estrogen stimulate in the placenta?
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cortisol to cortisone.
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initially where does DHEA come from?
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adrenals of the mother
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why do prolactin levels in the mother rise?
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due to increases in estrogen
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why does LH and FSH decrease with the maternal endocrine?
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due to negative feedback from high estrogen and progesterone
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what happens to the mother's thyroid gland during pregnancy?
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increases in size and level of T4 and T3 can double.
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what affect does estrogen have on thyroxine binding globulin?
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it increases it so it increased hormone binding.
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The first trimester changes of thyroid gland are in parallel with what?
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changes in hCG
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what happens late in pregnancy in regards to cortisol production? why is that important?
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there is a serge in cortisol production which is important for the initiation of lactation.
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how many days from ovulation is pregnancy? from last menstrual period?
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ovulation: 266 days; menstrual: 280 days
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how much does cardiac output increase during 1st trimester? when does it increase again?
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35-40%; slowly until term
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where is the majority of CO distribution targeted?
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40% increase in renal flow; 15% in uterine flow.
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why is than an increase in CO flow to the skin and breasts?
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skin= heat dissipation; breast- mammary glands
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what three organs experience no change in flow (cardiac) during pregnancy?
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brain, gut or skeleton
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How does pregnancy affect MAP? why?
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MAP decreases during mid-pregnancy with an increase in 3rd trimester. Due to a decrease in peripheral vascular resistance and the vasodilating effects of progesterone and estrogen
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what position gives the highest CO of the mother?
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lateral recumbent
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what will happen to venous return if the mother is supine?
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the fundus of the uterus rests on the inferior vena cava near L5 impeding venous return.
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what is the increase in blood volume during pregnancy due to? which trimesters are specifically affected?
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due to an increase in plasma volume and erythrocytes; 2nd and 3rd trimester.
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what affect does pregnancy have on the diaphragm?
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the diaphragm rises ~4 cm due to relaxing effects of P
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T/F
Pregnancy alters the Mother's vital capacity. |
FALSE
there is a net decrease in residual volume with no appreciable change in vital capacity. |
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what affect does pregnancy have on alveolar ventilation? what does this create for the mother?
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pulmonary resistance falls facilitating airflow. a decrease in maternal PCO2 (from 40-32)
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why is additional protein necessary during pregnancy? how much is necessary?
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protein is for the fetus, placenta, uterus, breasts and BV. need an additional 30 grams.
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why do you need an additional amount of iron during pregnancy? how much? how much do you need to absorb per day?
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to support maternal Hb mass, the placenta and the fetus. Need a net gain of ~800 mg. per day: 7.0 mg/day
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why is folate necessary during pregnancy?
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required to make additional RBC; lowered plasma folate can cause neural tube defects in fetus.
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in regards to maternal weight gain, how much can be attributed to intra-uterine things such as the fetus, placenta and amniotic fluid? what is the rest due to?
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5 kg; maternal gain such as the uterus, blood, breast and adipose/interstitial fluid.
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what is partuition?
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process of uterine contraction leading to childbirth
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what are the 3 stages of labor?
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1)Dilation and thinning of cervix due to uterine contractions forcing fetus against cervix (several hours)
2)Delivery of fetus (~ 1 hour) 3)Delivery of placenta (> 10 min) |
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which stage of labor is the fastest?
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delivery of the placenta
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what three things does increased cortisol from the fetus lead to?
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1) maturation of lungs
2) increase in liver glycogen stores 3) increase in intestinal transport and digestion |
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what stimulates the contraction of uterine smooth muscle cells?
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prostaglandin from uterus, placenta and fetal membranes.
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what potentiates contractions induced by oxytocin? how?
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PG by forming gap jxns between smooth muscle cells.
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what affect does PG have on the cervix?
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softening, dilation and thinning of the cervix
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what stimulates PG production? how?
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oxytocin by binding to the receptor on decidual cells
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T/F
Maternal oxy is thought to initiate labor but maintains labor |
False
Maternal oxy is NOT thought to initiate labor but maintains labor |
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when does fetal oxytocin rise? what is it involved in?
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at the beginning of labor. Involved in initiation of parturition.
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what hormone is relaxin related to? what produces it?
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insulin; corpus luteum, placenta and decidua.
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what is the job of relaxin? when does production increase?
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keeps uterus quiet during pregnancy, relaxes pelvic area prior to labor. Production increases during labor to help dilate cervix.
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what affect does estrogen have on the oxytocin receptors? where?
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increases the number of oxytocin receptors in myometrium and decidual layers.
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by how much does the receptor number rise during early labor?
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200 fold
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what are the four steps involved with the theory for the onset of strong contractions during labor?
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1) baby's head stretches cervix
2) cervical stretch excites fundic contraction 3) fundic contraction pushes baby down and stretches cervix some more 4) cycle repeats over and over again |
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what is mammogenesis?
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proliferation of alveolar and duct cells
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what is lactogenesis?
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milk production by alveolar cells
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what is galactorrhea?
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excessive or continued secretion of milk even after suckling has stopped
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what is lactation?
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lactogenesis and milk let down
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what does lactogenesis rely on?
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prolactin
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what allows the milk to let down?
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oxytocin
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what is the mammary gland made up of?
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supporting tissue and glandular tissue
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what does glandular tissue consists of?
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the alveoli and ducts
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where does the lactiferous duct carry secretions during lactation?
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outside
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during prenatal development of mammary glands, what are the mammaries sensitive to?
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estrogen
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what is present, in regards to mammary glands, at birth?
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rudimentary duct system
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what is present or developing, in regards to mammary glands, from birth until puberty?
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some growth of secretory tissue and development of supporting adipose tissue
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what happens to the mammary glands during puberty? why?
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sudden growth due to an increase in estrogen. The ducts grow, lobules and epithelial buds form at ductus terminus and there is an increase in CT and adipose tissue.
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what happens to the mammary glands during the menstrual cycle (folliculuar and luteal)?
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follicular: duct maintenance
luteal: lobular/alveolar maintenance |
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during pregnancy, what is high? what does that cause?
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high estrogen, progesterone and hCS which causes max growth of lobular/alveolar and duct system
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what is prolactin essential for?
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P and E to have mammotropic effects
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what does Prolactin stimulate? what prevents it?
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lactogenic apparatus; prevented by excess P and E
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why is milk synthesis initiated after parturition?
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due to decreased P and E
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what maintains high levels of prolactin after birth?
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sucking
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what can prevent subsequent ovulations (and therefor pregnancies) while lactating?
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high prolacting which can inhibit GnRH keeping LH low.
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what is milk?
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milk is an emulsification of fats in an aqueous solution containing sugar, proteins and inos
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