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28 Cards in this Set
- Front
- Back
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spermatozoa must penetrate the mass of ? cells that surround the "mature" secondary oocyte. the enzyme ? helps them do this.
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cumulus
hyaluronidase |
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reaction that causes a change in the zona pellucida, preventing polyspermy
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cortical reaction
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what causes the "calcium wave" in the secondary oocyte, which triggers the completion of meisosis II?
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spermatozoon entering cytoplasm
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rise of calcium ions in the secondary oocyte cytoplasm inactivates both ? and ? and allows meiosis II to proceed
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CSF, MPF
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stage before male & female pronuclei merge; zygote w/ two nuclei
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dikaryon zygote
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16-cell zygote
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morula
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60-100 cell zygote
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blastocyst
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hormone secreted by the trophoblast that signals that a woman is pregnant
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human chorionic gonadotrophin (hCG)
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3 steps in implantation
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-zona pellucida dissolves
-trophoblast attaches to endometrium & burrows in -development of the placenta |
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placenta is made of cells from ?
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trophoblast & mother's endometrium
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trophoblast differentiates into ? and ? during its burrowing process
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inner cytotrophoblast, outer syncytiotrophoblast
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3 tissues that from from ectoderm
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nervous system
portions of most sensory organs lens of eye adrenal medulla |
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3 tissues from mesoderm
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muscle tissue
skeletal tissue connective tissue blood vessels |
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3 tissues rom endoderm
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epithelial linings
liver pancreas thyroid |
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amnion develops from ?
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ectoderm
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yolk sac (and allantois) develop from ?
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endoderm
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chorion develops from ?
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trophoblast
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embryo floats in ? fluid
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amniotic
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function of yolk sac in humans
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produces blood cells; incorporated into umbilical cord
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? penetrate endometrial tissues of mother to begin formation of the placenta; blood capillaries grow into them
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chorionic villi
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maternal component of placenta?
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blood sinuses that enfold chorionic villi
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substances that move across placenta
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oxygen
carbon dioxide nutrients excretory products antibodies (from the mother) |
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2 reasons oxygen diffuses across placenta
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-fetal RBCs have a higher affinity for O2
-fetus has 50% higher concentration of hemoglobin |
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5 hormones secreted by placenta
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human chorionic gonadotropi (hCG)
progesterone estrogens human placental lactogen relaxin |
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function of human chorionic gonadotropin
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-prolongs life of the corpus luteum so that progesterone & estradiol will continue to be produced
-makes woman miss her period (b/c corpus luteum continues to produce progesterone) -stimulates secretion of testosterone in males |
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b/c the corpous luteum persists, progesterone levels remain high and the endometrium remains in its ? phase
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"receptive" secretory
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functions of progesterone
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-makes endometrium stimulate nutrients
-maintains uterine lining & quiets muscle activity -stimulates mammary gland development -used by fetus to make cortisol & aldosterone |
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functions of estrogen
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-enlargment of myometrium, breasts, and breast ducts
-tog. w/ relaxin, relaxes pelvic ligaments & symphis pubis to facilitate birth |
