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25 Cards in this Set
- Front
- Back
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Gametes
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specialized germ cells that are haploid
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Gametogenesis
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formation of fully-developed gametes
begins much earlier than meiosis, even before the time of gonad differentiation during embryonic development. Ends at fertilization |
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Mitosis vs. meiosis
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Primordial germ cells are amplified by mitosis during embryonic development
After the mitotic amplifications, germ cells undergo meiosis to make haploid gametes |
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Meiosis
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Meiosis produces only gametes.
It consists of one round of DNA synthesis as in mitosis A complex interphase with genetic recombination, followed by two successive cell divisions (Meiosis I and Meiosis II). The parent cell is diploid and the daughter cells are haploid. The parent and daughter cells are genetically very different. |
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Site of spermatogenesis
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Seminiferous tubules in the testes
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Spermiogenesis
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Acrosome is a specialized form of the Golgi
2) Mid-piece houses mitochondria to provide GTP for flagella (tail) 3) Sperm are produced throughout life of the male |
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HPO
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Hypo --> GnRH to pit --> FSH and LH to ovary --> estrogen and progesterone to uterus
LH stims ovulation |
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estrogen and progesterone
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help thicken uterine lining
corpus luteum secretes progest and estrogen |
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Gonadotropin Releasing Hormone (GnRH)
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From hypothalmus, targets ant pit
Synthesis and secretion of FSH and LH |
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FSH
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From ant pit, targets ovary
Stimulates ovarian follicle growth, differentiation, and steroidogenesis |
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LH
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From ant pit, targets ovary
Stimulates ovulation, corpus luteum formation and steroidogenesis |
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Estrogens
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From ovary (follicle cells) targets uterus, vagina, mammary glands
Growth and differentiation of targets |
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Progestins
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From corpus luteum, targets uterus, vagina, mammary glands
Growth and differentiation of targets |
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Downs syndrome
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trisomy 21
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Angelmanns
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csome 15 deletion
speech impairment, movement disorder, developmental delay |
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Prader-Willi
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Chromosome 15 deletion
developmental delay poor muscle tone short stature small hands and feet incomplete sexual development unique facial features insatiable appetite |
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Changes in the Number of Germ Cells in the Ovary over Life Span
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99.9% of oocyte decline is due to apoptosis; also call oocyte atresia; <0.01% are ovulated
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Human health issues involved in gametogenesis
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Thalidomide birth defects
Rubella (German Measles) birth defects Premature menopause (accelerated oocyte atresia) Egg donation Infertility Effect of maternal age on birth defects |
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Fertilization overview
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Sperm swim up the cervical canal and are drawn up through the uterus and fallopian tubes by muscular contractions and ciliary movements. Work: 1/3♂, 2/3♀
Fertilization occurs in the ampulla of the fallopian tube. Fertilization may occur elsewhere in the uterine tube, but not in the uterus. Fertilization is a complex sequence of coordinated molecular events that takes about 24 hours. Begins with contact between sperm and secondary oocyte. Ends with intermingling of maternal and paternal chromosomes at metaphase of first zygotic division |
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Phases of menstrual cycle
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Menstrual Phase: days 1-5
Proliferative Phase: days 5-14 Secretory Phase: days 14-27 Ischemic Phase: day 27-28 |
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Menstrual Phase
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Functional layer of the endometrium of the last cycle is sloughed off
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Proliferative Phase
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Days 5-14; also called the estrogenic phase, coincides with growth of ovarian follicles.
Estrogen levels rise and initiate restoration of a functional endometrium. |
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Secretory Phase
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Days 14-27; estrogen levels peak; progesterone levels are high
Corpus luteum makes progesterone If fertilization occurs, the embryo implants on day 20. hCG produced by the embryo prevents the corpus luteum from degenerating, resulting in continued production of estrogen and progesterone If no fertilization occurs, the corpus luteum degenerates, estrogen and progesterone levels fall, and the secretory endometrium enters the ischemic phase |
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Ischemic Phase
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Days 27-28
Progesterone and estrogen levels fall rapidly and the functional endometrium becomes ischemic. |
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Follicle Maturation
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primordial follicle -->primary --> secondary --> mature follicle (graffian -->ovulated secondary oocyte, corpus luteum, corpus albicans
size of the follicle, whether there is a fully developed antrum (Graafian, or mature follicle), and the nature/type of supporting cells (follicle cells that will become the corona radiata, and thecal cells |
