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24 Cards in this Set
- Front
- Back
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Female Reproductive System Internal Organs, External genitalia and role
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Internal Organs
Ovaries - endocrine and exocrine fxn Oviducts - Uterine or Fallopian tubes to conduct ova to uterus Uterus - implantation of zygote (blastula stage), conducts sperm up to oviducts, muscular sac for fetus to be developed and expulsed Cervix - opening of the uterus to the vagina Vagina - conducting canal External genitalia - labial folds, clitoris, vestibule Mammary glands not really part of system but developmentally and functionally related |
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Menarche and Menopause timeframe
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Female reproductive organs undergo cyclic changes from puberty to menopause related to hormonal changes and neural activity
Menarche - initiation of cycles btw ages 9-14 Menopause - ovaries cease reproductive and endocrine functions around 45-55 years of age Time between is 28-30 days |
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Fimbrae role
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Sits on top of ovary to catch ovulated egg. Ovary not actually attached to uterine tube
Ovary suspended by ligaments, fimbrae feeds into uterine tube |
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Primary functions of ovaries
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Production of gamets (oogenesis) - oocytes are developing gametes, mature ones are ova
Production of steroids a) Estrogens - promote growth and maturation of internal and external sex organs b) Progestogens - prepare internal sex organs for pregnancy by promoting secretory changes in endometrium |
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Ovaries Structure, Progression
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Paired, located in pelvis, almond shaped, surface epithelium continuous with mesothelium and often referred to as germinal epithelium even though it does not house germ cells or give rise to gametes (unlike male system)
Parts: Medulla - loose CT rich in vessels and nerves Cortex - periphery with developing ovarian follicles Progression - Primordial follicle to early primary follicle to late primary follicle to secondary follicle to mature follicule to large mature follicle to released oocyte (to fimbrae). Remnants form corpus hemorrhagicum and later corpus luteum (hormone production, nutrients) and corpus albicans (white,atrophied) Follicle is the oocyte with cells around it, growing/maturing are the cells around (follicular or granulosa cells) While in the ovary, the oocyte is always a primary oocyte, once ovulated it is a secondary oocyte |
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Ovarian Follicle, Stages
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An oocyte surrounded by one or more layers of epithelial cells
Stages: Primoridial follicle - oocyte with thin layer of cells Early Primary follicle (unilamilar) - surrounding cells enlarge Late Primary follicle (multilaminar) Secondary (Antral) follicle - fluid begins to build Mature Graafian follicle - pushing against ovary wall to be ovulated |
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Oogenesis
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Primoridal germ cell enters gonad to become oogonium
Diploid oogonium replicate by mitosis inside ovary (2N to 4N to 2N) One oogonium enters meiosis as PRIMARY OOCYTE (2N) Primary oocyte ARRESTS after diplotene of prophase I as primary oocyte grows (4N). PRIMARY OOCYTE = 4N. Continuoed growth and development of primary oocyte with cortical granules Later in life meiosis I continues, growth and devefinishes leaving 1 SECONDARY OOCYTE (2N) and 1 discarded polar body. In secondary meiosis - another 1/4 discarded as polar bodies and have on mature haploid egg (1N) Overall leaves 2-3 polar bodies and 1 haploid egg |
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Timeframe differences Spermatogenesis and Oogenesis
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Spermatogenesis - spermatogonia populate epithelium after puberty and develops perm throughout life
Oogenesis - primordial germ cells all go through mitotic division during 5th month fetal development. Only about 1 million survive and rest degenerate. Oogonia start meiosis and arrest in PROPHASE of MEIOSIS I. Houses a primary oocyte. Of these 1 million, half become atretic (apoptosis) So at menarche, females only have about 500,000 primordial follicles, ovulation hormones start and monthly one matures through cycle becoming secondary oocyte Though conventional to say at menarche there are NO oogonia, there may actually be some |
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Arrest of primary oocyte, induction later
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Occurs during 5th fetal month. Arrest in prophase of meiosis I. Afterwards only follicle cells and granulosa cells around grow to support.
FSH surge induces growth of 10-12 antral follicles, one of which dominates FSH+LSH surge triggers maturation and ovulation of dominant oocyte to form secondary oocyte |
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Structure of Primordial Follicle
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Primary oocyte arrested at prophase meiosis I
Thin layer of squamous or low cuboidal epithelial cells surrounding the oocyte with junctional complexes A BM encapsulates entire follicle. Stromal cells on other side Organelles of primary oocyte a) Balbiani bodies - pronounced secretory granules b) Annulate lamellae - "weird" nuclear membrane Primary oocyte is spherical, has asymmetric nucleus, chromatin appears vesicular; follicular cells are squamous, completely surround primary oocyte and are attached to each other by desmosomes |
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Structure of Early Primary Follicle
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At menarche, waves of LH, progesterone, FSH, and estrogen, One primary follicle starts progression.
Primary follicles grow to be very large, large nucleus, RER, Golgi, mitochondria are present ZONA PELLUCIDA begins to form (GAGs and glycoproteins) Follicular cells become CUBOIDAL - unilaminar still at early stage. Af/after this stage follicular cells become GRANULOSA Extensive gap junctions develop between granulosa cells, NO TIGHT JXNS so NO BLOOD-FOLLICLE barrier |
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Structure of Late Primary Follicile
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Granulosa cells proliferate - MULTILAMINAR
Zona pellucida appears around oocyte, produced by follicular cells Microvillia from oocyte and filopoda from granulosa cells penetrate zona pellucida to make contact with each other. Stromal cells organize around follicle forming theca folliculi (external to basal lamina of granulosa cells). Theca layer secretes STEROIDS a) Theca interna - composed of rich vascularized CT, LH receptors that induce estrogen precursor production b) Theca externa - fibrous CT and smooth muscle |
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Major components of zona pellucida
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ZP and glycoproteins ZP1,2,3
ZP 3 necessary for sperm binding |
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Secondary Follicle Structure
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Antral follicles
Presence of LIQUOR FOLLICULI - fluid buildup in antrum. Contains GAGs, proteoglycans, steroid binding proteins and steroids Nicely formed zona pellucida, lots of organization in thecal/stromal cells, blood vessels more prominent FSH stimulates fluid buildup Granulosa cells secrete Oocyte maturatoin inhibitor to keep oocyte from going any ruther through meisois Cumulus oophorus forms, single layer of granulosa cells (corona radiata) forms Cortical granules under oocyte PM evident |
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OMI
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oocyte maturation factor, secreted by granulosa cells to keep oocyte arrested at Prophase I of meiosis. If becomes secondary oocyte in ovary, then too late
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Corona radiata
Cumulus oophorus |
Corona radiata - single layer of cells around the oocyte
Cumulus oophorus - buildup of cells on one side of follicle near burst point on side Form in secondary follicles |
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Mature (Graafian) Follicle Structure
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Granulosa cells still producing a lot of fluid but slower rate
Egg moved to one side side of follicle creating a buldge and adhering to wall of follicle though cumulus oophorus fromed via granulosa cells This is follicle that undergoes OVULATION and MATURE SECONDARY OOCYTE when OMI decreased and meiosis inducing factor is increasing which tells the primary oocyte to complete meiosis I and stop again Theca layers more prominent Primordial to mature follicle takes 90 days |
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Fraternal Twins
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Have two mature follicles ovulated in one month
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What is actually ovulated
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cumulus oophorus and primary oocyte
Antrum, thecal layers and granulosa cells around are kept and become corporus leuteum |
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Correlation of Ovarian and Menstrual Cycles Hormones, Follicle and Uterine
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28 day cycle
Follicle - primary follicle at day 1 to Ovulation at Day 14, to corpus leuteum at Day 21, to corpus albicans at end Hormones - FSH higher than LH until Day 9 then LH surge Estrogen steadily rises then increases around Day 9 till large peak then drops back to baseline with a couple smaller peaks around Day 23. Progesterone steady till Day 15, rises and peaks at Day 23 then drops off (Progesterone RISES post-ovulation Uterine - Layer lost Days 1-5 with menstrual flow, steadily grows till Day 27, then begins to drop off again |
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Ovulation Sequence
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Estrogen released from Graafian follicle causes rise in blood estrogen. Induces LH surge causes blood to rush to ovary (blood vessels prominent and follicle matures) due to increased permeability in theca externa, causes release of meiosis inducing factor to finish meiosis I forming secondary oocyte and polar body
Secondary oocyte immediately enters and arrests at prophase of meiosis II Granulosa cells in mature follicle produce GAGs and hyaluronic acid in antrum causing it to swell, moves to outer ovarian cortex and pushes against capsule (T. albuginea). Rupture follows Secondary oocyte and corona radiata released into peritoneum near oviduct (infundibulum) Graafian follicle collapses and LH converts it to corpus luteum |
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Changes in oocyte genetic material at ovulation
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Arrests at prophase Meiosis II, until fertilization by sperm, at fertilization have impregnation of oocyte and resumption of meiosis II, second polar body formed, alignment of male and female pronuclei and zygote formation
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Ovary Post ovulation
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Forms Corpus Luteum
Granulosa cells of mature follicle differentiate into hormone producing cells as granulosa-lutein cells and make progesterone and estrogen Theca interna cells enlarge and become hormone producing cells known as theca-leutin cells - make progesterone No pregnancy - corpus luteum degenerates, if occurs placenta produces a hormone to maintain Old corpus luteum becomes filled with fibroblasts that secrete collagen and structure known as corpus albicans |
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Follicular Atresia
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Can be seen in ovary at any given time - follicles that did not ovulate (disassembly)
oocyte loosened from granulosa cells, never seen in healthy follicle |
