Human Reproductive Biology Quiz
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Questions and Answers

What is the primary purpose of meiotic divisions during gametogenesis?

  • To reduce the chromosomal number from diploid to haploid (correct)
  • To enhance the size of germ cells
  • To facilitate morphological changes in germ cells
  • To maintain the diploid chromosomal number
  • Which statement best describes the transformation of male germ cells during spermatogenesis?

  • They undergo mitotic division to remain diploid.
  • They lose most of their cytoplasm and form a definitive structure. (correct)
  • They remain large and round throughout the process.
  • They develop a head, neck, and tail through gradual protein synthesis.
  • At what stage do primary spermatocytes undergo their first meiotic division?

  • During the process of spermiogenesis
  • Immediately following fertilization
  • After transformation from spermatogonia (correct)
  • Prior to mitotic divisions of spermatogonia
  • What morphological change do female germ cells undergo during gametogenesis?

    <p>They gradually increase in size due to cytoplasmic growth.</p> Signup and view all the answers

    Which of the following best describes spermiogenesis?

    <p>The maturation process where spermatids develop into mature spermatozoa.</p> Signup and view all the answers

    During which phase of the menstrual cycle does implantation occur?

    <p>Secretory phase</p> Signup and view all the answers

    Which type of implantation is considered the most dangerous?

    <p>Tubal implantation</p> Signup and view all the answers

    What is the primary role of early pregnancy factor (EPF) in pregnancy?

    <p>To serve as a basis for pregnancy testing</p> Signup and view all the answers

    Which hormone's high levels in urine form the basis for a pregnancy diagnostic test by the end of the second week?

    <p>Chorionic gonadotrophic hormone</p> Signup and view all the answers

    Which phase does the uterine endometrium not undergo during the menstrual cycle?

    <p>Pre-ovulatory phase</p> Signup and view all the answers

    What can inhibit implantation in the event of conception?

    <p>High doses of hormone combinations</p> Signup and view all the answers

    Where does the implantation typically occur in the uterus?

    <p>Near the fundus</p> Signup and view all the answers

    Which of the following is a characteristic of the menstrual phase?

    <p>Endometrial glands disintegrate</p> Signup and view all the answers

    What primarily occurs during the ovarian cycle in response to GnRH from the hypothalamus?

    <p>Secretion of gonadotrophins FSH and LH</p> Signup and view all the answers

    What is formed from the notochordal plate during development?

    <p>Notochord</p> Signup and view all the answers

    During which phase does the secondary oocyte complete the second meiotic division?

    <p>After fertilization</p> Signup and view all the answers

    What occurs during the invagination process at the primitive streak?

    <p>Cells separate from the epiblast and move downward</p> Signup and view all the answers

    Which of the following statements about granulosa cells and the cumulus oophorus is true?

    <p>Cumulus oophorus is formed by intact granulosa cells during maturation</p> Signup and view all the answers

    What happens to the majority of follicles developed during an ovarian cycle?

    <p>They degenerate and become atretic</p> Signup and view all the answers

    What indicates the future site of the vertebral bodies?

    <p>Notochord</p> Signup and view all the answers

    Which of the following structures temporarily connects the yolk sac and amniotic cavity?

    <p>Neurenteric canal</p> Signup and view all the answers

    What event triggers the maturation of the follicle and subsequent ovulation?

    <p>Increase in LH levels</p> Signup and view all the answers

    During which week of development does the primitive streak begin to appear?

    <p>3rd week</p> Signup and view all the answers

    Which of the following best describes the state of primary oocytes by the onset of puberty?

    <p>Only 40,000 remain present</p> Signup and view all the answers

    Which cells are primarily responsible for estrogen production during follicle development?

    <p>Theca and follicular cells</p> Signup and view all the answers

    What happens to the notochord in the region of the vertebral bodies as the vertebral column forms?

    <p>It disappears but persists as the nucleus pulposus</p> Signup and view all the answers

    Which of the following regions does NOT have secondary mesoderm spread over it?

    <p>Prechordal plate</p> Signup and view all the answers

    What is the outcome for oocytes that are not fertilized within 24 hours after ovulation?

    <p>They degenerate</p> Signup and view all the answers

    What is the primary function of the notochord during embryonic development?

    <p>Support and organize the embryo</p> Signup and view all the answers

    Which division of the secondary mesoderm is responsible for forming the skeletal muscles of the trunk and limbs?

    <p>Paraxial mesoderm</p> Signup and view all the answers

    What structure is formed from the ventral portion of somites?

    <p>Vertebral body</p> Signup and view all the answers

    Which type of mesoderm is situated lateral to the intermediate mesoderm?

    <p>Lateral plate mesoderm</p> Signup and view all the answers

    Which of the following structures is NOT formed by derivatives of the lateral plate mesoderm?

    <p>Skeleton except skull</p> Signup and view all the answers

    At which day does the first pair of somites appear in the cervical region?

    <p>20th day</p> Signup and view all the answers

    How many pairs of somites are typically present by the end of the 5th week?

    <p>42 - 44 pairs</p> Signup and view all the answers

    Which embryonic structure does NOT correspond to a subdivision of the secondary mesoderm?

    <p>Somatopleuric mesoderm</p> Signup and view all the answers

    What does the term somite refer to in embryonic development?

    <p>A segment of paraxial mesoderm</p> Signup and view all the answers

    What is the primary function of the myotome?

    <p>Forming skeletal muscles</p> Signup and view all the answers

    Which component is exclusively formed by the sclerotome?

    <p>Cartilage and bone</p> Signup and view all the answers

    Which of the following is NOT a derivative of the ectoderm?

    <p>Dermis of the skin</p> Signup and view all the answers

    Which mesodermal component is responsible for developing the urogenital system?

    <p>Intermediate mesoderm</p> Signup and view all the answers

    What function do fetal membranes serve during embryonic development?

    <p>Providing growth and survival of the embryo</p> Signup and view all the answers

    From which germ layer does the thyroid gland develop?

    <p>Endoderm</p> Signup and view all the answers

    Which of the following structures is derived from mesoderm?

    <p>Urogenital system</p> Signup and view all the answers

    Which of the following statements about the dermatome is correct?

    <p>It gives rise to dermis and subcutaneous tissue.</p> Signup and view all the answers

    Study Notes

    General Embryology

    • This document covers general principles of embryology, including various stages and processes.
    • It provides detailed information on gametogenesis, ovarian cycle, fertilization, cleavage, implantation, formation of germ layers, fetal membranes, placenta, fetal period, multiple pregnancy, and teratogenesis.

    Gametogenesis

    • Gametogenesis is the process by which male and female germ cells undergo chromosomal and morphological changes.
    • Chromosomal changes reduce the diploid number of chromosomes to haploid.
    • Morphological changes alter the size and shape of the germ cells.

    Ovarian Cycle

    • The ovarian cycle is a cyclical process controlled by the hypothalamus and pituitary gland.
    • Follicular and theca cells produce estrogen, which stimulates the pituitary to secrete LH.
    • LH causes follicle maturation and oocyte shedding.

    Fertilization

    • It's the fusion of male and female gametes to form a zygote.
    • Sperm transport involves flagella and muscular contractions through the female reproductive tract.
    • The oocyte is transported by fimbriae and cilia, moving towards the uterine cavity.
    • Sperm maturation involves capacitation (removal of glycoprotein coat) and acrosome reaction (release of acrosomal enzymes).
    • Fertilization phases include penetration of the corona radiata and zona pellucida, and fusion of oocyte and sperm cell membranes.

    Cleavage

    • The single-celled zygote undergoes mitotic divisions.
    • It increases the number of cells (blastomeres).
    • Cleavage begins 30 hours after fertilization.
    • Zygote is within the zona pellucida during cleavage.

    Implantation

    • Implantation is the embedding of the blastocyst into the uterine endometrium.
    • Site of implantation is typically the posterior or anterior wall of the uterus near the fundus.
    • The endometrium is in the secretory phase at the time of implantation.
    • Abnormal sites of implantation include ectopic pregnancy (outside the uterus).

    Formation Of Germ Layers

    • During gastrulation, three germ layers, ectoderm, mesoderm, and endoderm, are established.
    • The primitive streak appears on the surface of the epiblast.
    • Cells migrate into the primitive streak, forming the endoderm and mesoderm.
    • Cells remaining in the epiblast form the ectoderm.

    Fetal Membranes

    • Tissues and structures, derived from the zygote, that support development until birth are fetal membranes.
    • They include the yolk sac, amnion, chorion, allantois, umbilical cord, and placenta.
    • Placenta develops to connect the embryo to the mother for nutrition exchange.
    • It is a feto-maternal organ about 15-25cm in diameter.
    • Maternal surface is irregular, with lobules (cotyledons).
    • Fetal surface is smooth, with the umbilical cord attachment.

    Placenta

    • The placenta supports the fetus during pregnancy for gas and nutrient exchange.
    • Maternal portion is derived from the decidua basalis, while the fetal portion from the chorion frondosum.
    • The chorionic villi extend into the decidua basalis, forming maternal-fetal exchange areas (intervillous spaces).

    Fetal Period

    • The fetal period (weeks 9-40) is characterized by the maturation of tissues and organs, and rapid growth.
    • The fetus's size (CRL or CHL) is a measure of development.
    • Many noticeable changes in the structure of the body and systems occur during this stage.

    Multiple Pregnancy

    • Multiple pregnancies (twins, triplets etc) result from the fertilization of multiple eggs (dizygotic) or a single fertilized egg that splits (monozygotic).
    • Monozygotic twins share a common placenta.
    • Dizygotic twins have separate placentas.

    Teratogenesis

    • Teratology is the study of abnormalities due to birth defects.
    • Causes include genetic, environmental factors.
    • There are four major categories of abnormalities:
      • Malformations
      • Disruptions
      • Deformations
      • Syndromes

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    General Embryology PDF

    Description

    Test your knowledge on human reproductive biology, focusing on gametogenesis, spermatogenesis, and the menstrual cycle. This quiz covers key concepts such as meiotic divisions, implantation stages, and hormonal roles in pregnancy. Challenge yourself and see how well you understand these essential biological processes!

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