Human Reproduction and Fertilization Quiz
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Questions and Answers

What physiological change must sperm undergo in the female genital tract to fertilize the ovum?

  • Motility enhancement
  • Capacitation (correct)
  • Capacitance action
  • Fertilization process
  • What occurs during the acrosomal reaction of sperm?

  • Enzyme release to soften the zona pellucida (correct)
  • Cortical reaction initiation
  • Sperm penetrate the ovum
  • Formation of the zygote
  • What is the primary purpose of the cortical reaction following fertilization?

  • Facilitate zygote formation
  • Alter sperm motility
  • Release sperm enzymes
  • Prevent additional sperm entry (correct)
  • What is the process called that occurs when a zygote burrows into the endometrial lining of the uterus?

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

    How long must sperm remain in the female reproductive tract before they can fertilize an ovum?

    <p>4-6 hours</p> Signup and view all the answers

    Which structure connects the fetus to the placenta?

    <p>Umbilical cord</p> Signup and view all the answers

    What is the primary function of amniotic fluid during pregnancy?

    <p>To protect the fetus from injury</p> Signup and view all the answers

    What happens to the zona pellucida after the first sperm penetrates it?

    <p>It undergoes cortical reaction</p> Signup and view all the answers

    At what age is a fetus considered to have reached the 'age of viability'?

    <p>20 weeks</p> Signup and view all the answers

    During which developmental period does implantation of the zygote into the endometrium occur?

    <p>Pre-embryonic period</p> Signup and view all the answers

    What is the primary role of the placenta during pregnancy?

    <p>Nutrient exchange and endocrine function</p> Signup and view all the answers

    What do male and female gametes contribute to form a zygote?

    <p>A total of 46 chromosomes</p> Signup and view all the answers

    What is the first action sperm take upon reaching the zona pellucida?

    <p>Release the acrosome</p> Signup and view all the answers

    How long is the ovum fertilizable after ovulation?

    <p>24 to 48 hours</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the umbilical cord?

    <p>Has pain receptors</p> Signup and view all the answers

    What happens during fertilization?

    <p>A sperm cell penetrates the ovum to form a zygote</p> Signup and view all the answers

    What is the term for the process where a zygote undergoes mitotic division to form smaller cells?

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

    During which stage does the morula transform into the blastocyst?

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

    What structure is formed from the inner cell mass of the blastocyst?

    <p>The fetus</p> Signup and view all the answers

    At which day does implantation occur following fertilization?

    <p>Day 6</p> Signup and view all the answers

    What is the role of pinopods during the apposition phase of implantation?

    <p>To absorb endometrial fluid</p> Signup and view all the answers

    Which of the following molecules is primarily involved in the adhesion of the blastocyst to the endometrium?

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

    What is the primary function of the trophoblast in the blastocyst?

    <p>To become the placenta</p> Signup and view all the answers

    What defines the endometrial fluid absorbed by pinopods during implantation?

    <p>It provides initial nutrition to the blastocyst</p> Signup and view all the answers

    What is the role of HCG during early pregnancy?

    <p>Ensures continued estrogen production from the corpus luteum.</p> Signup and view all the answers

    Which layer of the decidua lies directly under the embryo?

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

    What is the function of the Syncytiotrophoblast cells?

    <p>Produce hormones like HCG and estrogen.</p> Signup and view all the answers

    What facilitates the exchange of substances between mother and fetus in the placenta?

    <p>Selective osmosis through chorionic villi.</p> Signup and view all the answers

    Which hormone produced by the placenta acts as a glucose antagonist to ensure glucose availability for the fetus?

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

    How does maternal positioning affect placental circulation?

    <p>Lying on the left side enhances placental efficiency.</p> Signup and view all the answers

    What characteristic describes the fetal side of the placenta?

    <p>Smooth and shiny.</p> Signup and view all the answers

    What is the primary role of the placenta during pregnancy?

    <p>Serve as the main organ for nutrient and gas exchange.</p> Signup and view all the answers

    What is the primary function of HCG during early pregnancy?

    <p>Ensures continuous production of progesterone and estrogen</p> Signup and view all the answers

    Which hormone is responsible for reducing the contractility of the uterus during pregnancy?

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

    What role does the placenta play in fetal immunity?

    <p>Actively transports maternal antibodies</p> Signup and view all the answers

    Which statement accurately describes the umbilical cord?

    <p>Is approximately 55 cm long and 2 cm in diameter</p> Signup and view all the answers

    What is the primary function of human placental lactogen during pregnancy?

    <p>Regulates maternal glucose and protein levels</p> Signup and view all the answers

    Which general function is associated with estrogen during pregnancy?

    <p>Increasing uterine growth for the fetus</p> Signup and view all the answers

    What is the function of Wharton's jelly in the umbilical cord?

    <p>Provides cushioning for the umbilical blood vessels</p> Signup and view all the answers

    Which membranes are involved in the formation of amniotic fluid?

    <p>Amniotic membrane and chorion</p> Signup and view all the answers

    Study Notes

    Pregnancy Overview

    • Pregnancy refers to the period from conception to birth where a female carries a developing embryo or fetus.
    • Begins with fertilization, the union of a sperm and an ovum, resulting in a zygote, which carries genetic material from both parents.

    Fertilization Process

    • Conception occurs when one sperm penetrates one ovum, determining the child's sex at this moment.
    • Nidation, or implantation, occurs 7-10 days post-fertilization in the endometrial lining.
    • Sperm lifespan: 48-72 hours; ovum is fertilizable for 24-48 hours.

    Special Structures of Pregnancy

    • Fetal Membranes: Form from the zygote and surround the developing fetus, containing amniotic fluid.
    • Amniotic Fluid: Clear, yellowish liquid (average 1000 ml); allows fetal movement, maintains temperature, and provides oral fluid.
    • Umbilical Cord: Connects fetus to placenta; contains 2 arteries and 1 vein, protected by Wharton's jelly, with no pain receptors.
    • Placenta: Acts as an endocrine organ and protective barrier, facilitating nutrient and water exchange between mother and fetus.

    Stages of Fetal Development

    • Age of Viability: A fetus can potentially survive if born after 20 weeks or weighs at least 500 grams.
    • Zygote Development: Begins with fertilization and involves cell division (cleavage) and formation of blastomeres.

    Capacitation and Gamete Fusion

    • Capacitation: Physiological changes in sperm required for fertilization; requires 4-6 hours in female tract.
    • Acrosomal Reaction: Sperm releases enzymes to penetrate the ovum's layers; leads to the cortical reaction, making the ovum impermeable to additional sperm.

    Zygote Development Phases

    • Pre-embryonic Period: First 2 weeks post-fertilization; embryo travels to uterus and implants.
    • Embryonic Period: Weeks 2-8 with significant growth and differentiation.
    • Fetal Period: From 8 weeks until birth; further maturation and development.

    Implantation Process

    • Apposition: Pinopod formation aids in embryo absorption into the endometrial lining.
    • Adhesion: Blastocyst attaches to endometrium via adhesion molecules.
    • Penetration & Invasion: Blastocyst burrows into uterine wall through histolytic action.

    Decidua and Chorionic Villi

    • Decidua: The modified endometrium during pregnancy, composed of three layers.
    • Chorionic Villi: Villi develop to form the placenta, using fetal capillaries for nutrient exchange.

    Hormones Produced by the Placenta

    • Human Chorionic Gonadotropin (HCG): Maintains corpus luteum; suppresses maternal immunologic response.
    • Estrogen: Stimulates uterine growth and mammary development.
    • Progesterone: Maintains endometrial lining and reduces uterine contractions.
    • Human Placental Lactogen (HPL): Promotes mammary growth and regulates maternal metabolism for fetal needs.

    Placenta Functionality

    • Functions as fetal lungs, kidneys, and gastrointestinal tract; facilitates nutrient and waste exchange.
    • Maternal antibodies provide passive immunity; some drugs and viruses can cross the placental barrier.

    Umbilical Cord Structure

    • Transports oxygen/nutrients to fetus and waste to the placenta; typically 55 cm long and 2 cm in diameter.
    • Composed of 1 vein and 2 arteries; Wharton's jelly prevents pressure on vessels.

    Amniotic Membranes

    • Chorionic Membrane: Outermost membrane forming the amniotic fluid sac.
    • Amniotic Membrane: Produces amniotic fluid and initiates labor by generating prostaglandins.

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    Description

    Test your knowledge on key physiological changes in human reproduction, particularly focusing on sperm maturation, the acrosomal reaction, and the implantation of the zygote. This quiz covers essential concepts related to fertilization and early development. Challenge yourself on these critical reproductive processes.

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