Human Reproduction and Sexual Responses
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Questions and Answers

What hormone does the placenta require from the fetal adrenal cortex for estrogen synthesis during the first trimester?

  • Progesterone
  • Dehydroepiandrosterone (DHEA) (correct)
  • Cholesterol
  • Human chorionic gonadotropin (hCG)

    • Which of the following is NOT a function of progesterone during pregnancy?

  • Stimulates growth of myometrium musculature (correct)
  • Stimulates development of mammary milk glands
  • Suppresses contractions of uterine myometrium
  • Promotes formation of mucus plug

    • What is the approximate duration of human gestation calculated from the last menstrual period?

  • 38 weeks
  • 36 weeks
  • 40 weeks (correct)
  • 42 weeks

    • During pregnancy, which physiological change is primarily stimulated by estrogen?

    <p>Retention of sodium and water</p> Signup and view all the answers

    What role does human chorionic somatomammotropin (hCS) play during pregnancy?

    <p>Prepares breast glands for lactation</p> Signup and view all the answers

    What hormone is primarily responsible for maintaining the uterine lining during the first trimester of pregnancy?

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

    Which hormone is secreted by the placenta after 10 weeks of pregnancy?

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

    What is the role of hCG during the first trimester regarding the corpus luteum?

    <p>To sustain the corpus luteum for hormone production</p> Signup and view all the answers

    What change occurs in the male fetus at the end of the first trimester due to hCG?

    <p>Differentiation of male genitalia</p> Signup and view all the answers

    Why does the placenta not initially secrete estrogen in the early stages of pregnancy?

    <p>The corpus luteum is primarily responsible for hormone output at that time</p> Signup and view all the answers

    What role does Parathyroid hormone-related peptide (PTHrp) play during pregnancy?

    <p>It mobilizes maternal calcium for fetal bone development.</p> Signup and view all the answers

    Which hormone is primarily responsible for the production of Dehydroepiandrosterone (DHEA) in the fetal adrenal cortex?

    <p>Placental Corticotropin Releasing Hormone (CRH)</p> Signup and view all the answers

    During which stage of labor does cervical dilation occur?

    <p>1st stage</p> Signup and view all the answers

    What is a common sign that labor has begun?

    <p>Rupture of the amniotic sac</p> Signup and view all the answers

    What causes the softness of the cervix in preparation for labor?

    <p>Breakdown of cervical collagen fibers</p> Signup and view all the answers

    What physiological change occurs to the uterus after childbirth?

    <p>It shrinks back to pre-pregnancy size.</p> Signup and view all the answers

    What triggers the development of glandular structures in the breast during pregnancy?

    <p>Increased levels of progesterone and estrogen</p> Signup and view all the answers

    Which hormone is primarily involved in stimulating uterine contractions during parturition?

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

    What may indicate the end of the second stage of labor?

    <p>The baby is pushed through the cervix into the vagina.</p> Signup and view all the answers

    What primarily initiates the parturition process in mothers?

    <p>Corticotropin releasing hormone (CRH)</p> Signup and view all the answers

    Which physiological change occurs during the first stage of labor?

    <p>Dilation of the cervical canal</p> Signup and view all the answers

    What role does relaxin play during childbirth?

    <p>Loosens pelvic connective tissue</p> Signup and view all the answers

    What is the term for the process of the uterus shrinking to its pre-pregnancy size after delivery?

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

    Which of the following best describes the function of oxytocin during parturition?

    <p>It promotes uterine contractions through increased calcium levels</p> Signup and view all the answers

    What physiological change occurs during male orgasm that is not associated with female orgasm?

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

    Which statement accurately describes the female orgasm compared to the male orgasm?

    <p>Only females can experience multiple orgasms immediately.</p> Signup and view all the answers

    What effect does vasodilation of the lower third of the vagina have during sexual arousal?

    <p>Increases tension around the penis</p> Signup and view all the answers

    What triggers the expulsion of semen during ejaculation?

    <p>Motor neurone induced rhythmic contractions</p> Signup and view all the answers

    Which physiological responses are common to both male and female orgasms?

    <p>Increase in respiratory rate</p> Signup and view all the answers

    What is referred to as the 'orgasmic platform' during female orgasm?

    <p>The rhythmic contractions occurring in the lower third of the vagina</p> Signup and view all the answers

    What changes occur to the cervix during orgasm in females?

    <p>It raises and enlarges the upper half of the vagina.</p> Signup and view all the answers

    What hormonal change occurs at the end of the first trimester in male fetuses due to hCG?

    <p>Stimulation of gonads for steroid hormone production</p> Signup and view all the answers

    What is the primary source of progesterone during the first trimester of pregnancy?

    <p>The corpus luteum</p> Signup and view all the answers

    What is the main role of human chorionic gonadotropin (hCG) during early pregnancy?

    <p>Sustaining the corpus luteum's function</p> Signup and view all the answers

    Why is hCG detected in urine throughout pregnancy?

    <p>It is secreted by the chorion</p> Signup and view all the answers

    During which event does the placenta take over hormone production from the corpus luteum?

    <p>At 10 weeks of pregnancy</p> Signup and view all the answers

    What physiological event is primarily triggered by hCG during the first trimester?

    <p>Genitalia differentiation in male fetuses</p> Signup and view all the answers

    What potential symptom may be triggered by hCG during early pregnancy?

    <p>Nausea and vomiting (morning sickness)</p> Signup and view all the answers

    What can be inferred about the role of the corpus luteum as pregnancy progresses?

    <p>It regresses and is no longer needed for hormone output</p> Signup and view all the answers

    What hormonal factor maintains the uterine lining early in pregnancy?

    <p>Combined estrogen and progesterone from the corpus luteum</p> Signup and view all the answers

    Why doesn't estrogen initially come from the placenta?

    <p>The corpus luteum is responsible for early hormone production</p> Signup and view all the answers

    What is formed when the boundaries between trophoblast cells disintegrate?

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

    What substance is primarily responsible for preventing the menstruation process from expelling the implanted embryo?

    <p>Human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    Which structure allows the exchange of gases and nutrients between maternal and fetal blood?

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

    What is the role of trophoblast cells during implantation?

    <p>To tunnel into the endometrial lining</p> Signup and view all the answers

    What happens to the capillaries in the decidua during placenta development?

    <p>They break down to form cavities filled with maternal blood</p> Signup and view all the answers

    How does the blastocyst become buried in the uterine lining?

    <p>Expansion of trophoblast cells</p> Signup and view all the answers

    What is the primary function of the syncytiotrophoblast during its development?

    <p>To invade the decidua and create cavities</p> Signup and view all the answers

    What initiates decidualization of the endometrium?

    <p>Invasion by trophoblast cells</p> Signup and view all the answers

    What does the term 'placental villi' refer to?

    <p>Extensions of chorionic tissue providing nutrient exchange</p> Signup and view all the answers

    Which of the following describes the physiological changes that occur in the mother during pregnancy due to increased levels of estrogen?

    <p>Enlargement of the uterus and improvements in pulmonary function.</p> Signup and view all the answers

    What is one of the primary roles of progesterone during pregnancy?

    <p>Suppresses contractions of the uterine myometrium.</p> Signup and view all the answers

    During the first trimester, which hormone primarily maintains the production of progesterone?

    <p>Human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    What is the main source of dehydroepiandrosterone (DHEA) needed for estrogen synthesis during the first trimester?

    <p>Fetal adrenal cortex</p> Signup and view all the answers

    What change in the body occurs as a result of increased aldosterone during pregnancy?

    <p>Retention of sodium and water.</p> Signup and view all the answers

    Which of the following hormones is primarily responsible for preparing breast glands for lactation during pregnancy?

    <p>Human chorionic somatomammotropin (hCS)</p> Signup and view all the answers

    What is the approximate duration of human gestation calculated from conception?

    <p>38 weeks</p> Signup and view all the answers

    Which of these hormones is secreted by the placenta during gestation?

    <p>Human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    What is one of the physiological changes regarding nutritional requirements in pregnant women?

    <p>Nutritional requirements increase due to fetal development.</p> Signup and view all the answers

    Which substance is transformed into cholesterol to support the synthesis of hormones during pregnancy?

    <p>Fatty acids</p> Signup and view all the answers

    What physiological effect is commonly associated with orgasm in both males and females?

    <p>Increased muscle tension</p> Signup and view all the answers

    Which of the following correctly describes the physiological changes in the female during orgasm?

    <p>Upper half of vagina enlarges</p> Signup and view all the answers

    What triggers the expulsion of semen during ejaculation?

    <p>Sympathetic response activation</p> Signup and view all the answers

    In males, what phenomenon occurs immediately during ejaculation?

    <p>Rhythmic contractions every 0.8 seconds</p> Signup and view all the answers

    What physiological change allows the cervix to dilate during labor?

    <p>Breakdown of cervical collagen fibers</p> Signup and view all the answers

    Which region of the female reproductive system experiences rhythmic contractions during orgasm?

    <p>Lower third of the vagina</p> Signup and view all the answers

    Which hormone plays a significant role in increasing oxytocin sensitivity in the myometrium during parturition?

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

    What is the primary purpose of Braxton-Hicks contractions during pregnancy?

    <p>To prepare the uterus for the contractions of labor</p> Signup and view all the answers

    What is the primary mechanism that leads to the sensation of intense physical pleasure during orgasm?

    <p>Stimulation of mechanoreceptors</p> Signup and view all the answers

    What anatomical feature aids in providing 'tenting effect' during arousal?

    <p>Uterus lifting</p> Signup and view all the answers

    During which stage of labor is the baby delivered through the cervix to the vagina?

    <p>Second stage: Delivery of the baby</p> Signup and view all the answers

    What triggers involution of the uterus after childbirth?

    <p>Decrease in estrogen and progesterone levels</p> Signup and view all the answers

    What process must freshly ejaculated sperm undergo to become capable of fertilization?

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

    What is the role of allurin released by the mature ovum?

    <p>To attract sperm</p> Signup and view all the answers

    Which of the following events does NOT occur during the acrosomal reaction?

    <p>Initial sperm activation by weak acids</p> Signup and view all the answers

    What leads to the final meiotic division of the secondary oocyte?

    <p>Sperm entering the cytoplasm</p> Signup and view all the answers

    Which structure assists in moving the ovum into the oviduct?

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

    What is the approximate number of sperm in a normal ejaculate per 2.75 mL?

    <p>180 million</p> Signup and view all the answers

    What kind of period do males experience that prevents orgasms in quick succession?

    <p>Temporary refractory period</p> Signup and view all the answers

    What change occurs in sperm during capacitation?

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

    What is the function of integrin in the fertilization process?

    <p>Binds with fertilin on the sperm surface</p> Signup and view all the answers

    What is the primary role of oestrogen during pregnancy?

    <p>Stimulating the development of mammary gland ducts</p> Signup and view all the answers

    Which hormone does the placenta primarily synthesize during the early stages of pregnancy?

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

    What is the effect of progesterone on uterine contractions during pregnancy?

    <p>It suppresses contractions of the uterine myometrium.</p> Signup and view all the answers

    Human gestation is approximately how many weeks from conception?

    <p>38 weeks</p> Signup and view all the answers

    Which hormone is produced by the fetal adrenal cortex that is necessary for oestrogen synthesis by the placenta?

    <p>Dehydroepiandrosterone (DHEA)</p> Signup and view all the answers

    One of the functions of human chorionic somatomammotropin (hCS) is to:

    <p>Prepare breast glands for lactation.</p> Signup and view all the answers

    Which of the following is a physiological change that occurs in the mother during pregnancy due to oestrogen?

    <p>Increased pulmonary ventilation.</p> Signup and view all the answers

    What initiates the development of the 'foetoplacental unit'?

    <p>Fetal adrenal cortex function.</p> Signup and view all the answers

    During which trimester does the placenta take over production of hormones like oestrogen and progesterone?

    <p>Second trimester</p> Signup and view all the answers

    What is one of the effects of increased blood volume during pregnancy?

    <p>Increased GFR and urine output.</p> Signup and view all the answers

    What hormone is primarily responsible for sustaining the corpus luteum during the early stages of pregnancy?

    <p>Human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    At what point in pregnancy does the placenta begin to produce oestrogen?

    <p>After 10 weeks</p> Signup and view all the answers

    Which hormone is detected in urine and is commonly associated with pregnancy tests?

    <p>Human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    What is the role of hCG in the differentiation of male genitalia at the end of the first trimester?

    <p>Stimulates testosterone production</p> Signup and view all the answers

    Why is the corpus luteum important during early pregnancy?

    <p>It secretes oestrogen and progesterone</p> Signup and view all the answers

    Which of the following statements is accurate regarding morning sickness during pregnancy?

    <p>It may be triggered by human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    What happens to the corpus luteum as pregnancy progresses beyond the first trimester?

    <p>It eventually regresses and is no longer needed</p> Signup and view all the answers

    What is the primary role of the placenta after 10 weeks of pregnancy?

    <p>To take over hormone production from the corpus luteum</p> Signup and view all the answers

    What effect does hCG have on morning sickness in pregnant individuals?

    <p>It may trigger morning sickness by affecting the vomiting center</p> Signup and view all the answers

    What is the connection between hCG and fetal gonads at the end of the first trimester?

    <p>hCG stimulates the gonads to produce hormones for genital development</p> Signup and view all the answers

    Study Notes

    Human Reproduction, Pregnancy, and Parturition

    • Human reproduction, pregnancy, and parturition are covered.
    • Learning outcomes include explaining male and female sexual response, implantation, placenta development, changes in endocrinology during pregnancy, maternal adaptations, gestation maintenance, parturition phases, lactation, suckling response, and weaning.

    Sexual Arousal and Ejaculation

    • Sexual arousal involves four stages: excitement, plateau, orgasm, and resolution.
    • Excitement involves heightened sexual awareness, vasocongestion, and engorgement.
    • Plateau involves intensification of excitement.
    • Orgasm involves intense physical pleasure and rhythmic contractions.
    • Resolution involves the return of the body to a pre-excitement state.
    • Male and female sexual response have similar stages. The male experience also includes a refractory period after orgasm.
    • Different parts of the nervous system are involved in male sexual response.
    • Ejaculation is the expulsion of semen, a process involving sympathetic and parasympathetic responses. The number of sperm per ejaculate can be an indicator of infertility in males.

    Implantation and Pregnancy

    • Fertilization typically occurs in the ampulla of the fallopian tube.
    • Sperm must go through capacitation once inside the female reproductive tract.
    • Key stages of fertilization include zona pellucida binding, acrosome reaction, and cortical reaction.
    • The resulting zygote undergoes cleavage to form a morula, then a blastocyst.
    • Implantation occurs when the blastocyst attaches to the uterine wall and embeds itself.
    • Key factors in implantation include the trophoblast (surface layer of the blastocyst), cords of trophoblastic cells, and the endometrium (lining of the uterus).
    • The implanted blastocyst is nourished by the development of the placenta.

    Development of Placenta

    • The placenta originates from both trophoblast and decidual tissue.
    • Trophoblastic cells differentiate into multinucleate syncytiotrophoblasts, which invade the decidua and form cavities filled with maternal blood.
    • Developing embryo's capillaries enter the syncytiotrophoblast projections, forming placental villi.
    • Each villus contains fetal capillaries separated from maternal blood by a thin tissue layer.
    • The placenta plays a crucial role in nourishing the developing embryo/fetus, exchanging respiratory gases, nutrients, and metabolites.

    Hormonal Maintenance of Pregnancy

    • Human chorionic gonadotropin (hCG) maintains the corpus luteum, preventing menstruation, and supporting the development of progesterone and estrogen.
    • Progesterone and estrogen are crucial for maintaining the uterine lining and preparing for parturition.
    • Late in the first trimester, the placenta begins to produce these vital hormones that maintain pregnancy.
    • The hormones produced during pregnancy help to maintain the uterine lining and prepare the breast tissues for lactation.
    • Different hormones play specific roles in supporting pregnancy over the different trimesters.
    • Oestrogen and progesterone are critical in maintaining pregnancy, but the source varies throughout gestation (placenta takes over production of these hormones).

    Parturition and Lactation

    • Parturition (labor) involves cervical dilation to allow passage of the fetus and uterine contractions to expel the fetus.

    • Stages of labor include cervical dilation, the delivery of the baby, and delivery of the placenta.

    • Labor preparation includes Braxton–Hicks contractions and softening of the cervix.

    • Hormonal changes, such as increased estrogen and a rise in corticotropin releasing hormone, trigger labor.

    • Lactation is the secretion of milk by the mammary glands.

    • Suckling triggers a neuroendocrine reflex that leads to the secretion of prolactin and oxytocin.

    • Prolactin stimulates milk production, while oxytocin causes milk ejection.

    • Cessation of breast milk production after weaning is linked to decreased prolactin and oxytocin secretion.

    Development of the Breast

    • In non-pregnant women, the breasts comprise mostly adipose tissue and rudimentary ducts.
    • Duct development, lobule formation, and synthesis of milk-producing enzymes are stimulated by oestrogen and placental hormones, such as human chorionic somatomammotropin.
    • Prolactin continues to stimulate milk production after delivery.
    • Breast milk composition includes factors like water, lactose, lipids, vitamins and minerals, proteins and immunological agents, with colostrum being the milk produced in the first few days after birth.

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    Description

    Explore the intricacies of human reproduction, pregnancy, and parturition. This quiz covers stages of sexual arousal and ejaculation, including the physiological changes associated with male and female sexual responses, as well as key aspects of pregnancy and childbirth.

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