601. Which event is most directly associated with the initiation of parturition in humans?
ⓐ. Rupture of the Graafian follicle in the ovary
ⓑ. Sudden shedding of the endometrium during menstruation
ⓒ. Mild uterine contractions triggered by signals from the fully developed foetus and placenta
ⓓ. Completion of meiosis II in the secondary oocyte
Correct Answer: Mild uterine contractions triggered by signals from the fully developed foetus and placenta
Explanation: Parturition does not begin as an isolated uterine event without developmental context. Signals from the fully developed foetus and placenta help initiate mild uterine contractions near term. These early contractions are part of the foetal ejection reflex. They begin the process that later becomes stronger and leads to childbirth.
602. Which statement correctly describes the role of oxytocin during parturition?
ⓐ. It suppresses uterine contractions to delay birth
ⓑ. It intensifies uterine contractions once labour has begun
ⓒ. It causes fertilisation in the ampullary-isthmic junction
ⓓ. It converts colostrum into mature semen
Correct Answer: It intensifies uterine contractions once labour has begun
Explanation: Oxytocin is one of the key hormones associated with labour. Once the initial uterine contractions begin, oxytocin strengthens them and helps promote expulsion of the foetus. Its function is therefore contractile rather than inhibitory. This is why oxytocin is closely linked with active labour.
603. Which hormone is correctly matched with a major role near childbirth?
ⓐ. FSH — stimulates milk ejection
ⓑ. hCG — causes menstrual shedding
ⓒ. Relaxin — helps soften the cervix and relax pelvic ligaments
ⓓ. ADH — triggers ovulation
Correct Answer: Relaxin — helps soften the cervix and relax pelvic ligaments
Explanation: Relaxin contributes to preparation of the maternal body for delivery. It helps soften the cervix and relax pelvic ligaments, making childbirth easier. This role is different from the contractile effect of oxytocin. Together, these changes help facilitate parturition.
604. Which comparison between prolactin and oxytocin is correct?
ⓐ. Prolactin causes milk ejection, whereas oxytocin causes milk synthesis
ⓑ. Prolactin and oxytocin both act only during pregnancy and not after birth
ⓒ. Prolactin causes uterine implantation, whereas oxytocin forms colostrum
ⓓ. Prolactin mainly promotes milk production, whereas oxytocin mainly promotes milk ejection
Correct Answer: Prolactin mainly promotes milk production, whereas oxytocin mainly promotes milk ejection
Explanation: Lactation depends on more than one hormone acting in different ways. Prolactin primarily stimulates synthesis and secretion of milk in the mammary glands. Oxytocin, by contrast, helps in the let-down reflex and milk ejection. This functional difference is one of the most important distinctions in postnatal physiology.
605. Which event is most directly associated with the milk ejection reflex?
ⓐ. Contraction of cells around the alveoli under the influence of oxytocin
ⓑ. Mitotic division of oogonia in the ovary
ⓒ. Shedding of the zona pellucida by the blastocyst
ⓓ. Formation of the corpus luteum after ovulation
Correct Answer: Contraction of cells around the alveoli under the influence of oxytocin
Explanation: Milk ejection is not the same as milk synthesis. Oxytocin causes contraction of the cells around the mammary alveoli, helping push milk into the ducts and toward the nipple. This is known as the let-down reflex. It allows milk already produced to be delivered to the newborn.
606. Why is colostrum considered especially valuable for the newborn?
ⓐ. It is secreted only before fertilisation
ⓑ. It determines the chromosomal sex of the infant
ⓒ. It is rich in antibodies that provide early passive immunity
ⓓ. It replaces placental circulation immediately after implantation
Correct Answer: It is rich in antibodies that provide early passive immunity
Explanation: Colostrum is the first milk produced soon after childbirth and has a special protective role. It contains antibodies that help protect the newborn during the early period of life. This protection is especially useful because the infant's immune system is still developing. Its importance is therefore immunological as well as nutritive.
607. Which statement best distinguishes parturition from fertilisation?
ⓐ. Parturition occurs in the oviduct, whereas fertilisation occurs in the uterus
ⓑ. Parturition and fertilisation are both names for sperm entry into the ovum
ⓒ. Parturition occurs before implantation, whereas fertilisation occurs after birth
ⓓ. Parturition is delivery of the baby at the end of gestation, whereas fertilisation is fusion of gametes at the beginning of development
Correct Answer: Parturition is delivery of the baby at the end of gestation, whereas fertilisation is fusion of gametes at the beginning of development
Explanation: Fertilisation and parturition occupy opposite ends of the reproductive sequence. Fertilisation is the union of male and female gametes near the start of development, while parturition is childbirth at the end of gestation. One begins a new life, and the other completes intrauterine development. This makes them fundamentally different events in timing and meaning.
608. Which condition most directly stimulates continued milk production after childbirth?
ⓐ. Regression of the corpus luteum
ⓑ. Suckling stimulus acting through hormonal reflexes
ⓒ. Completion of meiosis II in the ovum
ⓓ. Formation of the blastocyst in the uterus
Correct Answer: Suckling stimulus acting through hormonal reflexes
Explanation: Lactation is reinforced by the baby's suckling. This stimulus helps maintain hormonal responses that support continued milk production and ejection. In this way, feeding itself promotes ongoing lactational activity. The process is therefore biologically coordinated between mother and infant.
609. Assertion: Parturition is aided by a positive-feedback-like pattern once labour contractions begin. Reason: Uterine contractions promote oxytocin release, and oxytocin further strengthens uterine contractions.
ⓐ. Both Assertion and Reason are true, and the Reason is the correct explanation of the Assertion.
ⓑ. Both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
ⓒ. Assertion is true, but the Reason is false.
ⓓ. Assertion is false, but the Reason is true.
Correct Answer: Both Assertion and Reason are true, and the Reason is the correct explanation of the Assertion.
Explanation: Labour intensifies because the contraction process helps reinforce itself. Initial contractions are followed by greater oxytocin release, and oxytocin in turn makes the contractions stronger. This creates an amplifying pattern until delivery occurs. The reason therefore directly explains the assertion.
610. Which sequence correctly represents the broad post-pregnancy functional order in humans?
ⓐ. Lactation → fertilisation → implantation → parturition
ⓑ. Parturition → ovulation → cleavage → implantation
ⓒ. Menstruation → parturition → fertilisation → lactation
ⓓ. Parturition → colostrum secretion → milk production and ejection
Correct Answer: Parturition → colostrum secretion → milk production and ejection
Explanation: After childbirth, the mother's physiology shifts toward nourishment of the newborn. Colostrum is secreted first and is followed by continued milk production and ejection during lactation. This makes the sequence a logical post-pregnancy progression. It links childbirth directly with the beginning of infant feeding.
611. Which event best completes the sequence associated with normal childbirth in humans? Foetal ejection reflex $\rightarrow$ oxytocin release $\rightarrow$ ______
ⓐ. stronger uterine contractions
ⓑ. menstrual shedding
ⓒ. ovulation of a new follicle
ⓓ. capacitation of sperm
Correct Answer: stronger uterine contractions
Explanation: The foetal ejection reflex helps initiate labour, and oxytocin then intensifies uterine contractions. These stronger contractions push the foetus toward the birth canal. This creates a reinforcing pattern that continues until delivery is completed. The sequence is therefore central to understanding parturition.
612. A mother has well-developed mammary glands and is producing milk after childbirth. Which hormone is most directly responsible for this milk synthesis?
ⓐ. Oxytocin
ⓑ. Relaxin
ⓒ. Estrogen
ⓓ. Prolactin
Correct Answer: Prolactin
Explanation: Prolactin primarily stimulates the mammary glands to synthesize milk after delivery. This hormone acts on the secretory tissue of the breast rather than on uterine muscle. Oxytocin has a different role and mainly helps in milk ejection. So milk production itself depends chiefly on prolactin.
613. Fill in the blank with the most accurate option: Colostrum is especially valuable for the newborn because it is rich in ______.
ⓐ. antibodies
ⓑ. bile pigments
ⓒ. sperm cells
ⓓ. thyroid hormones
Correct Answer: antibodies
Explanation: Colostrum is the first milk secreted after childbirth and is well known for its protective role. It contains antibodies that provide passive immunity to the newborn during an early vulnerable period of life. This helps protect the infant before its own immune defenses mature fully. That is why colostrum is considered highly beneficial.
614. Which statement correctly compares the role of oxytocin in childbirth and lactation?
ⓐ. It causes follicular growth during childbirth and implantation during lactation
ⓑ. It mainly supports milk synthesis during childbirth and ovulation during lactation
ⓒ. It strengthens uterine contractions during parturition and helps milk ejection after birth
ⓓ. It prevents labour pain during childbirth and forms colostrum during lactation
Correct Answer: It strengthens uterine contractions during parturition and helps milk ejection after birth
Explanation: Oxytocin acts in more than one reproductive context. During labour it intensifies uterine contractions, and after delivery it promotes milk ejection from the mammary glands. These are two distinct but important roles of the same hormone. This dual action makes oxytocin central to both childbirth and postnatal feeding.
615. A mother produces sufficient milk, but the baby suckles and little milk is released from the breast. Which hormone-related problem is most directly suggested?
ⓐ. reduced oxytocin action
ⓑ. reduced FSH secretion
ⓒ. reduced progesterone secretion
ⓓ. reduced hCG secretion
Correct Answer: reduced oxytocin action
Explanation: Milk production and milk ejection are not the same process. If milk is being produced but not effectively released, the most likely difficulty lies in the let-down reflex rather than synthesis. Oxytocin is the hormone most directly responsible for milk ejection. So poor release with adequate production suggests reduced oxytocin action.
616. Which structure of the mammary gland is the immediate site of milk secretion before milk enters the duct system?
ⓐ. Ampulla
ⓑ. Lactiferous duct
ⓒ. Alveolus
ⓓ. Mammary duct
Correct Answer: Alveolus
Explanation: The alveoli are the secretory units of the mammary gland. Milk is formed there first and then passes into mammary tubules and ducts. The ducts mainly conduct milk rather than produce it. This makes the alveolus the immediate site of secretion.
617. Which event most directly helps maintain continued lactation after childbirth?
ⓐ. regression of the placenta
ⓑ. repeated suckling by the infant
ⓒ. completion of menstruation
ⓓ. rupture of a new Graafian follicle
Correct Answer: repeated suckling by the infant
Explanation: Continued suckling provides an important physiological stimulus that helps maintain lactation. It supports hormonal reflexes involved in both milk production and milk ejection. In this way, the baby’s feeding behavior helps sustain the mother’s lactational state. This creates a biologically coordinated postnatal system.
618. Assertion: Breastfeeding helps the newborn beyond simple nutrition. Reason: Colostrum and milk provide protective factors, including antibodies, to the infant.
ⓐ. Both Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion.
ⓑ. Assertion is true, but the Reason is false.
ⓒ. Both Assertion and Reason are true, and the Reason is the correct explanation of the Assertion.
ⓓ. Assertion is false, but the Reason is true.
Correct Answer: Both Assertion and Reason are true, and the Reason is the correct explanation of the Assertion.
Explanation: Breastfeeding is important not only because it nourishes the infant but also because it contributes to early protection. Colostrum and breast milk contain antibodies and other beneficial components that support the newborn. This gives breastfeeding an immunological value in addition to its nutritive role. The reason therefore directly supports the assertion.
619. Which statement best distinguishes parturition from lactation in terms of timing and function?
ⓐ. Parturition nourishes the newborn, whereas lactation expels the foetus
ⓑ. Parturition and lactation both occur before implantation
ⓒ. Parturition is linked with pregnancy maintenance, whereas lactation is linked with ovulation
ⓓ. Parturition ends gestation by delivering the baby, whereas lactation begins postnatal nourishment
Correct Answer: Parturition ends gestation by delivering the baby, whereas lactation begins postnatal nourishment
Explanation: Parturition is the terminal event of pregnancy and results in childbirth. Lactation begins after this and provides nourishment to the infant through breast milk. These processes are therefore sequential but functionally different. One completes gestation, while the other supports life after birth.
620. Which sequence correctly represents the broad order of events near the end of human reproduction and early postnatal care?
ⓐ. Colostrum secretion $\rightarrow$ implantation $\rightarrow$ parturition
ⓑ. Fertilisation $\rightarrow$ suckling $\rightarrow$ ovulation
ⓒ. Parturition $\rightarrow$ prolactin-supported milk production $\rightarrow$ oxytocin-mediated milk ejection
ⓓ. Menstruation $\rightarrow$ placenta formation $\rightarrow$ lactation
Correct Answer: Parturition $\rightarrow$ prolactin-supported milk production $\rightarrow$ oxytocin-mediated milk ejection
Explanation: After childbirth, lactation becomes the next major reproductive-related function. Prolactin supports milk production, and oxytocin helps in milk ejection during feeding. This order links delivery with the start of postnatal nourishment in a biologically meaningful way. It captures the major late and postnatal events correctly.
