Fertilization Questions PDF

**1. During fertilization, what is the first step in the process?**\ A. Fusion of the sperm and egg membranes\ B. Cortical reaction\ C. Sperm penetration of the corona radiata\ D. Acrosomal reaction\ E. Formation of the zygote **Correct Answer:** C. Sperm penetration of the corona radiata **2. Wha...

**1. During fertilization, what is the first step in the process?**\ A. Fusion of the sperm and egg membranes\ B. Cortical reaction\ C. Sperm penetration of the corona radiata\ D. Acrosomal reaction\ E. Formation of the zygote **Correct Answer:** C. Sperm penetration of the corona radiata **2. What occurs during the acrosomal reaction?**\ A. Formation of the zygote\ B. Sperm cells attach to receptors on the zona pellucida, and acrosomal enzymes digest the zona pellucida\ C. Depolarization of the oocyte membrane\ D. Fusion of the pronuclei\ E. The oocyte completes the second meiotic division **Correct Answer:** B. Sperm cells attach to receptors on the zona pellucida, and acrosomal enzymes digest the zona pellucida **3. Which reaction prevents polyspermy?**\ A. Acrosomal reaction\ B. Formation of the male pronucleus\ C. Cortical reaction\ D. Fusion of the sperm and egg membranes\ E. Completion of meiosis II **Correct Answer:** C. Cortical reaction **4. How does the cortical reaction prevent additional sperm from entering the oocyte?**\ A. By depolarizing the oocyte membrane (fast block) and forming a perivitelline space in the zona pellucida (slow block)\ B. By digesting the zona pellucida with enzymes\ C. By forming the female pronucleus\ D. By fusing the sperm and egg membranes\ E. By enlarging the male pronucleus **Correct Answer:** A. By depolarizing the oocyte membrane (fast block) and forming a perivitelline space in the zona pellucida (slow block) **5. What happens immediately after the sperm enters the oocyte cytoplasm?**\ A. The male and female pronuclei fuse to form a zygote.\ B. The oocyte nucleus completes the second meiotic division.\ C. The zona pellucida forms a perivitelline space.\ D. The male pronucleus enlarges.\ E. The acrosomal reaction occurs. **Correct Answer:** B. The oocyte nucleus completes the second meiotic division. **6. When is the female pronucleus formed?**\ A. During the cortical reaction\ B. After the oocyte completes the second meiotic division\ C. After the fusion of the pronuclei\ D. During sperm penetration of the corona radiata\ E. Before the sperm enters the oocyte **Correct Answer:** B. After the oocyte completes the second meiotic division **7. What happens to the sperm head after it enters the oocyte cytoplasm?**\ A. It attaches to the zona pellucida.\ B. It becomes the male pronucleus.\ C. It completes meiosis II.\ D. It triggers depolarization of the oocyte membrane.\ E. It creates the perivitelline space. **Correct Answer:** B. It becomes the male pronucleus. **8. What marks the completion of fertilization?**\ A. Formation of the male pronucleus\ B. Completion of the cortical reaction\ C. Fusion of the male and female pronuclei to form a single nucleus\ D. Completion of meiosis II in the oocyte\ E. Depolarization of the oocyte membrane **Correct Answer:** C. Fusion of the male and female pronuclei to form a single nucleus **9. What results from the fusion of the male and female pronuclei?**\ A. The secondary oocyte\ B. A polar body\ C. A zygote\ D. The zona pellucida\ E. The perivitelline space **Correct Answer:** C. A zygote **10. What hormone is released by the fetal hypothalamus to initiate the process of parturition?**\ A. Oxytocin\ B. Progesterone\ C. Corticotropin-releasing hormone (CRH)\ D. Estrogen\ E. Prostaglandin **Correct Answer:** C. Corticotropin-releasing hormone (CRH) **11. What is the primary role of adrenocorticotropic hormone (ACTH) in parturition?**\ A. To stimulate the fetal adrenal gland to secrete adrenal cortical steroids\ B. To stimulate the secretion of oxytocin\ C. To level off progesterone synthesis\ D. To stimulate uterine contractions directly\ E. To produce estrogen **Correct Answer:** A. To stimulate the fetal adrenal gland to secrete adrenal cortical steroids **12. Where do adrenal cortical steroids travel after being secreted by the fetal adrenal gland?**\ A. The fetal hypothalamus\ B. The uterus\ C. The placenta\ D. The maternal bloodstream\ E. The posterior pituitary **Correct Answer:** C. The placenta **13. What effect do adrenal cortical steroids have in the placenta during parturition?**\ A. They stimulate oxytocin secretion.\ B. They cause progesterone synthesis to level off and estrogen and prostaglandin synthesis to increase.\ C. They trigger the release of ACTH.\ D. They inhibit uterine contractions.\ E. They stimulate uterine smooth muscle cells directly. **Correct Answer:** B. They cause progesterone synthesis to level off and estrogen and prostaglandin synthesis to increase. **14. What happens as a result of increased estrogen and prostaglandin levels in the uterus during parturition?**\ A. The placenta produces more progesterone.\ B. The uterus becomes more excitable.\ C. The fetal hypothalamus secretes oxytocin.\ D. The adrenal cortical steroids stop being produced.\ E. The uterine contractions decrease. **Correct Answer:** B. The uterus becomes more excitable. **15. What initiates the secretion of oxytocin from the posterior pituitary during parturition?**\ A. Increased levels of prostaglandin in the placenta\ B. The stretching of the uterus producing action potentials\ C. The secretion of CRH by the fetal hypothalamus\ D. The inhibition of progesterone synthesis\ E. The release of ACTH from the fetal pituitary **Correct Answer:** B. The stretching of the uterus producing action potentials **16. What is the function of oxytocin during parturition?**\ A. To stimulate the fetal adrenal gland\ B. To increase progesterone synthesis\ C. To level off estrogen levels\ D. To cause the uterine smooth muscles to contract\ E. To inhibit uterine contractions **Correct Answer:** D. To cause the uterine smooth muscles to contract **17. Which hormone(s) directly contribute to making the uterus more excitable during parturition?**\ A. Oxytocin and CRH\ B. Estrogen and prostaglandin\ C. Progesterone and ACTH\ D. Adrenal cortical steroids and oxytocin\ E. CRH and ACTH **Correct Answer:** B. Estrogen and prostaglandin