BIU MCQs of Week 1-8 Human Embryology Module Practice MCQs

### MCQ 1: **What is the term used to describe the biochemical changes in sperm that enable them to fertilize an egg?**\ A) Capacitation\ B) Acrosome reaction\ C) Cleavage\ D) Membrane fusion\ E) Zygote formation ### MCQ 2: **Which structure in the sperm releases enzymes to help digest the zona p...

### MCQ 1: **What is the term used to describe the biochemical changes in sperm that enable them to fertilize an egg?**\ A) Capacitation\ B) Acrosome reaction\ C) Cleavage\ D) Membrane fusion\ E) Zygote formation ### MCQ 2: **Which structure in the sperm releases enzymes to help digest the zona pellucida during fertilization?**\ A) Tail\ B) Midpiece\ C) Acrosome\ D) Nucleus\ E) Plasma membrane ### MCQ 3: **During fertilization, what reaction occurs in the egg after sperm fusion to prevent polyspermy?**\ A) Cortical reaction\ B) Capacitation\ C) Cleavage\ D) Zona pellucida reaction\ E) Acrosome reaction ### MCQ 4: **At which stage of cleavage does the zygote first divide into two cells?**\ A) Morula\ B) Four-cell stage\ C) Two-cell stage\ D) Blastocyst stage\ E) Eight-cell stage ### MCQ 5: **What is the name of the solid ball of cells formed by the 16-cell stage of cleavage?**\ A) Blastocyst\ B) Morula\ C) Zygote\ D) Trophoblast\ E) Inner cell mass ### MCQ 6: **Which of the following is a characteristic feature of spiral cleavage?**\ A) Cells arranged symmetrically\ B) Cells arranged at an angle\ C) The formation of the blastocoel\ D) Formation of the morula\ E) Formation of the trophoblast ### MCQ 7: **The outer layer of cells in the blastocyst, which contributes to the formation of the placenta, is called the:**\ A) Inner cell mass\ B) Trophoblast\ C) Blastocoel\ D) Morula\ E) Zygote ### MCQ 8: **Which stage follows the eight-cell stage of cleavage in human development?**\ A) Blastocyst\ B) Two-cell stage\ C) Morula\ D) Four-cell stage\ E) Sixteen-cell stage ### MCQ 9: **What is the primary function of capacitation in sperm cells?**\ A) To allow sperm to swim faster\ B) To enable sperm to bind to the egg\ C) To facilitate sperm entry into the zona pellucida\ D) To trigger the cortical reaction in the egg\ E) To allow sperm to respond to egg signals for fertilization ### MCQ 10: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### MCQ 11: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which of the following best describes the primary function of the ovaries in the female reproductive system? A. Production of sperm cells\ B. Secretion of testosterone\ C. Production of ova and secretion of estrogen and progesterone\ D. Storage of eggs in follicles\ E. Transport of eggs to the uterus ### MCQ 12: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### In the process of oogenesis, at what stage do primary oocytes arrest until puberty? A. Prophase I\ B. Metaphase I\ C. Anaphase II\ D. Telophase II\ E. Interphase II ### MCQ 13: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which structure in the female reproductive system is the typical site for fertilization? A. Uterus\ B. Ovary\ C. Fallopian tube\ D. Vagina\ E. Cervix ### MCQ 14: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What is the role of the fimbriae in the fallopian tube during the process of oogenesis? A. Capture the sperm during ejaculation\ B. Sweep the ovum into the fallopian tube after ovulation\ C. Support the developing fetus\ D. Release hormones for the menstrual cycle\ E. Transport sperm to the uterus ### MCQ 15: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which of the following hormones is primarily responsible for the release of an ovum during ovulation? A. Estrogen\ B. Progesterone\ C. Luteinizing hormone (LH)\ D. Follicle-stimulating hormone (FSH)\ E. Human chorionic gonadotropin (hCG) ### MCQ 16: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### During spermatogenesis, which type of cell is produced directly from primary spermatocytes? A. Spermatids\ B. Secondary spermatocytes\ C. Spermatogonia\ D. Sertoli cells\ E. Leydig cells ### MCQ 17: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What is the primary function of the Leydig cells in the male reproductive system? A. Nourish developing sperm cells\ B. Secrete testosterone\ C. Store sperm\ D. Produce seminal fluid\ E. Provide nutrients to the egg ### MCQ 18: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which of the following processes occurs in the seminiferous tubules of the testes? A. Fertilization\ B. Spermatogenesis\ C. Secretion of seminal fluid\ D. Maturation of sperm\ E. Storage of sperm ### MCQ 19: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### In the male reproductive system, which structure is responsible for sperm maturation and storage? A. Testes\ B. Epididymis\ C. Vas deferens\ D. Prostate gland\ E. Bulbourethral glands ### MCQ 20: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What is the primary function of the prostate gland in male reproduction? A. Production of sperm\ B. Secretion of semen\ C. Production of testosterone\ D. Secretion of seminal fluid to nourish sperm\ E. Regulation of sperm motility ### MCQ 21: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which of the following steps occurs first in the fertilization process after sperm enters the female reproductive tract? - A. Acrosomal reaction - B. Capacitation - C. Sperm binding to the zona pellucida - D. Fusion of sperm and egg membranes - E. Completion of meiosis II in the oocyte ### MCQ 22: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which structure of the sperm releases enzymes that help it penetrate the zona pellucida? - A. Tail - B. Mitochondrion - C. Acrosome - D. Midpiece - E. Nucleus ### MCQ 23: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What is the role of the cortical reaction in preventing polyspermy? - A. It releases sperm-binding factors into the egg\'s cytoplasm. - B. It triggers a rapid depolarization of the egg\'s membrane. - C. It releases enzymes that modify the zona pellucida to block additional sperm. - D. It facilitates the fusion of sperm and egg membranes. - E. It prevents the sperm from entering the egg\'s cytoplasm. ### MCQ 24: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What marks the completion of oocyte activation during fertilization? - A. Release of calcium from the endoplasmic reticulum - B. Fusion of sperm and egg membranes - C. Formation of the second polar body - D. Resumption of meiosis II - E. Formation of the male pronucleus ### MCQ 25: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which of the following is the mechanism that prevents multiple sperm from fertilizing an egg? - A. Fast block to polyspermy - B. Depolarization of the sperm membrane - C. Cortical reaction - D. Acrosomal reaction - E. Zona pellucida binding ### MCQ 26: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What happens during the acrosomal reaction? - A. The sperm releases enzymes to dissolve the zona pellucida. - B. The egg completes its second meiotic division. - C. The sperm binds to the oocyte's membrane. - D. The sperm nucleus merges with the egg's nucleus. - E. The zona pellucida becomes impermeable to all sperm. ### MCQ 27: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### At which stage of cleavage does compaction of the blastomeres occur? - A. Two-cell stage - B. Morula stage - C. Blastocyst stage - D. Four-cell stage - E. Eight-cell stage ### MCQ 28: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### Which cell type in the blastocyst is responsible for forming the placenta? - A. Trophoblast - B. Inner Cell Mass - C. Blastomeres - D. Zygote - E. Morula cells ### MCQ 29: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What triggers the oocyte to complete its second meiotic division? - A. The formation of the male pronucleus - B. A sudden increase in intracellular calcium ions - C. Sperm binding to the zona pellucida - D. The fusion of sperm and egg membranes - E. The formation of the female pronucleus ### MCQ 30: **When does the blastocyst typically arrive in the uterus for implantation?**\ A) 1-2 days after fertilization\ B) 5-6 days after fertilization\ C) 10-12 days after fertilization\ D) 24-30 hours after fertilization\ E) 3-4 days after fertilization ### What is the final result of the fusion of sperm and egg pronuclei? - A. The formation of a haploid zygote - B. The initiation of cleavage - C. The start of meiosis II - D. The formation of a diploid zygote - E. The development of the morula **1. Which of the following is the primary role of the decidua basalis during pregnancy?** a\) To secrete hormones that regulate pregnancy\ b) To anchor the embryo and facilitate placental development\ c) To protect the embryo from immune system attacks\ d) To encapsulate the embryo within the uterine cavity\ e) To store glycogen for the developing embryo **2. What is the primary source of energy for the embryo in the early stages of pregnancy before the placenta becomes fully functional?** a\) Glycogen and lipids stored in decidual cells\ b) Nutrient-rich blood vessels in the decidua basalis\ c) Endometrial secretions from the decidual glands\ d) Oxygen and nutrients supplied by the trophoblast\ e) Fetal tissue stores **3. Which of the following is true about the decidua parietalis?** a\) It directly interacts with the trophoblast to form the placenta\ b) It is involved in immune protection of the embryo\ c) It fuses with the decidua capsularis as pregnancy progresses\ d) It surrounds the embryo and provides structural support\ e) It forms a protective barrier between the embryo and maternal blood **4. The decidua serves an essential role in immune protection by:** a\) Actively recruiting specialized immune cells to destroy foreign pathogens\ b) Preventing the embryo from invading maternal tissues\ c) Secreting hormones that block immune responses to the embryo\ d) Expressing molecules that promote immune tolerance and prevent rejection\ e) Stimulating the production of antibodies to protect the embryo **5. Which of the following is a key feature observed in the histological examination of the decidua?** a\) Trophoblast cells infiltrating maternal tissues\ b) Small, round cells with little cytoplasm\ c) Decidual cells with abundant glycogen and lipid inclusions\ d) Inflammatory cells surrounding the embryo\ e) Absence of blood vessels **6. What is the role of the decidua capsularis in early pregnancy?** a\) It facilitates nutrient exchange between mother and embryo\ b) It surrounds and protects the embryo within the uterine cavity\ c) It forms the maternal-fetal boundary in the placenta\ d) It secretes prolactin to support embryo development\ e) It provides structural support for trophoblast invasion **7. During early pregnancy, which imaging modality would likely reveal a thickened, echogenic endometrial layer representing the decidua?** a\) X-ray\ b) MRI\ c) Ultrasound\ d) CT scan\ e) Mammography **8. In cases of ectopic pregnancy, what is a critical clinical feature related to the decidua?** a\) The decidua basalis is absent\ b) Decidualized endometrial tissue is present without a gestational sac\ c) The decidua capsularis is absent\ d) Decidual tissue is only present in the fallopian tube\ e) Excessive trophoblastic invasion of maternal tissues **9. Which of the following is a functional role of the decidua during early pregnancy?** a\) It produces growth factors and hormones essential for placental development\ b) It induces immune rejection of the embryo\ c) It prevents trophoblast invasion\ d) It serves as the primary source of blood supply for the fetus\ e) It breaks down the uterine lining to facilitate implantation **10. The process of decidualization is primarily stimulated by which of the following hormones?** a\) Estrogen\ b) Progesterone\ c) Prolactin\ d) Oxytocin\ e) Human chorionic gonadotropin (hCG) ### MCQ 1: **Scenario:** A woman presents at the clinic with a history of recurrent pregnancy loss. Histological examination of the endometrium during her current cycle reveals poor decidualization, with minimal glycogen accumulation in the stromal cells. What is the likely implication of this finding? **Options:** A) Normal implantation process\ B) Failure of implantation and possible pregnancy loss\ C) Enhanced immune protection for the embryo\ D) Successful trophoblast invasion\ E) Absence of decidual cells ### MCQ 2: **Scenario:** A 32-year-old woman undergoes an ultrasound at 7 weeks of pregnancy, which shows an increased thickness of the endometrial lining, suggestive of decidual changes. Which of the following features is most likely present in the decidua at this stage? **Options:** A) Increased vascularization and large decidual cells\ B) Complete fusion of the decidua basalis and capsularis\ C) Absence of glycogen storage\ D) Decreased blood flow to the developing embryo\ E) Reduced size of decidual cells ### MCQ 3: **Scenario:** In a case of ectopic pregnancy, histopathological examination reveals decidual reaction in the endometrial lining, but no intrauterine gestational sac is identified. What does this indicate? **Options:** A) The pregnancy is likely viable and intrauterine\ B) Decidualization is absent, indicating failed pregnancy\ C) The pregnancy is outside the uterus, possibly in the fallopian tube\ D) The pregnancy has progressed to the second trimester\ E) Normal early pregnancy in the uterine cavity ### MCQ 4: **Scenario:** A 28-year-old woman is 8 weeks pregnant. The ultrasound shows a thickened, echogenic endometrial layer. What histological feature is most likely to be observed in the decidua at this time? **Options:** A) Low vascularization and small decidual cells\ B) Large polyhedral decidual cells with glycogen and lipid inclusions\ C) Complete absence of blood vessels in the decidua\ D) Mature decidual cells with minimal glycogen content\ E) Immature trophoblast invasion into the decidua ### MCQ 5: **Scenario:** A woman in her first trimester has been diagnosed with recurrent pregnancy loss. Tests show abnormalities in her decidualization process. Which of the following most likely results from insufficient decidualization? **Options:** A) Proper implantation and trophoblast invasion\ B) Compromised maternal-fetal interface and failed implantation\ C) Normal placental development\ D) Successful maintenance of pregnancy and fetal growth\ E) Hypervascularity of the decidua ### MCQ 6: **Scenario:** During a biopsy of the decidua, you observe increased glycogen and lipid stores in the decidual cells. What is the primary function of these substances during early pregnancy? **Options:** A) Facilitation of fetal blood circulation\ B) Storage of energy for the embryo\ C) Regulation of immune response\ D) Stimulation of placental development\ E) Formation of the placental barrier ### MCQ 7: **Scenario:** A woman presents with a history of preterm labor. Histopathology of her decidual tissue shows abnormal cellular changes, with decreased vascularization and poor development of decidual cells. What is the most likely outcome in this scenario? **Options:** A) Proper fetal growth and placental development\ B) Reduced immune tolerance and pregnancy loss\ C) Delayed implantation and pregnancy failure\ D) Increased risk of preterm labor\ E) Full-term pregnancy without complications ### MCQ 8: **Scenario:** A 35-year-old pregnant woman undergoes ultrasound at 10 weeks, which shows the formation of decidual septa within the placenta. What does the formation of these septa indicate? **Options:** A) Immature placental development\ B) Normal placental maturation and lobular formation\ C) Failed placental development\ D) Incomplete fusion of the decidua capsularis and parietalis\ E) Excessive trophoblast invasion ### MCQ 9: **Scenario:** A woman has a history of ectopic pregnancy. Which of the following findings is most commonly associated with this condition? **Options:** A) Decidualization without intrauterine gestational sac\ B) Early placental formation within the fallopian tube\ C) Normal uterine implantation\ D) Increased vascularization within the uterine cavity\ E) Complete absence of decidual cells ### MCQ 10: **Scenario:** A woman at 6 weeks of pregnancy presents with a small uterine cavity and a thin endometrial lining. What is the likely explanation for this finding in early pregnancy? **Options:** A) Normal decidualization and uterine preparation\ B) Inadequate decidualization leading to poor pregnancy support\ C) Placental overgrowth at this stage\ D) Uterine infection preventing implantation\ E) Increased trophoblast invasion into the decidua **Question**: During gastrulation, which structure is formed by cells invaginating at the primitive streak? - a\) Ectoderm - b\) Endoderm - c\) Mesoderm - d\) Neural tube - e\) Epiblast **Question**: Which of the following is a critical signaling molecule involved in the specification of primordial germ cells (PGCs) during early embryogenesis? - a\) Wnt - b\) BMP - c\) Notch - d\) Retinoic acid - e\) FGF **Question**: The failure of the neural tube to close at the cranial end results in which of the following conditions? - a\) Anencephaly - b\) Spina bifida - c\) Hydrocephalus - d\) Meningocele - e\) Cerebral palsy **Question**: Which of the following structures does NOT derive from neural crest cells during embryonic development? - a\) Peripheral nerves - b\) Melanocytes - c\) Smooth muscle - d\) Cartilage and bone in the head - e\) Retina of the eye **Question**: The neural plate forms from which embryonic layer? - a\) Mesoderm - b\) Ectoderm - c\) Endoderm - d\) Epiblast - e\) Hypoblast **Question**: Somites are formed from which of the following embryonic structures? - a\) Mesoderm - b\) Endoderm - c\) Ectoderm - d\) Epiblast - e\) Primitive streak **Question**: Which of the following is derived from the myotome portion of a somite? - a\) Vertebral column - b\) Muscles of the limbs - c\) Bones of the skull - d\) Blood vessels - e\) Kidneys **Question**: The intraembryonic coelom eventually gives rise to which of the following cavities in the adult body? - a\) Thoracic and abdominal cavities - b\) Cranial cavity - c\) Digestive tract - d\) Peripheral nerves - e\) Skin **Question**: The development of the cardiovascular system begins with the formation of which structure? - a\) Heart tube - b\) Blood vessels - c\) Hemangioblasts - d\) Mesodermal nodes - e\) Primitive streak **Question**: During heart development, the heart tube undergoes looping to establish its characteristic shape. Which of the following is the result of this process? - a\) Formation of the right atrium - b\) Establishment of the left ventricle - c\) Formation of the sinoatrial node - d\) Development of the atrioventricular valve - e\) Segmentation of the aorta **Question**: The chorionic villi play an essential role in which of the following processes during early pregnancy? - a\) Blood-brain barrier formation - b\) Maternal-fetal nutrient exchange - c\) Limb development - d\) Neurulation - e\) Placental differentiation **Question**: Which of the following factors is most directly responsible for angiogenesis during early development? - a\) BMP signaling - b\) VEGF (Vascular Endothelial Growth Factor) - c\) FGF (Fibroblast Growth Factor) - d\) Wnt signaling - e\) Sonic hedgehog **Question**: The primitive streak is essential for the establishment of which of the following embryonic structures? - a\) Somites - b\) Primitive gut - c\) Neural tube - d\) All three germ layers - e\) Heart tube **Question**: The sclerotome of somites gives rise to which of the following structures? - a\) Muscles - b\) Vertebrae and ribs - c\) Skin - d\) Kidneys - e\) Blood vessels **Question**: The failure of which part of the neural tube to close can result in spina bifida? - a\) Cranial end - b\) Caudal end - c\) Midline - d\) Neural folds - e\) Neural plate **1. At what stage of human embryonic development does somite formation typically begin?**\ A) Day 10\ B) Day 15\ C) Day 20-22\ D) Day 30\ E) Day 40 **2. Somites arise from which of the following structures?**\ A) Lateral mesoderm\ B) Paraxial mesoderm\ C) Ectoderm\ D) Endoderm\ E) Neural crest cells **3. Which part of the somite is responsible for forming the vertebrae and ribs?**\ A) Myotome\ B) Dermomyotome\ C) Sclerotome\ D) Neural tube\ E) Somatic mesoderm **4. How many pairs of somites are typically formed by the end of the fourth week in human embryonic development?**\ A) 12-14 pairs\ B) 24-26 pairs\ C) 42-44 pairs\ D) 50-52 pairs\ E) 38-40 pairs **5. What is the primary role of the myotome in somite development?**\ A) To form the ribs\ B) To form the vertebrae\ C) To form muscles of the body wall and limbs\ D) To form the skin of the trunk\ E) To form cartilage of the vertebral column **6. In which region of the embryo do the first somites typically form?**\ A) Lumbar region\ B) Occipital region\ C) Thoracic region\ D) Sacral region\ E) Cervical region **7. Which signaling pathway is crucial in the segmentation of the paraxial mesoderm during somitogenesis?**\ A) Hedgehog signaling\ B) Notch signaling\ C) BMP signaling\ D) Wnt signaling\ E) TGF-beta signaling **8. What does the dermatome of the dermomyotome give rise to?**\ A) Vertebrae\ B) Muscles of the trunk\ C) Muscles of the limbs\ D) Dermis of the skin\ E) Ribs **9. Somite formation occurs at a rate of approximately how many pairs per day in humans?**\ A) 1 pair per day\ B) 2 pairs per day\ C) 3 pairs per day\ D) 4 pairs per day\ E) 5 pairs per day **10. The intraembryonic coelom plays a vital role in which of the following processes?**\ A) Neural tube closure\ B) Formation of the body cavities\ C) Blood vessel formation\ D) Somite segmentation\ E) Formation of the ectoderm **11. Which cavity formed from the intraembryonic coelom surrounds the developing heart?**\ A) Peritoneal cavity\ B) Pleural cavity\ C) Pericardial cavity\ D) Cranial cavity\ E) Abdominal cavity **12. By the end of the third week of embryonic development, the intraembryonic coelom forms a horseshoe shape that surrounds which structure?**\ A) Neural tube\ B) Developing heart\ C) Embryonic gut tube\ D) Limb buds\ E) Somites **13. Which of the following is a possible congenital malformation caused by abnormal somite development?**\ A) Hydrocephalus\ B) Scoliosis\ C) Anencephaly\ D) Polydactyly\ E) Cleft lip **14. The sclerotome contributes to the formation of which of the following structures?**\ A) Dermis of the skin\ B) Muscles of the trunk and limbs\ C) Vertebrae and ribs\ D) Limb bones\ E) Neural tube **15. Which signaling molecule is involved in somite segmentation and contributes to the development of the segmented body plan?**\ A) Wnt\ B) FGF\ C) Retinoic acid\ D) Notch\ E) TGF-beta ### 1. At what stage do the two paired endocardial tubes fuse to form the primitive heart tube? a\) Day 15\ b) Day 18-19\ c) Day 20-21\ d) Day 22\ e) Day 24 ### 2. The formation of the heart tube is a part of which process? a\) Gastrulation\ b) Neurulation\ c) Cardiogenesis\ d) Organogenesis\ e) Vasculogenesis ### 3. When do the first heartbeats occur during the development of the primitive heart tube? a\) Day 18\ b) Day 20\ c) Day 22\ d) Day 24\ e) Day 28 ### 4. Which of the following structures is formed by the fusion of two paired endothelial heart tubes during early cardiogenesis? a\) Aortic arches\ b) Primitive heart tube\ c) Umbilical veins\ d) Cardinal veins\ e) Pericardial cavity ### 5. Which of the following vascular structures forms the early venous system, returning blood from the body to the heart during early embryonic development? a\) Aortic arches\ b) Umbilical veins\ c) Cardinal veins\ d) Pulmonary veins\ e) Umbilical arteries ### 6. At which stage of pregnancy do the chorionic villi start to form primary villi? a\) Week 1\ b) Week 2\ c) Week 3\ d) Week 4\ e) Week 5 ### 7. Which of the following structures forms secondary villi during the development of the chorion? a\) Trophoblast cells\ b) Mesoderm cells\ c) Embryonic cells\ d) Hemangioblasts\ e) Angioblasts ### 8. By the end of which week do the mesodermal cells inside the secondary villi differentiate into blood vessels to form tertiary villi? a\) Week 1\ b) Week 2\ c) Week 3\ d) Week 4\ e) Week 5 ### 9. What is the primary function of the chorionic villi during early pregnancy? a\) Hormone production\ b) Exchange of oxygen, carbon dioxide, and nutrients\ c) Formation of the umbilical cord\ d) Formation of the amniotic sac\ e) Protection from maternal immune response ### 10. Which of the following conditions is associated with abnormal development of the chorionic villi? a\) Tetralogy of Fallot\ b) Transposition of the great arteries\ c) Molar pregnancy\ d) Spina bifida\ e) Cleft lip ### 1. Bilaminar Disc Formation occurs during which post-fertilization day? A\) Day 4-5\ B) Day 6-7\ C) Day 8-9\ D) Day 10-11\ E) Day 12-13 ### 2. Which of the following is the primary function of the hypoblast in the bilaminar disc? A\) Formation of the amniotic cavity\ B) Formation of the epidermis\ C) Formation of the yolk sac lining\ D) Formation of the mesoderm\ E) Formation of the neural tube ### 3. The epiblast layer of the bilaminar disc will eventually give rise to which of the following? A\) Yolk sac\ B) Extraembryonic mesoderm\ C) All three germ layers\ D) Primary umbilical vesicle\ E) Amniotic membrane ### 4. During the formation of the amniotic cavity, which cells differentiate to form the amniotic membrane? A\) Epiblast cells\ B) Hypoblast cells\ C) Amnioblasts\ D) Mesodermal cells\ E) Trophoblast cells ### 5. Which of the following is a significant role of the amniotic cavity during fetal development? A\) Nutrient exchange\ B) Blood cell formation\ C) Protection from mechanical shocks\ D) Formation of the primitive streak\ E) Formation of the mesoderm ### 6. What is the primary function of the yolk sac in human embryos? A\) Forming the central nervous system\ B) Nutrient transfer and hematopoiesis\ C) Formation of the ectoderm\ D) Formation of the amniotic fluid\ E) Supporting limb development ### 7. During gastrulation, the epiblast cells migrate and form which of the following? A\) Yolk sac\ B) Primitive streak\ C) Amniotic cavity\ D) Neural tube\ E) Mesoderm and ectoderm ### 8. The formation of the primitive streak during gastrulation is essential for establishing which of the following? A\) Left-right and cranio-caudal axes\ B) Formation of the neural crest\ C) Development of the amniotic cavity\ D) Initial site of hematopoiesis\ E) Formation of the germ layers ### 9. Which of the following germ layers gives rise to the musculoskeletal system? A\) Ectoderm\ B) Mesoderm\ C) Endoderm\ D) Neuroectoderm\ E) Extraembryonic mesoderm ### 10. The definitive endoderm is formed from which of the following during gastrulation? A\) Epiblast\ B) Hypoblast\ C) Primitive streak\ D) Amniotic cavity\ E) Neural tube ### 11. The ectoderm is responsible for the development of which of the following? A\) Kidneys and reproductive organs\ B) Epidermis and central nervous system\ C) Muscles and bones\ D) Digestive tract lining\ E) Blood cells ### 12. Which structure marks the transition from the bilaminar disc to the trilaminar disc? A\) Primitive streak\ B) Hypoblast layer\ C) Epiblast layer\ D) Amniotic membrane\ E) Yolk sac ### 13. In which week of gestation does gastrulation begin? A\) Week 1\ B) Week 2\ C) Week 3\ D) Week 4\ E) Week 5 ### 14. The amniotic fluid plays an important role in which of the following? A\) Facilitating the development of the nervous system\ B) Nourishing the embryo through the yolk sac\ C) Maintaining a stable temperature and preventing dehydration\ D) Forming the yolk sac\ E) Promoting the development of skeletal muscles ### 15. Which of the following describes the location of the epiblast layer in the bilaminar disc? A\) Ventral side\ B) Dorsal side\ C) Between the amniotic cavity and yolk sac\ D) Surrounding the primitive streak\ E) Beneath the hypoblast ### 1. Scenario: A 24-year-old woman is undergoing an early pregnancy ultrasound at 6 weeks. The physician notices a well-formed bilaminar embryonic disc, but the development of the three germ layers has not yet occurred. Which of the following processes is expected to take place next? - A\) Gastrulation - B\) Neurulation - C\) Organogenesis - D\) Somite formation - E\) Formation of the primitive streak ### 2. Scenario: During an early ultrasound of a 6-week pregnant woman, the physician observes an abnormal yolk sac that is significantly larger than expected. Which of the following is the most likely outcome associated with this abnormality? - A\) Ectopic pregnancy - B\) Healthy pregnancy with minor variation - C\) Chromosomal abnormality or miscarriage - D\) Multiple gestation - E\) Placental insufficiency ### 3. Scenario: A 30-year-old woman reports missing her period and is found to have a positive pregnancy test. An ultrasound shows a bilaminar embryonic disc without visible yolk sac or fetal heart tones. What is the most likely diagnosis? - A\) Ectopic pregnancy - B\) Complete molar pregnancy - C\) Intrauterine pregnancy with a delayed development - D\) Spontaneous abortion - E\) Blighted ovum ### 4. Scenario: A physician is examining a pregnant woman in her first trimester. She finds that the chorionic sac is well-formed, with the syncytiotrophoblast layer actively secreting hCG. What is the most likely role of the syncytiotrophoblast at this stage? - A\) Embryonic development - B\) Initiation of blood circulation - C\) Maintaining the uterine lining for pregnancy continuation - D\) Formation of germ layers - E\) Formation of the amniotic fluid ### 5. Scenario: A 28-year-old woman presents with abdominal pain and bleeding at 7 weeks of pregnancy. Ultrasound shows an irregular chorionic sac with abnormal trophoblast invasion. What is the likely complication? - A\) Molar pregnancy - B\) Placenta accreta - C\) Ectopic pregnancy - D\) Threatened miscarriage - E\) Normal pregnancy ### 6. Scenario: During a routine prenatal ultrasound, the physician notes that the developing embryo is situated near the fundus of the uterus. Where is the most likely implantation site of the blastocyst in a healthy pregnancy? - A\) Anterior uterine wall - B\) Posterior uterine wall near the fundus - C\) Lower uterine segment - D\) Fallopian tube - E\) Cervix ### 7. Scenario: A patient undergoing an ultrasound at 5 weeks of gestation shows a visible embryonic disc with a clear delineation between the epiblast and hypoblast layers. What is the most important role of the hypoblast at this stage? - A\) Formation of the ectoderm - B\) Formation of the yolk sac - C\) Development of the placenta - D\) Formation of the heart - E\) Differentiation into mesoderm ### 8. Scenario: A 32-year-old pregnant woman is diagnosed with a defect in the formation of her embryonic disc. This defect primarily affects the differentiation of the epiblast. Which of the following structures is most likely to be underdeveloped in this case? - A\) Amniotic cavity - B\) Extraembryonic mesoderm - C\) Primitive streak - D\) Germ layers (ectoderm, mesoderm, endoderm) - E\) Yolk sac ### 9. Scenario: During early pregnancy, the trophoblast layer of a blastocyst begins to invade the uterine lining, and the syncytiotrophoblast begins secreting hCG. What is the primary function of hCG at this stage? - A\) Support embryonic growth - B\) Inhibit ovulation - C\) Stimulate maternal immune response - D\) Maintain corpus luteum function - E\) Begin organogenesis ### 10. Scenario: A 25-year-old woman presents with an early pregnancy ultrasound at 6 weeks. The imaging shows a visible yolk sac, amniotic cavity, and trophoblast cells. Which of the following is the primary role of the yolk sac at this stage of pregnancy? - A\) Nutrient storage - B\) Early blood cell formation - C\) Formation of the placenta - D\) Development of the central nervous system - E\) Induction of limb development **Week 4: Embryonic Development** **MCQ 1:** **Scenario:** A 24-year-old woman at 4 weeks of pregnancy is concerned about the risk of neural tube defects. She has a family history of spina bifida. Which of the following plays a key role in the prevention of neural tube defects during this stage of pregnancy? A\) Vitamin C supplementation\ B) Folic acid supplementation\ C) Increased protein intake\ D) Regular exercise\ E) Vitamin D supplementation **MCQ 2** **Scenario:** A 25-year-old woman is at 4 weeks of gestation and is concerned about her baby\'s heart development. She asks about the process of heart tube fusion. Which of the following is the most important event in heart development that occurs during this stage? A\) Formation of the heart tube\ B) Formation of the ventricular septum\ C) Neural crest migration into the heart\ D) Closure of the foramen ovale\ E) Separation of the atria **MCQ 3** **Scenario:** A 23-year-old woman is at 4 weeks of pregnancy and is seeking advice on the formation of the neural tube and brain. What is the first structure formed during the neural tube closure that will give rise to the brain? A\) Prosencephalon\ B) Mesencephalon\ C) Rhombencephalon\ D) Spinal cord\ E) Neural crest **MCQ 4** **Scenario:** A 26-year-old woman at 4 weeks of pregnancy asks how her baby's face is developing. Which of the following is formed by the first pharyngeal arch during this period? A\) Mandible\ B) Hyoid bone\ C) Nasal cavity\ D) Ear ossicles\ E) Thyroid cartilage **MCQ 5** **Scenario:** A couple visits the clinic at 4 weeks of pregnancy concerned about the development of the baby\'s limbs. Which of the following structures first appears in the developing limbs at this stage? A\) Digital rays\ B) Limb buds\ C) Finger separation\ D) Apoptosis\ E) Joint formation **MCQ 6** **Scenario:** A 29-year-old woman at 4 weeks of pregnancy asks when the organs in her developing baby begin to form. At what stage of pregnancy does organogenesis begin? A\) Week 2\ B) Week 3\ C) Week 4\ D) Week 5\ E) Week 6 **MCQ 7** **Scenario:** A 22-year-old woman asks about the development of her baby's spinal cord at 4 weeks. What is the most critical event in the development of the spinal cord during this stage? A\) Formation of neural crest cells\ B) Closure of the neural tube\ C) Differentiation into dorsal and ventral horns\ D) Growth of somites\ E) Formation of the vertebral column **MCQ 8** **Scenario:** A 25-year-old woman is at 4 weeks of pregnancy and asks about the formation of facial structures. Which of the following is responsible for the formation of the upper lip during this stage? A\) Second pharyngeal arch\ B) First pharyngeal arch\ C) Nasal placodes\ D) Neural crest cells\ E) Maxillary process **MCQ 9** **Scenario:** A 27-year-old woman asks about her baby's gastrointestinal tract at 4 weeks of gestation. What is the first part of the gastrointestinal tract to form during embryonic development? A\) Stomach\ B) Intestines\ C) Esophagus\ D) Foregut\ E) Hindgut **MCQ 10** **Scenario:** A woman in the fourth week of pregnancy asks when her baby's limbs will start developing. When do limb buds begin to form in embryonic development? A\) Week 2\ B) Week 3\ C) Week 4\ D) Week 5\ E) Week 6 **Week 5** **MCQ 11: Facial Development** **Scenario:** A 25-year-old woman at 5 weeks of pregnancy asks when the facial structures of her baby begin to form. What structure primarily contributes to the formation of the upper jaw and lip? A\) First pharyngeal arch\ B) Second pharyngeal arch\ C) Neural crest cells\ D) Maxillary process\ E) Mandibular arch **MCQ 12** **Scenario:** A woman at 5 weeks of pregnancy is concerned about the development of her baby's limbs. At what point in limb development do digital rays first appear? A\) Week 4\ B) Week 5\ C) Week 6\ D) Week 7\ E) Week 8 **MCQ 13** **Scenario:** A woman in her fifth week of pregnancy asks about the closure of the neural tube. What is the main consequence of incomplete neural tube closure during the fifth week of development? A\) Spina bifida\ B) Hydrocephalus\ C) Anencephaly\ D) Craniofacial defects\ E) Limb malformations **MCQ 14** **Scenario:** A 23-year-old woman at 5 weeks of pregnancy asks when the baby's eyes will begin to develop. During week 5, the **optic vesicle** gives rise to which of the following? A\) Retina\ B) Lens\ C) Cornea\ D) Eyelids\ E) Optic nerve **MCQ 15** **Scenario:** A woman in her fifth week of pregnancy asks how the pharyngeal arches contribute to the face. Which of the following structures is derived from the **second pharyngeal arch**? A\) Mandible\ B) Stapes\ C) Maxilla\ D) Nasal cavity\ E) Thyroid cartilage **MCQ 16** **Scenario:** A 26-year-old woman at 5 weeks of pregnancy is concerned about her baby's heart formation. Which of the following best describes the development of the heart at Week 5? A\) Fusion of the heart tubes into a single heart tube\ B) Closure of the septum primum\ C) Formation of the atrial septum\ D) Formation of the cardiac outflow tract\ E) Neural crest migration into the heart **MCQ 17** **Scenario:** A couple is concerned about limb development in their baby, who is currently 5 weeks old in utero. At what stage do **digital rays** become visible in the limb buds? A\) Week 4\ B) Week 5\ C) Week 6\ D) Week 7\ E) Week 8 **MCQ 18** **Scenario:** A 28-year-old woman is in her fifth week of pregnancy and is concerned about the development of her baby\'s arms. Which of the following structures appears first in the development of the upper limbs? A\) Elbow joint\ B) Digital rays\ C) Limb buds\ D) Carpal bones\ E) Rotation of the upper limb **MCQ 19** **Scenario:** A 30-year-old woman at 5 weeks of pregnancy asks about her baby\'s heart development. What is the critical event in heart development that occurs around Week 5? A\) Heart tube formation\ B) Formation of the aortic arches\ C) Heart looping\ D) Division of the ventricles\ E) Closure of the foramen ovale **MCQ 20** **Scenario:** A 24-year-old woman at 5 weeks of pregnancy asks about the development of cleft lip. Which of the following structures contributes to the formation of the **upper lip** and may result in cleft lip if disrupted? A\) Mandibular arch\ B) First pharyngeal arch\ C) Nasal placode\ D) Maxillary process\ E) Second pharyngeal arch **MCQ 21** **Scenario:** A 27-year-old woman at 5 weeks of pregnancy asks about the role of neural crest cells. Which of the following structures is derived from **neural crest cells**? A\) Parathyroid glands\ B) Dorsal root ganglia\ C) Limb muscles\ D) Hepatic cells\ E) Spinal cord **MCQ 22** **Scenario:** A 25-year-old woman asks about the development of her baby\'s gastrointestinal tract during the fifth week. Which part of the gastrointestinal tract is developing at this stage? A\) Hindgut\ B) Midgut\ C) Foregut\ D) Rectum\ E) Stomach **MCQ 23** **Scenario:** A 23-year-old woman at 5 weeks of pregnancy asks when the digital separation occurs. At which week do the **fingers** begin to separate in limb development? A\) Week 4\ B) Week 5\ C) Week 6\ D) Week 7\ E) Week 8 **MCQ 24** **Scenario:** A 29-year-old woman is concerned about pharyngeal arch malformations in her baby, who is in the fifth week of development. Malformations of which pharyngeal arch are most commonly associated with congenital malformations of the face and neck? A\) First\ B) Second\ C) Third\ D) Fourth\ E) Sixth **MCQ 25** **Scenario:** A 25-year-old woman is in the fifth week of pregnancy and is asking about her baby's vertebral column development. The vertebral column develops from which embryological structure? A\) Somites\ B) Notochord\ C) Neural tube\ D) Pharyngeal arches\ E) Limb buds **MCQ 26** **Scenario:** A 26-year-old woman at 5 weeks of pregnancy is curious about how her baby's limbs are developing. At which stage of development does the upper limb **rotate** to its final anatomical position? A\) Week 4\ B) Week 5\ C) Week 6\ D) Week 7\ E) Week 8 **MCQ 27** **Scenario:** A 28-year-old woman asks when her baby's eyes will begin to develop. At what stage do the **optic cups** form and give rise to the retina? A\) Week 3\ B) Week 4\ C) Week 5\ D) Week 6\ E) Week 7 **MCQ 28** **Scenario:** A 24-year-old woman at 5 weeks of pregnancy asks about her baby's urogenital development. The **mesonephros** is primarily involved in the development of which system? A\) Nervous system\ B) Cardiovascular system\ C) Respiratory system\ D) Urinary system\ E) Digestive system **MCQ 29** **Scenario:** A 30-year-old woman is at 5 weeks of pregnancy and asks about muscle development in the embryo. At what stage do **muscle fibers** begin to appear in the developing limbs? A\) Week 4\ B) Week 5\ C) Week 6\ D) Week 7\ E) Week 8 **MCQ 30** **Scenario:** A 26-year-old woman at 5 weeks of pregnancy is worried about pharyngeal arch defects. What is a typical malformation associated with defects in the **second pharyngeal arch**? A\) Cleft lip\ B) Microtia\ C) Craniofacial anomalies\ D) Heart defects\ E) Limb malformations