Lecture 2 Flashcards
(25 cards)
What is the first stage of embryogenesis?
A) Gastrulation
B) Segmentation
C) Implantation
D) Blastocystogenesis
B) Segmentation
At what point does the embryo consist of 4 blastomeres?
A) 24 hours
B) 72 hours
C) 40 hours
D) 4 days
C) 40 hours
How many cells are present in the embryo at 4 days?
A) 4 cells
B) 8 cells
C) 16-32 cells
D) 64 cells
C) 16-32 cells
During segmentation, what does the micromere develop into?
A) Embryoblast
B) Trophoblast
C) Cytotrophoblast
D) Syncytiotrophoblast
B) Trophoblast
What marks the transition from morula to blastocyst?
A) The disappearance of the zona pellucida
B) The formation of the blastocyst cavity
C) Differentiation of the inner cell mass
D) Completion of implantation
B) Formation of the blastocyst cavity
When does the zona pellucida disappear during blastocystogenesis?
A) Day 3
B) Day 4
C) Day 5
D) Day 6
C) Day 5
What event initiates the implantation process?
A) Formation of the amniotic cavity
B) Secretion of hCG
C) The polar zone of the trophoblast adhering to the uterine lining
D) Completion of segmentation
C) The polar zone of the trophoblast adhering to the uterine lining
What role does the trophoblast play during early implantation?
A) It forms the amniotic cavity
B) It secretes fluid to form the blastocyst cavity
C) It secretes human chorionic gonadotropin (hCG)
D) It differentiates into the inner cell mass
C) secretes hCG
Elevated levels of hCG may indicate which of the following?
A) Miscarriage
B) Ectopic pregnancy
C) Multiple pregnancy
D) Placental abnormalities
C) Multiple pregnancy
Low levels of hCG may indicate which of the following?
A) Miscarriage
B) Ectopic pregnancy
C) Multiple pregnancy
D) Placental abnormalities
A) Miscarriage
What is the most common site of implantation in a normal pregnancy?
A) Fallopian tube
B) Abdominal cavity
C) Endometrium of the uterine body
D) Cervix
C) Endometrium of the uterine body
On what day of the implantation sequence do the isolated lacunae appear within the syncytiotrophoblast?
A) Day 5
B) Day 7
C) Day 9
D) Day 11
C) Day 9
When is maternal blood first seen flowing through the lacunar network?
A) Day 5
B) Day 9
C) Day 10
D) Day 12
D) Day 12
What forms the extraembryonic coelom during the trilaminar blastocyst stage?
A) Syncytiotrophoblast
B) Exocoelomic membrane
C) Spaces within the extra-embryonic mesoderm
D) Amniotic cavity
C) Spaces within the extra embryonic mesoderm
The primitive node forms at which end of the primitive streak during gastrulation?
A) Cranial
B) Caudal
C) Lateral
D) Dorsal
A) Cranial
What is the main function of the notochord during early development?
A) It forms the neural tube
B) It acts as the future spine of the embryo
C) It induces the formation of the neural plate in the ectoderm
D) It produces mesoderm for the heart
C) it induces the formation of the neural plate in the ectoderm
What is the final product of gastrulation?
A) Trilaminar disc
B) Bilaminar disc
C) Morula
D) Trophoblast
A) Trilaminar disc
What can the persistence of the primitive streak lead to?
A) Notochord formation
B) Ectopic pregnancy
C) Sacrococcygeal teratoma
D) Placental abnormalities
C) Scaroccygeal teratoma
Which cells secrete fluid that helps form the blastocyst cavity?
A) Embryoblast cells
B) Trophoblastic cells
C) Decidual cells
D) Endometrial cells
B) Trophoblastic cells
Which structure penetrates the uterus around 72 hours after fertilization?
A) Morula
B) Blastocyst
C) Gastrula
D) Embryonic disc
A) Morula
What forms the bilaminar embryonic disc during the bilaminar blastocyst stage?
A) Syncytiotrophoblast and cytotrophoblast
B) Hypoblast and epiblast
C) Amniotic cavity and yolk sac
D) Endometrium and trophoblast
B) Hypoblast and Epiblast
What happens on Day 7 during the bilaminar blastocyst stage?
A) Formation of the primitive streak
B) Formation of the amniotic cavity on the outer face of the embryonic disc
C) Disappearance of the zona pellucida
D) Differentiation of the mesoderm
B) Formation of the amniotic cavity on the outer face of the embryonic disc
What membrane borders the primary yolk sac during the bilaminar blastocyst stage?
A) Chorionic membrane
B) Amniotic membrane
C) Exocoelomic membrane
D) Endodermal membrane
C) Exocoelomic Membrane
During gastrulation, what is the third layer formed in the trilaminar disc?
A) Endoderm
B) Mesoderm
C) Ectoderm
D) Notochord
B) Mesoderm
