Embryonic Development and Placental Formation Quiz

Study Flashcards Play Quiz

Questions and Answers

What is the importance of sperm capacitation?

It allows the sperm to undergo changes that enable it to fertilize an egg

What are the mechanisms behind the blocks to polyspermy?

Acrosome reaction preventing entry of multiple sperms

What is fertilization?

The fusion of a sperm's chromosomes with those of an egg to form a zygote

What is the composition of the chorion?

Fetal blood vessels Signup and view all the answers

What structure does the Neural Tube eventually develop into?

Spinal cord and brain Signup and view all the answers

Which cells give rise to cranial, spinal, and sympathetic ganglia?

Neural crest cells Signup and view all the answers

What marks the beginning of mesodermal differentiation in the embryonic disc?

Appearance of the Notochord Signup and view all the answers

Which mesodermal structure contributes to the formation of vertebrae, skin, and muscles?

Somite Signup and view all the answers

What do the intermediate mesoderm and lateral plate mesoderm form, respectively?

Gonads and kidneys; somatic and splanchnic mesoderm Signup and view all the answers

What leads to pressure on abdominal and pelvic organs during pregnancy?

Uterine enlargement Signup and view all the answers

Which hormone causes pelvic ligaments and pubic symphysis to relax during pregnancy?

Relaxin hormone Signup and view all the answers

What is the approximate weight gain during pregnancy?

13 kg Signup and view all the answers

Which structures are influenced by placental growth hormone, human placental lactogen, and corticotropin-releasing hormone?

Maternal metabolism Signup and view all the answers

What is the conceptus called from fertilization through week 8?

Embryo Signup and view all the answers

When is fertilization most likely to occur for successful fertilization?

Within 24 to 48 hours after ejaculation Signup and view all the answers

What is the process enhancing sperm motility and membrane fragility before fertilization?

Capacitation Signup and view all the answers

What encapsulates the ovulated oocyte?

Corona radiata and zona pellucida Signup and view all the answers

How is monospermy ensured in humans?

Oocyte membrane block and cortical reaction Signup and view all the answers

What occurs as maternal and paternal chromosomes combine?

Fertilization Signup and view all the answers

What is the period of rapid mitotic divisions of the zygote without intervening growth called?

Cleavage Signup and view all the answers

What is the blastocyst composed of?

Trophoblast cells and an embryoblast Signup and view all the answers

What is the role of the trophoblast?

Implanting the embryo in the uterine wall Signup and view all the answers

When does implantation begin after ovulation?

Six to seven days Signup and view all the answers

What is the conceptus called from week 9 through birth?

Fetus Signup and view all the answers

What is the first cell of a new individual?

Diploid zygote Signup and view all the answers

Which hormone can lead to spontaneous abortion if its levels diminish?

Human chorionic gonadotropin (hCG) Signup and view all the answers

What is the role of estrogens and progesterone during pregnancy?

Encouraging mammary gland growth Signup and view all the answers

Which structure becomes the structural base for the umbilical cord in humans?

Allantois Signup and view all the answers

What provides a protective, temperature-regulated environment for the embryo?

Amnion Signup and view all the answers

Which membrane forms part of the gut, is a source of early blood cells, and facilitates germ cell migration?

Yolk sac Signup and view all the answers

What transforms the two-layered embryonic disc into a three-layered embryo with primary germ layers?

Gastrulation Signup and view all the answers

Which germ layer forms the nervous system and skin structures?

Ectoderm Signup and view all the answers

What does endoderm form?

Linings of digestive and respiratory systems Signup and view all the answers

What does mesoderm form?

Other body structures Signup and view all the answers

What does organogenesis involve?

The differentiation of the germ layers to form body organs and systems Signup and view all the answers

What leads to the formation of the brain and spinal cord from the ectoderm?

Neurulation Signup and view all the answers

What is the role of hCG in pregnancy?

Prevents the mother's immune system from rejecting the implanted embryo Signup and view all the answers

What is the function of the trophoblast during implantation?

Adheres to the endometrium and secretes digestive enzymes and growth factors Signup and view all the answers

When does the placenta assume the role of progesterone and estrogen production?

Between the second and third month Signup and view all the answers

What is the origin of the placenta?

Both embryonic and maternal tissues Signup and view all the answers

What is the function of the syncytiotrophoblast?

Secretes hCG and prevents the mother's immune system from rejecting the implanted embryo Signup and view all the answers

What happens if the endometrium is not optimally mature?

The blastocyst fails to attach and implants when it finds a suitable site Signup and view all the answers

What is the approximate duration of successful implantation?

Five days Signup and view all the answers

What is the function of the decidua capsularis?

Expands to accommodate the fetus after birth Signup and view all the answers

What is the primary function of the chorionic villi during placental formation?

Development of chorionic villi and invasion of maternal blood vessels Signup and view all the answers

What hormone rescues the corpus luteum and prevents its degeneration?

hCG Signup and view all the answers

When does the placenta begin to produce estrogens and progesterone?

From the beginning Signup and view all the answers

What is the timeline for the completion of successful implantation?

By day 12 of the menstrual cycle Signup and view all the answers

Study Notes

Embryonic Development and Organogenesis

Inadequate placental hormones can lead to spontaneous abortion if hCG levels diminish
Throughout pregnancy, blood levels of estrogens and progesterone increase, encouraging mammary gland growth
The placenta also produces human placental lactogen and relaxin
The blastocyst is converted to a Gastrula, with three primary germ layers forming
Extraembryonic membranes include the amnion, yolk sac, allantois, and chorion
The amnion provides a protective, temperature-regulated environment for the embryo
The yolk sac forms part of the gut, is a source of early blood cells, and facilitates germ cell migration
The allantois becomes the structural base for the umbilical cord in humans
Gastrulation transforms the two-layered embryonic disc into a three-layered embryo with primary germ layers
Ectoderm forms nervous system and skin structures, endoderm forms linings of digestive and respiratory systems, and mesoderm forms other body structures
Organogenesis involves the differentiation of the germ layers to form body organs and systems
Neurulation, induced by chemical signals from the notochord, leads to the formation of the brain and spinal cord from the ectoderm

Implantation and Formation of the Placenta

The endometrium becomes receptive to implantation due to surging levels of ovarian hormones.
If the endometrium is not optimally mature, the blastocyst fails to attach and implants when it finds a suitable site.
Trophoblast cells adhere to the endometrium and secrete digestive enzymes and growth factors.
The trophoblast proliferates and forms two distinct layers: Cytotrophoblast and Syncytiotrophoblast.
Successful implantation takes about five days and is usually completed by day 12 of the menstrual cycle.
The embryo rescues the corpus luteum by secreting human chorionic gonadotropin (hCG).
hCG prevents the mother's immune system from rejecting the implanted embryo.
The placenta assumes the role of progesterone and estrogen production between the second and third month.
The placenta is a temporary organ originating from both embryonic and maternal tissues.
The formation of the placenta involves the development of chorionic villi and the invasion of maternal blood vessels.
The placenta detaches and sloughs off after birth, and the decidua capsularis expands to accommodate the fetus.
The placenta secretes hCG from the beginning, but its ability to produce estrogens and progesterone matures more slowly.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.