Questions and Answers
What role does GnRH play in the ovarian cycle?
During which phase of the ovarian cycle does the surge of LH occur?
Which hormone is primarily responsible for follicle maturation?
What is the correct sequence of follicular development leading up to ovulation?
Signup and view all the answers
Which of the following is NOT a function of LH during the ovarian cycle?
Signup and view all the answers
What describes the phenomenon where both maternal and placental blood spills occur during implantation?
Signup and view all the answers
Which hormone is primarily responsible for stimulating increased production of LH during the maturation of vesicular follicles?
Signup and view all the answers
At what stage does an oocyte become arrested in meiosis II approximately 3 hours before ovulation?
Signup and view all the answers
Which type of follicles develops independently of FSH according to the maturation sequence?
Signup and view all the answers
During which phase of the ovarian cycle does FSH recruit growing follicles into development?
Signup and view all the answers
What type of follicle is characterized as vesicular or antral follicles?
Signup and view all the answers
From which cells are estrogens produced during the maturation of follicles?
Signup and view all the answers
What is the first step in the maturation process of follicles during the ovarian cycle?
Signup and view all the answers
Which phase involves spermatozoa passing through the corona radiata barrier?
Signup and view all the answers
What occurs during phase 2 of oocyte penetration?
Signup and view all the answers
In which phase does a spermatozoon lose its plasma membrane?
Signup and view all the answers
What is a necessary condition for sperm to fertilize an oocyte?
Signup and view all the answers
What structure is responsible for enabling spermatozoa to penetrate the zona pellucida?
Signup and view all the answers
What happens to the remaining follicular cells after ovulation?
Signup and view all the answers
During which phase do the spermatozoa penetrate the membranes of the oocyte?
Signup and view all the answers
What is the effect of hypertrophy in the corpus luteum?
Signup and view all the answers
What role do fimbriae play in the reproductive process?
Signup and view all the answers
At what stage is the zona pellucida still present?
Signup and view all the answers
What hormone is produced by the developing blastocyst to maintain the corpus luteum?
Signup and view all the answers
What is the correct sequence of development stages after fertilization?
Signup and view all the answers
What does the inner cell mass of the blastocyst develop into?
Signup and view all the answers
During which stage does the fluid enter the morula, leading to the formation of a blastocyst?
Signup and view all the answers
What occurs approximately 30 hours after fertilization?
Signup and view all the answers
Which hormone is NOT involved in the preparation of the endometrium for implantation?
Signup and view all the answers
What is the primary hormone produced by the corpus luteum if conception occurs?
Signup and view all the answers
At which day of development does the human blastocyst begin to penetrate the uterine mucosa?
Signup and view all the answers
What happens to the corpus luteum if fertilization does not occur?
Signup and view all the answers
Which layers of the endometrium are affected by degeneration if conception does not occur?
Signup and view all the answers
What initiates the secretory phase of the endometrium during pregnancy?
Signup and view all the answers
Which structure provides blood vessels to the basal layer of the endometrium?
Signup and view all the answers
What is the consequence of the absence of fertilization at the end of the menstrual cycle?
Signup and view all the answers
Which type of cells comprises the inner cell mass of the blastocyst?
Signup and view all the answers
Study Notes
Developmental Biology Overview
- Formation of extraembryonic membranes is crucial during early development, leading to the creation of two key cavities: chorionic cavity and amniotic cavity.
- The hypothalamus releases GnRH, prompting the pituitary gland to secrete gonadotropins such as FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone).
- FSH stimulates primordial follicles to grow and mature, while LH triggers ovulation by surging in concentration.
- After ovulation, LH supports the development of the corpus luteum, essential for maintaining pregnancy.
Follicular Development
- Development stages of follicles include primordial, growing, vesicular (antral), and mature vesicular (Graafian) stages.
- Primordial follicles exist initially, but some develop independently into growing follicles.
- FSH also recruits growing follicles to transition into vesicular follicles, supported by estrogen production from the follicular and thecal cells.
- The mature follicle undergoes meiosis I and enters meiosis II, pausing in metaphase before ovulation.
Fertilization Phases
- Three critical phases of fertilization:
- Penetration of the corona radiata.
- Penetration of the zona pellucida.
- Penetration of the oocyte membrane by a sperm cell after it undergoes capacitation.
Early Embryonic Development
- Zygote development follows fertilization:
- The two-cell stage occurs about 30 hours post-fertilization.
- Four-cell stage at 40 hours and the 12-16 cell stage at approximately 3 days.
- The late morula stage is reached by day 4, with blastomeres enclosed by the zona pellucida, which disintegrates at the end of day 4.
Implantation Process
- Following fertilization, embryoblasts form the inner cell mass, which will develop into the embryo, while trophoblasts create the outer layer.
- By the sixth day, the human blastocyst begins penetrating the uterine mucosa for implantation.
- Successful implantation prompts the blastocyst to produce human chorionic gonadotropin (HCG), which preserves the corpus luteum and sustains progesterone levels, crucial for maintaining the pregnancy environment in the endometrium.
Menstrual Cycle and Fertility
- If no fertilization occurs, the corpus luteum degenerates, leading to menstruation, where the basal layer of the endometrium also sheds due to lack of progesterone support.
- In case of conception, progesterone and HCG levels remain elevated, influencing the uterine environment and resulting in the continuation of the secretory phase of the endometrium.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the crucial processes in developmental biology, with a focus on the formation of extraembryonic membranes and the hormonal regulation of follicles. This quiz covers the stages of follicular development and the roles of key hormones such as FSH and LH in reproduction. Test your knowledge on these essential biological concepts.