What is the most common type of Assisted Reproductive Technology (ART)?
In vitro Fertilization (IVF)
Fertilization occurs outside the woman’s genital tract.
What happens during the fusion of oocyte and sperm cell membranes?
- Adhesion of sperm to the oocyte
- Fusion of sperm and egg plasma membranes
- Male nucleus enters oocyte to become male pronucleus
- Oocyte completes 2nd meiotic division
- Formation of diploid zygote
The haploid male and female pronuclei fuse to form a diploid zygote.
What is the role of the zona pellucida in fertilization?
- Protects the released egg
- Allows sperm to penetrate via acrosomal enzymes
- Changes permeability upon sperm contact
The zona pellucida is crucial for the fertilization process.
List the phases of fertilization.
- Acquisition of sperm motility and chemotaxis
- Penetration of corona radiata
- Penetration of zona pellucida
- Fusion of oocyte-sperm cell membranes
- Constitution of male & female pronuclei
- Fusion of the pronuclei
- Commencement of cleavage
These phases outline the process leading to fertilization.
What is the result of fertilization?
- Formation of zygote
- Restoration of diploid number of chromosomes
- Determination of sex
- Initiation/activation of cleavage
These results are critical for the development of the embryo.
What is implantation bleeding?
Occurs when the fertilized zygote attaches to the uterine endometrium, causing bleeding per vagina
Usually lasts a few hours to 24 hours, sometimes days, and can be confused with normal menstrual periods.
Define cleavage in the context of fertilization.
A process of mitotic subdivision of the fertilized ovum, reducing size but increasing number of cells
The cleavage process leads to the formation of a morula.
What is the inner cell mass in a blastocyst?
Forms the embryo
The outer cell mass forms the placenta.
What is the goal of implantation?
To provide nutrition for the blastocyst in absence of yolk material
Implantation begins on day 6/7 and ends on day 13.
What is capacitation in sperm cells?
Physiological, biochemical, and biophysical changes that bestow fertility on sperm
It involves removing the glycoprotein coat from the plasma membrane of the spermatozoa.
What are the phases of the ovarian cycle?
- Follicular Phase
- Luteal Phase
The ovarian cycle is controlled by hormones secreted by the pituitary gland.
What occurs during the menstrual phase?
The functional layer of endometrium undergoes necrosis and sloughs off
This phase lasts for 1-4 days after ovulation if the ovum is not fertilized.
What is the corpus luteum?
The empty follicle that develops after ovulation and secretes progesterone
It degenerates after 10 days if the ovum is not fertilized.
What hormones control the menstrual cycle?
- GnRh (hypothalamus)
- FSH (Pituitary)
- LH (Pituitary)
- Estrogen (Ovarian follicles)
- Progesterone (Corpus luteum)
These hormones regulate the phases of the menstrual cycle.
What is amenorrhea?
The absence of menstruation
It can be classified as primary or secondary.
What is the definition of fertilization?
A coordinated sequence of cellular and molecular processes involving the fusion of male and female gametes
It results in the formation of a zygote.
What is hypomenorrhea?
Scanty blood flow during the menstrual cycle
It is one of the abnormal menstrual cycles.
What is menorrhagia?
Profuse blood flow during the menstrual cycle
It is another type of abnormal menstrual cycle.
What is metorrhagia?
Occurrence of bleeding between menstrual cycles
This condition can indicate underlying health issues.
What is oligomenorrhea?
Reduced frequency of menstrual cycles
It can be a sign of hormonal imbalance.
What hormone is secreted by the corpus luteum?
Progesterone
The corpus luteum is responsible for secreting progesterone after ovulation.
What does estrogen stimulate in the uterine endometrium?
Proliferative phase
The level of estrogen rises to a peak just before the LH surge.
What event does the LH surge stimulate?
Ovulation
The LH surge is a critical trigger for the ovulation process.
Following ovulation, what do the lutein cells of the corpus luteum secrete?
Progesterone
Progesterone is essential for preparing the uterine endometrium for potential implantation.
