General Embryology Flashcards
OMI means
Oocyte Maturation Inhibitor
Trisomy 21 is also known as
Down Syndrome
The only monosomy compatible with life is
Turner Syndrome which is a monosomy of the X chromosome
Angelman’s syndrome occurs due to
Microdeletion on maternal chromosome 15 (15q11-15q13)
Prader Willi’s syndrome occurs due to
Microdeletion on paternal chromosome 15 (15q11-15q13)
Oogenesis is
The differentiation of oogonium to mature oocyte
Spermatogenesis can be divided into three phases, namely
Spermatocytosis
Spermatidogenesis
Spermiogenesis
When do the Primordial Germ cells reach the gonads in a developing embryo
By the end of the fifth week
Chromosomal abnormalities such as Trisomy occurs mostly in which chromosomes
Chromosomes 8, 9 ,13, 18 and 21, but mostly in chromosome 21
When does Oogenesis and Spermatogenesis begin
Oogenesis begins before birth while Spermatogenesis begins at puberty
The four major groups or families of Paracrine signaling factors or growth and differentiation factors (GDFs) are
- Fibroblast Growth Factors (FGF)
- Wingless and Int-1 (WNT)
- Hedgehog
- Transforming growth factor-B (TGFBeta)
What are the the three phases of fertilization?
- Penetration of Corona Radiata
- Penetration of Zona Pellucida
- Fusion of oocyte and sperm cell membranes
What is the main cause of infertility in men
Low sperm count
What is the main cause of infertility in women
Occlusion of uterine (fallopian) tube which can be caused by Pelvic Inflammatory diseases such as gonorrhea
Corpus luteum originated from
Theca interna (ovarian stromal cells) and Granulosa cells.
When does the corpus luteum degenerate during pregnancy
Approximately by the beginning of the fourth month when the placenta has fully developed
What are the results of fertilization
- Restoration of diploid number of chromosomes
- Determination of chromosomal sex
- Initiation of cleavage
The three stages the uterine endometrium passes through during the menstrual cycle
- Follicular or Proliferative phase
- Secretory or Progestational phase
- Menstrual phase (Gravid phase during pregnancy)
Approximately what day is the morula formed
By the third day
When does implantation begin
By the 6th day
When does ovulation occur during the menstrual cycle
Approximately at the 14th day (mid cycle) in a 28 day cycle
Why is the second week of development known as the week of 2’s
- The trophoblast differentiates into two: Syncytiotrophoblast and Cytotrophoblast
- The embryoblast differentiates into two layers: Epiblast and Hypoblast (Bilaminar germ disc)
- The extraembryonic mesoderm splits into two: extraembryonic splanchnic (visceral) mesoderm and extraembryonic somatic (parietal) mesoderm
- Formation of two cavities: Amniotic cavity and yolk sac
Why is the conceptus not rejected by immunological response of the mother’s body upon it is a foreign body
This is not fully understood but recent evidences show it is due to
1. Secretion of Immunosuppressive molecules such as cytokines and proteins
2. The expression of unrecognizable antigens of major histocompatibility complex
which protect the foetus from rejection
What condition cause one to have high plasma human chorionic gonadotropin (hCG) and placental tissue but absence of an embryo
Hydatidiform mole which can eventually cause invasive mole or choriocarcinoma
