Anatomy And Histology I Flashcards
How is fetal sex determined?
Fetal sex is determined genetically by the Sry gene located on the Y chromosome.
What does the Sry gene encode?
The Sry gene encodes a DNA-binding protein that regulates the transcription of genes on autosomes and on the X chromosome that instruct testis formation.
What is the default development observed in the absence of a Y chromosome?
The development of a female fetus is observed as the default in the absence of a Y chromosome.
What gene is required for ovary development?
The expression of the Wnt4 gene is required to provide a key signal that channels the developmental fate of the indifferent mammalian gonad toward the ovary.
What are the four stages of fetal ovary development?
The four stages of fetal ovary development are: 1) indifferent gonad stage, 2) stage of differentiation, 3) period of oogonial proliferation and oocyte formation, and 4) stage of follicle formation.
At what gestational age can paired gonads be identified?
Paired gonads can be identified at about 5 weeks of gestation.
What are the components of the paired gonads at 5 weeks of gestation?
The paired gonads are composed of primitive germ cells intermingled with coelomic surface epithelial cells surrounding an inner core of medullary mesenchymal tissue.
From where are the somatic cells of the gonad derived?
The somatic cells of the gonad are derived from both coelomic epithelium and mesonephric cells.
Where do primordial germ cells originate?
Primordial germ cells originate within the primitive ectoderm.
What is the survival requirement for germ cells?
Germ cells can only survive in the genital ridge.
How do germ cells migrate during development?
Germ cells migrate from the yolk sac, around the hindgut to the gonadal ridges after 4-6 weeks of gestation and begin mitotic proliferation during migration.
