Female tract, oogenesis and endocrine control Flashcards
What is the cell development stages of an oocyte?
In FETAL development, the oogernium migrate into the gonadal ridge from the yolk sac and then to the ovary and undegoe mitosis to increase the number of cells.
This then undergoes miosis but is stopped in prophase 1. This creates an oocyte.
Meiosis 1 is only completed in one primary oocyte per month from puberty to menopause.
What happens when an oocyte undergoes meiosis?
It produces a secondary oocyte, which completes meiosis 1, and a first polar body, which does not usually deferentiate
What are the steps in the generation of a follice?
Primordial follicle - 12-50 years -> Primary follicles (30-50) - 2-3 months to grow in a follicular wave -> secondary follicle (15-20) - 2 weeks growth, these are very sensitive to gonadotropins -> tertiary follicles (1-2), has a theca interna and a theca extrna
What cells regulate an oocyte and how?
Granulosa cells they stick projections in to the oocyte to facilitate movement of substances to and from.
What happens to the granulosa cells after a follicular wave?
They go from being flat to being a flat layer of granulosa cells in the primordial follicles to being cuboidal granulosa cells in the primary follicle. In the secondary follicle the granulosa cells proliferate increasing the size of that layer (from single to multilayered.
They express FSH receptors, and is stimulated by FSH produced by the pituitary. This stimulates them to produce estrogen, inhibin and AMH (anti-malirian hormone) and induce their proliferation.
What receptors do the theca cells express during a follicular wave and what do they produce?
LH receptors - produce androgens
What is the pathway for estrogen development?
Progesterone -> androgen -> estrogen
The theca cells outside of the basement membrane are stimulated by luteinizing hormrone to produce progesterones and androgens. These are shuttled into the granulosa cells inside the follicle then converted to estrogens. These can then enter the blood.
What are the features of a tertiary follicle?
Has an antrum that contains follicular fluid, multilayered cuboidal cells, theca interna and theca externa
What is the zona pellucida and what does it do?
Found in the primary follicule in a basic form made up of ZP-1.The other two proteins, ZP-2 and ZP-3 are added in secondary and tertiary stages and the zona pellucida thickens.
Prevents multiple sperm binding to block polyspermy. Prevents sperm from other species.
What is a corpus luteum and what do they produce?
It is the remnants of a follicle following release of the secondary oocyte from the tertiary follicle.
They produce large amounts of progesterone and estrogens
When do the oogonia become oocytes?
When they have began meiosis and have halted just prior to metaphase 1 at the end of prophase
What differentiates a secondary and a tertiary follicle?
A tertiary follicle has an antrum filled with follicular fluid.
What is the cumulus oophorus?
The oocyte surrounded by granulosa cells
What is the cycle of hormone production in the ovary?
Min 52 of lecture 3/ page 3/4.5
What hormone causes an increase in body temp that can be measured to predict ovulation?
Progesterone
