Ovary And Testis Flashcards
Where does oogenesis begin
In utero
Mitosis division of oogonia
At what stage does the oogonia arrest
Prophase where suspended for many years and begins again prior to ovulation
Completed at fertilisation
What is the first polar body
One of two products in the first stage of meiosis
Both relatively small and little cytoplasm
What does the presence of two polar bodies signify
Spermatogenesis entry and the completion of second meiotic division
How long does the average menstrual cycle last
28 days
How many stages are in the menstrual cycle and what are they
2 stages
Follicular phase
Lateral phase
What roughly happens in the follicular phase
Maturation of the egg
Ready for ovulation at mid cycle
Occupation signals end of follicular phase
What roughly happens in the literal phase
Development of the corpus luteum
Induces prep of reproductive tract for pregnancy if fertilisation occurs
What is a corpus luteum
A hormone secreting structure that develops in an ovary
after an ovum has been discharged after a few days unless pregnancy has begun
Secretes volumes of progesterone and oestrogens making uterus more favourable for implantation
What is GnRH and where is it produced and what does it do
Gonadotropin releasing hormone
Syn by neurones in hypothalamus
Pulsatile release
Stim FSH and LH syn/release form ant pit
What is FSH, where is it produced and what does it do
Follicle stim hormone
Secreted by ant pit
Stimulates follicular development
Thickens endometrium
What is LH, where is it produced and what does it do
Luteinising homone Sec by ant pit Peak stim at ovulation Stimulates corpus luteum development Thickend endometrium
Where is oestrogen primarily sec form
Ovaries
Adrenal cortex
Placenta when pregnant
What does oestrogen do
Thicken endometrium
Prod fertile cervical mucus
Mature ovarian follicles
Responsible for secondary sexual characteristics
Accelerate sodium and water reabs by kidney tubules
What does a high or low level of oestrogen do
High - inhibits sec of FSH and prolactin stimulates LH
Low - after pregnancy, stimulates secretion of prolactin
What sec progesterone
Corpus luteum and placenta when pregnant
What does progesterone do
Inhibit LH sec
Thermogenin effect
Relaxes smooth muscle
Infertile mucus
Maintain thickness of endometrium
Maintain pregnancy
What is the follicular phase in full
Follicular development stimulated –> follicle makes follicular fluid which has estrogen –> thicken endometrium –> increase of estrogen inhib FSH and increase LH –> LH stimulates ovulation and initiates development of corpus luteum
What is the luteal phase in full
Follows ovulation –> ruptured follicle cavity is replaced by corpus luteum( sec or gesturing and estrogen) –> progesterone stim changes in endometrium for impnatation during early phase of pregnancy –> if fertilisation doesn’t happen curious luteum regress and prod progesterone and estrogen decreases
What is the menstrual phase in full
Corpus luteum regresses
Progesterone and estrogen decreases
Endometrium degenerates and menstraujtion occurs
Drop of estrogen in blood and progesterone causes a stim production of FSH which starts cycle again
What is the LH surge
Oocyte resumes meiosis
Secondary oocyte + polar body (degenerates)
Stops at metaphase II only co,pelted if fertilised
Cytoplasmic maturation
LH receptors stimulated to synthesise orgiesteorne
Collapsed follicle becomes corpus luteum
What colour is lutein
Yellow/orange carotenoid pigment
What is the route of sperm
Testes –> epididymis –> vas deferens –> ejaculatory duct –> urethra
Where does spermatogenesis occur and when
Within seminiferous tubules of testes
Germ cell mitosis re activated at puberty
Constant
What hormones control the testes
LH –> acts on leydig cells - reg testosterone sec
FSH –> act of Sertoli cells to enhance spermatogenesis essential for spermatid remodelling
LH and FSH release stimulated by GnRH
Where are the Sertoli cells and what do they secrete
In the seminiferous tubule
Sec androgen binding globulin and inhibin
What are some adverse effects on human spermatogenesis
Heat Alcohol Smoking Chemo/radiotherapy Vasectomy
What are the two major differences between oogenesis and spermatogenesis
- oogenesis prod one ovum, spermatogenesis prod millions of sperm
- once a month p, spermatogenesis constant
What does a high level of FSH mean
Loss of ovarian function
Menopause
What is the production of eggs and sperm
Eggs - oogenesis
Sperm - spermatogenesis
