Fertilization , implantation and development of the fertilized egg Flashcards
in what phase is the secondary oocyte from the garaffian follicle released . And what day is this in a women’s menstral cycle
end of follicular PHASE - follicular phase takes days - 1-14 days so day 14
in the menstrual cycle - follicular phase takes the period phase and proliferative phase
and secondary oocyte is released in proliferative phase in the menstrual cycle
which hormones causes ovulation to take place ?
in end of follicular phase day14 - estrogen levels start rising again - it stimulates the hypothalamus to produce tons of GRH and stimulates the anterior pituitary gland to stimulate tones of LH (not a lot of FSH - because the garrafian follicle in the end of the follicular phase notices this rise in oestrogen - and it produces inhibinB - it comes over and inhibits the anterior pituitary to stop FSH
when you produce a massive amount of LH - produce and LH surge - THIS PHASE CREATES THE OVULATORY PHASE
increases the blood flow and permeability into the garaffian follicle - producing a lot of follicular fluid- increasing the antrum
and activates special enzymes called proteases - which starts degrading the garaffian follicle - leaving the secondary oocyte , zona pellucida and granulosa cells - to pop out of the follicle - this is called ovulation - which occurs
where is the secondary oocyte released for it to get fertilised ?
it is the localised in the ampulla of the fallopian tube - for fertilisation to occur
in what phase is the secondary oocyte arrested in ?
SECONDARY OOCYTE has undergone meiosis 1 and gets stuck in metaphase 2 in meiosis 2 - it now is a haploid
how is the uterus getting prepared for fertilisation in the proliferative phase (6-14)
the oestrogen produced in the follicular phase of days 6-14 -regenerate stratum functionalis - regenerate spirally and coiled arteries
estrogen also starting the production of uterine glands - NOT SECRETING ANYTHING
estrogen also tells the gland in the cervix to produce mucus - the mucus is very thin - also contains chemicals to aid capacitation and catch the weak spermatocytes
how does the uterus in the secretory phase (day 15-28) following the proliferative phase aid implantation.
SECRETORY PHASE - 15-28 days
progesterone driven phase - from corpus luteum it causes :
makes the stratum functionalis thicker , spiral coily arteries are made a bit longer
the uterine glands that were synthesised - stimulate them to produce - nutrient rich broth - rich in glycogen , lipids , specific proteins
switches the cervical mucus production to form THICK MUCUS - because if implantation does occur you don’t want any access to that area - CERVICAL PLUG
if fertilisation does occur , how does the embryo ensure that the uterus environment does not shed
if fertilisation does happen the embryo will implant itself into the uterine wall of the uterine and starts producing human choirnic gonadotropin - continuously stimuli corpus luteum to stimulate progesterone
what happens to the uterus if there is no fertilisation taking place
if the female not fertilised - no progesterone is produces from corpus luteum
the coiled arteries in stratum functionalis is dependant on stable levels of progesterone for contracting and relaxing - if progesterone levels go down these vessels starts to under go spasms - that over time these vessels become very weak and so do their walls
that AFTER one strong vasoconstriction the vessels dilate so much that they rupture - so much blood leaks and accumulate in the stratum functionalis - therefore the oxygen and nutrients cannot be delivered to the stratum functionalis - and they become ischemic - and become necrotic - and sloughing off the stratum functionalis
the corpus luteum starts dying and become scarced and fatty fibrous tissue - corpus albicans - because fertilisation not occurring
goes back to day 1-6 - for menstruation cycle to occur all over again and bleed
what is the definition of fertilisation ?
fertilisation is the fusion of two haploid cells (created my by mieosis)- one a spermatocyte and the other an oocyte which results in a diploid cell that is a zygote
what are the two importnat layers of the seoncdary oocyte
the corona radiate the outer layer - surrounds the egg and consists of two or three layers of cells from the folliclular / granulosa cells, which are attached to the zona pellucida , forming the outer protective layer of the egg. There sole purpose is to supply vital proteins to the egg
the zona pellucida which is the inner layer - which contains special glycoproteins for the sperm to attach itself
describe the journey through all the female genital organs to reach the oocyte in the fallopian tube
The spermatozoa during copulation goes through active motion to travel from the vagina , through the cervix, through the uterus to the fallopian tube to meet the oocyte
with the sperm there is seminal fluids , which organs produces the seminal fluid
the seminal vesicles - creates 60-70 percent of the seminal fluid
the prostate gland makes up the rest of the seminal fluid
what do the seminal vesicles make for the seminal fluid to aid the spermatocyte
has fructose for energy ,
prostaglandins - the prostglandin acts on the smooth muscle of the uterus - to start contracting from the bottom up
and coagulase - whenever the sperm is ejaculated it can easily drain out of the vagina - vesiculase (coagulase) - causes the sperm cell to latch on to the wall of the vagina while coagulating a lot of seminal fluid , the sperm that did not latch on are lost
seminoplasmin -seminoplasmin destroys a lot of the bacteria or microbes in the genital tract
what do the prostate gand make to aid the term
has citrate - energy
fibrinolysis - fibrinolysis helps to break up some o that sperm and move them up into the uterus
PSA
relaxin - speeds up the motility when reaching the uterus
when does capacitation occur
the occur when the sperm goes through the cervix and at any point when it moves along the female reproductive tract
what is capacitation
there is surface protein/ cholesterol redistribution on the head of the sperm to allow only specific glycoprotein
calcium influx surging in motility.
what Ph is the reproductive tract and what is the use with the ph level
alkaline environment
sperm moves fast through the alkaline environment
how many sperm reach the fallopian tube from how many ?
almost 800 spermatozoa reach the fallopian tube from the 5 million
point out the major stations in fertilisation
1) binding of the sperm
2) acrosomal reaction
3) Fast block to polyspermia
4) Gentic material from sperm transfer
5) Slow block to polyspermia
6) oocyte finishes meiosis2
7) zygote ss formed
