Flashcards in Female Reproductive System Deck (47):
Where are the ovaries located?
Inside the pelvis suspended on either side of the uterus
What are oocytes?
The reproductive cells of a female
How are oocytes produced?
Process called oogenesis
How does oogenesis start?
With oogonia and these cells are produced prior to birth
-5-10 oogonia are produced one each ovary
-up to 1million oogonia progress to the primary oo yet stage around the time of birth
What happens to primary oocytes when puberty occurs?
Undergo a recruitment process which is stimulated by hormones
-small pool of oocytes will continue to develop to produce a secondary oocyte that eventually will be ovulated
Describe the whole process of oogenesis
Millions of oogonia are produced via mitosis before brith. The oogonia are converted to primary oocytes before brith via meiosis 1 but it is paused. When puberty occurs, completion of meiosis 1 for one primary oocyte to 1 secondary oocyte occurs every month. The secondary oocyte is termed the ovum when it is released during ovulation as it travels through the Fallopian tubes. Meiosis 2 only occurs when there is fertilization. if fertilization occurs, a zygote is produced
What is a polar body?
Secondary cell after primary oocyte converts to secondary oocyte.
-Not a functional cell but a garbage can for DNA ignorer to get rid of access chromosomes so the oocyte can be haploid
What are supporting cells?
Cells that promote the maturation of the oocyte.
Are all supporting cells the same?
No, the cells undergo different patterns of cell division depending on the hormonal fluctuations that occur during the monthly cycle
What is a follicle?
Secondary oocyte with its surrounding support cells
What are the 2 kins of supporting cells?
Theca and Granulose cells
What is a corpus leutem?
Structure remaining after oocytes bursts through the ovary
What is a Graafin follicle?
Contains the the secondary oocyte to be ovulated
-can be up 2cm
At menopaus do women still have primordial follicles?
Describe the process in which the follicle is released
Primodial follicle starts out pre birth can continues to be primordial until stimulated and turns into a primary follicular cell post puberty. A number of primary follicular cells are made and only a handful go onto become a secondary follicular cell. After that only one becomes a Graafian follicle and then proceeded to come out of the ovary to create the corpus luted structure on the ovary
What are characteristics of a primordial follicular?
Granulosa cells (squamous=square)
What are characteristics of Primary follicular cells?
Granulose cells (cubocidal)
What is a zone pellucida?
Layer surrounding the oocyte
Where the sperm will bind eventually (has sperm receptors)
What happens to follicular cells when they do not progress to become a secondary follicular?
They go through abresia
What are characteristics of secondary follicular cells?
Layers of granulose cells
Theca cells (surrounding the outside of the follicular)
What are characteristics of Graafian follicular cells?
Antrum (fluid filled space)
Primary to secondary oocyte
In the Graafian follicular cell, when does the oocyte go from primary to secondary?
During early stages, the Graafian is a primary, but in the later stages, right before ovulation, it finishes meiosis 1 and turns into a secondary and is then released into the Fallopian tubes
How long does it take for a primordial follicular cell to turn into a graafian follicular cell?
About 90 days, and only one Graafian is released
What do theca and granulose cells produce and are stimulated by?
Theca: Produce androgens which are stimulated by LH
Granulosa: Produce estrogens and stimulated by FSH
How is estrogen produced?
Outer cells are theca cells which are stimulated by LH to produce androgens which are the precursors for the sex hormones. Theca cells send the steroid androgens to diffuse to the granulosa cells in the cell. The granulose cells have the aromatase enzyme to covert the androgen into estrogen
How does the follicle know what stage of development it is undergoing?
Relies on hormonal messages
What happens in the phase of the menstrual cycle?
Follicle is developing int he ovary prior to ovulation and is known as the follicular phase
What are the hormones that control follicular development?
What predominantly regulates the feedback pathway in females?
Depending on the phase of follicular development, what kind of feedbacks do we see?
Positive and negative feedbacks
When do we see a positive feedback?
When estrogen levels are high, it signals an increase in FSH
What happens during the early to mid follicular phase?
-FSH and LH are low so there is a negative feedback
-Oocyte is going from secondary to Graafian (this progresses over ~12 days)
-Estrogen is being made and levels are increasing
--> this is because since FSH is never 0 in the blood, always low, as you go from secondary to Graafian there is an increase in the number of granulose cells within which are responsible for making more estrogen which is why estrogen levels increase in this phase
What happens during the late follicular phase?
-There is still a follicle developing to create the Graafian
-Positive feedback because of a surge (~2days) in LH between day 12-14
--> as the estrogen increases, a switch turns on in the anterior pituitary and more LH is released
--->the trigger for the switch is high estrogen levels which trigger the positive feedback
-LH surge is what triggers ovulation (~day 14)
--> LH also triggers meiosis 1 to finish (going from primary to secondary) right before ovulation
What happens during the corpus luteal phase?
When the Graafian secondary oocyte has left, most of the support cells are left behind on the ovary and form the corpus luteum structure which remains there for the remainder of the cycle (~14days).
-Function of the corpus luteum is to produce a lot of progesterone and estrogen
--> making all these hormones for pregnancy to make sure the baby isn't lost
-still a negative feedback here from LH and FSH levels
What are fimbriae?
Finger like structures to catch and sweep the secondary oocyte into the Fallopian tubes
Where does fertilization occur?
In the Fallopian tubes
What is the endometrium?
Lining of the uterus that is shed every month
What is the uterine changes phase and why does it occur
Changes in the endometrium layer go through a cycle of build up and shedding
Happens because when the corpus luteum drops, hormone levels drop and triggers the changes in the endometrium
What are the 3 phases for the uterine change?
2. Proliferative Phase
3. Secretory Phase
What happens in the menses phase?
There are low levees of hormones, the oocyte is going from primary to secondary, uterine wall is shedding
What happens in the Proliferative phase?
The lining of the endometrium is getting thicker because of the multiplying of the cells
-Because of estrogen the lining enlarges and undergoes a lot of mitosis
What happens in the secretory phase?
Lining is no longer getting thicker but it starts secreting nutrients (glycogen and lipids)
-high hormone levels, corpus luteum is formed
What are the other effects of female sex hormones on the body?
--estrogen and progesterone help protect these structures
How do oral contraceptive pills influence the monthly cycle?
Pills do not allow for positive feedback
-Hormone levels are stable and maintained at a certain level for 21 days so the woman will not ovulate but still shed the lining
-staying in negative feedback
What is endometriosis?
When there is endometrial tissue outside of the endometrium
-every month this extra tissue bleeds with the regular endometrium. The more it bleeds and the more it spreads
-can be found on or covering ovaries, bladder, rectum
What are the symptoms of endometriosis and how do you detect it?
Extreme, bending over with pain cramping
-occurs in 10% of women
-Found through exploratory surgery