Reproduction 2 - FEMALE Flashcards
What does pool established at birth mean?
Limited gamete production
Female reproductive tract composed of
Uterus, uterine tube, vagina
Ovaries function:
- Site of ova maturation
– Consists of connective tissue with follicles
– Separate from reproductive tract
Uterine Tubes function:
Also called fallopian tube / oviduct
Transports ova from ovaries to uterus. Site of fertilization.
– Infundibulum and fimbriae
– Movement of ovum through uterine tube
Infundibulum and fimbriae
• pick up released ovum
– Movement of ovum through uterine tube
- Initially – peristaltic contractions
- Mostly – ciliary actions
- Duration – 4 days to uterus
Ectopic pregnancy
Implantation occurs in fertilization site rather then uterus = no baby = pain
Why doesn’t ectopic pregnancy end in baby ?
Cuz no nutritional capacity in fertilization site.
Causes for ectopic pregnancies
- chlamdydia infection
Wall of Uterus layers?
1) Outer layer: perimetrium
2) Middle layer: myometrium
3) Inner layer: endometrium
Outer layer = Perimetrium
• Epithelial cells and connective tissue
Middle layer = Myometrium
- Smooth muscle
* Thickest layer
Inner layer = Endometrium
- Layer of epithelial cells
- Layer of connective tissue
- Numerous glands
Uterus
Site of fetal development
- Body = upper portion
- Cervix = canal leading to vagina
- Cervix + vagina = birth canal
Steps of oocyte release from ovary
1) immature follicles
2) maturing follicles
3) Mature (graafian follicles)
4) expel oocyte = follicle empty
5) follicle = corpus luteum (no prego=dies)
Ovarian cycle
2 phases: follicular & Luteal (28 days)
- Follicular phase: day 1-14
- Luteal phase: 14-28
- day 14 = ovulation
Luteal phase is the phase that starts from the
release of the oocyte to the menstrual bleeding. Does vary.
- within this phase is the secretory phase of the uterine cycle and the progestational phase of the hormones cycle
Follicular phase starts from the
Formation of the follicle (day 1) to the point where the oocyte is released (day 14). This phases varies.
- within this phase is the menstrual phase, proliferative phase of the uterine cycle and the estrgenic phase of the hormone cycle.
The menstrual phase of the uterine cycle begins from day
Day 1-5.
The proliferative phase of the uterine cycle starts from
Day 5-14. The cell layers of the endometrium degrade = increase blood vessel growth.
The secretory phase of the uterine cycle begins from
Day 14-28. Blood vessels become more profuse and start branching. Secrete a lot of stuff.
Hormone cycle, explain its phases
Estrogenic phase: day 1-14. From day 14 the follicle is converted to corpus luteum which produces progesterone —->
Progesterone phase: influence growth of endometrial layer of ovarian cycle.
Follicles
- each contain 1 oocyte (primary oocyte)
- start as primordial follicle
- single layer of epithelial cells
- single layer divides to become granulosa cells ——> forms theca cells
Types of theca cels
Theca externa and theca interna
Stages in follicle growth
1) primordial follicle (single layer, small)
2) primary follicle (nucleus grow large)
3) peantral follicle (granulosa layer grew, theca cells appeared)
4) early antral follicle (antrum appears)
5) Mature / graffian follicle (large antrum)
What kind of cells directly surround the oocyte in the follicle?
Zona pellucida
At the beginning of each cycle 10-25 _______ random follicles are selected
Preantral or early antral follicles
Where does the antrum grow
Within the granulosa cells
After the mature follicle forms, what happens next?
1) The follicle bursts and releases oocyte
2) forms corpus luteum (dies if no fertilization)
What does the corpus luteum become
Becomes an endocrine cell secreting hormones for several days. Dies and becomes corpus albicans
What does the corpus luteum become after it dies?
Corpus albicans
Folliculogenesis is triggered by the
Release of FSH
FSH exerts ______ effect on _______ cells
mitotic
granulosa
When the oocyte is release form the mature follicle, what kind of oocyte has it become?
Second army oocyte. Started off as primary.
How does the oocyte grow from a primary to secondary oocyte?
Granulosa cells send out cytoplasmic processes through the zona pellucida and form gap junctions with oocyte.
Nutrients and paracrine factors are extended through these junctions to help the growth of the oocyte.
When do follicles begin to develop
During the fetal stage
How many and what kind of follicles at birth?
4 million primordial follicles
How many and what kind of follicles at puberty?
400 follicles which can reach the stage of ovulation during reproductive lifetime.
——> run out = menopause
How does FSH trigger follicolugensis ?
FSH stimulates the follicle and causes mitotic changes on the granulosa cells = start prollipherating.
Granulosa cells surrounding oocyte send nutrients through tight junctions.
From day 1-7, during early to mid follicular phase, what are the effects of FSH
- stimulates granulosa cell proliferation = produce estrogen = grow antrum
- increase aromatase synthesis and activity in granulosa cells and INC estrogen production
From day 1-7, during early to mid follicular phase, what are the effects of LH?
LH stimulate the LH receptors on the thecal cells = secrete androgens.
Wat do the androgens released from the theca cells that were stimulated by LH do?
• Androgens go into granulosa cells and convert to Estrogen.
• Estrogen secretion rises and dominant follicle selected (one that secreted the most)
The effects of estrogen secreted by granulosa cells after androgens from theca cells entered and converted to it?
- Further growth of granulosa cells
- Up regulate LH receptors on Granulosa cells
- Progesterone receptors on uterine endometrial cells
How is the dominant follicle selected?
The follicle that produces the most estrogen form the granulosa cells = will gorw the largest. The rest of them die off.
Two cell theory
Thecal cell produces progesterone —> androgen.
Androgen travel to inside the granulosa cell —-> estrogen, its released to blood and antrum.
Two cell theory of early/mid follicle
Thecal: (LH receptors)
C —> P —> A
Grsanulosa: (FSH receptors)
—-> A —-> E —-> released
Through this process the dominant follicle is selected.
Two cell theory of late follicle/corpus luteum
Thecal: (LH receptors)
C —> P —> A
Grsanulosa: (FSH and LH receptors)
—-> A —-> E —-> released
—-> C -—> P —-> released
New Granulosa cells can produce both E and P.
Granulose cells functions
- Secrete antral fluid
- secrete inhibin
Inhibin
Peptide hormone that controls with (-) feedback to FSH form the Ant Pit.
The hypothalamus-pituitary-ovarian Axis
Hypothalamus(GnRH) —-> Ant. Pit. (LH and FSH) —-> ovary (E and P)
- hypoth. Releases GnRH in pulse generator
- P has (-) feedback with Ant. Pit and hypo
- E has (-)/(+) feedback with Ant. Pit and hypo
Pulse generator:
frequency and amplitude of these pulses change every 24 h over the course of the menstrual cycle
With the onset of puberty, hypo begins to release GnRH in
pulses, neruoendocrine cells are called the pulse generator as the frequency of these pulses change over the 24 hour period and as the day go on along the menstrual cycle.
• Progesterone work on the
negative feedback level on both the ant pit and the hypo.
• Estrogen has both
negative and postive feedback on both the ant pit and hypo.
Oognesis
Oogonia —> ovum
1) mitosis/differentiation of oogonia = primary
2) meiosis I of primary oocyte = secondary
3) meiosis II secondary oocyte = ovum
The number of oogonia for women is
Fixed prior to birth.
As opposed to males that continually produce spermatogonia
When does the mitosis phase of the oogensis process begin?
Mitosis starts in the first 2 months of embryonic life
When does the meiosis I phase of the oogensis process begin?
Meiosis I begins in fetal life
– Meiosis I goes into mitotic arrest where all the oocyte are in primary oocyte stage. Arrests lasts until puberty.
1 st meiotic division completed in the
dominant follicle at the time just prior to ovulation
When is the meiosis II phase of the oogensis process completed?
Meiosis II only completed after
fertilization
So throughout the lifespan of a women, when could mitosis occur? And when can meiosis occur ?
Mitosis occurs BEFORE BIRTH
Meiosis occurs AFTER PUBERTY
Decrease the oogenesis pathway
1) MITOSIS and Differentiation: Oogonia (2n) —-> 2X oogonia (DNA replicated (1 turns into primary, 1 dies)
2) the single primary oocyte (2n) produced goes into meiotic arrest just prior to ovulation
(until puberty)
3) MEIOSIS I: After puberty, primary —> secondary oocyte (n X 2) + polar body
4) MEIOSIS II: After fertilization, secondary—> ovum (2n) [zygote now] + polar body
Meiosis I is completed
Prior to ovulation
Follicle development stages
1) primordial germ cell
2) oogonia (2n)
3) primary oocyte (2n)
4) secondary oocyte (n)
5) ovum (zygote)
Follicle states correlating to what oocyte development stage
1) primordial germ cell —> primordial follicle
2) oogonia (2n) —> primordial follicle
3) primary oocyte (2n) —> preantal and early antral follicle
4) secondary oocyte (n)—> Graafian follicle to ovulation
5) ovum (zygote) —> follicle w no oocyte develops into corpus luteum.
Wha period does each oocyte stage exist in?
1) primordial germ cell —> fetal
2) oogonia (2n) —> fetal
3) primary oocyte (2n)–>fetal life to ovulation
4) secondary oocyte (n) —> just prior to ovulation until fertilization
5) ovum (zygote) —> fertilization
At birth all oocyte exists as
Primary oocyte
Do Internal female organs require hormones for them to develop?
Internal female organs dont require hormones for them to develop as those are the default, males need hormones for male reproductive organs to form.
Are ovarian hormones required for female sexual differentiation?
No
What are ovarian hormones required for?
Required for :
- sexual maturation at puberty and secondary sex characteristics
- Maintaining sexual capacity in adult life
• Regulation of the hypothalamic-pituitary gonadal axis
– E: both +ve and –ve feedback effect
– P: –ve feedback only
– Inhibin: –ve feedback on FSH
Hormones levels during menstrual cycle and directly after?
• FSH > LH during, at beginning of menstrual theres small increases in both LH and FSH due to 10-25 random follicles getting ready for mensuration.
- After LH platues and FSH decreases due to inhibin
• E > P during, both low, which removes (-) on LH and FSH = small increase in LH/FSH secretion.
- After menstrual E rises a lot, P stays low.
At the beginning of menstrual cycle, FSH starts
increasing and LH increases slightly as well.
It’s mainly FSH that causes the
follicles to start growing rapidly (granulosa cells prolipherate and produce estrogen = spike in E
After the menstrual cycle (day 7)
- One follicle selected = dominant follicle = Estrogen level rises gradually, still has (-) feedback effect on LH and FSH, and they begin to plague,
- As E increases, there’s a further decrease in FSH levels which is due the effect of inhibin.
What does the decrease in FSH due to inhibin right after the menstrual cycle (day 7) cause?
This decreases causes all follicles other then the dominant follicle to start dying off. This programmed death of follicles is known as astresia.
programmed death of follicles is known as.
astresia
After atresia and dominant follicle secretes ALOT of E, E will
Peak and cause it to have a (+) feedback effect on Hypothalamus = GnRH = sharp increase in LH just before ovulation = LH surge
What causes the LH surge?
The high level os E secreted by the dominant follicle causes it to have a (+) feedback to hypothalamus = GnRH = INC in LH = surge
LH surge is very important and occurs_______ before ovulation, without the LH surge a …
18 hours
Graafian follicle cannot go through proper release of the egg.
Along with the LH surge, there’s a
small release of FSH because both LH and FSH are secreted form the same cell in the ant pit.
After the estrogen peaks and caused the surge and the dominant follicle is ready to ovulate, the estrogen
goes down.
Then rises up at the Luteal phase after day 14.
During Luteal phase there’s high level of
progesterone that stays up up to day 23, and estrogen levels are also high.
During the Luteal phase, high levels of both E and P causes
(-) feedback in hypo and ant pit = decrease in both LH and FSH
Once FSH and LH decreased, the levels of progesterone will
remain high with high levels of estrogen until the point where the body stops keeping the corpus Latium viable.
(No fertilization = corpus dies)
If there’s no fertilization (no reason to keep the corpus Latium alive), progesterone and estrogen levels
go down and corpus corpus luteum degenerate, once these go down, because of (-) feedback, LH and FSH begin to go up once again, repeat cycle.
During earl to mid follicular phase, estrogen levels are
Low which causes them to have (-) feedback to Ant. Pit. & hypothamlus.
When LH and FSH contact the ovary, which hormones affects which cell type?
LH —-> theca cells = estrogen
FSH —-> Granulosa cells = inhibin / follicle development
Early to mid filicular phase = from day 1 to day 7.
- LH works -—> theca cells = androgen secretion = granulosa cells release enzymatic modifications of androgens = estrogen secretion.
- FSH —-> granulosa cells release inhibin and follilar development occurs inside the follicles
LH works on theca cells to increase
androgen secretion that causes granulosa cells to release enzymatic modifications of androgens = estrogen secretion.
Early to mid filicular phase = from day 1 to day 7.
The inhibin that was released by granulosa cells via FSH has
has a (-) feedback effect on the ant pit.
Early to mid filicular phase = from day 1 to day 7.
The estrogen from the granulosa cells has a
(-) feedback effect on the hypothalamus and ant pit.
What are the effects of estrogen secretion
- Proliferative phase = uterine changes
- LH receptors on granulosa cells INC
- Progesterone receptors in uterus INC
- growth and genitalia growth INC
- bone growth in adolescence INC
During the cycle, the increase in FSH during the ovulation mark helps
the growth of randomly selected follicles
Main things to remember from the multi-cycle graphs
Beginning of FOLLICULAR PHASE: FSH peak at beginning = follicular growth of randomly selected follicles
- day 7 = dominant follicle selected (atresia)
= FSH decreases due to inhibin = E rises. - when mid follicular phase finishes = dominant follicle sec E = (+) feedback on GnRH = LH surge (helps with ovulation) and FSH INC
- LUTEAL PHASE : after ovulation, both LH and FSH decrease, no other follicle selected rn
- corpus Luteal goes through 10 days of Luteal phase where P and E are at their peak = low levels in LH and FSH cuz (-)feedback .
—> no fertilization = E and P decrease and corpus dies = LH and FSH increase = cycle restarts
-
Early to mid follicles phase is between day
1 to day 7
Late follicular phase starts from day
7 to day 14
Regulation of Hormone Secretion – Early to Mid-Follicular Phase
High levels of estrogen secreted by dominant follicle = (+) feedback on hypothalamus and Ant. Pit. = high LH secretion (LH surge)
What do the granulosa cells cause after being contacted by LH and FSH during late follicular phase (day 7- day 14)
- stimulate meiosis I in oocyte
- estrogen sec DEC after ovulation
- progesterone sec INC
- ovulation
- transforms follicle —-> corpus luteum
The corpus luteum contains what kind of cells?
Granulosa and theca cells.
Menstrual Phase (day 1 - day 5)
- shedding of uterine lining
- blood flow to tissue decreases
- tissues dies and slough into vagina = menstrual flow.
Hormonal Control of Menstruation
- triggered by decrease in E and P
- E and P decrease when corpus luteum dies
Proliferative Phase ( day 5 - day 14)
Uterus prepares for fertilized ovum: – Endometrial lining develops - Endometrial layer grows - Endometrial glands enlarge - smooth muscle layer thickens - cervical glands secrete thin mucus
What is the proliferative phase controlled by ?
The high levels of E released by dominant follicle
In proliferative phase, estrogen stimulates
development of uterine lining
Secretory Phase
Endometrium prepared for implantation:
- fertilization occurs in this phase
– Blood supply increased (branching)
– Glands enlarge and secrete glycogen-rich fluids
– Cervical secretions more sticky forming a plug
What is the secretory phase controlled by ?
High levels of progesterone
(+ estrogen) released in Luteal phase
What does the formation of a plug in the secretory phase do?
Protective function.
Prevents other sperm from getting into zygote after implantation
Estrogen on the Ovary causes:
- Increased growth of follicles
(E = proliferates granulosa cell) - Increased receptors for E, P, FSH, LH
Estrogen on the Fallopian tube /uterine tube causes:
Increases growth, contractility, cilia activity and secretion =
(moves zygote to uterus)
Estrogen on the uterus causes:
- increases growth of endometrium and myometrium
- increases contractility, blood flow, sensitivity to oxytocin
(E prepares endometrium by INC sensitivity to oxytocin)
Estrogen on the cervix causes:
“Sperm-friendly” mucus, (abundant, watery and alkaline)
Helps sperm move to fertilization site
Estrogen on the vagina causes:
Proliferation and cornification of epithelium
Estrogen on the breasts causes:
Increased duct growth, fat deposition,
size and pigmentation of areola
Progesterone on the Ovary causes:
Decreases FSH-induced E production and receptors for E
(-) feedback
Progesterone on the fallopian / uterine tube causes:
Decreased contractility, cilia number, and secretions
Calms everything down
Progesterone on the uterus causes:
- Increased endometrial secretions
- Decreased contractility and sensitivity to oxytocin
Progesterone on the cervix causes:
“Sperm-unfriendly” mucus” (small amount, viscous, cellular)
Once fertilization occurs
Progesterone on the vagina causes:
WBC infiltration, decreased cornification
Progesterone on the progesterone causes:
Increased alveolar growth
What effect does E and P have on temp
Increases body temp, following ovulation cuz of increased progesterone
