Reproduction 2 (female development) Flashcards
What are the characteristics of the female reproductive system?
- Cyclic changes in activity = menstrual cycle
- Restricted period of fertility = ovulation
- Limited gamete production = pool established at birth
What are female hormones made up of?
They are very steroid based
What are female gonads?
Ovaries
What makes up the female reproductive tract?
Uterus, uterine tubes, vagina
What is the external female genitalia?
Vulva
What happens in the ovaries?
Site of ova maturation
What do the ovaries consist of?
Consists of connective tossue with follicles
Seperate from reproductive tract
What do follicles contain?
Contain one ovum
Where does the ovum develop?
In the ovary
What does the ovum start of as?
(It develops in the ovary)
Starts as a primordal follicle
- Oocyte = ovum
- Granulosa cells
Later in development, some granulosa cells become theca cells
What are oocytes like?
Oocyte is much bigger & has a significant amount of cytoplasm
They have surrounding granulosa cells, granulosa cells go on to become theca cells
What are the main roles of granulosa cells?
- Target cells of estrogen & FSH
- Secrete inhibin
- Transport nutrients to oocytes through gap junctions
- Secrete estrogens
What happens when estrogen & FSH target the granulosa cells?
Secrete chemical messengers in response
What does granulosa cells secreteing inhibin cause?
Provides -ive feedback to FSH secretion
This has a role in mentrual cycle timing - which is incredibly important
Summary slide on Granulosa cells:
List all the functions of Granulosa cells:
- Secrete antral fluid
- Provide nutrients for developing cycle
- Secrete paracrines that support follicle development
- Secrete inhibin
- Secrete estrogens
- Secrete substance that forms zona pellucida
Describe the general appearance of the vagina:
- Female organ of copulation
- Wall contains smooth muscle
- Inner surface bathed in acid fluid secreted from uterus or glands in cervix
How is the vagina being bathed in acid beneficial?
Protects against bacterial infections
(This is why semen must be alkaline - to combat this)
What are the areas of the uterus?
- Body = upper portion
- Cervix = canal leading to vagina
- Cervix & vagina = birth canal
What is the uterus the site of?
Fetal development
What are the 3 layers lining the uterus called?
- Outer layer = perimetrium
- Middle layer = myometrium
- Inner layer = endometrium
What is the outer layer (permetrium) of the uterus made of?
Epithelial cells & connective tissue
What is the middle layer (myometrium) of the uterus made of?
- Smooth muscle
- Thickest layer
What is the inner layer (endometrium) of the uterus made of?
- Layer of epithelial cells
- Layer of connective tissue
- Numerous glands
What is the role of the inner layer (endometrium) of the uterus?
Has a secretory role, many glands to move these things to the uterus
What is the role of the middle layer (myometrium) of the uterus?
Thick muscular wall, this drives contractions that you have during childbirth
What are the uterine tubes also called?
Fallopian tubes or oviducts
What is the role of the uterine tubes (fallopian)?
- Ova transported from ovaries to uterus
- Site of fertilisation
(When gamete is released at ovulation, it is collected by these tubes & moved to the womb)
How does the uterine tube connect to the ovary?
Fimbrae
What is the role of the infundibulum & fimbrae (attached to uterine tube)?
Pick up the released ovum form the ovary
How does the ovum move thru the uterine tube?
- Initially = peristaltic contractions
- Mostly = ciliary actions
- Duration = 4 days to uterus
What are the stages of development to produce an ova?
Oogenesis –> oogonia –> ova
How many oogonia can women have in their lifetime?
Number of oogonia is fixed prior to birth
Wasn’t sure how to put this into a question:
(This is about oogenesis)
- Meiosis begins in fetal life
- Meiosis only completed after fertilisation
Describe the process of oogenesis:
- Oogenesis - we get mitosis in embryonic phase of development –> produces primary oocyte that goes thru a meiotic division which doesn’t happen until puberty
- Cell undergoes uneven cell division, most of the cytoplasm goes into one cell to give you a polar body that disintergates
- Secondary oocyte will only complete secondary meiosis when fertilised, gives a second polar body as uneven cell division used to give the ovum which is much larger - contains 2n once fertilised
What does oogenesis result in?
Only 1 daughter cell
What does the menstrual cycle include?
- The ovarian cycle
- The uterine cycle
What is the menstrual cycle run by?
Caused by changes in estrogen & progesterone contractions (carefully timed changes)
What are the 3 stages in the ovulatory cycle?
- Pre-ovulatory
- Ovulation
- Post-ovulatory
What happens in the pre-ovulatory stage?
- Follicular (Proliferative) phase –> oestrogens
- Menstruation –> ovulation
- ~14 days
What happens in the post-ovulatory stage?
- Luteal (Secretory) phase –> progestins
- Ovulation –> before menstruation
- 14 days
Describe the basic process of an oocyte being released?
- One follicle is chosen from one ovary - start w primary follicle & then you get a secondary follicle
- When follicle matures it is released from the ovary & ovulation happens
- Corpus lutemum produces progesterone & breaks down to start the process again (was surrounding the oocyte before it left ovary)
What are the stages of the uterine cycle?
- Mestural phase = 1-5 days
- Proliferative phase = day 14
- Secretory phase = days 15-28
(First two are the follicular phase, last one is the luteal phase)
What happens in the follicular phase?
- A few follicles begin to develop from primordial follicles
- Oocyte grows, granulosa cells proliferate
- Zona pellucida & antrum form
- Dominant follicle continues development, rest regress
- Corona radiata develops
- Graafian follicles = mature follicle
- Ovulation
- FSH & estrogens stimulate follicle growth & developemnt
What are the parts of a graafian follicle:
(Probs should look at the diagram they may ask you to label it)
- Cumulus oophorus
- Oocyte
- Zona pellucida
- Corona radiata
- Antrum
- Theca cells
What triggers ovulation?
LH surge triggers ovulation & development of corpus leuteal phase
What happens during ovulation?
- Ovulation –> wall of Graafian follicle ruptures
- Antral fluid with oocyte flows to ovary surface
- Released
- Ova enters fimbrae
(Graafian follicle is recycled)
Which comes first, the luteal phase or the follicular phase?
Follicular phase
What happens in the luteal phase?
- Ruptured follicle –> gland = corpus luteum
- Corpus luteum secretes estrogens & progesterone
- Corpus luteum reaches max activity 10 days, then degenrates
- Degeneration –> decrease estrogens & progesterone –> menstruation (end of luteal phase)
- If oocyte fertilised, degeneration does not occur
How are fraternal twins produced?
- Two or more follicles may become dominant & released at ovulation
- If both are fertilised - fraternal twins
- Also called dizygotic twins (develop from 2 zygotes)
Summarise the menstural phase:
- Shedding of uterine linging
- Blood flow to tissue decreases
- Tissue die & slough into vagina causing menstrual flow
- Triggered by dec estrogen & progesterone
- Hormones dec when corpus luteum degenerates
What happens in the prolifertive phase?
- Uterus prepares for fertilised ovum
- Endometrial lining develops
- Endometrial layer gows
- Endometrial glands enlarge
- Smooth muscle layer thickens
- Cervical glands secrete mucus
- Estrogens stimulate development of uterine lining
Summarise the secretory phase:
- Endometrium prepared for impantation
- Blood supply inc
- Glands enlarge & secrete glycogen-rich fluids
- Cervical secretions more sticky forming a plug
What are the hormonal changes during the menstrual cycle?
- Estrogen is first secreted from follicle then from the corpus luteum
- Progesterone secreted from corpus luteum
- LH and FSH secreted from anterior pituitary
- Estrogens & progesterone inhibit LH & FSH secretion
Refer to the regulation of hormone secretion diagram:
Can’t insert pictures sorry
Which 2 hormones are involved in the mid-follicular phase?
- FSH
- Estrogens
What is FSH’s role in the mid-follicular phase?
- Granulosa cells –> theca cells
- Theca cells have LH receptors
What is estrogen’s role in the mid-follicular phase?
- LH receptors on granulosa cells
- Progesterone receptors on endometrial cells
Refer to the flow diagram of the late follicular phase
;
:)
What is the actions of estrogen in the follicualr phase?
- Promote endometrial growth
- Promote oogenesis & follicle development
- Inc LH receptors on granulosa cells
- Inc progesterone receptors in uterus
- Inc LH secretion (late follicular phase only)
What is the actions of estrogen in pregnancy (and luteal phase)?
- Promote growth of duct tissue & deposition of fat in breast
- Suppress lactation
- Inc prolactin secretion
- Growth & contractile activity of uterine smooth muscle
- Inc oxytocin receptors in uterus
- Promote fluid retention
What are the actions of progesterone on the luteal phase & pregnancy?
- Promotes secretory-phase uterine conditions
- Suppress uterine contractile activity
- Promotes growth of glandular tissue in breasts
- Suppress milk production
What are the 3 stages of Lon-term regualtion of female reproductive function?
- Puberty
- Reproductive years
- Menopause
What happens during female puberty?
Estrogen - secondary sex characteristics
What happens during the female reproductive years?
Estrogen levels high to maintain secondary sex characteristics
What happens in the meopause?
- Estrogen levels dec
- Reversal of some secondary sex characteristics
- Hot-flushes
- Inc risk of heart disease & osteoperosis
