Female Anatomy and Function Flashcards
What are the organs of the female reproductive system
- Ovary: Ova produced, female gonad, flattened, inner medulla (BV / nerves) and outer cortex (follicles)
- Cervix: Lower outlet of the uterus extending into the vagina
- Uterus: Hollow, thick-walled organ, receives, retains, nourishes fertilised egg, embryo develops, body, fundus, isthmus, wall (endometrium, myometrium, perimetrium)
- Urethra: Canal through which urine passes from the bladder to outside the body, vestibule, urination
What is / are the features of the female duct system
- Duct System: Uterine tube system does not have direct contact with ovaries
- Uterine Tubes: Tube through which the ovum is transported to the uterus, also called fallopian tube
- Uterus: Hollow, thick-walled organ, receives, retains, and nourishes fertilised egg, embryo develops
- Vagina: Elastic muscular tube, inferior to urethral opening, may be covered by hymen, receives the penis during coitus, acidic environment (protection)
What is the ovarian cycle (brief)
- Ovarian Cycle: Maturation / growth of follicle / oocyte and initiation of meiosis for dominant follicle
- Folliculogenesis
- Maturation of ovarian follicles, one dominant follicle ruptures at LH surge (due to LH receptors)
- Causing release of oocyte
- Atresia follicles degenerate and are re-absorbed
What hormones are involved in the ovarian cycle / HPG axis
- Oestrogen: Produced by developing follicle builds up endometrial lining, makes mucous fluid so sperm can pass to reach oocyte
- Progesterone: Produced by corpus luteum maintains endometrial lining (and oestrogen’s), menses is due to progesterone withdrawal (corpus luteum dies)
- Female HPG Axis: Oestrogen and progesterone levels feedback to hypothalamus and anterior pituitary
What are the different phases of the ovarian cycle
Follicular Phase:
- FSH facilitates vascular and antral follicle growth before ovulation (days 1-14)
Ovulation:
- Oestrogen levels peak
- LH and FSH surge from AP
- Stimulates secondary oocyte formation and ovulation (rupture of ovary wall)
Luteal Phase:
- Corpus luteum activity, becomes a gland and secretes hormones (days 14-28)
Corpus Luteum:
- Ruptured follicle after ovulation, becomes a gland and secretes progesterone, estradiol and inhibin
- Regresses if not pregnancy occurs after 10-12 days, forms corpus albicans (scar tissue)
- If pregnancy occurs, corpus luteum is supported by hCG
Provide a summary of steps of the ovarian cycle (follicle)
- Primordial follicle (single layer of granulosa surrounding primary oocyte)
- Late primary follicle (antral), layers of granulosa cells and outer layer of theca cells, fluid (antrum)
- Secondary follicle (one will become dominant follicle)
- Graafian follicle (ruptures and releases oocyte during ovulation)
What is the menstrual cycle (brief)
- Menstrual Cycle: Cyclical growth, loss and repair of endometrial lining in uterus, on average 28 days
- Involves changes in endometrium (simple columnar)
- Stratum Functionalis: Functional, cyclic changes in response to ovarian hormones, sheds during menstruation,
- Stratum Basalis: Basal, doesn’t shed, forms new functional layer after menstruating
- Blood Supply: Abdominal aorta, uterine / arcuate arteries (myometrium), radial branches (endometrium), straight (basal) and spiral (functionalis) arteries
What are the stages of the menstrual cycle
- Menstrual (1-4): Lack of progesterone, loss of blood due to breakdown of superficial layers of uterine endometrium, 30-50 mL of mainly arterial blood, 3-6 days heaviest on 2nd day
- Proliferative (5-14): Endometrium thickens, repair of endometrium via proliferation facilitated by FSH, uterine glands are small, short and straight
- Secretory (15-26): Endometrium thickens, glands elongated and coiled, facilitated by LH, uterine glands secrete uterine milk (glycogen rich), cervical plug reforms to block further entry of sperm
- Premenstrual (27-28): Lack of progesterone, glands start breaking down, tissue death, takes 2 days for hormone levels to fall sufficiently for menstruation to start
What is the cervix and cervical mucous
- Cervix is the neck of uterus to vagina
- Cervical mucous consistency changes during cycle, integral role in conception, regulates sperm transport, nourishes sperm, protection from infection, lubrication
- Endometrium of Cervix: Mucous secreting simple columnar epithelium, luminal surface, continues with moist non-keratinised stratified squamous epithelium covering external surface of cervix
- Transformation Zone: Area between columnar and squamous cells, most common place for abnormal cells to develop
How does the cervical mucous change throughout a cycle
- Follicular Phase: Mucous is copious, watery, thin and alkaline, dries in fernlike pattern (oestrogen / NaCl)
- Ovulatory Period: Mucous thinnest at time of ovulation, dries in arborising fernlike pattern (oestrogen / NaCl)
- Luteal Phase: Mucous thick, viscous, cellular, mucous scanty, no ferning pattern when dry, progesterone
Provide and overview of menstrual and ovarian cycles (days)
Days 1-4:
- Menstrual phase (menses)
- Early follicular phase
- Little oestrogen / progesterone withdrawal
- Functional layer of endometrial breaks down (dead cells), fluid (edema) in tissue
Days 5-14:
- Proliferative phase
- Late follicular phase
- Increasing oestrogen (follicle)
- FSH causes development of follicle, peak LH causes ovulation (LH receptors = rupture)
- Oestrogen produced by follicle stimulates repair of endometrium (thickens, new stratum functionalis)
- Uterine glands short straight and narrow
Days 15-26:
- Secretory phase
- Early luteal phase
- Increasing / peak progesterone
- Corpus luteum forms, produces progesterone (thick)
- Endometrium thickens, BV lengthen, uterine glands elongated, coiled, secreting
Days 27-28:
- Pre-menstrual phase
- Late luteal phase
- If no fertilisation oestrogen and progesterone decrease, corpus luteum becomes a gland, causes withdrawal, glands start breaking down
What is oogenesis
- Aim: Production of ova (oocytes) with haploid (single) chromosome set
- Generation: Begins during foetal development, no new ova formed after birth, ovary contains at birth ~2 million primordial follicles each containing and immature oocyte (not all develop)
- Female Meiosis: Begins at foetal stages and completes at time for fertilisation
- Summary: primordial germ cells - oogonium (2n) - primary oocyte (2n) - secondary oocyte (n) + polar body - ovulation - fertilised (zygote) / not fertilised (dies) - ovum (n) + second polar body
What are the steps involved in oogenesis
- Oogonia (diploid) undergo mitosis and become develop to primary oocytes (diploid) which rest in prophase 1
- FSH stimulates one primary oocyte (diploid) to undergo meiotic division to secondary oocyte (haploid) and polar body right before ovulation
- Secondary oocyte (haploid) develops to metaphase II
- If fertilised completion of meiosis II, if not fertilised the secondary oocyte dies
What is the function of LH and FSH
LH:
- Stimulate thecae cells to secrete androgens
- Stimulate granulosa cells to secrete inhibin (-ve feedback)
- Conversion of androgens to oestrogen (-ve feedback)
- During LH surge (luteal phase), stimulates rupturing of follicle and formation of corpus lutem
FSH:
- Stimulates growth of primordial / primary follicles
