Lecture 2 – Reproductive Tract of Females

name the four primary organs of the female reproductive system

• ovaries

• fallopian tubes

• uterus

• vagina

what are the two main functions of the ovaries?

1. producing oocytes

2. secreting the key female sex hormones

• oestrogen

• progesterone

what’s the typical site where fertilisation occurs?

the ampulla of the fallopian tubes

list three functions of the uterus

1. site of implantation and foetal development

2. provides mechanical protection, nutrition, and waste removal

3. its powerful contractions are essential for childbirth

list three functions of the vagina

1. receives the penis during intercourse

2. passageway for menstrual fluid

3. forms the lower part of the birth canal

why’s it important that the female reproductive organs aren’’t rigidly fixed but suspended by ligaments?

it allows for some movement while maintaining relative positions, which is important because the fallopian tubes aren’t directly connected to the ovaries

describe the broad ligament. what is its primary function?

• a large, double-layered fold of peritoneum that ‘drapes’ over the uterus and encloses the uterine tubes and ovaries

• primary function is as a primary stabiliser, preventing lateral movement

which ligament contains the ovarian artery and vein, providing the major blood supply to the ovary?

the suspensory ligament

which ligament connects the medial surface of the ovary to the lateral wall of the uterus?

the ovarian ligament

name the three uterine ligaments that stabilise the position of the uterus

• uterosacral ligament

• round ligament

• cardinal ligament

what’s the normal position of the uterus, and is a retroverted uterus considered abnormal?

• the normal position is anteverted (angled forward over the bladder)

• a retroverted uterus (tipped backward) is found in 20–25% of women and is considered a normal variation

name the four layers/regions of the ovary form outside to inside

1. germinal epithelium

• single layer of cuboidal cells

2. tunica albuginea

• dense CT

3. cortex

• contains follicles

4. medulla

• loose CT and blood vessels

at what stage of meiosis are human oocytes arrested at birth?

prophase I

how long does it take for a follicle to progress form the primordial stage to the point of antrum formation?

approximately 85 days

match the follicle stage with its description

1. primordial follicle

2. primary follicle

3. secondary follicle

4. tertiary follicle

1. oocyte surrounded by a single layer of flattened granulosa cells

2. oocyte surrounded by a single layer of cuboidal granulosa cells; oocyte begins to grow

3. granulosa cells proliferate to form multiple layers

4. a fluid-filled space called the antrum forms

what happens to the non-dominant follicles during the follicular phase of each menstrual cycle?

they undergo atresia (degeneration)

name the three layers of the uterine wall (outside to inside)

1. perimetrium (outer protective layer)

2. myometrium (thick middle smooth muscle layer)

3. endometrium (inner mucosal layer)

what are the two subdivisions of the endometrium, and which one is shed during menstruation?

1. functional zone – shed

• superficial, thick, rich in glands and spiral arteries

2. basal zone – this regenerates the functional layer and isn’t shed

• deep, thin, adjacent to myometrium

describe the myometrium’s contractions during the proliferative phase, secretory phase, and labour

proliferative phase – gentle ‘upward’ contractions (may aid sperm transport)

secretory phase – ‘downward’ contractions (may aid embryo transport)

labour – powerful, coordinated contractions for foetal expulsion

what triggers the menstrual phase?

• if no pregnancy occurs, the corpus luteum degenerates, causing a sharp drop in oestrogen and progesterone

• this causes spiral arteries to constrict, leading to ischemia and necrosis of the functional zone, which is then shed

what hormone drives the proliferative phase, and what happens to the endometrium during this phase?

• rising oestrogen from the developing dominant follicle drives the proliferative phase

• the functional zone regenerates and thickens, glands proliferate, and spiral arteries elongate and becomes coiled

• this phase ends at ovulation

what hormone drives the secretory phase, and what happens to the endometrium during this phase?

• progesterone from the corpus luteum drives the secretory phase

• the endometrium becomes secretory – glands produce glycogen-rich fluid to nourish a potential embryo

• the decidual reaction also occurs

what is the decidual reaction? how does it differ in humans vs. most other mammals?

• a change in the endometrial stroma where fibroblasts swell and accumulate glycogen and lipids

• in humans, it occurs spontaneously during the secretory phase

• in most other mammals, it only occurs after implantation

what is the ‘window of implantation’? how long does it last?

a short period when the endometrium is receptive to the implanting blastocyst, mediated by expression of specific adhesion molecules

name the three distinct regions of the fallopian tube

1. infundibulum – funnel-shaped end with fimbriae

2. ampulla – longest, widest; typical site of fertilisation

3. isthmus – narrower portion connecting to uterus

what are the fimbriae, and what do they do?

finger-like projections on the infundibulum that sweep over the ovary to capture the oocyte after ovulation

how is the oocyte/embryo moved along the fallopian tube?

a combination of ciliary beating and peristaltic contractions of the smooth muscle wall

what is the squamocolumnar junction, and why is it clinically important?

• the area where the endocervix (single layer of columnar epithelium) meets the ectocervix (multi-layered)

• this transition zone is where most cervical cancers arise

describe how cervical mucous changes to facilitate sperm passage

it changes from thick and impenetrable to thin, watery, and alkaline

what happens to the cervix during pregnancy and labour?

• during pregnancy, it remains tightly closed to retain the foetus

• during labour, it thins and opens to allow passage of the foetus

what is an ectopic pregnancy, and where is the most common site?

• implantation of the embryo outside the uterine cavity

• the most common site is the fallopian tube

  • often due to scarring or damage that impedes embryo transport

what causes almost all cervical cancers?

persistent infection with high-risk strains of HPV, primarily serotypes 16 and 18

what’s a Pap smear, and why is the transition zone the target?

• a screening tool that collects cells from the transition zone (squamocolumar junction) to detect pre-cancerous changes

• regular screening every three years can reduce cervical cancer risk by up to 90%

how effective are HPV vaccines, and which strains do they primarily target?

HPV vaccines are highly effective at preventing infection with the most common high-risk HPV strains, primarily serotypes 16 and 18