Module 3, Lecture 1: Female reproduction

Vocabulary flashcards covering key terms and definitions from the Female Reproduction lecture notes.

Ovarian follicle

A structure in the ovary that houses a developing oocyte and its supporting cells (theca and granulosa) as it matures through folliculogenesis.

Primordial follicle

The earliest follicle stage containing a primary oocyte arrested in prophase I; numerous at birth and progressively depleted.

Primary follicle

Follicle with a single layer of granulosa cells surrounding the oocyte.

Secondary follicle

Follicle with multiple layers of granulosa cells and theca cells surrounding the oocyte.

Preantral follicle

Early growing follicle with granulosa and theca cell layers but no fluid-filled antrum.

Early antral follicle

Follicle with initial fluid accumulation and formation of a small antrum; theca and granulosa cells are present.

Antral follicle

Follicle with a defined antral (fluid-filled) cavity; a stage close to ovulation with cumulus surrounding the oocyte.

Dominant (preovulatory) follicle

The selected mature follicle that proceeds to ovulation; estrogen is high and LH surge occurs to trigger ovulation.

Oocyte

The female gamete contained within the follicle; undergoes meiosis to become a haploid ovum after fertilization triggers completion of meiosis II.

Oogenesis

The development of the female gametes (oocytes) within the ovary, including meiotic divisions and maturation.

Folliculogenesis

Growth and development of ovarian follicles from primordial stages to ovulation.

Meiosis

Reduction division that halves chromosome number (2n to n) to form haploid gametes; includes meiosis I and II and genetic recombination.

Prophase I arrest

Oocytes in primordial/primary follicles are arrested in prophase I; meiosis I begins but is paused until puberty.

Metaphase II arrest

Secondary oocytes arrest at metaphase II until fertilization occurs.

2-cell 2-gonadotropin hypothesis

Concept describing cooperation between theca cells (LH-stimulated) and granulosa cells (FSH-stimulated) to produce estrogens via aromatase.

Theca cells

Ovarian cells surrounding the follicle that synthesize androgens under LH stimulation; contribute to estrogen production through aromatization.

Granulosa cells

Ovarian cells lining the follicle that respond to FSH and convert androgens to estrogens via aromatase; produce estrogen.

Aromatase

Enzyme in granulosa cells that converts androgens to estrogens (e.g., estradiol) during follicle development.

Estrogen (estradiol)

Major female sex hormone produced by developing follicles; promotes growth of reproductive organs, endometrium, and ovulation; exerts negative and positive feedback on the HPG axis.

Progesterone

Hormone produced mainly by the corpus luteum; promotes the secretory phase of the uterus and supports pregnancy; provides negative feedback on GnRH.

Inhibin

Hormone from granulosa cells that inhibits FSH secretion; part of intra-ovarian feedback.

FSH (follicle-stimulating hormone

Gonadotropin that stimulates follicle growth and granulosa cell activity; regulated by GnRH and feedback from ovarian hormones.

LH (luteinizing hormone)

Gonadotropin that stimulates theca cells to produce androgens, triggers ovulation, and supports corpus luteum function.

GnRH

Gonadotropin-releasing hormone from the hypothalamus that stimulates the anterior pituitary to release FSH and LH.

HPG axis

Hypothalamic-Pituitary-Gonadal axis; regulatory loop connecting hypothalamus, pituitary, and gonads via GnRH, FSH/LH, and sex hormones.

Endometrium

Uterine lining that undergoes cyclic changes; consists of functional and basal layers, contains glands and blood vessels, shed during menstruation.

Functional layer

Superficial endometrium that thickens and is shed during menstruation; regenerates from the basal layer.

Basal layer

Deep endometrium that remains after menstruation and regenerates the functional layer.

Menstrual phase

Days 1–5 of the cycle; the functional layer of the endometrium is shed; gonadotropins rise thereafter.

Proliferative phase

Days 6–14; estrogen-driven regeneration of the functional endometrium; ovulation typically occurs near day 14.

Secretory phase

Days 15–28; post-ovulation; progesterone from the corpus luteum promotes a secretory endometrium and prepares for implantation.

Uterine glands

Glands within the endometrium that secrete during the secretory phase to nourish potential embryo.

Ovarian reserve

Total pool of non-growing primordial follicles; from conception to menopause; ~millions at birth, ~450 ovulate; menopause when <1000 primordial follicles remain.

Menopause

Cessation of ovarian function with depletion of follicles; occurs when ovarian reserve is extremely low.

Ovulation

Release of the secondary oocyte from the dominant follicle, triggered by the LH surge and followed by corpus luteum formation.

LH surge

Rapid rise in LH that triggers ovulation and transformation of the ruptured follicle into the corpus luteum.

Polar bodies

Small haploid cells produced during oogenesis; extruded during meiosis I and II and typically degenerate.

Zona pellucida

Glycoprotein layer surrounding the oocyte; essential for sperm binding and fertilization.

Cumulus cells

Granulosa cells surrounding the oocyte within the cumulus mass, supporting oocyte maturation and signaling.

Ovarian cycle

Cycle of follicular growth and ovulation, coupled with formation and regression of the corpus luteum; syncs with the uterine (endometrial) cycle.

Endometrial glands

Glands in the endometrium that secrete nutrients to support implantation during the secretory phase.