Female Reproductive System 1: Parts and Oogenesis

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What is the point?

The female reproductive system has several important functions, all of which are summarised below:
  1. To provide haploid ova (oocytes)
  2. To provide an environment for the fertilisation and development of ova
  3. To expel offspring from the body
  4. To provide the initial nutrition to the offspring my lactation.
The parts of the female reproductive system are all simplified below:

Ovaries: have an endocrine function, produce oocyte

Fallopian tubes: transport and nourish oocyte, most common site of fertilisation with spermatozoa

Uterus: mechanical protection, nutritional support and waste removal for embryo/foetus, contraction during childbirth to eject the foetus

Vagina: muscular tube that allows for the elimination of menstrual fluids, holds spermatozoa after sexual intercourse, final portion of the birth canal.

Vulva: includes the vestibule, labia major, labia minor and mons pubis, vaginal opening, urethral opening and the clitoris

Greater vestibular glands: secrete lubricating fluids onto the surface of the vestibule during sexual intercourse

Paraurethral glands: secrete at the opening of the urethra

Mammary glands: milk production (lactation) for infant nourishment after birth

How are ova produced?

Oogenesis is the term denoted to the production of immature ova, i.e. eggs, called oocytes. Oogenesis occurs in the ovaries which are the sole location in the female body where meiosis occurs. The ovaries are approximately 5cm in length and are held in place by the mesovarium (portion of broad ligament), ovarian ligament and suspensory ligaments.
  1. Primary oocytes are arranged in clusters called a primordial follicle. These are activated at puberty.
  2. Oocytes have not yet completed meiosis 1 at this point. The primordial follicle then comes the primary follicle, with layers of cells forming around the primary oocyte. These include theca and granulosa cells, which secrete oestrogen when stimulated by FSH and LH (see Endocrine System 1).
  3. Meiosis 1 stays suspended by the oocyte begins to grow in size. The spaces between the theca and granulosa cells merge, forming a fluid-filled space called an antrum. This space separates the inner and outer follicle layers.
  4. Meiosis 1 is completed and meiosis 2 begins, but the secondary oocyte halts in metaphase (day 8-10). The antrum continues to expand, with the granulosa cells still attached to the oocyte, forming the corona radiata (a protective layer). It is now a tertiary (Graafian) follicle.
  5. The tertiary follicle releases a secondary oocyte and the wall of the follicle ruptures, ejecting its contents. The fimbrae move the oocyte into the fallopian tube. The process of releasing and capturing the secondary oocyte is triggered by luteneizing hormone. Ovulation occurs on day 14.
  6. The corpus luteum forms in the ovary, which is then broken down my macrophages to the regressed form, the corpus albicans.
In general, the above steps make up the ovarian cycle. The ovarian cycle can be divided into the follicular phase up until the secondary oocyte is released, i.e. ovulation. After ovulation, and the corpus luteum and corpus albicans forms, this is termed the luteal phase.


The fallopian tubes are open-ended tubes with finger-like projections called fimbrae. There are three layers; serosa, the outermost, muscularis, the central muscle layer and mucosa, the ciliated columnar cells, secretory cells and peg cells on the innermost surface. The way that an oocyte can move along the fallopian tube is by the beating of the cilia found on the epithelium and contraction of smooth muscle. Fertilisation normally occurs within 48 hours, although it may take many days for the oocyte to reach the uterus.

The uterus is much larger during pregnancy than it is normally. It is covered externally by the peritoneum, except for the lower anterior portion. Normally the uterus is anteverted or anteflexed. There are three layers to the uterus; the perimetric, an incomplete serosal layer, the myometrium, a thick muscular layer, and the endometrium, the inner glandular layer with a vast blood supply. The endometrium is composed of simple columnar epithelium, uterine glands and stroma (connective, structural tissue). The endometrium is also said to have to layers; the stratum functionalis (which is sloughed off during the menstrual cycle) and the stratum basalis (which is permanent).

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