Biology · Ch 2 — Human Reproduction
The Female Reproductive System
The Female Reproductive System
The female reproductive system consists of a pair of primary sex organs, the ovaries, together with the fallopian tubes, uterus, cervix and vagina, and the external genitalia (vulva). The ovaries are a pair of solid, almond-shaped organs, each about 2–4 cm long, situated in the pelvic cavity, one on each side of the uterus, and held loosely in position by ligaments (including the ovarian ligament, attaching each ovary to the uterus). Each ovary is covered by a thin epithelial layer, beneath which lie two ill-defined regions: an outer cortex, which contains the ovarian follicles at their various stages of development (described in section 2.5), and an inner medulla, made of looser connective tissue carrying blood vessels, lymphatics and nerves. The ovaries serve a dual role, comparable to the testis in the male: they produce the female gamete (the ovum) and they secrete the female sex hormones oestrogen and progesterone.
Close to, but not directly attached to, each ovary lies the opening of a fallopian tube (oviduct), a muscular, ciliated tube about 10–12 cm long that extends from near the ovary to the uterus and is conventionally divided into three parts. Nearest the ovary, the tube widens into a funnel-shaped infundibulum, whose rim carries finger-like projections called fimbriae; at the time of ovulation, the fimbriae move to sweep the released egg into the tube. The infundibulum leads into a wider middle segment, the ampulla, which is the normal site of fertilisation, and this in turn narrows into a shorter, thicker-walled isthmus that joins the uterus. Both muscular contraction of the tube wall and the beating of cilia lining its inner surface help move the egg (or, after fertilisation, the developing embryo) toward the uterus. …
What this figure shows. A frontal-view diagram of the human female internal reproductive organs showing a pair of almond-shaped ovaries positioned on either side of the uterus in the pelvic cavity, each held in place by ligaments. From each ovary, a fallopian tube (oviduct) is shown curving toward the midline: its funnel-shaped, finger-fringed opening near the ovary (the infundibulum, with its fimbriae) leads into a wider ampulla, which narrows into a shorter isthmus that opens directly into the uterus. The uterus itself is shown as a single, inverted-pear-shaped, thick-walled, muscular organ in the midline, with the two fallopian tubes entering its upper corners; its wall is drawn with three layers labelled — an outer serous perimetrium, a thick middle muscular myometrium, and an inner glandular endometrium that lines the uterine cavity and changes thickness across the menstrual cycle. The lower, narrow neck of the uterus, the cervix, is shown opening into the vagi …