How many cavities are there in the ovary

If fertilization does not occur, the second meiotic division is never completed and the secondary oocyte degenerates. Here again there are obvious differences between the male and female. In spermatogenesis, four functional sperm develop from each primary spermatocyte.

In oogenesis, only one functional fertilizable cell develops from a primary oocyte. The other three cells are polar bodies and they degenerate. An ovarian follicle consists of a developing oocyte surrounded by one or more layers of cells called follicular cells. At the same time that the oocyte is progressing through meiosis, corresponding changes are taking place in the follicular cells. Primordial follicles, which consist of a primary oocyte surrounded by a single layer of flattened cells, develop in the fetus and are the stage that is present in the ovaries at birth and throughout childhood.

Beginning at puberty, follicle-stimulating hormone stimulates changes in the primordial follicles. The follicular cells become cuboidal, the primary oocyte enlarges, and it is now a primary follicle. The follicles continue to grow under the influence of follicle-stimulating hormone, and the follicular cells proliferate to form several layers of granulose cells around the primary oocyte. Most of these primary follicles degenerate along with the primary oocytes within them, but usually one continues to develop each month.

The granulosa cells start secreting estrogen and a cavity, or antrum , forms within the follicle. When the antrum starts to develop, the follicle becomes a secondary follicle. The granulose cells also secrete a glycoprotein substance that forms a clear membrane , the zona pellucida, around the oocyte.

After about 10 days of growth the follicle is a mature vesicular graafian follicle, which forms a "blister" on the surface of the ovary and contains a secondary oocyte ready for ovulation. Ovulation, prompted by luteinizing hormone from the anterior pituitary, occurs when the mature follicle at the surface of the ovary ruptures and releases the secondary oocyte into the peritoneal cavity.

The ovulated secondary oocyte, ready for fertilization is still surrounded by the zona pellucida and a few layers of cells called the corona radiata.

If it is not fertilized, the secondary oocyte degenerates in a couple of days. The ascending limb passes upward alongside the uterus and continues below the fallopian tube. Frequent anterior and posterior branches go to vagina, cervix, and uterus. Arterial blood supply of the normal tube, ovary, and uterus. Courtesy of Dr John A. From Norris: Gonorrhoea in Women. Philadelphia: Saunders. Ventral view of a deep dissection of the urinary bladder and the blood supply to the left side of the internal genitalia, showing the relation of the uterine vessels to the ureter.

Blood supply of the reproductive organs with relation to the ureter and trigone of the urinary bladder. The ovarian artery, which ordinarily arises from the aorta, passes along the ovary, dividing into a number of branches. At several places in the broad ligament there are anastomotic connections between the tubal branch of the uterine artery and the ovarian artery. A branch of the uterine artery nourishes the round ligament. The veins generally accompany the arteries.

Using injection and microradiographic and histologic techniques to study the vascular anatomy of the uterus, Farrer-Brown et al. In the broad ligament each uterine artery supplies lateral branches that immediately enter the uterus and give off tortuous anterior and posterior arcuate divisions, which run circumferentially in the myometrium approximately at the junction of its outer and middle thirds.

In the midline the terminal branches of both arcuate arteries anastomose with those of the contralateral side. Each arcuate artery throughout its course gives off numerous branches running both centrifugally towards the serosa and centripetally towards the endometrium. The arteries to the serosa at first are directed radially and then frequently became more circumferential. There is a plexus of small arterial radicals with a radial distribution located immediately below the serosa.

The inner two-thirds of the myometrium is supplied by tortuous radial branches of the arcuate arteries. They provide numerous branches terminating in a capillary network which surrounds groups of muscle fibers. An abrupt change in the density of the arterial pattern occurs at the junction of the basal layer of the endometrium with the subjacent myometrium.

The endometrial vessels are relatively sparse in comparison with those of the myometrium at all stages of the menstrual cycle. The uterus is partially supported by three pairs of ligaments. The paired round ligaments extend from the anterosuperior surface of the uterus through the internal inguinal rings and through the inguinal canals to end in the labia majors. They are composed of muscle fibers, connective tissue, blood vessels, nerves, and lymphatics.

The round ligaments stretch with relative ease, particularly in pregnancy. The uterosacral ligaments are condensations of endopelvic fascia that arise from the posterior wall of the uterus at the level of the internal cervical os. They fan out in the retroperitoneal layer and attach broadly at the second, third, and fourth segments of the sacrum. They are predominately composed of smooth muscle but also contain connective tissue, blood vessels, lymphatics, and parasympathetic nerve fibers.

The cardinal ligaments form the base of the broad ligament. They are composed of perivascular connective tissue and nerves that surround the uterine artery and veins. The cardinal and uterosacral ligament complex is collectively called the parametrium. The broad ligament is formed by folds of peritoneum covering the fallopian tubes, the infundibulopelvic vessels, and the hilus of the ovary.

It contains a number of structures: fallopian tube, round ligament, ovarian ligament, uterine and ovarian blood vessels, nerves, lymphatics, and mesonephric remnants. Below the infundibulopelvic structures, the anterior and posterior leaves of peritoneum lie in apposition, leaving a clear space below the tube with its tubal branch of the uterine artery. This avascular area is useful to the surgeon in isolating the adnexal structures and in avoiding blood vessels while performing tubal ligations.

The endometrium lines the uterine cavity and is considered to have three layers: the pars basalis, the zona spongiosa, and the superficial zona compacta. The straight branches of the radial arteries of the uterus terminate in capillaries in the basal layer, while the spiral or coiled branches penetrate to the surface epithelium, where they give rise to superficial capillaries. The endometrium varies greatly depending on the phase of the menstrual cycle.

Proliferation of the endometrium occurs under the influence of estrogen; maturation occurs under the influence of progesterone. The uterine endometrial cycle can be divided into three phases: the follicular or proliferative phase, the luteal or secretory phase, and the menstrual phase.

The follicular, or proliferative phase, spans from the end of the menstruation until ovulation. Increasing levels of estrogen induce proliferation of the functionalis from stem cells of the basalis, proliferation of endometrial glands, and proliferation of stromal connective tissue. Endometrial glands are elongated with narrow lumens and their epithelial cells contain some glycogen. Glycogen, however, is not secreted during the follicular phase.

Spiral arteries elongate and span the length of the endometrium. After formation of the corpus luteum, the endometrial glands grow, become tortuous, and secrete. The luteal, or secretory, phase begins at ovulation and lasts until the menstrual phase of the next cycle Fig. At the beginning of the luteal phase, progesterone induces the endometrial glands to secrete glycogen, mucus, and other substances.

These glands become tortuous and have large lumens due to increased secretory activity. The spiral arteries extend into the superficial layer of the endometrium. The spiral capillaries develop a terminal network of superficial capillaries.

These changes result in the formation of a predeciduum prepared for the arrival of the trophoblast. Luteal phase endometrium. In the absence of fertilization by day 23 of the menstrual cycle, the corpus luteum begins to degenerate and ovarian hormone levels decrease.

As estrogen and progesterone levels decrease, the endometrium undergoes involution. During days 25—26 of the menstrual cycle, endothelin and thromboxin begin to mediate vasoconstriction of the spiral arteries. The resulting ischemia may cause menstrual cramps. By day 28 of the menstrual cycle, intense vasoconstriction and subsequent ischemia cause mass apoptosis of the functionalis, with associated bleeding. The menstrual phase begins as the spiral arteries rupture secondary to ischemia, releasing blood into the uterus, and the apoptosed endometrium is sloughed off Fig.

During this period, the functionalis is completely shed. Arterial and venous blood, remnants of endometrial stroma and glands, leukocytes, and red blood cells are all present in the menstrual flow. Menstrual phase endometrium. Data on the lymphatic vessels of the uterus have been coordinated by Reynolds.

The lymphatic capillary bed is arranged in four zones: 1 the lower uterine segment with its rich supply of fine capillaries, 2 the subserosa of the corpus with a few lymphatics, 3 a deep subserosal network, and 4 a plentiful supply in the muscularis proper.

These vessels increase greatly in number and size during pregnancy. The collecting system of the uterine lymphatics is formed from anastomoses of a lateral-uterine descending network of lymph vessels which unites with collecting vessels from the utero-ovarian pedicle and the external iliac area. Lymphatic drainage of the uterus and upper two-thirds of the vagina is primarily to the obturator and internal and external iliac nodes. The fallopian tubes are bilateral muscular structures of paramesonephric duct origin.

They are from 7 to 12 cm in length and usually less than 1 cm in diameter. The tubes or oviducts have a lumen that varies considerably in diameter. It is extremely narrow, being less than 1 mm at its opening into the uterine cavity. It is wider in the isthmus Fig. The tube begins in the uterine cavity at the cornu and penetrates the myometrium intramural or interstitial portion.

The second portion is the relatively straight and narrow portion of the tube which emerges from the uterus posterior to and a little above the origin of the round ligament. The lumen of the narrow isthmus is relatively simple, with a few longitudinal folds. This portion of its tube is 2 or 3 cm long. There are three layers of musculature: the inner longitudinal, the middle circular layer, and the outer longitudinal layer.

There is some evidence that the isthmus may act as a sphincter. Photomicrograph showing the isthmic portion of the fallopian tube; it is in this portion of the tube that spasm may occur and close the lumen. The mucosa is lined by columnar epithelium which surrounds the lumen. The columnar cells have cilia.

The circular muscle layer is thickest at the isthmus and thinnest at the infundibulum. Photomicrograph low power of the ampullary portion of the fallopian tube. The mucosa forms folds which in transsection of the tube simulate glandular structures.

There are, however, no true secreting glands in the oviduct. The ampulla is the largest and longest portion of the tube, approximately 5 cm or more in length. The lumen enlarges from 1 or 2 mm near the isthmus to over a centimeter at the distal portion. The mucosa has multiple longitudinal folds. It lines the abdominal cavity and pelvis parietal peritoneum and covers the visceral organs visceral peritoneum , thereby allowing organs to move freely.

Cancer can begin in the peritoneum and then spread to the ovary. Figure 1. Reproductive System , Female, Anatomy.