Ovary – Female Reproductive System
The biological system made up of all the anatomical organs involved in sexual reproduction is known as an organism’s reproductive system, also referred to as the genital system. Numerous inanimate materials, including fluids, hormones, and pheromones, are crucial reproductive system add-ons. The sexes of distinct species frequently differ significantly from one another, unlike other organ systems. Due to these variations, two people’s genetic makeup can be combined, potentially resulting in kids with higher genetic fitness.
The female reproductive organ known as the ovary houses an egg known as an ovum. After being discharged, this continues its journey through the fallopian tube and enters the uterus, where sperm may fertilize it. An ovary is located on either side of the body. The ovaries also release hormones that are important for fertilization and the menstrual cycle. Beginning in the prenatal phase and continuing into menopause, the ovary goes through a number of stages. It is frequently categorized as an endocrine gland because of the hormones it metabolizes.
The term “ovaries” refers to the female gonads. The ovarian fossa, which runs parallel to the uterus’ lateral wall, is where each ovary can be found. The area in front of the ureter and internal iliac artery, which is encircled by the external iliac artery, appears to be the ovarian fossa. This area is roughly 4 cm by 3 cm by 2 cm in size. The outer cortex and inner medulla of the ovaries, which are enclosed by a capsule, are seen in the anatomy of the ovary. A capsule called the tunica albuginea is constructed of thick connective tissue.
Each menstrual cycle, one of the two ovaries experiences ovulation, which results in the release of an egg.
The portion of the ovary closest to the fallopian tube is connected to the tube by the infundibulopelvic ligament, while the portion on the other side is joined to the uterus by the ovarian ligament. One of the additional tissues and structures of the ovaries is the hilum.
Structure of Ovary in Human
- Ligaments: The ovary’s slice reveals that the ovaries are joined by a fibrous ligament known as the ovarian ligament and are situated on either side of the uterus inside the peritoneal cavity. The ovary suspensory ligament, which seems to be a posterior extension of the uterus’ broad ligament, attaches the exposed ovaries to the body wall despite the fact that they are located in the peritoneal cavity. The part of the uterus’ thick ligament that covers the ovary is called the mesovarium. The ovarian pedicle is made up of fragments of the ovarian ligament, mesovarium, and blood vessels.
- Microanatomy: Simple cuboidal-to-columnar-shaped mesothelium makes up the membrane that covers the top of the ovaries, known as the germinal epithelium. The ovary’s internal architecture. Claims that the ovarian cortex is the outer layer, with the stroma in between the ovarian follicles. The follicles contain the cumulus oophorus, membrana granulosa (and its granulosa cells), zona pellucida, corona radiata, and primary oocyte. Theca of follicle, antrum, and liquid folliculin is frequently found in the follicle. The inner lining is called the ovarian medulla. Although it might be challenging to tell the cortex from the medulla, follicles are almost never found there. The ovary’s surface epithelium gives birth to follicular cells, which are flat epithelial cells. They are surrounded by granulosa cells, which have changed from flat to cuboidal and multiply to form a stratified epithelium. The ovary has lymphatic and blood arteries as well.
A child’s ovary starts to secrete more hormones when they approach puberty. The hormones cause secondary sex characteristics to manifest. The structure and function of the ovary alter beginning during puberty. The ovaries are important for fertility and pregnancy because they have the capacity to regulate hormones. Once egg cells (oocytes) are removed from the Fallopian tube, several feedback mechanisms activate the endocrine system, causing hormone levels to change. These feedback systems are under the direction of the hypothalamus and pituitary gland. The pituitary gland receives information from the hypothalamus.
In addition, the pituitary gland distributes hormones into the ovaries. In response to this signaling, the ovaries release their own hormones.
- Gamete Production: The ovaries are the site of the regular production and release of female gametes, also known as egg cells. The ovarian follicles, which are filled with fluid, are where the immature egg cells, also known as oocytes, mature. In the majority of cases, only one oocyte matures at a time, however, it is possible for others to mature concurrently. According to their stage of development, follicles include different kinds and numbers of cells, and the size of a follicle corresponds to the stage of oocyte growth. The pituitary gland releases luteinizing hormone when the oocyte has finished maturing in the ovary, which triggers the release of the egg by follicular rupture, or ovulation.
- Hormone Secretion: The mature ovaries secrete the hormones estrogen, inhibin, androgen, and progestogen. Up until menopause, 50% of a woman’s testosterone is found in the ovaries; beyond that, it is directly discharged into the circulation. DHEA and androstenedione, which are adrenal pre-androgens, are converted by other parts of the body into testosterone to make up the remaining 50% of testosterone in the blood. During puberty, estrogen plays a role in the development of secondary sex traits in females as well as the maturity and maintenance of fully developed reproductive organs.
- Ovarian Aging: As a woman matures, her ability to reproduce lessens, resulting in menopause. This drop is associated with a decrease in the number of ovarian follicles. At birth, the human ovary contains roughly 1 million oocytes, but only 500 (or about 0.05 percent) of these ovulate, with the rest being destroyed. As women get older, their ovarian reserves tend to decline at a constant rate, approaching total depletion around age 52. Age-related declines in ovarian reserve and fertility are accompanied by an increase in pregnancy failure and meiotic mistakes, which lead to chromosomally abnormal pregnancies. Ovarian reserve and fertility peak between the ages of 20 and 30. Around the age of 45, the menstrual cycle begins to change, and the follicular pool tends to significantly decrease. We don’t know what causes ovarian aging. Aging variability is influenced by environmental circumstances, dietary habits, and genetic factors.
A woman’s menstrual cycle typically lasts around 28 days, though this varies widely from woman to woman. When the endometrial lining sheds, the first day of the menstrual cycle is regarded as the first day of menstruation.
Every woman’s monthly cycle has specific times when significant things take place, making her fertile and may be able to produce a kid. The cycle begins with the follicular phase, which is followed by ovulation. The luteal phase continues for the remainder of the period till the cycle restarts.
Each of these procedures is triggered by hormones produced by the anterior lobe of the pituitary gland under the direction of the hypothalamus. Two particularly significant hormones for the menstrual cycle are luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
- The follicular phase sometimes referred to as the proliferative phase, lasts from the start of menstruation through ovulation and is the time when the follicles in the ovaries mature.
- Both cumulus oophorous granulosa cells and corona radiate must assist the egg for ovulation to occur successfully. These cells multiply and become mucous during cumulus expansion, secreting a fluid rich in hyaluronic acid. It has been demonstrated that this material must combine with the cell network to create a sticky matrix surrounding the egg in order for fertilization to occur.
- Additionally, there are more cumulus cells, which results in more antrum fluid being produced. As a result, the follicle enlarges to a diameter of over 20 millimetres (mm), generating the blister, a protrusion at the surface of the ovary.
- Estrogen levels peak near the conclusion of this period, which triggers the hormonal shifts required to start ovulation.
- The pituitary gland releases an abrupt increase in LH and FSH hormones as a result of the estrogen peak.
- Before the follicle bursts and releases the egg from the ovary through the oviduct, this normally lasts for 1 to 2 days. Due to LH, which makes the follicle secrete proteolytic enzymes that weaken the tissue surrounding the follicle’s blister and finally form a hole known as the stigma, the egg is released.
- The cumulus-oocyte complex, which is the name given to the egg encircled by cumulus cells, then goes into the peritoneal cavity and attaches to the fimbriae at the end of the fallopian tube. The egg gently moves towards the uterus while being propelled along the tube by cilia.
- The egg goes through meiosis I at the same time to split into two distinct cells: a polar body that is dormant and one that contains the cytoplasm.
- The egg then enters Meiosis II, although it does not finish since it continues in the metaphase until fertilization. The egg will deteriorate if it is not fertilized within 24 hours. The endometrial glands are still non-secretory, and the functional, uterine mucous membrane, has reached its maximal size at this time.
- The follicle reaches the end of its life during this phase. The follicle collapses in on itself without the egg to create the corpus luteum, which can secrete the hormones progesterone and estrogen.
- These hormones cause the endometrial glands to produce proliferative endometrium, which is where the embryo will develop if implantation does place.
- Because progesterone is present, the basal body temperature slightly rises. The paracrine function of the corpus luteum keeps the endometrium healthy for the rest of the menstrual cycle.
- When the endometrium breaks down into scar tissue and menstruation starts, the cycle is over and the follicular phase officially begins.
FAQs on Female Reproductive System
Question 1: How Can Your Ovaries Be Affected by Certain Factors?
The following list includes the elements that can affect your ovaries:-
- Ovulation abnormalities are issues with the ovaries’ ability to release eggs.
- Uterine or cervical malformations, as well as fibroids or polyps in the uterus.
- Damage to or obstruction of the fallopian tube, which is frequently brought on by inflammatory pelvic illness.
Question 2: What is the cervix?
The cervix is the lower, more restricted, and bifurcated section of the uterus. The lower vaginal portion projects into the anterior wall of the vagina, while the upper supravaginal portion interacts with the uterus’s body. The birth canal is made by the vagina and the cervical canal.
Question 3: What are the uterus’ three layers?
The uterus’s outer, serous layer, which develops from the peritoneum, is covered by this layer. The middle muscular layer, or myometrium, follows. It is formed of smooth muscle fibres and is the thickest layer. The endometrium or inner mucus layer, a glandular layer, is the third layer.
Question 4: What are the ovary’s purposes?
Endocrine and gametogenic functions are both carried out by female ovaries. The release of female sex hormones including oestrogen and progesterone is an endocrine function. The development and release of the egg or ovum for reproduction is the gametogenic function.
Question 5: What is an Ovary?
One of two female glands that produce the feminine hormones progesterone and oestrogen as well as the eggs. These hormones are crucial for the development of the breasts, body form, and body hair in women.
Question 6: What is secreted by the corpus luteum?
Progesterone is the main hormone secreted by the corpus luteum, however it also makes inhibin A and estradiol. The corpus luteum will eventually regress in the absence of fertilisation.
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