What is the difference between ovary and womb

The point where the labia minora attach to the clitoris is called the frenulum clitoridis. A prepuce, the clitoral hood, normally covers and protects the clitoris; however, in women with particularly large clitorises or small prepuces, the clitoris may be partially or wholly exposed.

The clitoral hood is the female equivalent of the male foreskin and may be partially hidden inside of the pudendal cleft. The area between the labia minora is called the vulval vestibule, and it contains the vaginal and urethral openings. The urethral opening meatus is located below the clitoris and just in front of the vagina. This is where urine passes from the urinary bladder. The opening of the vagina is located at the bottom of the vulval vestibule toward the perineum.

The introitus is sometimes partly covered by a membrane called the hymen. The hymen will rupture during the first episode of vigorous sex, and the blood produced by this rupture has been traditionally seen as a sign of virginity.

However, the hymen may also rupture spontaneously during exercise or be stretched by normal activities such as use of tampons. Slightly below and to the left and right of the vaginal opening are two Bartholin glands which produce a waxy, pheromone-containing substance, the purpose of which is not yet fully known.

The perineum is the region between the genitals and the anus, including the perineal body and surrounding structures. In human anatomy, the perineum is the surface region between the pubic symphysis and coccyx in both males and females, including the perineal body and surrounding structures.

The boundaries vary in classification but generally include the genitals and anus. It is an erogenous zone for both males and females. Perineum Illustration : Illustrated drawing of the muscles of the female perineum. The term perineum may refer to only the superficial structures in this region or be used to include both superficial and deep structures.

The term lower rabbus is used colloquially in the UK to describe this structure. Perineal tears and episiotomy often occur in childbirth with first-time deliveries, but the risk of these injuries can be reduced by preparing the perineum through massage. The perineum includes two distinct regions separated by the pelvic diaphragm. Its structures include:. The basic components of a mature mammary gland are the alveoli, hollow cavities, a few millimeters large lined with milk-secreting cuboidal cells and surrounded by myoepithelial cells.

These alveoli join to form groups known as lobules, and each lobule has a lactiferous duct that drains into openings in the nipple. The myoepithelial cells can contract under the stimulation of oxytocin, excreting milk secreted from alveolar units into the lobule lumen toward the nipple where it collects in sinuses of the ducts. Mammary Gland : Cross-section of the mammary-gland. Chest wall 2. Pectoralis muscles 3. Lobules 4. Nipple 5. Areola 6. Milk duct 7. Fatty tissue 8. Skin EndFragment.

All the milk-secreting tissue leading to a single lactiferous duct is called a simple mammary gland; a complex mammary gland is all the simple mammary glands serving one nipple. Humans normally have two complex mammary glands, one in each breast, and each complex mammary gland consists of 10—20 simple glands. The presence of more than two nipples is known as polythelia, and the presence of more than two complex mammary glands as polymastia. Mammary glands develop during different growth cycles.

They exist in both sexes during the embryonic stage, forming only a rudimentary duct tree at birth. In this stage, mammary gland development depends on systemic and maternal hormones, but is also under the local regulation of paracrine communication between neighboring epithelial and mesenchymal cells by parathyroid hormone-related protein. This locally-secreted factor gives rise to a series of outside-in and inside-out positive feedback between these two types of cells, so that mammary bud epithelial cells can proliferate and sprout down into the mesenchymal layer until they reach the fat pad to begin the first round of branching.

Lactiferous duct development occurs in females in response to circulating hormones, first during pre- and postnatal stages and later during puberty. Estrogen promotes branching differentiation, which is inhibited by testosterone in males. A mature duct tree reaching the limit of the fat pad of the mammary gland is formed by bifurcation of duct terminal end buds, secondary branches sprouting from primary ducts and proper duct lumen formation.

Secretory alveoli develop mainly in pregnancy, when rising levels of prolactin, estrogen, and progesterone cause further branching, together with an increase in adipose tissue and a richer blood flow. In gestation, serum progesterone remains at a high concentration so signaling through its receptor is continuously activated.

As one of the transcribed genes, Wnts secreted from mammary epithelial cells act paracrinely to induce branching of neighboring cells. When the lactiferous duct tree is almost ready, alveoli are differentiated from luminal epithelial cells and added at the end of each branch.

In late pregnancy and for the first few days after giving birth, colostrum is secreted. Milk secretion lactation begins a few days after birth, caused by reduction in circulating progesterone and the presence of prolactin, which mediates further alveologenesis and milk protein production and regulates osmotic balance and tight junction function.

The binding of laminin and collagen in the myoepithelial basement membrane with beta-1 integrin on the epithelial surface insures correct placement of prolactin receptors on basal lateral side of alveoli cells and directional secretion of milk into lactiferous ducts. Suckling of the baby causes release of hormone oxytocin which stimulates contraction of the myoepithelial cells.

With combined control from the extracellular matrix ECM and systemic hormones, milk secretion can be reciprocally amplified to provide enough nutrition for the baby. During weaning, decreased prolactin, lack of mechanical stimulation through suckling, and changes in osmotic balance caused by milk stasis and leaking of tight junctions cause cessation of milk production. In some species there is complete or partial involution of alveolar structures after weaning; however, in humans there is only partial involution, which widely varies among individuals.

Shrinkage of the mammary duct tree and ECM remodeling by various proteinase is under the control of somatostatin and other growth-inhibiting hormones and local factors. This structure change leads loose fat tissue to fill the empty space.

However, a functional lactiferous duct tree can be reformed when a female is pregnant again. Privacy Policy. Skip to main content. The Reproductive System. Search for:. The Female Reproductive System. Learning Objectives Outline the anatomy of the female reproductive system from external to internal. The female reproductive system contains two main parts: the uterus, which hosts the developing fetus, produces vaginal and uterine secretions, and passes the anatomically male sperm through to the fallopian tubes; and the ovaries, which produce the anatomically female egg cells.

Key Terms ovary : A female reproductive organ, often paired, that produces ova and in mammals secretes the hormones estrogen and progesterone. Ovaries The ovaries are the ovum-producing organs of the internal female reproductive system. Learning Objectives Describe the location and function of the ovaries. Key Takeaways Key Points In addition to producing ova, the ovaries are endocrine organs and produce hormones that act during the female menstrual cycle and pregnancy.

Ovaries secrete estrogen and progesterone. Each ovary is located in the lateral wall of the pelvis in a region called the ovarian fossa.

The ovaries are attached to the uterus via the ovarian ligament which runs in the broad ligament. Usually, the ovaries take turns releasing eggs every month; however, if one ovary is absent or dysfunctional then the other ovary releases eggs every month.

Key Terms intraperitoneal : Located within the inner layer of the peritoneum serous membrane that forms the lining of the abdominal cavity. Uterus The uterus is the largest and major organ of the female reproductive tract that is the site of fetal growth and is hormonally responsive.

Learning Objectives Describe the structure and function of the uterus. Key Takeaways Key Points The body of the uterus is connected to the ovaries via the fallopian tubes, and opens into the vagina via the cervix. Key Terms linea terminalis : Part of the pelvic brim, which is the edge of the pelvic inlet. Female Duct System The Fallopian tubes, or oviducts, connect the ovaries to the uterus. Learning Objectives Describe the structures of the female duct system.

The lining of the Fallopian tubes are ciliated and have several segments, including the infundibulum, ampullary, isthmus, and interstitial regions. Interspersed between the ciliated cells are peg cells, which contain apical granules and produce the tubular fluid that contains nutrients for spermatozoa, oocytes, and zygotes. Key Terms oviduct : A duct through which an ovum passes from an ovary to the uterus or to the exterior.

They are held in place by ligaments attached to the uterus. The ovaries have three functions. First, they shelter and protect the eggs a female is born with until they are ready for use. It is thought that women are born with their lifetime supply of eggs, but a study by the University of Edinburgh's School of Biological Sciences found that chemotherapy might spark the development of new eggs.

Second, ovaries produce female reproductive hormones called estrogen and progesterone, and some lesser hormones called relaxin and inhibin.

There are three different types of estrogen: estrone, estradiol and estriol. They are used by the body to help develop adult female characteristics, such as breasts and larger hips, and to aid in the reproduction cycle. Progesterone is also key to reproduction more on that later. Relaxin loosens the pelvic ligaments so they can stretch during labor.

Inhibin prevents the pituitary gland from producing hormones. Third, ovaries release one egg, or sometimes more, each menstrual cycle. This process is called ovulation. Inside each ovary, there are follicles and inside of each follicle is a dormant egg. When a female is born, she has around , to , follicles in her ovaries. By the time she is sexually mature, the female will have around 34, follicles, according to the Encyclopedia Britannica.

When a particular egg is stimulated to maturity by hormones released from the pituitary gland, the follicle migrates to the ovary wall. Cancer Grand Challenges. Research Program Contacts. Funding Strategy. Grants Policies and Process. Introduction to Grants Process. NCI Grant Policies. Legal Requirements. Step 3: Peer Review and Funding Outcomes.

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