What is the difference between ovary and uterus

Teixeira, J. Uterus is pear-shaped hollow muscular organ located at the top of the vagina. It is held by broad, round, uterosacral ligaments in the pelvis and is not attached to any part of the skeleton.

It provides a site for menstruation , implantation of a fertilized ovum, development of the fetus during pregnancy, and labor. The uterine wall is relatively thick and has three layers;. Endometrium makes the major portion of the uterus and is composed of smooth muscles. 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.

Here, the egg and the follicle grow and mature. When mature, they are ready for ovulation. 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. Vagina The vagina is the female reproductive tract and has two primary functions: sexual intercourse and childbirth.

Learning Objectives Describe the vagina and its functions. Key Takeaways Key Points The vagina is situated between the cervix of the uterus and the external genitalia, primarily the vulva. Although there is wide anatomical variation, the length of the unaroused vagina of a woman of child-bearing age is approximately 6 to 7. During sexual arousal the vagina expands in both length and width. The uterus, also known as the womb, is a hollow, muscular, pear-shaped organ found in the pelvic region of the abdominopelvic cavity.

It is located posterior to the urinary bladder and is connected via the cervix to the vagina on its inferior border and the fallopian tubes along its superior end. Many smooth muscle cells in the walls of the uterus provide it with great extensibility and contractile strength. During pregnancy, the tiny embryo implants itself into the tissues of the endometrium and begins to grow inside of the uterine lining.

Tissue from the embryo begins to merge with the tissues of the uterus to form the placenta and umbilical cord that allow for the exchange of respiratory gases, nutrients, and wastes between the mother and the developing embryo.