Female Reproductive System in Humans
Female Reproductive System:
Components: Ovaries, oviducts (fallopian tubes), uterus, cervix, vagina, external genitalia (mons pubis, labia majora, labia minora, hymen, clitoris), and mammary glands.
· Ovaries: Primary female sex organs that produce ova (eggs) and ovarian hormones. Located on each side of the lower abdomen, connected to the pelvic wall and uterus by ligaments.
· Oviducts (Fallopian Tubes): Extend from the periphery of each ovary to the uterus. Consists of infundibulum (funnel-shaped part with fimbriae), ampulla (wider part), and isthmus (narrow part connecting to the uterus).
1. Infundibulum: The infundibulum is the funnel-shaped, outermost part of each oviduct. It is located near the ovary and has finger-like projections called fimbriae. The fimbriae sweep over the surface of the ovary, helping to capture the released egg (ovum) during ovulation. The fimbriae guide the egg into the oviduct.
2. Ampulla: The ampulla is the wider, middle part of the oviduct. It provides an environment conducive to fertilization. The ampulla is the typical site where fertilization occurs when sperm meets the egg. The fertilized egg, now called a zygote, begins its journey toward the uterus from the ampulla.
3. Isthmus: The isthmus is the narrowest part of the oviduct, located closer to the uterus. It connects the ampulla to the uterine cavity. The isthmus is responsible for transporting the fertilized egg from the oviducts to the uterus.
· Uterus (Womb): Single, inverted pear-shaped organ supported by ligaments attached to the pelvic wall. Opens into the vagina through the cervix. Consists of the perimetrium (external layer), myometrium (thick smooth muscle layer), and endometrium (the glandular inner layer that undergoes cyclical changes during the menstrual cycle).
Structure: The uterus is supported by several ligaments that attach it to the pelvic wall. These ligaments help keep the uterus in its proper position within the pelvis.
· Cervix: The cervix is the lower narrow part of the uterus that connects it to the vagina. It acts as a passageway between the uterus and the outside of the body. During childbirth, the cervix dilates to allow the passage of the baby.
Layers of the Uterus:
- Perimetrium: The perimetrium is the outermost layer of the uterus. It is a thin serous membrane that covers the surface of the uterus, providing protection and support.
- Myometrium: The myometrium is the middle and thickest layer of the uterus. It is composed of smooth muscle tissue. The myometrium plays a crucial role during labor by contracting forcefully to facilitate the expulsion of the fetus. It also contracts during menstruation to shed the inner lining of the uterus.
- Endometrium: The endometrium is the innermost layer of the uterus. It is a highly glandular and vascularized tissue that undergoes cyclical changes throughout the menstrual cycle. The endometrium thickens and prepares itself to receive a fertilized egg (embryo) during the early stages of the menstrual cycle. If pregnancy does not occur, the endometrium is shed during menstruation.
· Vagina: The birth canal, extends from the cervix to the external opening. Connected to the uterus.
· External Genitalia: Includes mons pubis (fatty tissue covered by skin and pubic hair), labia majora (fleshy folds surrounding the vaginal opening), labia minora (inner folds under the labia majora), hymen (partially covers the vaginal opening), and clitoris (sensitive structure at the upper junction of labia minora).
· Hymen: The membrane covering the vaginal opening can be torn by various activities, but its presence or absence is not a reliable indicator of virginity or sexual experience.
Diagrammatic representation of female external genitalia
· Mammary Glands:
- Mammary Glands: The mammary glands, commonly referred to as breasts, are paired structures located on the anterior chest wall of females. They consist of glandular tissue, adipose (fat) tissue, and a network of ducts.
- Mammary Lobes: Within each breast, the glandular tissue is divided into smaller units called mammary lobes. These lobes are separated by adipose tissue. Each lobe contains clusters of milk-secreting cells called alveoli.
- Alveoli and Lumens: Alveoli are small, hollow sacs within the mammary lobes. They are responsible for producing milk. The alveoli are lined with specialized cells that synthesize and secrete milk components. The secreted milk collects in the cavities or lumens within the alveoli.
- Mammary Tubules: The alveoli open into tiny ducts called mammary tubules. These tubules serve to transport milk from the alveoli to the larger ducts.
- Mammary Ducts: Mammary tubules join together to form larger ducts, known as mammary ducts. These ducts act as conduits for the milk, carrying it towards the nipple. The ducts are interconnected within the breast tissue.
- Mammary Ampulla: Several mammary ducts join together to form a wider structure called the mammary ampulla. The ampulla acts as a reservoir for storing milk before it is released.
- Lactiferous Ducts: The mammary ampulla is connected to lactiferous ducts. These ducts carry the milk towards the nipple, where it can be released during breastfeeding.
- The structure of the mammary glands is designed to produce, store, and transport milk. During pregnancy, hormonal changes prepare the mammary glands for milk production. After childbirth, the suckling stimulus from the baby triggers the release of hormones, leading to the contraction of the mammary ducts and the release of milk from the nipple.