Anatomy - Female reproductive system

Female Reproductive System • The female reproductive system is composed of the ovaries, genital ducts, external genitalia, and mammary glands. • Female reproductive system functions are under the control of a complex interplay of hormonal, neural, and psychological factors. Female Reproductive System • Primary female reproductive organ is the ovary. • Small, almond-shaped organs found in the abdominal cavity attached to the uterus by the ovarian ligament and cradled by the fallopian or uterine tube. Ovary • Ovary is surrounded by a tough capsule called the tunica albuginea (note that this is the same name as layer over testis) • The outer layer of the capsule is a single layer of germinal epithelium. • Outer portion of ovary proper is the cortex and the inner region is the medulla. Ovary • The outer cortex houses the female germ cells the oogonia which have undergone cells division to form numerous oocytes. • Before birth, oogonia are formed and remain as diploid cells until puberty. • Thereafter, during each menstrual cycle, several of these begin development usually with a single mature follicle formed. Ovary • Each oocyte is surrounded by a single layer of epithelia cells and this forms an ovarian follicle. These are referred to as primodial follicles • Under stimulation of follicle stimulating hormone (FSH), follicles enlarge and become encapsulated by connective tissue called the stroma. Ovary • The primodial follicle (surrounded by a single layer of epithelial cells) enlarges and gives rise to the unilaminar primary follicle (larger in size, one layer of cuboidal epithelial cells) • Multilaminar primary follicles become surrounded with multiple layers of epithelial cells. Ovary • It is difficult to determine when a follicle ceases to be a multilaminar primary follicle and a growing follicle. • During this process, a membrane the zona pellucida forms. This stains brilliantly with the periodic acid-Schiff (PAS) stain and distinctly with eosin stain. • Follicle enlarges and is called growing follicle. Ovary • Soon it is referred to as a secondary follicle. • There is now a distinct corona radiata (ring of cells just outside the zona pelucida), several layers of granulosa cells and a theca interna outside the granulosa cells. • As this continues to enlarge, the oocyte is located toward one side and a large space called the Antrum forms. It is filled with fluid. Ovary • Usually only a few follicles reach this stage and most of them regress. Usually only one reaches the stage of being a mature follicle. • During ovulation, the follicle will fuse with the wall of the ovary and release the ovum from the ovary. • After this, the follicle will develop into the corpus luteum (yellow body) and release hormones that will maintain the uterus. Ovary • After the ovum is ovulated, the corpus luteum continues to grow and secretes estrogen and progesterone which maintains the buildup of the endometrium. • If the ovum is not fertilized, the corpus luteum regresses. It ceases to secrete hormones and the endometrium is sloughed off. • Corpus luteum forms the corpus albicans. Ovulation Ovary cortex with many primordial follicles. To the bottom of the slide is the tissue capsule, the tunica albuginea. Ovary http://www.siumed.edu/~dking2/erg/RE007b.htm Blue arrow = primodial follicle Red arrow = primary follicle 1= primodial follicles 2= primary oocyte 3=nucleus of oocyte 4= zona pellcida 5= Corpora radiata 6= Zona granulosa 7= Follicular spac 8= Theca interna 9= theca externa 10= Stroma 11= germinal epithelium Graafian follicle with large atrium and the corona radiata that Surrounds the oocyte and extends into the antrum. Large ruptured follicle just after ovulation. The letter a represents the granulosa cells that will give rise to corpus luteum. Letter b is corpus albicans. Corpus albicans Fallopian Tube or Uterine Tube • Sometimes simply called oviduct • Extend from the ovary to the uterus • Modified end near ovary has ciliated fingerlike projections known as the fimbriae. • Functions to capture and transport oocyte to the uterus. • Has secretory “non-ciliated “peg” cells that provide nutrients for oocyte • Functions as usual site of conception. Oviduct also called fallopian tube or uterine tube http://www.bio.calpoly.edu/BioSci/C ourses/ReproHisto/13.htm Ampulla section of oviduct. Mucosal folds project into lumen. Mu = mucosa L = Lumen M = muscularis Ampulla is near middle of its length Ciliated epithelium of fimbriae with arrows at non-ciliated “peg”cells That are secretory. Uterus • About size of Bartlett pear in non-pregnant female • Three major components include the muscular wall the myometrium, epithelial lining the endometrium, and opening the cervix. • The endometrium undergoes drastic changes during the monthly menstral cycle. Uterus • Phases of the menstrual cycle • Proliferate (follicular) phase is characterized by rapid growth and development of the endometrium. • Starts at end of menstrual flow • Mitotic activity produces abundance of uterine glands and epithelial cells. • Associated with production of estrogen from developing follicle Uterus • Second phase is the secretory (luteal) phase. • Occurs shortly after ovulation and is result of increased secretion of estrogen and progesterone from corpus luteum. • Endometrium thickens and there is accumulation of glycogen rich secretions. • Abundant infiltration of blood vessels • Glands enlarge and coil throughout area. • Preparing a nice bed for a fertilized egg. Uterus • Third phase is the Menstrual phase. • This occurs if there is no fertilized egg. • Developing embryo secretes human chorionic gonadotropin (HCG) hormone which maintains the corpus luteum. If the egg is not fertilized, this hormone is not produced. • In its absence, corpus luteum deteriorates and ceases to produce estrogen. • Result is the breakdown of endometrium Uterus – Proliferative stage Uterus – secretory phase Uterus – later secretory phase The placenta is composed of both maternally and fetally derived tissues. There is no mixing of maternal and fetal blood. Maternal portion of placenta is the dedicua basalis and fetal portion is the chorionic plate and its extensions. Anchoring villi anchor to the decidua basilis.