Reproductive system part# 2 Flashcards
Oogenesis -
During fetal development, oogonia change into primary oocytes that enter prophase of meiosis I and stay there until puberty. Meiosis I is completed with ovulation each month to produce a seconday oocyte and a polar body. From puberty to menopause, the seconday oocyte enters meiosis II but is stopped at metapahse II. Meiosis II is completed only after fertilization to form the ovum and secondary polar body. 2 or 3 polar bodies result because the first polar body may or may not divide. Zona pellucidia - a special layer of glycoprotein that forms in between the primary oocyte and the granulosa cells. It is important to fertilazation. Corona radiata - the innermost layer of granulosa cells that is attached to the zona pellucida. Theca follicui - outer most layer that forms a “box” of connective tissue around the follicle.
Uterine tubes -
Uterine tubes - aka fallopian tubes, oviducts. They function to transport the fertilization ovum or a secondary oocyte. Infundibulum - the funnel - shaped portion of the tube that has finger like extensions called fimbriae. Fimbraie glide over the ovary to move the oocyte into the uterine tube because of the gap between the ovary and the uterine tube. Ampulla - the widest portion of the tube is just past the infundibulum. Isthmus of the uterine tube - narrow passage but thick walled, makes the tube continuous with the uterus. 3 layers of the uterine tube: 1. Mucosa - ciliated columnar epithelial cells plus nonciliated columnar epithelial cells with microvilli. 2. muscularis externa - an inner layer of circular smooth muscle and outer longitudinal muscle. 3. outer serousa - the peritoneum Note : that because of the gap between the ovary and the fimbraie of the uterine tube, sperm can enter the pelvic cavity.
Uterus -
Uterus subdivisions : Fundus - widest portion, that lies just above the uterine tubes. Body - central portion ( uterine cavity is the hallow portion0. Crivix - narrow projection that opens into the vagina. Isthmus of the uterus - the narrow region of the tissue between the body and the cervix. Cervical canal = the hallow portion of the cervix that starts with the internal os and ends with the external os. 3 Layers of the uterus : Perimetrium ( aka Epimetrium) - the outer layers derived from the vesceral peritoneum. Myometrium - middle layer contains layers of smooth muscle. Endometrium - innermost layer, simple ciliated columnar with secretory cells, has 2 sublayers - strantum functionalis (shed during menstration) and the stratum basalis ( dforms a new stratum functionalism). Cervical mucus - cells of the mucosa of the cervix secret water, glycoproteins, serum- type proteins, lipids,enzymes and inorganic salts.
Functions of cervical mucus -
supplements the nutrition for the sperm, reduces the acidity of the vigina by being alkaline, forms a plug during pregnancy, assits sperm in the movement toward the uterine tube and protects it from phagocytosis.
Vagina -
Functions as the organ of coupulation as well as the birth canal. Extends 4 inches from the cervix to the exterior, fornix is the recessed portion that surrounds the cervix, Epithelium is nonkeratinized stratified squamous epithelium and areolar connective tissue with rugae ( wrinkels). The muscularis and adventitia from the other layers. Hymen - a thin fold of very vascular mucosa that if present can partially cover the vaginal orifice.
Vulva - aka external genitalia
Mons pubis - an adipose padding that covers the pubic symphysis and is covered with hair after puberty. Labia Majora - larger, more external folds that are homologus to the scroyum. They have adipose, pubic hair, sebaceous and sweat glands. Labia minora - aka labia minus, smaller, more internal folds, no pubic hair or adipose, a few sweat glands and many sebaceous glands. Clitoris - where the anterior labia minora come together, homologus to the penis, also has a prepuce, a glans, and two corpus cavernosa. Vestobule - region between the two labia minora. it also contains the greater vestibular glands. The greater vestibular glands are homologous to the bulbourethral glands in function. These glands cleanse the area and provide lubrication for copulation.
Perineum -
diamond shaped region that is formed by the pubic symphysis, ischial tuberosities and the coccyx, divided into 2 triangular shaped regions : urogenital triangle and the anal triangle.
Mammary Glands -
Modified sudoriferious glands (sweat glands), lie over the serratus anterior and pectoralis major muscles, nipple, the external projection that the lactiferous ducts open into, areola - the pigmented portion surrounding the nipple. Each mammary gland is divided into 15 - 20 lobes that are further divided into 15 - 20 lobes and further divided into loubules which contain the alveoli. Alveoli - milk factories. The flow of milk is from the alveolus to lactiferous ducts to the lactiferous sinus to the nipple.
Female reproductive cycle -
Menarche - first menses, usually about 2 years after onset of puberty. Menopause - end of menses, functional follicles is reduced, ovaries become less sensitive to LH and FSH, so less estrogen is produced. Ovarian cycle - the maturation of the oocyte which occurs in the ovaries. Uterine cycle - the changes in the endometrium which occurs in the uterus. GnRH - gonadotropin-releasing hormone, just as we saw before, it stimulates the release of LH and FSH.
FSH and LH -
Fsh - follicle stimulating hormone, stimulates the growth of follicles and stimulates the release of estrogen by the follicle. LH - lutenizing Horne, stimulates further development of follicles. A dramatic increase in LH release causes ovulation, more estrogen release, and the formation of the corpus luteum. Corpus luteum - remnant that produces estrogen, progesterone,relaxin and inhibin. Estrogen - promote the development of female reproductive structures, secondary sex characteristics and breasts, increases protein anabolism,lower blood cholestrol and can inhibit GnRH,LH and FSH release. (note: very high levels of estrogen stimulate gnRH and Lh release). Progestrone - secreted by the corpus luteum. This secretion prepares the endometrium for implantation and prepares mammary glands, inhibits gnRH and LH release. Relaxin - inhibits the contractions of the uterus, the placenta secretes relaxin during pregnancy. Inhibin - secreted by the granular cells, inhibits FSH release.
Menstrual phase - aka menses, menstruation -
Days 1 - 5 , start of the cycle by convention, events in the ovaries: primary follicles start to enlarge from secondary follicles. In the uterus: menstrual flow, the stratum functionalis ( aka Functional layer) is shed. Hormones : the level of most hormones is low, a sharp decrease in progesterone and estrogen trigger menstruation. Proliferative phase (aka preovulatory/follicular) - Days 6 - 13 (most likely the phase to vary in length). Events in the ovaries : the slight increase in FSH that started the menstrual phase stimulates a single follicle to outgrow the others. In the uterus : formation of a new stratum functionalis and an increase in the number of blood vessels. Hormones : estrogen and inhibin levels increase and inhibit the release of FSH. When estrogen gets high enough it stimulates GnRH to release LH and FSH. Ovulation - Day 14, Lh surge from the previous phase results in the rupture of the follicle. Secretory phase (aks post ovulatory phase / luteal) - Days 15 -28 , after ovulation and before menses, Events in the ovaries : the corpus luteum develops due to the release of LH and the corpus luteum secretes progesterone, inhibin, and estrogen. If the oocyte is not fertilized - then the corpus luteum only lasts 2 weeks degenerating and reducing its secreations over time. In the uterus : increased thickening of the endometrium, more vascularization stimulated by the estrogen and progesterone produced. Cervical mucus thickens forming the cirvical plug. Hormones : progesterone is the predominant hormone. The combonation of estrogen and progesterone inhibt the release of LH and FSH.
