Female Reproductive System



Female Reproductive System











Anatomy and Physiology


Internal Anatomy


Because the primary function of the female reproductive system is to create new life through the successful fertilization of an ovum, discussion of this system begins with this very important germ cell.




Ova and Ovaries


From menarche (meh NAR kee), the first menstrual period, to menopause (MEN oh poz), the cessation of menstruation, mature ova are produced by the female gonads, the ovaries (OH vuh reez) (Fig. 8-1). The ovaries are small, almond-shaped, paired organs located on either side of the uterus in the female pelvic cavity. They are attached to the uterus by the ovarian ligaments and lie close to the opening of the fallopian (fuh LOH pee un) tubes, the ducts that convey the ova from the ovaries to the uterus. Approximately every 28 days, in response to hormonal stimulation, the ovaries alternate releasing one ovum. This egg matures in one of the follicles (FALL ih kuls), which are tiny secretory sacs within an ovary. The pituitary (pih TOO ih tair ee) gland, an endocrine gland located in the cranial cavity, secretes two hormones that influence the activity of the ovaries. Follicle-stimulating hormone (FSH) causes the ovarian follicles to begin to mature and secrete estrogen. Because of the increase of estrogen in the bloodstream, luteinizing (LOO tin eye zing) hormone (LH) is released by the anterior lobe of the pituitary gland. LH then stimulates the follicle to mature and release its ovum (ovulation) and aids in the development of the corpus luteum (KORE pus LOO tee um). The corpus luteum is then responsible for secreting estrogen (ES troh jen) and progesterone (proh JES teh roan), hormones responsible for female secondary sex characteristics and the cyclical maintenance of the uterus for pregnancy.




If two eggs are released and fertilized, the resulting twins will be termed fraternal, because they will be no more or less alike in appearance than brothers (or sisters) occurring in sequential pregnancies. If, however, one of the fertilized eggs divides and forms two infants, these are identical twins, who share the same appearance and genetic material.



Fallopian Tubes


Once the mature ovum has been released, it is drawn into the fimbriae (FIM bree ee) (sing. fimbria), the feathery ends of the fallopian tube (see Fig. 8-1). These tubes, about the width of a pencil, and about as long (10 to 12 cm), transport the ovum to the uterus. The fallopian tubes (also called oviducts or uterine tubes) and the ovaries make up what is called the uterine adnexa (YOO tuh rin add NECKS ah), or accessory organs of the uterus.




Uterus


Once the ovum has traversed the fallopian tube, it is secreted into the uterus, or womb, a pear-shaped organ that is designed to nurture a developing embryo/fetus (see Fig. 8-1). The uterus is composed of three layers: the outer layer, called the perimetrium (pair ih MEE tree um), or serosa; the myometrium (mye oh MEE tree um), or muscle layer; and the endometrium (en doh MEE tree um), the lining of the uterus. As a whole, it can be divided into several areas. The body or corpus (which means body in Latin) is the large central area; the fundus (FUN dus) is the raised area at the top of the uterus between the outlets for the fallopian tubes; and the cervix (SUR vicks) is the narrowed lower area, often referred to as the neck of the uterus.









External Genitalia


The external female genitalia collectively are called the vulva (VUL vah) (Fig. 8-2). The vulva consists of the vaginal opening, or orifice (ORE ih fis); the membrane covering the opening, or hymen (HYE men); the two folds of skin surrounding the opening, or labia majora (LAY bee ah muh JOR ah) (the larger folds) and labia minora (LAY bee ah min NOR uh) (the smaller folds); the clitoris (KLIT uh ris), which is sensitive, erectile tissue; and the perineum (pair ih NEE um), the area between the opening of the vagina and the anus. The paired glands in the vulva that secrete a mucous lubricant for the vagina are the Bartholin (BAR toh lin) glands. The mons pubis (mons PYOO bis) is a fatty cushion of tissue over the pubic bone.








Pregnancy And Delivery


Pregnancy begins with the fertilization of an ovum by a spermatozoon, often in the fallopian tube, as the ovum travels toward the uterus. Conception is usually the result of sexual intercourse (also termed copulation or coitus). However, other methods of conception are possible if the couple has difficulty conceiving. These methods are discussed in the section on therapeutic interventions and may include artificial insemination and in vitro fertilization.



The fertilized egg, or zygote (ZYE gote), divides as it moves through the fallopian tube to the uterus, where it becomes implanted. From the third to the eighth week of life, it is called an embryo (EM bree oh). From the ninth through the thirty-eighth week of life (a normal length for gestation [jes TAY shun], or pregnancy), it is called a fetus (FEE tus). During implantation, the zygote functions as an endocrine gland by secreting human chorionic gonadotropin (hCG) (kore ee AH nick goh nad doh TROH pin). The function of the hormone is to prevent the corpus luteum from deteriorating, which allows the continued production of estrogen and progesterone to support the pregnancy and prevent menstruation.



At the same time that the embryo is developing, extraembryonic membranes are forming to sustain the pregnancy: Two of these, the amnion (AM nee on) and the chorion (KORE ee on), form the inner and outer sacs that contain the embryo (Fig. 8-4). The fluid that forms inside the amnion is the amniotic (am nee AH tick) fluid. It functions to cushion the embryo, protect it against temperature changes, and allow it to move. The placenta (plah SEN tah) is a highly vascular structure that acts as a physical communication between the mother and the embryo. The umbilical (um BILL ih kul) cord is the tissue that connects the embryo to the placenta (and hence to the mother). When the baby is delivered, the umbilical cord is cut, and the baby is then dependent on his/her own body for all physiologic processes. The remaining “scar” is the umbilicus (um BILL il kus), or navel. The delivery of an infant is termed parturition (par tur RIH shun).




A woman who is pregnant for the first time is a primigravida. If she has two or more pregnancies, she is referred to as a multigravida. If she has never been pregnant, she is a nulligravida.



A woman who has delivered her first baby is referred to as a primipara. If she delivers more than one baby, she is a multipara. A woman who has never delivered a child is referred to as a nullipara.



The abbreviation GPA is used in obstetric notation to indicate the number of pregnancies (G for gravida), the number of deliveries of a live or stillborn infant at more than 20 weeks of gestation (P for para), and the number of miscarriages/abortions that occur before 20 weeks of gestation (A for abortion). A woman described as G4P3A1 has had 4 pregnancies, 3 deliveries, and 1 abortion.



The terms antenatal and prenatal both mean “pertaining to before birth,” and postnatal means “Pertaining to after birth.” Antepartum means “before delivery,” and postpartum means “after delivery.” The puerperium is the approximate 6-week time period after childbirth.


Babies born before 37 weeks are referred to as premature infants. Those weighing less than 2500 g (5 lb, 8 oz) are referred to as low–birth-weight infants.


Each pregnancy is divided into three equal trimesters of 3 months each. The first trimester is week 1-14, the second trimester is week 15-28, and the third trimester is week 29 to the day of delivery.





image Exercise 5 Pregnancy


Label the drawing with the correct anatomic terms and combining forms where appropriate.


image


The following word part tables can be used as a reference and a review of the anatomy and physiology word parts you’ve learned for the female reproductive system.






Pathology







image Exercise 6 Ovarian and Fallopian Tube Disorders


Fill in the blanks with the terms provided.


polycystic ovary syndrome, adhesions, hematosalpinx, salpingitis, hydrosalpinx, pyosalpinx



Decode the terms.



Oct 6, 2017 | Posted by in GENERAL SURGERY | Comments Off on Female Reproductive System
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