Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Chapter 35: Female Reproductive System Anatomy & Physiology

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Overview of the Female Reproductive System Function of the female reproductive system  To produce offspring and thereby ensure continuity of the genetic code  To produce eggs, or female gametes, each of which has the potential to unite with a male gamete to form the first cell of an offspring  To provide nutrition and protection to the offspring for up to several years after conception 2

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Overview of the Female Reproductive System Structural plan of the female reproduction system  Reproductive organs are classified as essential or accessory (Figure 35-1) Essential organs—gonads are the paired ovaries; gametes are ova produced by the ovaries—the ovaries are also internal genitals Accessory organs  Internal genitals—uterine tubes, uterus, and vagina— ducts or duct structures that extend from the ovaries to the exterior  External genitals—the vulva  Additional sex glands such as the mammary glands 3

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Overview of the Female Reproductive System Perineum (Figure 35-2)  Skin-covered region between the vaginal orifice and the rectum  Area that may be torn during childbirth 5

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Ovaries Location of the ovaries  Nodular glands located on each side of the uterus, below and behind the uterine tubes (Figure 35-3)  Ectopic pregnancy— development of the fetus in a place other than the uterus 7

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Ovaries Microscopic structure of the ovaries (Figure 35-4)  Surface of the ovaries is covered by the germinal epithelium  Ovarian follicles contain the developing female sex cells  Ovum—an oocyte released from the ovary 9

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Ovaries Functions of the ovaries  Ovaries produce ova—the female gametes  Oogenesis—process that results in formation of a mature egg (Figure 35-5)  Ovaries are endocrine organs that secrete the female sex hormones (estrogens and progesterone) 11

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Structure of the uterus (Figure 35- 3)  Size and shape of the uterus Pear-shaped structure with two main parts—the cervix and the body Bulging upper part of the body called the fundus 13

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Structure of the uterus (cont)  Location of the uterus Located in the pelvic cavity between the urinary bladder and the rectum (Figure 35-1) Uterus position (Figure 35-6) is altered by age, pregnancy, and distention of related pelvic viscera Uterus descends, between birth and puberty, from the lower abdomen to the true pelvis Uterus begins to decrease in size at menopause 14

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Structure of the uterus (cont)  Position of the uterus Body lies flexed over the bladder Cervix points downward and backward, joining the vagina at a right angle Several ligaments hold the uterus in place but allow some movement 16

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Structure of the uterus (cont)  Wall of the uterus—composed of three layers—the inner endometrium (mucous membrane), the middle myometrium (smooth muscle), and the perimetrium (outer incomplete layer of parietal peritoneum)  Cavities of the uterus—small because of the thickness of the uterine walls The body cavity’s apex constitutes the internal os and opens into the cervical canal Cervical canal is constricted at its lower end and forms the external os that opens into the vagina 17

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Structure of the uterus (cont)  Blood supply of the uterus— supplied by uterine arteries 18

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Functions of the uterus  Uterus is part of the reproductive tract and facilitates sperm ascending toward the uterine tubes  If conception occurs, an offspring develops in the uterus Embryo is supplied with nutrients by endometrial glands until the production of the placenta Placenta is an organ that permits the exchange of materials between the mother’s blood and the fetal blood but keeps the two circulations separate Myometrial contractions occur during labor and help push the offspring out of the mother’s body 19

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterus Functions of the uterus (cont)  If conception does not occur, outer layers of endometrium are shed during menstruation—a cyclical event that allows the endometrium to renew itself 20

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterine Tubes Uterine tubes also called fallopian tubes, or oviducts Location of uterine tubes  Attached to the uterus at its upper outer angles  Extend upward and outward toward the sides of the pelvis and then curve downward and backward 21

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterine Tubes Structure of the uterine tubes  Uterine tubes consist of mucous, smooth muscle, and serous lining (Figure 35-7)  Mucosal lining is directly continuous with the peritoneum lining the pelvic cavity Tubal mucosa is continuous with that of the vagina and uterus, which means it may become infected with organisms introduced into the vagina and thereby cause salpingitis or peritonitis Inflammation of uterine tubes may lead to scarring and partial or complete closure of the lumen  Each uterine tube has three divisions: isthmus, ampulla, and infundibulum 22

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Uterine Tubes Function of the uterine tubes— serve as transport channels for ova and as the site of fertilization (Figure 35-8) 24

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Vagina Location of the vagina—a tubular organ located between the rectum, urethra, and bladder Structure of the vagina  A collapsible tube capable of distention, composed of smooth muscle, and lined with mucous membrane arranged in rugae  Anterior wall shorter than the posterior wall because the cervix protrudes into its uppermost portion  Hymen—a mucous membrane that typically forms a border around the vagina in young premenstrual girls 26

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Vagina Functions of the vagina  Lining of the vagina lubricates and stimulates the penis during sexual intercourse and acts as a receptacle for semen  Vagina is the lower portion of the birth canal  Vagina transports tissue and blood shed during menstruation to the exterior 27

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Vulva Structure of the vulva (pudendum; the female external genitals)—mons pubis, labia majora, labia minora, clitoris, urinary meatus, vaginal orifice, and greater vestibular glands (Figure 35- 9) Functions of the vulva  Mons pubis and labia protect the clitoris and vestibule  Clitoris contains sensory receptors that send information to the sexual response area of the brain (Figure 35-10)  Vaginal orifice is the boundary between the internal and external genitals 28

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Female Reproductive Cycle Female reproductive system has many cyclical, recurring changes that start with the beginning of menses  Ovarian cycle Ovaries at time of birth contain oocytes in primary follicles in which the meiotic process has been suspended At the beginning of menstruation each month, several of the oocytes resume meiosis Meiosis will stop again just before the cell is released during ovulation (Figure 35-11) 31

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Female Reproductive Cycle Female reproductive system (cont)  Menstrual cycle (endometrial cycle) is divided into four phases Menses Postmenstrual phase Ovulation Premenstrual phase  Myometrial cycle  Gonadotropic cycle 33

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Female Reproductive Cycle Control of female reproductive cycles  Hormones control cyclical changes  Cyclical changes in the ovaries result from changes in the gonadotropins secreted by the pituitary gland (Figures and 35-13)  Cyclical changes in the uterus are caused by changes in estrogens and progesterone (Figure 35-14) 34

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Female Reproductive Cycle Control of female reproductive cycles (cont)  Low levels of FSH and LH cause regression of the corpus luteum if pregnancy does not occur; this causes a decrease in estrogen and progesterone, which triggers endometrial sloughing of the menstrual phase  Control of cyclical changes in gonadotropin secretion is caused by positive and negative feedback mechanisms and involves estrogens, progesterone, and secretion of releasing hormones by the hypothalamus 38

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Female Reproductive Cycle Importance of the female reproductive cycles  Ovarian cycle Primary function is to produce ova at regular intervals Secondary function is to regulate the endometrial cycle through estrogen and progesterone  Endometrial cycle—functions to make the uterus suitable for implantation of a new offspring  Cyclical nature of the reproductive system and the fact that fertilization will occur within 24 hours after ovulation mean that a woman is fertile only a few days of each month 39

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Female Reproductive Cycle Infertility—failure to conceive after 1 year of regular unprotected intercourse  Causes are varied and can involve either or both partners  Fertility drugs and other assisted reproductive procedures such as IVF (in vitro fertilization) are available Menstrual flow begins at puberty, and the menstrual cycle continues for about 3 decades (Figure 35-15) 40

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Breasts Location and size  Breasts lie over the pectoral muscles  Estrogens and progesterone control breast development  Breast size is determined by the amount of fat around glandular tissue (Figure 35-16)  Alveoli of the mammary gland produce milk (Figure 35-17), and a system of lactiferous ducts carries it to the nipple (Figure 35-18), surrounded by an areola 42

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Breasts Structure of the breasts  Each consists of several lobes separated by septa of connective tissue  Lobes consist of several lobules, composed of connective tissue embedded with pouches of milk-secreting cells (alveoli)  Lactiferous duct from each lobe converges toward nipple  Suspensory ligaments help support the breast 46

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Breasts Function of the breasts  Function of mammary glands is lactation  Mechanism of lactation (Figure 35-19) Ovarian hormones make the breasts structurally ready to produce milk Shedding of the placenta results in a decrease of estrogens and thus stimulates prolactin Prolactin stimulates lactation Additional hormones (e.g., oxytocin) also support lactation (Table 35-2) 47

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Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. Breasts Function of the breasts (cont)  Importance of lactation Can provide nutrient-rich milk to offspring for up to several years from birth Some advantages of breast milk  Nutrients  Passive immunity from antibodies present in the colostrum and milk  Emotional bonding between mother and child 49

Mosby items and derived items © 2013, 2010, 2007, 2003 by Mosby, Inc., an affiliate of Elsevier Inc. The Big Picture: The Female Reproductive System and The Whole Body Reproductive system imparts immortality to genes and ensures survival of the species Relationship of the female reproductive system with other body systems  Close proximity to the urinary system; share a common structure: the vulva  Anatomical relationship with the skeletal muscles in the perineum  Breasts are actually modifications of the skin in the integumentary system 50