PowerPoint ® Lecture Slides prepared by Janice Meeking, Mount Royal College C H A P T E R Copyright © 2010 Pearson Education, Inc. 27 The Reproductive System: Part B
Copyright © 2010 Pearson Education, Inc. Hormonal Regulation of Male Reproductive Function A sequence of hormonal regulatory events involving the hypothalamus, anterior pituitary gland, and the testes The hypothalamic-pituitary-gonadal (HPG) axis
Copyright © 2010 Pearson Education, Inc. HPG Axis 1.Hypothalamus releases gonadotropin- releasing hormone (GnRH) 2.GnRH stimulates the anterior pituitary to secrete FSH and LH 3.FSH causes sustentacular cells to release androgen-binding protein (ABP), which makes spermatogenic cell receptive to testosterone 4.LH stimulates interstitial cells to release testosterone
Copyright © 2010 Pearson Education, Inc. HPG Axis 5.Testosterone is the final trigger for spermatogenesis 6.Feedback inhibition on the hypothalamus and pituitary results from Rising levels of testosterone Inhibin (released when sperm count is high)
Copyright © 2010 Pearson Education, Inc. Figure 27.9 Anterior pituitary Inhibin GnRH Testosterone Via portal blood Interstitial cells Sustentacular cell Spermatogenic cells Seminiferous tubule Somatic and psychological effects at other body sites LH FSH Stimulates Inhibits
Copyright © 2010 Pearson Education, Inc. Mechanism and Effects of Testosterone Activity Testosterone Synthesized from cholesterol Transformed to exert its effects on some target cells Dihydrotestosterone (DHT) in the prostate Estrogen in some neurons in the brain
Copyright © 2010 Pearson Education, Inc. Mechanism and Effects of Testosterone Activity Prompts spermatogenesis Targets all accessory organs; deficiency leads to atrophy Has multiple anabolic effects throughout the body Is the basis of the sex drive (libido) in males
Copyright © 2010 Pearson Education, Inc. Male Secondary Sex Characteristics Features induced in the nonreproductive organs by male sex hormones (mainly testosterone) Appearance of pubic, axillary, and facial hair Enhanced growth of the chest and deepening of the voice Skin thickens and becomes oily Bones grow and increase in density Skeletal muscles increase in size and mass
Copyright © 2010 Pearson Education, Inc. Female Reproductive Anatomy Ovaries: female gonads Produce female gametes (ova) Secrete female sex hormones (estrogen and progesterone) Accessory ducts include Uterine tubes Uterus Vagina
Copyright © 2010 Pearson Education, Inc. Female Reproductive Anatomy Internal genitalia Ovaries Uterine tubes Uterus Vagina External genitalia The external sex organs
Copyright © 2010 Pearson Education, Inc. Figure Peritoneum Infundibulum Uterine tube Ovary Uterus Round ligament Vesicouterine pouch Urinary bladder Pubic symphysis Mons pubis Urethra Clitoris External urethral orifice Hymen Labium minus Labium majus Suspensory ligament of ovary Uterosacral ligament Perimetrium Rectouterine pouch Rectum Posterior fornix Cervix Anterior fornix Vagina Anus Urogenital diaphragm Greater vestibular (Bartholin’s) gland Fimbriae
Copyright © 2010 Pearson Education, Inc. Ovaries Held in place by several ligaments Ovarian ligament: anchors ovary medially to the uterus Suspensory ligament: anchors ovary laterally to the pelvic wall Mesovarium: suspends the ovary Broad ligament: supports the uterine tubes, uterus, and vagina; also contains the suspensory ligament and the mesovarium
Copyright © 2010 Pearson Education, Inc. Figure 27.12a Vagina External os Cervical canal Internal os Wall of uterus Perimetrium Myometrium Endometrium Round ligament of uterus Uterine tube Infundibulum Fimbriae Isthmus Ampulla Lumen (cavity) of uterus Suspensory ligament of ovary Uterine (fallopian) tube Ovarian blood vessels Mesosalpinx Mesovarium Broad ligament Mesometrium Ovary Ovarian ligament Body of uterus Ureter Uterine blood vessels Isthmus Uterosacral ligament Lateral cervical (cardinal) ligament Lateral fornix Cervix (a) Fundus of uterus
Copyright © 2010 Pearson Education, Inc. Ovaries Blood supply: ovarian arteries and the ovarian branch of the uterine artery Surrounded by a fibrous tunica albuginea Two poorly defined regions Cortex: ovarian follicles Medulla: large blood vessels and nerves
Copyright © 2010 Pearson Education, Inc. Ovaries Follicle Immature egg (oocyte) surrounded by Follicle cells (one cell layer thick) Granulosa cells (when more than one layer is present)
Copyright © 2010 Pearson Education, Inc. Follicles Several stages of development Primordial follicle: squamouslike follicle cells + oocyte Primary follicle: cuboidal or columnar follicle cells + oocyte Secondary follicle: two or more layers of granulosa cells + oocyte Late secondary follicle: contains fluid-filled space between granulosa cells; coalesces to form a central antrum
Copyright © 2010 Pearson Education, Inc. Ovaries Vesicular (Graafian) follicle Fluid-filled antrum forms; follicle bulges from ovary surface Ovulation Ejection of the oocyte from the ripening follicle Corpus luteum develops from ruptured follicle after ovulation
Copyright © 2010 Pearson Education, Inc. Figure 27.11a Medulla Tunica albuginea Germinal epithelium Cortex Oocyte Granulosa cells Late secondary follicle Antrum Primary follicles Oocyte Zona pellucida Theca folliculi Ovulated oocyte Mesovarium and blood vessels Vesicular (Graafian) follicle Corona radiata Developing corpus luteum Corpus luteum Ovarian ligament Degenerating corpus luteum (corpus albicans) (a) Diagrammatic view of an ovary sectioned to reveal the follicles in its interior
Copyright © 2010 Pearson Education, Inc. Female Duct System Uterine (fallopian) tubes or oviducts Uterus Vagina
Copyright © 2010 Pearson Education, Inc. Uterine Tubes Ampulla Distal expansion with infundibulum near ovary Usual site of fertilization Ciliated fibriae of infundibulum create currents to move oocyte into uterine tube Isthmus: constricted region where tube joins uterus
Copyright © 2010 Pearson Education, Inc. Uterine Tubes Oocyte is carried along by peristalsis and ciliary action Nonciliated cells nourish the oocyte and the sperm Mesosalpinx: mesentery that supports the uterine tubes
Copyright © 2010 Pearson Education, Inc. Figure 27.12a Vagina External os Cervical canal Internal os Wall of uterus Perimetrium Myometrium Endometrium Round ligament of uterus Uterine tube Infundibulum Fimbriae Isthmus Ampulla Lumen (cavity) of uterus Suspensory ligament of ovary Uterine (fallopian) tube Ovarian blood vessels Mesosalpinx Mesovarium Broad ligament Mesometrium Ovary Ovarian ligament Body of uterus Ureter Uterine blood vessels Isthmus Uterosacral ligament Lateral cervical (cardinal) ligament Lateral fornix Cervix (a) Fundus of uterus
Copyright © 2010 Pearson Education, Inc. Uterus Body: major portion Fundus: rounded superior region Isthmus: narrowed inferior region
Copyright © 2010 Pearson Education, Inc. Uterus Cervix: narrow neck, or outlet; projects into the vagina Cervical canal communicates with the Vagina via the external os Uterine body via the internal os Cervical glands secrete mucus that blocks sperm entry except during midcycle
Copyright © 2010 Pearson Education, Inc. Supports of the Uterus Mesometrium—lateral support: portion of the broad ligament Lateral cervical (cardinal) ligaments: from the cervix and superior part of the vagina to the walls of the pelvis Uterosacral ligaments secure uterus to the sacrum Round ligaments bind to the anterior wall
Copyright © 2010 Pearson Education, Inc. Figure 27.12a Vagina External os Cervical canal Internal os Wall of uterus Perimetrium Myometrium Endometrium Round ligament of uterus Uterine tube Infundibulum Fimbriae Isthmus Ampulla Lumen (cavity) of uterus Suspensory ligament of ovary Uterine (fallopian) tube Ovarian blood vessels Mesosalpinx Mesovarium Broad ligament Mesometrium Ovary Ovarian ligament Body of uterus Ureter Uterine blood vessels Isthmus Uterosacral ligament Lateral cervical (cardinal) ligament Lateral fornix Cervix (a) Fundus of uterus
Copyright © 2010 Pearson Education, Inc. Peritoneal Pouches Sacs of peritoneum exist around the uterus Vesicouterine pouch is between bladder and uterus Rectouterine pouch is between rectum and uterus
Copyright © 2010 Pearson Education, Inc. Uterine Wall Three layers 1.Perimetrium: serous layer (visceral peritoneum) 2.Myometrium: interlacing layers of smooth muscle 3.Endometrium: mucosal lining
Copyright © 2010 Pearson Education, Inc. Endometrium Stratum functionalis (functional layer) Changes in response to ovarian hormone cycles Is shed during menstruation Stratum basalis (basal layer) Forms new functionalis after menstruation Unresponsive to ovarian hormones
Copyright © 2010 Pearson Education, Inc. Uterine Vascular Supply Uterine arteries: arise from internal iliacs Arcuate arteries: in the myometrium Radial branches in the endometrium branch into Spiral arteries stratum functionalis Straight arteries stratum basalis Spasms of spiral arteries leads to shedding of stratum functionalis
Copyright © 2010 Pearson Education, Inc. Figure 27.13b Lumen of uterus Uterine glands Smooth muscle fibers Straight artery Radial artery Arcuate artery Uterine artery Endometrial vein Capillaries Venous sinusoids Epithelium Spiral (coiled) artery Lamina propria of connective tissue (b)
Copyright © 2010 Pearson Education, Inc. Vagina Birth canal and organ of copulation Extends between the bladder and the rectum from the cervix to the exterior Urethra embedded in the anterior wall
Copyright © 2010 Pearson Education, Inc. Vagina Layers of wall 1.Fibroelastic adventitia 2.Smooth muscle muscularis 3.Stratified squamous mucosa with rugae Mucosa near the vaginal orifice forms an incomplete partition called the hymen Vaginal fornix: upper end of the vagina surrounding the cervix
Copyright © 2010 Pearson Education, Inc. Figure 27.14a Mons pubis Prepuce of clitoris Clitoris (glans) Vestibule Anus (a) Labia majora Labia minora Urethral orifice Hymen (ruptured) Opening of the duct of the greater vestibular gland Vaginal orifice
Copyright © 2010 Pearson Education, Inc. External Genitalia (Vulva or Pudendum) Mons pubis: fatty area overlying pubic symphysis Labia majora: hair-covered, fatty skin folds Labia minora: skin folds lying within labia majora Vestibule: recess between labia minora
Copyright © 2010 Pearson Education, Inc. External Genitalia Greater vestibular glands Homologous to the bulbourethral glands Release mucus into the vestibule for lubrication
Copyright © 2010 Pearson Education, Inc. External Genitalia Clitoris Erectile tissue hooded by a prepuce Glans clitoris: exposed portion Perineum Diamond-shaped region between the pubic arch and coccyx Bordered by the ischial tuberosities laterally
Copyright © 2010 Pearson Education, Inc. Figure 27.14b Pubic symphysis Labia minora Clitoris Labia majora Anus Body of clitoris, containing corpora cavernosa Clitoris (glans) Crus of clitoris Urethral orifice Vaginal orifice Greater vestibular gland Fourchette Bulb of vestibule Inferior ramus of pubis (b)
Copyright © 2010 Pearson Education, Inc. Mammary Glands Modified sweat glands consisting of 15–25 lobes Areola: pigmented skin surrounding the nipple Suspensory ligaments: attach the breast to underlying muscle Lobules within lobes contain glandular alveoli that produce milk
Copyright © 2010 Pearson Education, Inc. Mammary Glands Milk lactiferous ducts lactiferous sinuses open to the outside at the nipple
Copyright © 2010 Pearson Education, Inc. Figure Skin (cut) Pectoralis major muscle Suspensory ligament Adipose tissue Lobe Areola Nipple Opening of lactiferous duct Lactiferous sinus Lactiferous duct Hypodermis (superficial fascia) Intercostal muscles Lobule containing alveoli (a)(b) First rib
Copyright © 2010 Pearson Education, Inc. Breast Cancer Usually arises from the epithelial cells of small ducts Risk factors include: Early onset of menstruation and late menopause No pregnancies or first pregnancy late in life Family history of breast cancer 10% are due to hereditary defects, including mutations to the genes BRCA1 and BRCA2
Copyright © 2010 Pearson Education, Inc. Breast Cancer: Detection and Treatment 70% of women with breast cancer have no known risk factors Early detection via self-examination and mammography Treatment depends upon the characteristics of the lesion: Radiation, chemotherapy, and surgery followed by irradiation and chemotherapy
Copyright © 2010 Pearson Education, Inc. Figure (b) Film of normal breast (a) Mammogram procedure (c) Film of breast with tumor Malignancy
Copyright © 2010 Pearson Education, Inc. Oogenesis Production of female gametes Begins in the fetal period Oogonia (2n ovarian stem cells) multiply by mitosis and store nutrients Primary oocytes develop in primordial follicles Primary oocytes begin meiosis but stall in prophase I
Copyright © 2010 Pearson Education, Inc. Oogenesis Each month after puberty, a few primary oocytes are activated One is selected each month to resume meiosis I Result is two haploid cells Secondary oocyte First polar body
Copyright © 2010 Pearson Education, Inc. Oogenesis The secondary oocyte arrests in metaphase II and is ovulated If penetrated by sperm the second oocyte completes meiosis II, yielding Ovum (the functional gamete) Second polar body
Copyright © 2010 Pearson Education, Inc. Figure Meiotic eventsFollicle development in ovary Before birth Infancy and childhood (ovary inactive) Primary oocyte Primary oocyte (still arrested in prophase I) Vesicular (Graafian) follicle Primary follicle Primordial follicle Oocyte Ovulated secondary oocyte In absence of fertilization, ruptured follicle becomes a corpus luteum and ultimately degenerates. Degenating corpus luteum Secondary follicle Primary oocyte (arrested in prophase I; present at birth) Oogonium (stem cell) Each month from puberty to menopause Meiosis I (completed by one primary oocyte each month in response to LH surge) First polar body Mitosis Growth Meiosis II of polar body (may or may not occur) Polar bodies (all polar bodies degenerate) OvumSecond polar body Meiosis II completed (only if sperm penetration occurs) Sperm Ovulation Secondary oocyte (arrested in metaphase II) Follicle cells Spindle
Copyright © 2010 Pearson Education, Inc. Ovarian Cycle Monthly series of events associated with the maturation of an egg Two consecutive phases (in a 28-day cycle) Follicular phase: period of follicle growth (days 1–14) Ovulation occurs midcycle Luteal phase: period of corpus luteum activity (days 14–28)
Copyright © 2010 Pearson Education, Inc. Follicular Phase Primordial follicle becomes primary follicle 1.The primordial follicle is activated Squamouslike cells become cuboidal 2.Follicle enlarges to become a primary (1 ) follicle
Copyright © 2010 Pearson Education, Inc. Figure (1 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Primordial follicles 1
Copyright © 2010 Pearson Education, Inc. Figure (2 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Primary follicle 2
Copyright © 2010 Pearson Education, Inc. Follicular Phase 3.Primary follicle becomes a secondary follicle Stratified epithelium (granulosa cells) forms around oocyte Granulosa cells and oocyte guide one another’s development
Copyright © 2010 Pearson Education, Inc. Follicular Phase 4.Secondary follicle becomes a late secondary follicle Connective tissue (theca folliculi) and granulosa cells cooperate to produce estrogens Zona pellucida forms around the oocyte Fluid begins to accumulate
Copyright © 2010 Pearson Education, Inc. Figure (3 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Secondary follicle 3
Copyright © 2010 Pearson Education, Inc. Figure (4 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Late secondary follicle 4
Copyright © 2010 Pearson Education, Inc. Follicular Phase 5.Late secondary follicle becomes a vesicular follicle Antrum forms and expands to isolate the oocyte with its corona radiata on a stalk Vesicular follicle bulges from the external surface of the ovary The primary oocyte completes meiosis I
Copyright © 2010 Pearson Education, Inc. Ovulation Ovary wall ruptures and expels the secondary oocyte with its corona radiata Mittelschmerz: twinge of pain sometimes felt at ovulation 1–2% of ovulations release more than one secondary oocyte, which, if fertilized, results in fraternal twins
Copyright © 2010 Pearson Education, Inc. Figure (5 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Mature vesicular follicle carries out meiosis I; ready to be ovulated 5
Copyright © 2010 Pearson Education, Inc. Figure (6 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Follicle ruptures; secondary oocyte ovulated 6
Copyright © 2010 Pearson Education, Inc. Luteal Phase Ruptured follicle collapses Granulosa cells and internal thecal cells form corpus luteum Corpus luteum secretes progesterone and estrogen
Copyright © 2010 Pearson Education, Inc. Luteal Phase If no pregnancy, the corpus luteum degenerates into a corpus albicans in 10 days If pregnancy occurs, corpus luteum produces hormones until the placenta takes over at about 3 months
Copyright © 2010 Pearson Education, Inc. Figure (7 of 7) Theca folliculi Primary oocyte Zona pellucida Antrum Secondary oocyte Secondary oocyte Corona radiata Corpus luteum (forms from ruptured follicle) 7
Copyright © 2010 Pearson Education, Inc. Establishing the Ovarian Cycle During childhood, ovaries grow and secrete small amounts of estrogens that inhibit the hypothalamic release of GnRH As puberty nears, GnRH is released; FSH and LH are released by the pituitary, and act on the ovaries These events continue until an adult cyclic pattern is achieved and menarche occurs