Chapter 16 Reproductive System PDF

Chapter 16 The Reproductive System Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical...

Chapter 16 The Reproductive System Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College © 2018 Pearson Education, Inc.  The Reproductive System  Gonads—primary sex organs  Testes in males  Ovaries in females  Gonads produce gametes (sex cells) and secrete hormones  Sperm—male gametes  Ova (eggs)—female gametes © 2018 Pearson Education, Inc.  Anatomy of the Male Reproductive System  Testes  Duct system  Epididymis  Ductus (vas) deferens  Urethra © 2018 Pearson Education, Inc.  Anatomy of the Male Reproductive System  Accessory organs  Seminal glands (vesicles)  Prostate  Bulbourethral glands  External genitalia  Penis  Scrotum © 2018 Pearson Education, Inc. Figure 16.2a Male reproductive organs. Ureter Urinary bladder Seminal vesicle Prostatic urethra Ampulla of Pubis ductus deferens Membranous urethra Ejaculatory duct Urogenital diaphragm Rectum Erectile tissue Prostate of the penis Bulbo-urethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce Scrotum External urethral (a) orifice © 2018 Pearson Education, Inc. Figure 16.2b Male reproductive organs. Urinary bladder Ureter Ampulla of ductus deferens Seminal vesicle Ejaculatory Prostate duct Prostatic Bulbourethral urethra gland Membranous Ductus urethra deferens Root of penis Erectile tissues Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) orifice © 2018 Pearson Education, Inc.  Testes  Each testis is connected to the trunk via the spermatic cord, which houses:  Blood vessels  Nerves  Ductus deferens  Coverings of the testes  Tunica albuginea—capsule that surrounds each testis  Septa—extensions of the capsule that extend into the testis and divide it into lobules © 2018 Pearson Education, Inc. Figure 16.1 Sagittal section of the testis and associated epididymis. Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2018 Pearson Education, Inc.  Testes  Each lobule contains one to four seminiferous tubules  Tightly coiled structures  Function as sperm-forming factories  Empty sperm into the rete testis  Sperm travels from the rete testis to the epididymis  Interstitial cells in the seminiferous tubules produce androgens such as testosterone © 2018 Pearson Education, Inc.  Duct System  The duct system transports sperm from the body and includes:  Epididymis  Ductus deferens  Urethra © 2018 Pearson Education, Inc.  Duct System  Epididymis  Highly convoluted tube 6 m (20 ft) long  Found along the posterior lateral side of the testis  First part of the male duct system  Temporary storage site for immature sperm  Sperm mature as they journey through the epididymis  During ejaculation, sperm are propelled to the ductus deferens © 2018 Pearson Education, Inc. Figure 16.1 Sagittal section of the testis and associated epididymis. Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2018 Pearson Education, Inc.  Duct System  Ductus (vas) deferens  Runs from the epididymis via the spermatic cord through the inguinal canal and arches over the urinary bladder  Ampulla—end of the ductus deferens, which empties into the ejaculatory duct  Ejaculatory duct—passes through the prostate to merge with the urethra  Moves sperm by peristalsis into the urethra © 2018 Pearson Education, Inc.  Duct System  Ductus (vas) deferens (continued)  Ejaculation—smooth muscle in the walls of the ductus deferens create peristaltic waves to squeeze sperm forward  Vasectomy—cutting of the ductus deferens at the level of the testes prevents transportation of sperm (form of birth control) © 2018 Pearson Education, Inc.  Duct System  Urethra  Extends from the base of the urinary bladder to the tip of the penis  Carries both urine and sperm  Sperm enters from the ejaculatory duct © 2018 Pearson Education, Inc.  Duct System  Urethra regions 1. Prostatic urethra—surrounded by prostate gland 2. Membranous urethra—prostatic urethra to penis 3. Spongy (penile) urethra—runs the length of the penis to the external urethral orifice  Ejaculation causes the internal urethra sphincter to close  Prevents urine from passing into the urethra  Prevents sperm from entering the urinary bladder © 2018 Pearson Education, Inc. Figure 16.2a Male reproductive organs. Ureter Urinary bladder Seminal vesicle Prostatic urethra Ampulla of Pubis ductus deferens Membranous urethra Ejaculatory duct Urogenital diaphragm Rectum Erectile tissue Prostate of the penis Bulbo-urethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce Scrotum External urethral (a) orifice © 2018 Pearson Education, Inc. Figure 16.2b Male reproductive organs. Urinary bladder Ureter Ampulla of ductus deferens Seminal vesicle Ejaculatory Prostate duct Prostatic Bulbourethral urethra gland Membranous Ductus urethra deferens Root of penis Erectile tissues Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) orifice © 2018 Pearson Education, Inc.  Accessory Glands and Semen  Seminal vesicles  Prostate  Bulbourethral glands © 2018 Pearson Education, Inc.  Accessory Glands and Semen  Seminal vesicles  Located at the base of the bladder  Produce a thick, yellowish secretion (60% of semen) that contains:  Fructose (sugar)  Vitamin C  Prostaglandins  Other substances that nourish and activate sperm  Duct of each seminal vesicle joins that of the ductus deferens on each side to form the ejaculatory duct © 2018 Pearson Education, Inc.  Accessory Glands and Semen  Prostate  Encircles the upper (prostatic) part of the urethra  Secretes a milky fluid  Helps to activate sperm  Fluid enters the urethra through several small ducts © 2018 Pearson Education, Inc.  Accessory Glands and Semen  Bulbourethral glands  Pea-sized glands inferior to the prostate  Produce a thick, clear mucus  Mucus cleanses the spongy (penile) urethra of acidic urine prior to ejaculation  Mucus serves as a lubricant during sexual intercourse © 2018 Pearson Education, Inc. Figure 16.2a Male reproductive organs. Ureter Urinary bladder Seminal vesicle Prostatic urethra Ampulla of Pubis ductus deferens Membranous urethra Ejaculatory duct Urogenital diaphragm Rectum Erectile tissue Prostate of the penis Bulbo-urethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce Scrotum External urethral (a) orifice © 2018 Pearson Education, Inc. Figure 16.2b Male reproductive organs. Urinary bladder Ureter Ampulla of ductus deferens Seminal vesicle Ejaculatory Prostate duct Prostatic Bulbourethral urethra gland Membranous Ductus urethra deferens Root of penis Erectile tissues Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) orifice © 2018 Pearson Education, Inc.  Accessory Glands and Semen  Semen  Milky white mixture of sperm and accessory gland secretions  Components of accessory gland secretions  Liquid portion acts as a transport medium to dilute sperm  Sperm are streamlined cellular ―tadpoles‖  Fructose provides energy for sperm cells  Alkalinity of semen helps neutralize the acidic environment of vagina  Semen inhibits bacteria © 2018 Pearson Education, Inc.  External Genitalia  Scrotum  Penis © 2018 Pearson Education, Inc.  External Genitalia  Scrotum  Divided sac of skin outside the abdomen that houses the testes  Viable sperm cannot be produced at normal body temperature  Maintains testes at 3°C lower than normal body temperature © 2018 Pearson Education, Inc. Figure 16.1 Sagittal section of the testis and associated epididymis. Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2018 Pearson Education, Inc.  External Genitalia  Penis  Male organ of copulation that delivers sperm into the female reproductive tract  Regions of the penis  Shaft  Glans penis (enlarged tip)  Prepuce (foreskin)  Folded cuff of skin around proximal end  Often removed by circumcision © 2018 Pearson Education, Inc.  External Genitalia  Penis (continued)  Internally there are three areas of spongy erectile tissue around the urethra  Erections occur when this erectile tissue fills with blood during sexual excitement © 2018 Pearson Education, Inc. Figure 16.2a Male reproductive organs. Ureter Urinary bladder Seminal vesicle Prostatic urethra Ampulla of Pubis ductus deferens Membranous urethra Ejaculatory duct Urogenital diaphragm Rectum Erectile tissue Prostate of the penis Bulbo-urethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce Scrotum External urethral (a) orifice © 2018 Pearson Education, Inc. Figure 16.2b Male reproductive organs. Urinary bladder Ureter Ampulla of ductus deferens Seminal vesicle Ejaculatory Prostate duct Prostatic Bulbourethral urethra gland Membranous Ductus urethra deferens Root of penis Erectile tissues Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) orifice © 2018 Pearson Education, Inc.  Male Reproductive Functions  Chief roles of the male in the reproductive process  Produce sperm  Produce a hormone, testosterone © 2018 Pearson Education, Inc.  Spermatogenesis  Sperm production  Begins at puberty and continues throughout life  Millions of sperm are made every day  Sperm are formed in the seminiferous tubules of the testis  Spermatogonia (primitive stem cells) begin the process by dividing rapidly  During puberty, follicle-stimulating hormone (FSH) is secreted in increasing amounts © 2018 Pearson Education, Inc. © 2018 Pearson Education, Inc. Figure 16.3 Spermatogenesis. Seminiferous tubule Basement membrane Spermatogonium 2n 2n Daughter cell (stem cell) type A (remains at basement Mitosis 2n membrane as a stem cell) Growth Daughter cell type B Enters (moves toward tubule prophase of lumen) meiosis I 2n Primary Meiosis spermatocyte Meiosis I completed n n Secondary spermatocytes Spermatogenesis Meiosis II n n n n Early spermatids Spermiogenesis Late n n n n spermatids Sperm n n n n Lumen of seminiferous tubule © 2018 Pearson Education, Inc. Figure 16.3 Spermatogenesis (1 of 2). Seminiferous tubule © 2018 Pearson Education, Inc. Figure 16.3 Spermatogenesis (2 of 2). Basement membrane Spermatogonium 2n 2n Daughter cell (stem cell) type A (remains at basement Mitosis membrane 2n as a stem cell) Growth Daughter cell type B Enters (moves toward tubule prophase of lumen) meiosis I 2n Primary Meiosis spermatocyte Meiosis I completed n n Secondary spermatocytes Spermatogenesis Meiosis II n n n n Early spermatids Spermiogenesis n n n n Late spermatids Sperm n n n n Lumen of seminiferous tubule © 2018 Pearson Education, Inc.  Spermatogenesis  Each division of a spermatogonium stem cell produces:  Type A daughter cell, a stem cell, that continues the stem cell population  Type B daughter cell, which becomes a primary spermatocyte, destined to undergo meiosis and form four sperm © 2018 Pearson Education, Inc.  Spermatogenesis  Meiosis  Special type of nuclear division that differs from mitosis  Occurs in the gonads  Includes two successive divisions of the nucleus (meiosis I and II)  Results in four daughter cells (gametes) © 2018 Pearson Education, Inc.  Spermatogenesis  Gametes are spermatids with 23 chromosomes  23 chromosomes are half the usual 46 found in other body cells  23 is known as the haploid number (n)—half the genetic material as other body cells  Union of a sperm (23 chromosomes, n) with an egg (23 chromosomes, n) creates a zygote (2n, or 46 chromosomes) © 2018 Pearson Education, Inc. Figure 16.4 The human life cycle. Gametes (n = 23) n Egg n Sperm Meiosis Fertilization Multicellular adults Zygote 2n (2n = 46) (2n = 46) Mitosis and development © 2018 Pearson Education, Inc.  Spermatogenesis  Spermiogenesis  Spermatids are nonmotile and not functional as sperm  A streamlining process is needed to strip excess cytoplasm from a spermatid and modify it into a sperm  A sperm has three regions: head, midpiece, tail  Acrosome sits anterior to the sperm head (nucleus)  The entire process of spermatogenesis, including spermiogenesis, takes 64 to 72 days © 2018 Pearson Education, Inc. Figure 16.5a Structure of sperm. (a) © 2018 Pearson Education, Inc. Figure 16.5b Structure of sperm. Provides genetic Provides instructions and a energy for means of penetrating mobility the follicle cell capsule and Plasma membrane oocyte membrane Neck Provides Tail for mobility Head Midpiece Axial filament Acrosome of tail Nucleus Mitochondria Proximal centriole (b) © 2018 Pearson Education, Inc.  Testosterone Production  During puberty:  Follicle-stimulating hormone (FSH) begins prodding seminiferous tubules to produce sperm  Luteinizing hormone (LH) begins activating the interstitial cells to produce testosterone © 2018 Pearson Education, Inc.  Testosterone Production  Testosterone  Most important hormonal product of the testes  Stimulates reproductive organ development  Underlies sex drive  Causes secondary sex characteristics  Deepening of voice  Increased hair growth  Enlargement of skeletal muscles  Increased bone growth and density © 2018 Pearson Education, Inc. Figure 16.6 Hormonal control of testosterone release and sperm production. Slide 1 Hypothalamus 1 The hypothalamus releases gonadotropin-releasing hormone 1 (GnRH). GnRH 2 GnRH stimulates the anterior Anterior pituitary pituitary to release gonadotropins —FSH and LH. 3 FSH stimulates spermatogonia to produce sperm. 5 2 4 LH stimulates the interstitial cells to release testosterone, FSH LH which serves as the final trigger Testosterone for spermatogenesis. 3 4 Testosterone then enhances 5 spermatogenesis. 5 The rising level of testosterone exerts negative feedback control on the hypothalamus and pituitary. Testosterone Primary and secondary sex characteristics Supporting cell Seminiferous tubule in testis FSH and testosterone stimulate sperm production Spermatogonia Spermatogenesis KEY: Stimulates Inhibits © 2018 Pearson Education, Inc. Figure 16.6 Hormonal control of testosterone release and sperm production. Slide 2 Hypothalamus 1 The hypothalamus releases gonadotropin-releasing hormone 1 (GnRH). GnRH Anterior pituitary Supporting cell Seminiferous tubule in testis Spermatogonia Spermatogenesis KEY: Stimulates Inhibits © 2018 Pearson Education, Inc. Figure 16.6 Hormonal control of testosterone release and sperm production. Slide 3 Hypothalamus 1 The hypothalamus releases gonadotropin-releasing hormone 1 (GnRH). GnRH 2 GnRH stimulates the anterior Anterior pituitary pituitary to release gonadotropins —FSH and LH. 2 FSH LH Supporting cell Seminiferous tubule in testis Spermatogonia Spermatogenesis KEY: Stimulates Inhibits © 2018 Pearson Education, Inc. Figure 16.6 Hormonal control of testosterone release and sperm production. Slide 4 Hypothalamus 1 The hypothalamus releases gonadotropin-releasing hormone 1 (GnRH). GnRH 2 GnRH stimulates the anterior Anterior pituitary pituitary to release gonadotropins —FSH and LH. 3 FSH stimulates spermatogonia to produce sperm. 2 FSH LH 3 Supporting cell Seminiferous tubule in testis Spermatogonia Spermatogenesis KEY: Stimulates Inhibits © 2018 Pearson Education, Inc. Figure 16.6 Hormonal control of testosterone release and sperm production. Slide 5 Hypothalamus 1 The hypothalamus releases gonadotropin-releasing hormone 1 (GnRH). GnRH 2 GnRH stimulates the anterior Anterior pituitary pituitary to release gonadotropins —FSH and LH. 3 FSH stimulates spermatogonia to produce sperm. 2 4 LH stimulates the interstitial cells to release testosterone, FSH LH which serves as the final trigger for spermatogenesis. 3 4 Testosterone then enhances spermatogenesis. Testosterone Primary and secondary sex characteristics Supporting cell Seminiferous tubule in testis Spermatogonia Spermatogenesis KEY: Stimulates Inhibits © 2018 Pearson Education, Inc. Figure 16.6 Hormonal control of testosterone release and sperm production. Slide 6 Hypothalamus 1 The hypothalamus releases gonadotropin-releasing hormone 1 (GnRH). GnRH 2 GnRH stimulates the anterior Anterior pituitary pituitary to release gonadotropins —FSH and LH. 3 FSH stimulates spermatogonia to produce sperm. 5 2 4 LH stimulates the interstitial cells to release testosterone, FSH LH which serves as the final trigger Testosterone for spermatogenesis. 3 4 Testosterone then enhances 5 spermatogenesis. 5 The rising level of testosterone exerts negative feedback control on the hypothalamus and pituitary. Testosterone Primary and secondary sex characteristics Supporting cell Seminiferous tubule in testis FSH and testosterone stimulate sperm production Spermatogonia Spermatogenesis KEY: Stimulates Inhibits © 2018 Pearson Education, Inc.  Anatomy of the Female Reproductive System  Ovaries  Duct system  Uterine (fallopian) tubes  Uterus  Vagina  External genitalia © 2018 Pearson Education, Inc. Figure 16.8a The human female reproductive organs. Suspensory ligament of ovary (part of broad ligament) Infundibulum Uterine tube Ovary Fimbriae Uterus (fundus) Uterosacral ligament Round ligament Urinary bladder Pubic symphysis Rectum Mons pubis Cervix Urethra Vagina Clitoris Anus Hymen Greater vestibular gland Labium minus Labium majus (a) © 2018 Pearson Education, Inc.  Ovaries  Ovaries  Produce eggs (ova) and hormones (estrogen and progesterone)  Each ovary houses ovarian follicles consisting of:  Oocyte (immature egg)  Follicle cells—layers of different cells that surround the oocyte © 2018 Pearson Education, Inc. Figure 16.7 Sagittal section of a human ovary showing the developmental stages of an ovarian follicle. Primary follicle Growing follicles Degenerating corpus luteum Blood vessels Antrum Corona radiata Mature vesicular (Graafian) follicle Germinal epithelium Corpus luteum Developing Ruptured Ovulation Secondary oocyte corpus luteum follicle © 2018 Pearson Education, Inc.  Ovaries  Ovarian follicles  Primary follicle—contains an immature oocyte  Vesicular (Graafian) follicle—growing follicle with a maturing oocyte  Ovulation—the follicle ruptures when the egg is mature and ready to be ejected from the ovary; occurs about every 28 days  The ruptured follicle is transformed into a corpus luteum © 2018 Pearson Education, Inc.  Ovaries  Ovary support  Suspensory ligaments secure the ovaries to the lateral walls of the pelvis  Ovarian ligaments anchor ovaries to the uterus medially  Broad ligaments, a fold of peritoneum, enclose and hold the ovaries in place © 2018 Pearson Education, Inc. Figure 16.8a The human female reproductive organs. Suspensory ligament of ovary (part of broad ligament) Infundibulum Uterine tube Ovary Fimbriae Uterus (fundus) Uterosacral ligament Round ligament Urinary bladder Pubic symphysis Rectum Mons pubis Cervix Urethra Vagina Clitoris Anus Hymen Greater vestibular gland Labium minus Labium majus (a) © 2018 Pearson Education, Inc. Figure 16.8b The human female reproductive organs. Suspensory Uterine (fallopian) tube ligament of ovary Fundus Lumen (cavity) Ovarian of uterus of uterus blood vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Wall of Myometrium Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Vagina Cervix (b) © 2018 Pearson Education, Inc.  Duct System  Uterine (fallopian) tubes  Uterus  Vagina © 2018 Pearson Education, Inc.  Duct System  Uterine (fallopian) tubes (continued)  Form the initial part of the duct system  Receive the ovulated oocyte from the ovaries  Provide a site for fertilization  Empty into the uterus  Little or no contact between ovaries and uterine tubes  Supported and enclosed by the broad ligament © 2018 Pearson Education, Inc.  Duct System  Uterine (fallopian) tube structure  Infundibulum  Distal, funnel-shaped end  Fimbriae  Fingerlike projections of the infundibulum  Receive the oocyte from the ovary  Cilia located inside the uterine tube transport the oocyte © 2018 Pearson Education, Inc. Figure 16.8b The human female reproductive organs. Suspensory Uterine (fallopian) tube ligament of ovary Fundus Lumen (cavity) Ovarian of uterus of uterus blood vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Wall of Myometrium Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Vagina Cervix (b) © 2018 Pearson Education, Inc.  Duct System  Uterus  Situated between the urinary bladder and rectum  Size and shape of a pear, in a woman who has never been pregnant  Receives, retains, nourishes a fertilized egg © 2018 Pearson Education, Inc.  Duct System  Uterine support  Broad ligament suspends the uterus in the pelvis  Round ligament anchors the uterus anteriorly  Uterosacral ligament anchors the uterus posteriorly © 2018 Pearson Education, Inc.  Duct System  Regions of the uterus  Body—main portion  Fundus—superior rounded region above where uterine tube enters  Cervix—narrow outlet that protrudes into the vagina © 2018 Pearson Education, Inc.  Duct System  Layers of the uterus  Endometrium  Inner layer (mucosa)  Site of implantation of a fertilized egg  Sloughs off if no pregnancy occurs (menstruation or menses)  Myometrium is the middle layer of smooth muscle that contracts during labor  Perimetrium (visceral peritoneum) is the outermost serous layer of the uterus © 2018 Pearson Education, Inc.  Duct System  Vagina  Passageway that extends from cervix to exterior of body and is located between urinary bladder and rectum  Serves as the canal that allows a baby or menstrual flow to leave the body  Female organ of copulation  Receives the penis during sexual intercourse  Hymen—partially closes the vagina until it is ruptured © 2018 Pearson Education, Inc. Figure 16.8a The human female reproductive organs. Suspensory ligament of ovary (part of broad ligament) Infundibulum Uterine tube Ovary Fimbriae Uterus (fundus) Uterosacral ligament Round ligament Urinary bladder Pubic symphysis Rectum Mons pubis Cervix Urethra Vagina Clitoris Anus Hymen Greater vestibular gland Labium minus Labium majus (a) © 2018 Pearson Education, Inc. Figure 16.8b The human female reproductive organs. Suspensory Uterine (fallopian) tube ligament of ovary Fundus Lumen (cavity) Ovarian of uterus of uterus blood vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Wall of Myometrium Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Vagina Cervix (b) © 2018 Pearson Education, Inc.  External Genitalia and Female Perineum  The female external genitalia, or vulva, includes:  Mons pubis  Labia  Clitoris  Urethral orifice  Vaginal orifice  Greater vestibular glands © 2018 Pearson Education, Inc. Figure 16.9 External genitalia of the human female. Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Opening of duct of greater vestibular gland Labia minora Perineum Anus © 2018 Pearson Education, Inc.  External Genitalia and Female Perineum  Mons pubis  Fatty area overlying the pubic symphysis  Covered with pubic hair after puberty © 2018 Pearson Education, Inc.  External Genitalia and Female Perineum  Labia—skin folds  Labia majora  Hair-covered skin folds  Enclose the labia minora  Also encloses the vestibule  Labia minora—delicate, hair-free folds of skin © 2018 Pearson Education, Inc.  External Genitalia and Female Perineum  Vestibule  Enclosed by labia majora  Contains external openings of the urethra and vagina  Greater vestibular glands  One is found on each side of the vagina  Secretions lubricate vagina during intercourse © 2018 Pearson Education, Inc.  External Genitalia and Female Perineum  Clitoris  Contains erectile tissue  Corresponds to the male penis  The clitoris is similar to the penis in that it is:  Hooded by a prepuce  Composed of sensitive erectile tissue  Swollen with blood during sexual excitement  The clitoris lacks a reproductive duct © 2018 Pearson Education, Inc.  External Genitalia and Female Perineum  Perineum  Diamond-shaped region between the anterior ends of the labial folds, anus posteriorly, and ischial tuberosities laterally © 2018 Pearson Education, Inc. Figure 16.9 External genitalia of the human female. Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Opening of duct of greater vestibular gland Labia minora Perineum Anus © 2018 Pearson Education, Inc.  Female Reproductive Functions and Cycles  The total supply of eggs is determined by the time a female is born  Ability to release eggs begins at puberty with the onset of the menstrual cycle  Reproductive ability ends at menopause (in female’s fifties) © 2018 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle  Oogenesis is the process of producing ova (eggs) in a female  Oogonia are female stem cells found in a developing fetus  Oogonia undergo mitosis to produce primary oocytes that are surrounded by cells that form primary follicles in the ovary © 2018 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle  Primary oocytes are inactive until puberty  Follicle-stimulating hormone (FSH) causes some primary follicles to mature each month  Cyclic monthly changes constitute the ovarian cycle © 2018 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle  Meiosis starts inside maturing follicle  First meiotic division produces a larger secondary oocyte and a smaller first polar body  A vesicular follicle contains a secondary oocyte (maturation from a primary follicle takes about 14 days)  Ovulation of a secondary oocyte occurs with the release of luteinizing hormone (LH)  Secondary oocyte is released and surrounded by a corona radiata © 2018 Pearson Education, Inc. Figure 16.11 Ovulation. Oocyte © 2018 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle  Meiosis is completed after ovulation only if sperm penetrates the oocyte  Ovum is produced  Two additional polar bodies are produced  Once ovum is formed, the 23 chromosomes can be combined with the 23 chromosomes of the sperm to form the fertilized egg (zygote)  If the secondary oocyte is not penetrated by a sperm, it dies and does not complete meiosis to form an ovum © 2018 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle  Meiosis  Males—produces four functional sperm  Females—produces one functional ovum and three tiny polar bodies  Sex cell size and structure  Sperm are tiny, motile, and equipped with nutrients in seminal fluid  Egg is large, is nonmotile, and has nutrient reserves to nourish the embryo until implantation © 2018 Pearson Education, Inc. Figure 16.10 Events of oogenesis. Meiotic Events Follicle Development in Ovary Before birth 2n Oogonium (stem cell) Follicle cells Mitosis Oocyte 2n Primary oocyte Primary follicle Growth 2n Primary oocyte Primary (arrested in prophase I; follicle present at birth) Childhood (ovary inactive) Monthly from Primary puberty to menopause follicle 2n Primary oocyte (still arrested in prophase I) Growing follicle Mature vesicular Meiosis I (completed by one (Graafian) primary oocyte each month) Secondary oocyte follicle (arrested in First polar body n metaphase II) Ovulation Sperm Ovulated secondary Meiosis II of polar body oocyte (may or may not occur) Meiosis II completed (only if sperm n n n n penetration occurs) Polar bodies (all polar bodies Second Ovum degenerate) polar body © 2018 Pearson Education, Inc.  Hormone Production by the Ovaries  Estrogens are produced by follicle cells  Cause secondary sex characteristics  Enlargement of accessory organs of the female reproductive system  Development of breasts  Appearance of axillary and pubic hair  Increase in fat beneath the skin, particularly in hips and breasts  Widening and lightening of the pelvis  Onset of menses (menstrual cycle) © 2018 Pearson Education, Inc.  Hormone Production by the Ovaries  Progesterone is produced by the corpus luteum  Production continues until LH diminishes in the blood  Does not contribute to the appearance of secondary sex characteristics  Other major effects  Helps maintain pregnancy  Prepares the breasts for milk production © 2018 Pearson Education, Inc.  Uterine (Menstrual) Cycle  Cyclic changes of the endometrium, about 28 days in length  Regulated by cyclic production of estrogens and progesterone by the ovaries  FSH and LH, from the anterior pituitary, regulate the production of estrogens and progesterone by the ovaries  Ovulation typically occurs about midway through cycle, on day 14 © 2018 Pearson Education, Inc.  Uterine (Menstrual) Cycle  Stages of the menstrual cycle  Menstrual phase  Proliferative stage  Secretory stage © 2018 Pearson Education, Inc.  Uterine (Menstrual) Cycle  Days 1–5: menstrual phase  Functional layer of the endometrium is sloughed  Bleeding occurs for 3 to 5 days  Ovarian hormones are at their lowest levels  By day 5, growing ovarian follicles are producing more estrogen © 2018 Pearson Education, Inc.  Uterine (Menstrual) Cycle  Days 6–14: proliferative stage  Regeneration of functional layer of the endometrium  Endometrium is repaired, thickens, and becomes well vascularized  Estrogen levels rise  Ovulation occurs in the ovary at the end of this stage © 2018 Pearson Education, Inc.  Uterine (Menstrual) Cycle  Days 15–28: secretory phase  Levels of progesterone rise and increase the blood supply to the endometrium, which becomes more vascular  Endometrium increases in size and readies for implantation © 2018 Pearson Education, Inc.  Uterine (Menstrual) Cycle  Days 15–28: secretory phase (continued)  If fertilization does occur:  Embryo produces a hormone that causes the corpus luteum to continue producing its hormones  If fertilization does NOT occur:  Corpus luteum degenerates as LH blood levels decline  The phases are repeated about every 28 days © 2018 Pearson Education, Inc. Figure 16.12a Hormonal interactions of the female cycles. Plasma hormone level LH FSH (a) Fluctuation of gonadotropin levels: Fluctuating levels of pituitary gonadotropins (FSH and LH) in the blood regulate the events of the ovarian cycle. © 2018 Pearson Education, Inc. Figure 16.12b Hormonal interactions of the female cycles. Primary Secondary Vesicular Ovulation Corpus Degenerating follicle follicle follicle luteum corpus luteum Follicular Ovulation Luteal phase (Day 14) phase (b) Ovarian cycle: Structural changes in the ovarian follicles during the ovarian cycle are correlated with (d) changes in the endometrium of the uterus during the uterine cycle. © 2018 Pearson Education, Inc. Figure 16.12c Hormonal interactions of the female cycles. Plasma hormone level Estrogens Progesterone (c) Fluctuation of ovarian hormone levels: Fluctuating levels of ovarian hormones (estrogens and progesterone) cause the endometrial changes of the uterine cycle. The high estrogen levels are also responsible for the LH/FSH surge in (a). © 2018 Pearson Education, Inc. Figure 16.12d Hormonal interactions of the female cycles. Endometrial Blood vessels Functional layer glands Menstrual flow Basal layer 1 5 10 15 20 25 28 Days Menstrual Proliferative Secretory phase phase phase The menstrual and proliferative phases occur before ovulation and together correspond to the follicular phase of the ovarian cycle. The secretory phase corresponds in time to the luteal phase of the ovarian cycle. (d) The three phases of the uterine cycle: Menstrual: Shedding of the functional layer of the endometrium. Proliferative: Rebuilding of the functional layer of the endometrium. Secretory: Begins immediately after ovulation. Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo. © 2018 Pearson Education, Inc. Figure 16.7 Sagittal section of a human ovary showing the developmental stages of an ovarian follicle. Primary follicle Growing follicles Degenerating corpus luteum Blood vessels Antrum Corona radiata Mature vesicular (Graafian) follicle Germinal epithelium Corpus luteum Developing Ruptured Ovulation Secondary oocyte corpus luteum follicle © 2018 Pearson Education, Inc.  Mammary Glands  Present in both sexes, but function only in females  Modified sweat glands  Function is to produce milk to nourish a newborn  Stimulated by sex hormones (mostly estrogens) to increase in size © 2018 Pearson Education, Inc.  Mammary Glands  Parts of the mammary gland  Areola—central pigmented area  Nipple—protruding central area of areola  Lobes—internal structures that radiate around nipple  Lobules—located within each lobe and contain clusters of alveolar glands  Alveolar glands—produce milk when a woman is lactating (producing milk)  Lactiferous ducts—connect alveolar glands to nipple  Lactiferous sinus—dilated portion where milk accumulates © 2018 Pearson Education, Inc. Figure 16.13a Female mammary glands. Skin (cut) Pectoralis major muscle Connective tissue suspensory ligament Adipose tissue Lobe Areola Nipple Lactiferous sinus Lactiferous duct Lobule containing alveoli (a) © 2018 Pearson Education, Inc. Figure 16.13b Female mammary glands. First rib Skin (cut) Pectoralis major muscle Connective tissue suspensory ligament Adipose tissue Lobe Areola Nipple Opening of lactiferous duct Lactiferous sinus Lactiferous duct Lobule containing alveoli Hypodermis (superficial fascia) Intercostal muscles (b) © 2018 Pearson Education, Inc.  Mammography  Mammography is X-ray examination that detects breast cancers too small to feel  American Cancer Society recommends mammography annually for women between 45 and 54 years old and every 2 years thereafter if the results are normal  Breast cancer is often signaled by a change in skin texture, puckering, or leakage from the nipple © 2018 Pearson Education, Inc. Figure 16.14 Mammograms. Malignancy (a) Mammogram procedure (b) Film of normal breast (c) Film of breast with tumor © 2018 Pearson Education, Inc.  Pregnancy and Embryonic Development  Pregnancy—time from fertilization until infant is born  Conceptus—developing offspring  Embryo—period of time from fertilization until week 8  Fetus—week 9 until birth  Gestation period—from date of last period until birth (approximately 280 days) © 2018 Pearson Education, Inc. Figure 16.15 Diagrams showing the approximate size of a human conceptus from fertilization to the early fetal stage. Embryo Fertilization 1-week 3-week 5-week embryo conceptus embryo (10 mm) 8-week embryo (3 mm) (22 mm) 12-week fetus (90 mm) © 2018 Pearson Education, Inc.  Accomplishing Fertilization  An oocyte is viable up to 24 hours after ovulation  Sperm are viable up to 48 hours after ejaculation  For fertilization to occur, sexual intercourse must occur no more than 2 days before ovulation and no later than 24 hours after  Sperm cells must make their way to the uterine tube for fertilization to be possible  Sperm cells are attracted to the oocyte by chemicals © 2018 Pearson Education, Inc. © 2018 Pearson Education, Inc.  Accomplishing Fertilization  When sperm reach the oocyte:  Enzymes break down the follicle cells of the corona radiata around the oocyte  Sperm undergo an acrosomal reaction  Membrane receptors on the oocyte pull in the head of the first sperm cell to make contact  Oocyte undergoes second meiotic division to produce an ovum and a polar body © 2018 Pearson Education, Inc. Figure 16.16 Sperm and oocyte during fertilization. © 2018 Pearson Education, Inc.  Accomplishing Fertilization  Fertilization occurs when the genetic material of a sperm combines with that of an oocyte © 2018 Pearson Education, Inc.  Events of Embryonic & Fetal Development  Zygote  First cell of a new individual  The zygote is the result of the fusion of DNA from sperm and egg  The zygote begins rapid mitotic cell divisions, known as cleavage, 24 hours after fertilization  The zygote journeys down the uterine tube, moving toward the uterus © 2018 Pearson Education, Inc.  Events of Embryonic & Fetal Development  Cleavage  Rapid series of mitotic divisions that begins with the zygote  3 days after ovulation, the embryo reaches the uterus and floats as a morula, a ball of 16 cells © 2018 Pearson Education, Inc.  Events of Embryonic & Fetal Development  Blastocyst (chorionic vesicle)  Hollow, ball-like structure of 100 cells or more  Secretes human chorionic gonadotropin (hCG) to induce the corpus luteum to continue producing hormones, preventing menses, until the placenta assumes its role © 2018 Pearson Education, Inc.  Events of Embryonic & Fetal Development  Functional areas of the blastocyst 1. Trophoblast—large fluid-filled sphere 2. Inner cell mass—cluster of cells to one side  By day 7 after ovulation, the blastocyst has attached to the endometrium © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 1 (a) Zygote (b) 4-cell stage (c) Morula (d) Early blastocyst (e) Implanting (fertilized egg) 2 days (a solid ball of (morula hollows out blastocyst blastomeres) and fills with fluid) (consists of a sphere 3 days 4 days of trophoblast cells and an eccentric cell cluster called the inner cell mass) Zona 7 days pellucida Inner cell Blastocyst mass Fertilization cavity (sperm Sperm meets and enters egg) Uterine tube Blastocyst Ovary cavity Oocyte Trophoblast (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 2 Uterine tube Ovary Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 3 Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 4 (a) Zygote (fertilized egg) Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 5 (a) Zygote (fertilized egg) Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 6 (a) Zygote (b) 4-cell stage (fertilized egg) 2 days Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 7 (a) Zygote (b) 4-cell stage (fertilized egg) 2 days Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 8 (a) Zygote (b) 4-cell stage (c) Morula (fertilized egg) 2 days (a solid ball of blastomeres) 3 days Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 9 (a) Zygote (b) 4-cell stage (c) Morula (d) Early blastocyst (fertilized egg) 2 days (a solid ball of (morula hollows out blastomeres) and fills with fluid) 3 days 4 days Zona pellucida Blastocyst Fertilization cavity (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2018 Pearson Education, Inc. Figure 16.17 From fertilization and cleavage to implantation. Slide 10 (a) Zygote (b) 4-cell stage (c) Morula (d) Early blastocyst (e) Implanting (fertilized egg) 2 days (a solid ball of (morula hollows out blastocyst blastomeres) and fills with fluid) (consists of a sphere 3 days 4 days of trophoblast cells and an eccentric cell cluster called the inner cell mass) Zona 7 days pellucida Inner cell Blastocyst