Essentials of Human Anatomy and Physiology Reproductive System PDF

PowerPoint® Lecture Slides Prepared by Patty Bostwick-Taylor, Florence-Darlington Technical College CHAPTER 16 The Reproduct...

PowerPoint® Lecture Slides Prepared by Patty Bostwick-Taylor, Florence-Darlington Technical College CHAPTER 16 The Reproductive System © 2012 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 © 2012 Pearson Education, Inc.  Male Reproductive System Overview Testes Duct system Epididymis Ductus (vas) deferens Urethra © 2012 Pearson Education, Inc.  Male Reproductive System Overview Accessory organs Seminal vesicles Prostate Bulbourethral glands External genitalia Penis Scrotum © 2012 Pearson Education, Inc.  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 Bulbourethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce (a) Scrotum External urethral orifice © 2012 Pearson Education, Inc. Figure 16.2a  Urinary Ureter bladder Prostate Ampulla of ductus deferens Seminal vesicle Prostatic Ejaculatory urethra duct Orifices of Bulbourethral prostatic ducts gland Membranous Ductus urethra deferens Root of penis Erectile tissue of penis Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) © 2012 Pearson Education, Inc. orifice Figure 16.2b  Testes 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 © 2012 Pearson Education, Inc.  Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2012 Pearson Education, Inc. Figure 16.1  Testes Each lobule contains one to four seminiferous tubules Tightly coiled structures Function as sperm-forming factories Empty sperm into the rete testis (first part of the duct system) Sperm travels through the rete testis to the epididymis Interstitial cells in the seminiferous tubules produce androgens such as testosterone © 2012 Pearson Education, Inc.  Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2012 Pearson Education, Inc. Figure 16.1  Duct System Epididymis Ductus (vas) deferens Urethra © 2012 Pearson Education, Inc.  Epididymis Comma-shaped, tightly coiled tube Found on the superior part of the testis and along the posterior lateral side Functions to mature and store sperm cells (at least 20 days) Expels sperm with the contraction of muscles in the epididymis walls to the vas deferens © 2012 Pearson Education, Inc.  Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2012 Pearson Education, Inc. Figure 16.1  Ductus Deferens (Vas Deferens) Carries sperm from the epididymis to the ejaculatory duct Passes through the inguinal canal and over the bladder Moves sperm by peristalsis Spermatic cord—ductus deferens, blood vessels, and nerves in a connective tissue sheath © 2012 Pearson Education, Inc.  Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2012 Pearson Education, Inc. Figure 16.1  Ductus Deferens (Vas Deferens) Terminates in the ejaculatory duct which unites with the urethra Expanded end of the ductus deferens is called the ampulla 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 to prevent transportation of sperm (form of birth control) © 2012 Pearson Education, Inc.  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 © 2012 Pearson Education, Inc.  Urethra Regions of the urethra Prostatic urethra—surrounded by prostate Membranous urethra—travels from prostatic urethra to penis Spongy (penile) urethra—runs the length of the penis © 2012 Pearson Education, Inc.  Urinary Ureter bladder Prostate Ampulla of ductus deferens Seminal vesicle Prostatic Ejaculatory urethra duct Orifices of Bulbourethral prostatic ducts gland Membranous Ductus urethra deferens Root of penis Erectile tissue of penis Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) © 2012 Pearson Education, Inc. orifice Figure 16.2b  Accessory Organs Seminal vesicles Prostate Bulbourethral glands © 2012 Pearson Education, Inc.  Urinary Ureter bladder Prostate Ampulla of ductus deferens Seminal vesicle Prostatic Ejaculatory urethra duct Orifices of Bulbourethral prostatic ducts gland Membranous Ductus urethra deferens Root of penis Erectile tissue of penis Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) © 2012 Pearson Education, Inc. orifice Figure 16.2b  Seminal Vesicles Located at the base of the bladder Produces a thick, yellowish secretion (60 percent of semen) Fructose (sugar) Vitamin C Prostaglandins Other substances that nourish and activate sperm © 2012 Pearson Education, Inc.  Urinary Ureter bladder Prostate Ampulla of ductus deferens Seminal vesicle Prostatic Ejaculatory urethra duct Orifices of Bulbourethral prostatic ducts gland Membranous Ductus urethra deferens Root of penis Erectile tissue of penis Epididymis Shaft (body) of penis Testis Spongy urethra Glans penis Prepuce External urethral (b) © 2012 Pearson Education, Inc. orifice Figure 16.2b  Prostate Encircles the upper part of the urethra Secretes a milky fluid Helps to activate sperm Enters the urethra through several small ducts Prostatitis–inflammation of the prostate Prostate cancer–third most common cancer in males © 2012 Pearson Education, Inc.  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 Bulbourethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce (a) Scrotum External urethral orifice © 2012 Pearson Education, Inc. Figure 16.2a  Bulbourethral Glands Pea-sized gland inferior to the prostate Produces a thick, clear mucus Cleanses the urethra of acidic urine prior to ejaculation Serves as a lubricant during sexual intercourse Secreted into the penile urethra © 2012 Pearson Education, Inc.  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 Bulbourethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce (a) Scrotum External urethral orifice © 2012 Pearson Education, Inc. Figure 16.2a  Semen Mixture of sperm and accessory gland secretions Advantages of accessory gland secretions Fructose provides energy for sperm cells Alkalinity of semen helps neutralize the acidic environment of vagina Semen inhibits bacterial multiplication Elements of semen enhance sperm motility © 2012 Pearson Education, Inc.  External Genitalia Scrotum Penis © 2012 Pearson Education, Inc.  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 Bulbourethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce (a) Scrotum External urethral orifice © 2012 Pearson Education, Inc. Figure 16.2a  External Genitalia Scrotum Divided sac of skin outside the abdomen Maintains testes at 3°C lower than normal body temperature to protect sperm viability © 2012 Pearson Education, Inc.  External Genitalia Penis 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 © 2012 Pearson Education, Inc.  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 Bulbourethral gland Spongy urethra Shaft of the penis Ductus (vas) deferens Epididymis Glans penis Testis Prepuce (a) Scrotum External urethral orifice © 2012 Pearson Education, Inc. Figure 16.2a  External Genitalia Internally there are three areas of spongy erectile tissue around the urethra Erections occur when this erectile tissue fills with blood during sexual excitement © 2012 Pearson Education, Inc.  Spermatic cord Blood vessels and nerves Seminiferous tubule Rete testis Ductus (vas) deferens Lobule Septum Tunica Epididymis albuginea © 2012 Pearson Education, Inc. Figure 16.1  Spermatogenesis Production of sperm cells Begins at puberty and continues throughout life Occurs in the seminiferous tubules © 2012 Pearson Education, Inc.  Seminiferous tubule Basement membrane Spermatogonium Daughter cell (stem cell) type A (remains at basement Mitosis membrane Growth as a stem cell) Daughter cell type B Enters (moves toward tubule prophase of lumen) meiosis I Primary Meiosis spermatocyte Meiosis I completed Secondary spermatocytes Spermatogenesis Meiosis II Early spermatids Spermiogenesis Late spermatids Sperm Lumen of seminiferous tubule © 2012 Pearson Education, Inc. Figure 16.3  Seminiferous tubule Basement membrane Spermatogonium Daughter cell (stem cell) type A (remains at basement membrane Mitosis as a stem cell) Growth Daughter cell type B Enters (moves toward tubule prophase of lumen) meiosis I Primary Meiosis spermatocyte Meiosis I completed Secondary spermatocytes Meiosis II Early spermatids © 2012 Pearson Education, Inc. Figure 16.3 (1 of 2)  Spermiogenesis Late spermatids Sperm Lumen of seminiferous tubule © 2012 Pearson Education, Inc. Figure 16.3 (2 of 2)  Spermatogenesis Spermatogonia (stem cells) undergo rapid mitosis to produce more stem cells before puberty Follicle-stimulating hormone (FSH) modifies spermatogonia division One cell produced is a stem cell, called a type A daughter cell The other cell produced becomes a primary spermatocyte, called a type B daughter cell © 2012 Pearson Education, Inc.  Spermatogenesis Primary spermatocytes undergo meiosis One primary spermatocyte produces four haploid spermatids Spermatids—23 chromosomes (half as much material as other body cells) © 2012 Pearson Education, Inc.  Human Life Cycle Union of a sperm (23 chromosomes) with an egg (23 chromosomes) creates a zygote (2n or 46 chromosomes) © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 16.4  Spermiogenesis Late spermatids are produced with distinct regions Head Midpiece Tail Sperm cells result after maturing of spermatids Spermatogenesis (entire process, including spermiogenesis) takes 64 to 72 days © 2012 Pearson Education, Inc.  Plasma membrane Neck Tail Midpiece Head Axial filament Distal Acrosome of tail centriole Nucleus Mitochondria Proximal centriole (b) © 2012 Pearson Education, Inc. Figure 16.5b © 2012 Pearson Education, Inc. Figure 16.5a  Anatomy of a Mature Sperm Cell The only human flagellated cell Head Contains DNA Acrosome—“helmet” on the nucleus, similar to a large lysosome Breaks down and releases enzymes to help the sperm penetrate an egg Midpiece Wrapped by mitochondria for ATP generation © 2012 Pearson Education, Inc.  Testosterone Production The most important hormone of the testes Produced in interstitial cells During puberty, luteinizing hormone (LH) activate the interstitial cells In turn, testosterone is produced © 2012 Pearson Education, Inc.  Testosterone Production Functions of testosterone Stimulates reproductive organ development Underlies sex drive Causes secondary sex characteristics Deepening of voice Increased hair growth Enlargement of skeletal muscles Thickening of bones © 2012 Pearson Education, Inc.  Hypothalamus 1 The hypothalamus releases gonadotropin-releasing 1 hormone (GnRH). GnRH 2 GnRH stimulates the Anterior anterior pituitary to release pituitary gonadotropins—FSH and LH. 3 FSH stimulates spermatogenic cells 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 spermatogenesis. 5 5 Rising level of testosterone exerts feedback inhibition on the hypothalamus and pituitary. Testosterone Primary and secondary sex characteristics Seminiferous Supporting cell tubule in testis FSH and testosterone stimulate sperm production Spermatogenic cells Spermatogenesis KEY: Stimulates Inhibits © 2012 Pearson Education, Inc. Figure 16.6  Hypothalamus 1 The hypothalamus releases gonadotropin-releasing 1 hormone (GnRH). GnRH Anterior pituitary Seminiferous Supporting cell tubule in testis Spermatogenic cells Spermatogenesis KEY: Stimulates Inhibits © 2012 Pearson Education, Inc. Figure 16.6, step 1  Hypothalamus 1 The hypothalamus releases gonadotropin-releasing 1 hormone (GnRH). GnRH 2 GnRH stimulates the Anterior anterior pituitary to release pituitary gonadotropins—FSH and LH. 2 FSH LH Seminiferous Supporting cell tubule in testis Spermatogenic cells Spermatogenesis KEY: Stimulates Inhibits © 2012 Pearson Education, Inc. Figure 16.6, step 2  Hypothalamus 1 The hypothalamus releases gonadotropin-releasing 1 hormone (GnRH). GnRH 2 GnRH stimulates the Anterior anterior pituitary to release pituitary gonadotropins—FSH and LH. 3 FSH stimulates spermatogenic cells to produce sperm. 2 FSH LH 3 Seminiferous Supporting cell tubule in testis Spermatogenic cells Spermatogenesis KEY: Stimulates Inhibits © 2012 Pearson Education, Inc. Figure 16.6, step 3  Hypothalamus 1 The hypothalamus releases gonadotropin-releasing 1 hormone (GnRH). GnRH 2 GnRH stimulates the Anterior anterior pituitary to release pituitary gonadotropins—FSH and LH. 3 FSH stimulates spermatogenic cells 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 Seminiferous Supporting cell tubule in testis Spermatogenic cells Spermatogenesis KEY: Stimulates Inhibits © 2012 Pearson Education, Inc. Figure 16.6, step 4  Hypothalamus 1 The hypothalamus releases gonadotropin-releasing 1 hormone (GnRH). GnRH 2 GnRH stimulates the Anterior anterior pituitary to release pituitary gonadotropins—FSH and LH. 3 FSH stimulates spermatogenic cells 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 spermatogenesis. 5 5 Rising level of testosterone exerts feedback inhibition on the hypothalamus and pituitary. Testosterone Primary and secondary sex characteristics Seminiferous Supporting cell tubule in testis FSH and testosterone stimulate sperm production Spermatogenic cells Spermatogenesis KEY: Stimulates Inhibits © 2012 Pearson Education, Inc. Figure 16.6, step 5  Female Reproductive System Ovaries Duct System Uterine tubes (fallopian tubes) Uterus Vagina External genitalia © 2012 Pearson Education, Inc.  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) © 2012 Pearson Education, Inc. Figure 16.8a  Ovaries Composed of ovarian follicles (sac-like structures) Each follicle consists of Oocyte (immature egg) Follicular cells—surround the oocyte © 2012 Pearson Education, Inc.  Growing follicles Primary follicle Degenerating corpus luteum Blood vessels Antrum Corona radiata Mature vesicular (Graafian) follicle Germinal epithelium Corpus luteum Developing Ruptured Ovulation Secondary oocyte corpus luteum follicle © 2012 Pearson Education, Inc. Figure 16.7  Ovarian Follicle Stages Primary follicle—contains an immature oocyte Graafian (vesicular) follicle—growing follicle with a maturing oocyte Ovulation—when the egg is mature, the follicle ruptures; occurs about every 28 days The ruptured follicle is transformed into a corpus luteum © 2012 Pearson Education, Inc.  Support for Ovaries Suspensory ligaments—secure ovary to lateral walls of the pelvis Ovarian ligaments—attach to uterus Broad ligament—a fold of the peritoneum, encloses suspensory ligament © 2012 Pearson Education, Inc.  Suspensory ligament of ovary Uterine (fallopian) tube Ovarian Fundus Lumen (cavity) blood of uterus of uterus vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Myometrium Wall of Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Cervix Vagina (b) © 2012 Pearson Education, Inc. Figure 16.8b  Duct System Uterine tubes (fallopian tubes) Uterus Vagina © 2012 Pearson Education, Inc.  Uterine (Fallopian) Tubes Receive the ovulated oocyte Provide a site for fertilization Attach to the uterus Little or no contact between ovaries and uterine tubes Supported and enclosed by the broad ligament © 2012 Pearson Education, Inc.  Uterine Tube Anatomy and Physiology Fimbriae Finger-like projections at the distal end of the uterine tube Receive the oocyte from the ovary Cilia Located inside the uterine tube Slowly move the oocyte towards the uterus (takes 3 to 4 days) Fertilization occurs inside the uterine tube since oocyte lives about 24 hours © 2012 Pearson Education, Inc.  Suspensory ligament of ovary Uterine (fallopian) tube Ovarian Fundus Lumen (cavity) blood of uterus of uterus vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Myometrium Wall of Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Cervix Vagina (b) © 2012 Pearson Education, Inc. Figure 16.8b  Uterus Located between the urinary bladder and rectum Hollow organ Functions of the uterus Receives a fertilized egg Retains the fertilized egg Nourishes the fertilized egg © 2012 Pearson Education, Inc.  Support for the Uterus Broad ligament—attached to the pelvis Round ligament—anchored anteriorly Uterosacral ligaments—anchored posteriorly © 2012 Pearson Education, Inc.  Suspensory ligament of ovary Uterine (fallopian) tube Ovarian Fundus Lumen (cavity) blood of uterus of uterus vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Myometrium Wall of Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Cervix Vagina (b) © 2012 Pearson Education, Inc. Figure 16.8b  Regions of the Uterus Body—main portion Fundus—superior rounded region above where uterine tube enters Cervix—narrow outlet that protrudes into the vagina © 2012 Pearson Education, Inc.  Walls of the Uterus Endometrium Inner layer Allows for implantation of a fertilized egg Sloughs off if no pregnancy occurs (menses) Myometrium—middle layer of smooth muscle Perimetrium (visceral peritoneum)—outermost serous layer of the uterus © 2012 Pearson Education, Inc.  Suspensory ligament of ovary Uterine (fallopian) tube Ovarian Fundus Lumen (cavity) blood of uterus of uterus vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Myometrium Wall of Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Cervix Vagina (b) © 2012 Pearson Education, Inc. Figure 16.8b  Vagina Extends from cervix to exterior of body Located between bladder and rectum Serves as the birth canal Receives the penis during sexual intercourse Hymen—partially closes the vagina until it is ruptured © 2012 Pearson Education, Inc.  Suspensory ligament of ovary Uterine (fallopian) tube Ovarian Fundus Lumen (cavity) blood of uterus of uterus vessels Ovary Broad Infundibulum Uterine ligament Fimbriae tube Ovarian ligament Round ligament of uterus Body of Endometrium uterus Myometrium Wall of Perimetrium uterus Ureter Uterine blood Cervical canal vessels Uterosacral ligament Cervix Vagina (b) © 2012 Pearson Education, Inc. Figure 16.8b  External Genitalia (Vulva) Mons pubis Labia Clitoris Urethral orifice Vaginal orifice Greater vestibular glands © 2012 Pearson Education, Inc.  Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Orifice of greater vestibular gland Labia minora Perineum Anus © 2012 Pearson Education, Inc. Figure 16.9  Mons Pubis Fatty area overlying the pubic symphysis Covered with pubic hair after puberty © 2012 Pearson Education, Inc.  Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Orifice of greater vestibular gland Labia minora Perineum Anus © 2012 Pearson Education, Inc. Figure 16.9  Labia 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 © 2012 Pearson Education, Inc.  Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Orifice of greater vestibular gland Labia minora Perineum Anus © 2012 Pearson Education, Inc. Figure 16.9  Vestibule and Greater Vestibular Glands 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 Secretes lubricant during intercourse © 2012 Pearson Education, Inc.  Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Orifice of greater vestibular gland Labia minora Perineum Anus © 2012 Pearson Education, Inc. Figure 16.9  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 Becomes swollen with blood during sexual excitement © 2012 Pearson Education, Inc.  Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Orifice of greater vestibular gland Labia minora Perineum Anus © 2012 Pearson Education, Inc. Figure 16.9  Perineum Diamond-shaped region between the anterior ends of the labial folds, anus posteriorly, and ischial tuberosities laterally © 2012 Pearson Education, Inc.  Mons pubis Labia majora Prepuce of clitoris Clitoris Vestibule Urethral orifice Vaginal orifice Orifice of greater vestibular gland Labia minora Perineum Anus © 2012 Pearson Education, Inc. Figure 16.9  Oogenesis and the Ovarian Cycle The total supply of eggs are present at birth Ability to release eggs begins at puberty Reproductive ability ends at menopause Oocytes are matured in developing ovarian follicles © 2012 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle Oogonia—female stem cells found in a developing fetus Oogonia undergo mitosis to produce primary oocytes Primary oocytes are surrounded by cells that form primary follicles in the ovary Oogonia no longer exist by the time of birth © 2012 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 © 2012 Pearson Education, Inc.  Oogenesis and the Ovarian Cycle Meiosis starts inside maturing follicle Produces a secondary oocyte and the first polar body Follicle development to the stage of a vesicular 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 © 2012 Pearson Education, Inc.  Oocyte © 2012 Pearson Education, Inc. Figure 16.11  Oogenesis and the Ovarian Cycle Meiosis is completed after ovulation only if sperm penetrates Ovum is produced Two additional polar bodies are produced Once ovum is formed, the 23 chromosomes can be combined with those 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 © 2012 Pearson Education, Inc.  Male and Female Differences Meiosis Males—produces four functional sperm Females—produces one functional ovum and three polar bodies Sex cell size and structure Sperm are tiny, motile, and equipped with nutrients in seminal fluid Egg is large, non-motile, and has nutrient reserves to nourish the embryo until implantation © 2012 Pearson Education, Inc.  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 © 2012 Pearson Education, Inc. Figure 16.10  Uterine (Menstrual) Cycle Cyclic changes of the endometrium Regulated by cyclic production of estrogens and progesterone FSH and LH regulate the production of estrogens and progesterone Both menstrual and ovarian cycles are about 28 days in length Ovulation typically occurs about midway through cycle on day 14 © 2012 Pearson Education, Inc.  Uterine (Menstrual) Cycle Stages of the menstrual cycle Menstrual phase Proliferative stage Secretory stage © 2012 Pearson Education, Inc.  Uterine (Menstrual) Cycle Menstrual phase Days 1 to 5 Functional layer of the endometrium is sloughed Bleeding occurs for 3 to 5 days By day 5, growing ovarian follicles are producing more estrogen © 2012 Pearson Education, Inc.  Uterine (Menstrual) Cycle Proliferative stage Days 6 to 14 Regeneration of functional layer of the endometrium Estrogen levels rise Ovulation occurs in the ovary at the end of this stage © 2012 Pearson Education, Inc.  Uterine (Menstrual) Cycle Secretory stage Days 15 to 28 Levels of progesterone rise and increase the blood supply to the endometrium Endometrium increases in size and readies for implantation © 2012 Pearson Education, Inc.  Uterine (Menstrual) Cycle Secretory stage (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 © 2012 Pearson Education, Inc.  (a) Fluctuation of gonadotropin levels: Plasma hormone level Fluctuating levels of pituitary gonadotropins (FSH and LH) in the LH blood regulate the events of the ovarian cycle. FSH © 2012 Pearson Education, Inc. Figure 16.12a  (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. Primary Secondary Vesicular Ovulation Corpus Degenerating follicle follicle follicle luteum corpus luteum Follicular Ovulation Luteal phase (Day 14) phase © 2012 Pearson Education, Inc. Figure 16.12b  (c) Fluctuation of ovarian hormone Plasma hormone level levels: Fluctuating levels of ovarian hormones (estrogens and progesterone) cause the endometrial changes of the Estrogens uterine cycle. The high estrogen levels are also responsible for Progesterone the LH/FSH surge in (a). © 2012 Pearson Education, Inc. Figure 16.12c  Endometrial Blood vessels (d) The three phases of the uterine cycle: Basal layer Functional layer glands Menstrual: Shedding of the functional layer of the endometrium. Proliferative: Rebuilding of the functional layer of the endometrium. Menstrual Secretory: Begins immediately after flow ovulation. Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo. 1 5 10 15 20 25 28 Days Menstrual Proliferative Secretory The menstrual and proliferative phases occur phase phase phase 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. © 2012 Pearson Education, Inc. Figure 16.12d  Hormone Production by the Ovaries Estrogens 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) © 2012 Pearson Education, Inc.  Hormone Production by the Ovaries Progesterone 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 Prepare the breasts for milk production © 2012 Pearson Education, Inc.  Growing follicles Primary follicle Degenerating corpus luteum Blood vessels Antrum Corona radiata Mature vesicular (Graafian) follicle Germinal epithelium Corpus luteum Developing Ruptured Ovulation Secondary oocyte corpus luteum follicle © 2012 Pearson Education, Inc. Figure 16.7  Mammary Glands Present in both sexes, but only function in females Modified sweat glands Function is to produce milk Stimulated by sex hormones (mostly estrogens) to increase in size © 2012 Pearson Education, Inc.  Anatomy of Mammary Glands 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 © 2012 Pearson Education, Inc.  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 (a) © 2012 Pearson Education, Inc. Figure 16.13a  Skin (cut) First rib 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) © 2012 Pearson Education, Inc. Figure 16.13b  Mammography X-ray examination that detects breast cancers too small to feel Recommended every 2 years for women between 40 and 49 years old and yearly thereafter © 2012 Pearson Education, Inc.  Malignancy (a) Mammogram procedure (b) Film of normal breast (c) Film of breast with tumor © 2012 Pearson Education, Inc. Figure 16.14a-c  Introduction to Pregnancy and 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) © 2012 Pearson Education, Inc.  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) © 2012 Pearson Education, Inc. Figure 16.15  Accomplishing Fertilization The oocyte is viable for 12 to 24 hours after ovulation Sperm are viable for 24 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 © 2012 Pearson Education, Inc.  Accomplishing Fertilization When sperm reach the oocyte, enzymes break down the follicle cells of the corona radiata around the oocyte Once a path is cleared, sperm undergo an acrosomal reaction (acrosomal membranes break down and enzymes digest holes in the oocyte membrane) Membrane receptors on an oocyte pull in the head of the first sperm cell to make contact © 2012 Pearson Education, Inc.  Mechanisms of Fertilization The membrane of the oocyte does not permit a second sperm head to enter The oocyte then undergoes its second meiotic division to form the ovum and a polar body Fertilization occurs when the genetic material of a sperm combines with that of an oocyte to form a zygote © 2012 Pearson Education, Inc.  The Zygote First cell of a new individual The result of the fusion of DNA from sperm and egg The zygote begins rapid mitotic cell divisions The zygote stage is in the uterine tube, moving toward the uterus © 2012 Pearson Education, Inc.  Cleavage Rapid series of mitotic divisions that begins with the zygote and ends with the blastocyst Zygote begins to divide 24 hours after fertilization Three to 4 days after ovulation, the preembryo reaches the uterus and floats freely for 2 to 3 days Late blastocyst stage—embryo implants in endometrium (day 7 after ovulation) © 2012 Pearson Education, Inc.  (e) Implanting (d) Early blastocyst blastocyst (a) Zygote (b) 4-cell stage (c) Morula Morula hollows (Consists of a (fertilized egg) 2 days (a solid ball of out sphere blastomeres) and fills with of trophoblast 3 days fluid. cells 4 days and an eccentric cell cluster called the inner cell Zona mass) pellucida 7 days Inner cell Blastocyst mass Fertilization cavity (sperm Sperm meets and enters egg) Uterine tube Blastocyst Ovary cavity Oocyte (egg) Trophoblast Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16  Uterine tube Ovary Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16, step 1  Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16, step 2  (a) Zygote (fertilized egg) Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16, step 3  (a) Zygote (fertilized egg) Zona pellucida Fertilization (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16, step 4  (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 © 2012 Pearson Education, Inc. Figure 16.16, step 5  (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 © 2012 Pearson Education, Inc. Figure 16.16, step 6  (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 © 2012 Pearson Education, Inc. Figure 16.16, step 7  (d) Early blastocyst (a) Zygote (b) 4-cell stage (c) Morula Morula hollows (fertilized egg) 2 days (a solid ball of out blastomeres) and fills with 3 days fluid. 4 days Zona pellucida Blastocyst Fertilization cavity (sperm Sperm meets and enters egg) Uterine tube Ovary Oocyte (egg) Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16, step 8  (e) Implanting (d) Early blastocyst blastocyst (a) Zygote (b) 4-cell stage (c) Morula Morula hollows (Consists of a (fertilized egg) 2 days (a solid ball of out sphere blastomeres) and fills with of trophoblast 3 days fluid. cells 4 days and an eccentric cell cluster called the inner cell Zona mass) pellucida 7 days Inner cell Blastocyst mass Fertilization cavity (sperm Sperm meets and enters egg) Uterine tube Blastocyst Ovary cavity Oocyte (egg) Trophoblast Uterus Ovulation Endometrium Cavity of uterus © 2012 Pearson Education, Inc. Figure 16.16, step 9  Events of Embryonic and Fetal Development Embryo—period of time from fertilization until week 8 Morula—16-cell stage Blastocyst (chorionic vesicle)—hollow, ball-like structure containing about 100 cells Fetus–week 9 until birth © 2012 Pearson Education, Inc.  The Embryo The embryo first undergoes division without growth The embryo enters the uterus at the 16-cell state (called a morula) about 3 days after ovulation The embryo floats free in the uterus temporarily Uterine secretions are used for nourishment © 2012 Pearson Education, Inc.  The Blastocyst (Chorionic Vesicle) Ball-like circle of cells Begins at about the 100-cell stage Secretes human chorionic gonadotropin (hCG) to induce the corpus luteum to continue producing hormones Functional areas of the blastocyst Trophoblast—large fluid-filled sphere Inner cell mass—cluster of cells to one side © 2012 Pearson Education, Inc.  The Blastocyst (Chorionic Vesicle) Primary germ layers are eventually formed Ectoderm—outside layer Mesoderm—middle layer Endoderm—inside layer The late blastocyst implants in the wall of the uterus (by day 14) © 2012 Pearson Education, Inc.  Derivatives of Germ Layers Ectoderm Nervous system Epidermis of the skin Endoderm Mucosae Glands Mesoderm Everything else © 2012 Pearson Education, Inc.  Umbilical cord Amnion Chorionic Uterine villi cavity Chorion Ectoderm Forming Embryo mesoderm Endoderm © 2012 Pearson Education, Inc. Figure 16.17  Development After Implantation Chorionic villi (projections of the blastocyst) develop Cooperate with cells of the uterus to form the placenta Amnion—fluid-filled sac that surrounds the embryo Umbilical cord Blood vessel-containing stalk of tissue Attaches the embryo to the placenta © 2012 Pearson Education, Inc.  Umbilical cord Amnion Chorionic Uterine villi cavity Chorion Ectoderm Forming Embryo mesoderm Endoderm © 2012 Pearson Education, Inc. Figure 16.17  Amniotic sac Umbilical cord Umbilical vein Chorionic villi Yolk sac Cut edge of chorion © 2012 Pearson Education, Inc. Figure 16.18  Functions of the Placenta Forms a barrier between mother and embryo (blood is not exchanged) Delivers nutrients and oxygen Removes waste from embryonic blood Becomes an endocrine organ (produces hormones) and takes over for the corpus luteum (by end of second month) by producing Estrogen Progesterone Other hormones that maintain pregnancy © 2012 Pearson Education, Inc.  The Fetus (Beginning of the Ninth Week) All organ systems are formed by the end of the eighth week Activities of the fetus are growth and organ specialization This is a stage of tremendous growth and change in appearance © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 16.19a-b  Effects of Pregnancy on the Mother Pregnancy—period from conception until birth Anatomical changes Enlargement of the uterus Accentuated lumbar curvature (lordosis) Relaxation of the pelvic ligaments and pubic symphysis due to production of relaxin © 2012 Pearson Education, Inc. © 2012 Pearson Education, Inc. Figure 16.20a-d  Effects of Pregnancy on the Mother Physiological changes Gastrointestinal system Morning sickness is common due to elevated progesterone and estrogens Heartburn is common because of organ crowding by the fetus Constipation is caused by declining motility of the digestive tract © 2012 Pearson Education, Inc.  Effects of Pregnancy on the Mother Physiological changes (continued) Urinary system Kidneys have additional burden and produce more urine The uterus compresses the bladder, causing stress incontinence © 2012 Pearson Education, Inc.  Effects of Pregnancy on the Mother Physiological changes (continued) Respiratory system Nasal mucosa becomes congested and swollen Vital capacity and respiratory rate increase Dyspnea (difficult breathing) occurs dur