© 2016 Pearson Education, Inc.

I. Reproductive System Primary sex organs (gonads): testes and ovaries
1. Produce gametes (sex cells): sperm and ova 2. Secrete steroid sex hormones a. Androgens (males) b. Estrogens and progesterone (females) B. Accessory reproductive organs: 1. ducts, glands, and external genitalia © 2016 Pearson Education, Inc.

II. Anatomy of Male Reproductive System
A. The Testes and Scrotum 1. Testes: sperm-producing male gonads that lie within the scrotum a. Sperm is delivered to body through system of ducts b. Testis divided into ~250 lobules, each cotaining of one to four seminiferous tubules i. Site of sperm production © 2016 Pearson Education, Inc.

i. Testicular veins surround each testicular artery
c. Blood supply i. Testicular veins surround each testicular artery Absorb heat from testicular arteries Keep testes cool © 2016 Pearson Education, Inc.

Peritoneum Ureter Seminal gland (vesicle) Urinary bladder Ampulla of
Figure 27.1 Reproductive organs of the male, sagittal view. Peritoneum Ureter Seminal gland (vesicle) Urinary bladder Ampulla of ductus deferens Prostatic urethra Pubis Ejaculatory duct Intermediate part of the urethra Rectum Urogenital diaphragm Prostate Corpus cavernosum Bulbo-urethral gland Corpus spongiosum Anus Spongy urethra Bulb of penis Glans penis Ductus (vas) deferens Prepuce (foreskin) Epididymis External urethral orifice Scrotum Testis © 2016 Pearson Education, Inc.

27.1 Scrotum and Testes 2. The Scrotum a. Sac of skin
i. Hangs outside abdominopelvic cavity ii. Contains paired testes b. 3°C lower than core body temperature i. Lower temperature is necessary for sperm production ii. Temperature is kept constant by two sets of muscles © 2016 Pearson Education, Inc.

Superficial inguinal ring (end of inguinal canal)
Figure 27.2 Relationships of the testis to the scrotum and spermatic cord. Urinary bladder Superficial inguinal ring (end of inguinal canal) Testicular artery Spermatic cord Ductus (vas) deferens Penis Autonomic nerve fibers Pampiniform venous plexus Septum of scrotum Epididymis Cremaster muscle Tunica vaginalis (from peritoneum) External spermatic fascia Tunica albuginea of testis Superficial fascia containing dartos muscle Scrotum Internal spermatic fascia Skin © 2016 Pearson Education, Inc.

Spermatic cord Blood vessels and nerves Ductus (vas) deferens Testis
Figure 27.3a Structure of the testis. Spermatic cord Blood vessels and nerves Ductus (vas) deferens Testis Head of epididymis Seminiferous tubule Efferent ductule Rete testis Lobule Straight tubule Septum Tunica albuginea Body of epididymis Tunica vaginalis Duct of epididymis Cavity of tunica vaginalis Tail of epididymis © 2016 Pearson Education, Inc.

Spermatic cord Ductus deferens Epididymis Testis
Figure 27.3b Structure of the testis. Spermatic cord Ductus deferens Epididymis Testis © 2016 Pearson Education, Inc.

1. External genitalia: scrotum and penis a. Male copulatory organ
B. Penis 1. External genitalia: scrotum and penis a. Male copulatory organ b. Penis consists of: i. Root and shaft that ends in glans penis © 2016 Pearson Education, Inc.

Circumcision: surgical removal of foreskin
ii. Foreskin: cuff of loose skin covering glans Circumcision: surgical removal of foreskin Studies show 60% reduction in HIV risk and reduced risk for other reproductive infections © 2016 Pearson Education, Inc.

2. Internally, penis made up of spongy urethra and erectile tissue a
2. Internally, penis made up of spongy urethra and erectile tissue a. spongy network of connective tissue and smooth muscle with vascular spaces b. Erection: erectile tissue fills with blood, causing penis to enlarge and become rigid © 2016 Pearson Education, Inc.

Figure 27.4 Male reproductive structures.
Ureter Urinary bladder Ampulla of ductus deferens Prostate Seminal gland Prostatic urethra Ejaculatory duct Orifices of prostatic ducts Intermediate part of the urethra (membranous urethra) Bulbo-urethral gland and duct Urogenital diaphragm Bulb of penis Root of penis Crus of penis Bulbo-urethral duct opening Ductus deferens Corpora cavernosa Epididymis Corpus spongiosum Body (shaft) of penis Testis Section of (b) Spongy urethra Glans penis Prepuce (foreskin) External urethral orifice Dorsal vessels and nerves Corpora cavernosa Urethra Skin Tunica albuginea of erectile bodies Deep arteries Corpus spongiosum © 2016 Pearson Education, Inc.

1. Ducts carry sperm from testes to body exterior
C. Male Duct System 1. Ducts carry sperm from testes to body exterior 2. Epididymis a. Located on testis b. Nonmotile sperm enter, pass slowly through (~20 days), become motile i. can be stored for several months c. During ejaculation, epidiymis contracts, expelling sperm into ductus deferens © 2016 Pearson Education, Inc.

3. Ductus Deferens and Ejaculatory Duct
a. Ductus deferens (vas deferens) ~ 45 cm long i. Joins duct of seminal vesicle to form ejaculatory duct b. Ejaculatory Duct i. Smooth muscle in walls propels sperm from epididymis to urethra c. Vasectomy: cutting and ligating ductus deferens i. Nearly 100% effective form of birth control © 2016 Pearson Education, Inc.

Spermatic cord Blood vessels and nerves Ductus (vas) deferens Testis
Figure 27.3a Structure of the testis. Spermatic cord Blood vessels and nerves Ductus (vas) deferens Testis Head of epididymis Seminiferous tubule Efferent ductule Rete testis Lobule Straight tubule Septum Tunica albuginea Body of epididymis Tunica vaginalis Duct of epididymis Cavity of tunica vaginalis Tail of epididymis © 2016 Pearson Education, Inc.

4. Urethra a. Conveys both urine and semen (at different times)
© 2016 Pearson Education, Inc.

D. Male Accessory Glands 1. Seminal glands
a. Produces seminal fluid i. Comprises 70% volume of semen b. Duct of seminal gland joins ductus deferens to form ejaculatory duct © 2016 Pearson Education, Inc.

2. Prostate a. Size of peach pit
b. Secretes milky, slightly acid fluid i. Plays a role in sperm activation ii. Makes up one-third of semen volume © 2016 Pearson Education, Inc.

3. Bulbo-urethral glands a. Pea-sized glands inferior to prostate
b. Produce thick, clear mucus during sexual arousal i. Lubricate glans penis ii. Neutralize traces of acidic urine in urethra © 2016 Pearson Education, Inc.

2. Characteristics of semen
a. Contain a hormone that allows sperm to travel through cervix and stimulate reverse peristalsis in uterus b. Contains a hormone and other enzymes that enhance sperm motility c. Contains ATP for energy d. Can suppress female immune response e. Antibiotic chemicals destroy some bacteria f. Clotting factors coagulate semen initially to prevent draining out, then liquefy it so sperm can finish journey © 2016 Pearson Education, Inc.

III. Male Reproductive Physiology
A. Erection 1. Arterioles are normally constricted 2. Sexual excitement causes release of nitric oxide (NO) a. Causes relaxation of local smooth muscle b. When smooth muscles relax, arterioles dilate 3. Can be induced or inhibited by emotions or higher mental activity © 2016 Pearson Education, Inc.

B. Ejactulation 1. Propulsion of semen from male duct system a
B. Ejactulation 1. Propulsion of semen from male duct system a. Bladder sphincter muscle constricts, preventing expulsion of urine 2. Ducts and accessory glands contract and empty their contents a. Muscles undergo rapid series of contractions that cause expulsion of semen at ~ 500 cm/s (close to 11 mph) © 2016 Pearson Education, Inc.

1. Production of gamete: sperm (spermatozoa)
C. Spermatogenesis 1. Production of gamete: sperm (spermatozoa) a. Most body cells have 46 chromosomes: i. Two sets (23 pairs) of chromosomes b. Gametes have only 23 chromosomes i. Only one member of homologous pair © 2016 Pearson Education, Inc.

2. Spermatogenic cells give rise to sperm a
2. Spermatogenic cells give rise to sperm a. Mitosis of spermatogonia (stem cell) forms two spermatocytes b. Meiosis of spermatocytes form spermatids c. Spermiogenesis: Spermatids become sperm i. Streamlining process where spermatid elongates, loses excess cytoplasm, and forms a tail to become a spermatozoon (sperm) © 2016 Pearson Education, Inc.

Scanning electron micrograph of a cross-
Figure 27.9a Spermatogenesis. Scanning electron micrograph of a cross- sectional view of a seminiferous tubule (165×) © 2016 Pearson Education, Inc.

Figure 27.9b Spermatogenesis.
Basal lamina Spermatogonium (stem cell) 2n 2n Type A daughter cell (remains at basal lamina as a precursor cell) Mitosis 2n Type B daughter cell Growth Enters meiosis I and moves to adluminal compartment 2n Primary spermatocyte Meiosis I completed (early spermatogenesis) Meiosis n n Secondary spermatocytes Meiosis II Spermatogenesis n n n n Early spermatids n n n n Late spermatids (late spermatogenesis) Spermiogenesis n n n n Spermatozoa Events of spermatogenesis, showing the relative position of various spermatogenic cells © 2016 Pearson Education, Inc.

Adluminal compartment
Figure 27.9c Spermatogenesis. Tight junction between sustentocytes Spermatogonium (stem cell) Cytoplasm of adjacent sustentocytes Sustentocyte nucleus Basal lamina Type A daughter cell (remains at basal lamina as a precursor cell) Type B daughter cell Basal compartment Primary spermatocyte Secondary spermatocytes Early spermatids Late spermatids Adluminal compartment Cytoplasmic bridge Lumen of seminiferous tubule Spermatozoa A portion of the seminiferous tubule wall, showing the spermatogenic cells surrounded by sustentocytes (colored gold) © 2016 Pearson Education, Inc.

Spermatogenesis takes 64-72 days if conditions are hospitable
a. Sperm are unable to swim b. Pressure of testicular fluid pushes immotile sperm into epididymis i. They gain motility and fertilizing power © 2016 Pearson Education, Inc.

Acrosomal vesicle Mitochondria Acrosome Nucleus
Figure Spermiogenesis: transformation of a spermatid into a functional sperm. Approximately 24 days Golgi apparatus Acrosomal vesicle Mitochondria Acrosome Nucleus 1 2 Spermatid nucleus Centrioles Microtubules Midpiece Head 3 Flagellum Excess cytoplasm 4 Tail 5 6 7 © 2016 Pearson Education, Inc.

D. Major regions of sperm: 1
D. Major regions of sperm: 1. Head: genetic region that includes nucleus and enzymes that enable sperm to penetrate egg 2. Midpiece: metabolic region containing mitochondria that produce ATP to move tail 3. Tail: locomotor region that includes flagellum © 2016 Pearson Education, Inc.

IV. Female Reproductive Anatomy
Ovaries 1. Female gonads: Produce Ova (female gametes) a. Secrete female sex hormones, estrogen and progesterone © 2016 Pearson Education, Inc.

2. Two poorly defined regions
a. Outer cortex: houses forming gametes b. Inner medulla: contains large blood vessels and nerves © 2016 Pearson Education, Inc.

3. Ovarian follicles: tiny saclike structures embedded in cortex
a. Contain immature egg (oocyte) 4. Ovulation a. Ejection of oocyte from ripening follicle © 2016 Pearson Education, Inc.

Round ligament of uterus
Figure 27.15a Internal female reproductive organs. Suspensory ligament of ovary Uterine (fallopian) tube Fundus of uterus Lumen (cavity) of uterus Ovarian blood vessels Uterine tube Broad ligament Ovary • Ampulla • Mesosalpinx • Isthmus • Infundibulum • Mesovarium • Mesometrium • Fimbriae Ovarian ligament Round ligament of uterus Wall of uterus Body of uterus • Endometrium Ureter • Myometrium • Perimetrium Uterine blood vessels Isthmus Internal os Uterosacral ligament Cervical canal Cardinal (lateral cervical) ligament External os Lateral fornix Vagina Cervix Posterior view © 2016 Pearson Education, Inc.

Sigmoid colon Rectouterine pouch Rectum Right ovary Left ovary
Figure 27.15b Internal female reproductive organs. Sigmoid colon Rectouterine pouch Rectum Right ovary Left ovary Right uterine tube Left uterine tube Right round ligament Left round ligament Uterus Mesosalpinx Vesicouterine pouch Mesometrium of the broad ligament Urinary bladder Superoanterior view © 2016 Pearson Education, Inc.

B. Female Duct System 1. Uterine tube system does not have direct contact with ovaries 2. The Uterine Tubes a. Also called fallopian tubes b. Receive ovulated oocyte and are usual site of fertilization c. Oocyte is carried along toward uterus by smooth muscle peristalsis and ciliary action © 2016 Pearson Education, Inc.

3. The Uterus a. Hollow, thick-walled, muscular organ b
3. The Uterus a. Hollow, thick-walled, muscular organ b. Function is to receive, retain, and nourish fertilized ovum © 2016 Pearson Education, Inc.

c. Regions of uterus i. Body: major portion ii. Fundus: rounded superior region iii. Isthmus: narrowed inferior region iv. Cervix: narrow neck, or outlet; projects into vagina Cervical glands secrete mucus that blocks sperm entry except during midcycle d. Fertilied egg burrows into the uterine wall and resides there during development © 2016 Pearson Education, Inc.

External urethral orifice Anus Hymen Urogenital diaphragm Labium minus
Figure Organs of the female reproductive system, midsagittal section. Suspensory ligament of ovary Peritoneum Infundibulum Perimetrium Uterine tube Ovary Uterosacral ligament Fimbriae Uterus Rectouterine pouch Round ligament Vesicouterine pouch Rectum Urinary bladder Pubic symphysis Posterior fornix Mons pubis Cervix Urethra Anterior fornix Clitoris Vagina External urethral orifice Anus Hymen Urogenital diaphragm Labium minus Greater vestibular gland Labium majus © 2016 Pearson Education, Inc.

4. The Vagina a. Functions as birth canal, passageway for menstrual flow, and organ of copulation b. Vaginal secretions are acidic in adult females c. Mucosa near vaginal orifice forms incomplete partition called hymen that ruptures with intercourse © 2016 Pearson Education, Inc.

External urethral orifice Anus Hymen Urogenital diaphragm Labium minus
Figure Organs of the female reproductive system, midsagittal section. Suspensory ligament of ovary Peritoneum Infundibulum Perimetrium Uterine tube Ovary Uterosacral ligament Fimbriae Uterus Rectouterine pouch Round ligament Vesicouterine pouch Rectum Urinary bladder Pubic symphysis Posterior fornix Mons pubis Cervix Urethra Anterior fornix Clitoris Vagina External urethral orifice Anus Hymen Urogenital diaphragm Labium minus Greater vestibular gland Labium majus © 2016 Pearson Education, Inc.

C. External Genitalia 1. Also called vulva 2. Includes:
a. Labia majora: hair-covered, fatty skin folds i. Counterpart of male scrotum b. Labia minora: skin folds lying within labia majora © 2016 Pearson Education, Inc.

c. Greater vestibular glands i. Flank vaginal opening ii
c. Greater vestibular glands i. Flank vaginal opening ii. Release mucus into vestibule for lubrication d. Clitoris: anterior to vestibule i. Glans of the clitoris: exposed portion ii. Prepuce of the clitoris: hoods glans iii. Counterpart of penis © 2016 Pearson Education, Inc.

of the greater vestibular gland
Figure 27.17a The external genitalia (vulva) of the female. Labia majora Mons pubis Labia minora Prepuce of clitoris Clitoris (glans) External urethral orifice Vestibule Hymen (ruptured) Anus Vaginal orifice Opening of the duct of the greater vestibular gland © 2016 Pearson Education, Inc.

Clitoris Labia minora Labia majora Pubic symphysis Anus
Figure 27.17b The external genitalia (vulva) of the female. Clitoris Labia minora Labia majora Pubic symphysis Anus Body of clitoris, containing corpora cavernosa Inferior pubic ramus Clitoris (glans) Crus of clitoris External urethral orifice Vaginal orifice Greater vestibular gland Bulb of vestibule Fourchette © 2016 Pearson Education, Inc.

1. Main function is milk production to nourish newborn
D. Mammary Glands 1. Main function is milk production to nourish newborn a. Modified sweat glands consisting of 15–25 lobes b. Contain glandular alveoli that produce milk i. Milk is passed into lactiferous ducts, ii. Then into lactiferous sinuses that open to outside at nipple c. In non-nursing women, glandular structure is undeveloped © 2016 Pearson Education, Inc.

3. Breast size is due to amount of fat deposits
2. Areola: pigmented skin surrounding nipple 3. Breast size is due to amount of fat deposits © 2016 Pearson Education, Inc.

Pectoralis major muscle
Figure Structure of lactating mammary glands. First rib Skin (cut) Pectoralis major muscle Suspensory ligament Adipose tissue Lobe Areola Nipple Opening of lactiferous duct Lactiferous sinus Lactiferous duct Lobule containing alveoli Hypodermis (superficial fascia) Intercostal muscles © 2016 Pearson Education, Inc.

Bell Ringer 12.08 Which region of the ovary houses forming gametes? Which part of the female duct system functions as the birth canal? How many lobes do the mammary glands have © 2016 Pearson Education, Inc.

V. Female Reproductive Physiology
A. Always assumed that females’ total supply of eggs was determined at birth 1. New evidence suggests stem cells can arise from epithelial cells at ovary surface 2. May overturn previous assumption © 2016 Pearson Education, Inc.

1. Production of female gametes takes years to complete
B. Oogenesis 1. Production of female gametes takes years to complete a. Begins in fetal period 2. Oogonia (ovarian stem cells) multiply by mitosis and store nutrients 3. Primary oocytes develop in primordial follicles that become surrounded by follicle cells a. Primary oocytes begin meiosis but stall in prophase I b. At birth, female presumed to have lifetime supply of primary oocytes © 2016 Pearson Education, Inc.

C. Oogenesis After Puberty
1. Each month after puberty, a few primary oocytes are activated a. One from this group is “selected” each month to become dominant follicle that resumes meiosis I 2. After division of meiosis I is completed, two haploid cells of different sizes are produced: a. Secondary oocyte: large cell with almost all of mother cell cytoplasm and organelles b. First polar body: small cell almost devoid of cytoplasm © 2016 Pearson Education, Inc.

a. If not penetrated by sperm, it deteriorates
3. Secondary oocyte arrests in metaphase II and becomes the ovulated ovum a. If not penetrated by sperm, it deteriorates b. If penetrated by sperm, second oocyte completes meiosis II, yielding: i. Ovum (functional gamete) ii. Second polar body © 2016 Pearson Education, Inc.

Figure 27.20 Events of oogenesis.
Meiotic events Follicle development in ovary Before birth 2n Oogonium (stem cell) Follicle cells Mitosis Oocyte 2n Primary oocyte Primordial follicle Infancy and childhood (ovary functionally inactive) 2n Primary oocyte (arrested in prophase I; present at birth) Primordial follicle Each month from puberty to menopause Primary follicle 2n Primary oocyte (still arrested in prophase I) Secondary follicle Spindle Vesicular (antral) follicle Meiosis I (completed by one primary oocyte each month in response to LH surge) Secondary oocyte (arrested in metaphase II) First polar body n Ovulation Meiosis II of polar body (may or may not occur) Sperm Ovulated secondary oocyte Meiosis II completed (only if sperm penetrates oocyte) Ruptured follicle becomes a corpus luteum and ultimately degenerates. n n n n Polar bodies (all polar bodies degenerate) Second polar body Ovum Degenerating corpus luteum © 2016 Pearson Education, Inc.

D. Comparison of Oogenesis and Spermatogenesis
1. Number of functional gametes differ a. Oogenesis produces one viable ovum with three polar bodies i. Unequal divisions ensure oocyte has ample nutrients for 6- to 7-day journey to uterus ii. Polar bodies degenerate and die b. Spermatogenesis produces four viable sperm 2. Error rates differ a. Spermatogenesis has an error rate of 3–4% b. Oogenesis has an error rate of 20% © 2016 Pearson Education, Inc.

E. The Ovarian cycle 1. Monthly (~28 day) series of events associated with maturation of egg a. Two consecutive phases i. Follicular phase: period of vesicular follicle growth (days 1–14) ii. Luteal phase: period of corpus luteum activity (days 14–28) b. Ovulation occurs midcycle between phases © 2016 Pearson Education, Inc.

c. Only 10–15% women have 28-day cycle
i. Follicular phase varies, but luteal phase is always 14 days from ovulation to end of cycle © 2016 Pearson Education, Inc.

© 2016 Pearson Education, Inc.
Figure Schematic and microscopic views of the ovarian cycle: development and fate of ovarian follicles. Primordial follicles 1 Primary follicle 2 3 Secondary follicle Theca folliculi 3 4a Early vesicular follicle 4a Forming antrum Theca folliculi 2 Primary oocyte 7 Zona pellucida Antrum Secondary oocyte 4b 6 5 Secondary oocyte 6 Corona radiata Zona pellucida Antrum Corpus luteum (forms from ruptured follicle) 6 Follicle ruptures; secondary oocyte ovulated 5 Mature vesicular follicle carries out meiosis I; ready to be ovulated 4b © 2016 Pearson Education, Inc.

Figure 27.20 Events of oogenesis.
Meiotic events Follicle development in ovary Before birth 2n Oogonium (stem cell) Follicle cells Mitosis Oocyte 2n Primary oocyte Primordial follicle Infancy and childhood (ovary functionally inactive) 2n Primary oocyte (arrested in prophase I; present at birth) Primordial follicle Each month from puberty to menopause Primary follicle 2n Primary oocyte (still arrested in prophase I) Secondary follicle Spindle Vesicular (antral) follicle Meiosis I (completed by one primary oocyte each month in response to LH surge) Secondary oocyte (arrested in metaphase II) First polar body n Ovulation Meiosis II of polar body (may or may not occur) Sperm Ovulated secondary oocyte Meiosis II completed (only if sperm penetrates oocyte) Ruptured follicle becomes a corpus luteum and ultimately degenerates. n n n n Polar bodies (all polar bodies degenerate) Second polar body Ovum Degenerating corpus luteum © 2016 Pearson Education, Inc.

F. The Uterine (menstrual) cycle
1. Cyclic series of changes in endometrium that occur in response to fluctuating ovarian hormone levels 2. Three phases: a.. Days 1–5: menstrual phase i. Ovarian hormones are at lowest levels ii. Stratum functionalis (special lining) detaches from uterine wall and is shed iii. Menstrual flow of blood and tissue lasts 3–5 days © 2016 Pearson Education, Inc.

b. Days 6–14: proliferative (preovulatory) phase i
b. Days 6–14: proliferative (preovulatory) phase i. Rising estrogen levels prompt generation of new stratum functionalis layer ii. Normally thick, sticky cervical mucus to facilitate sperm passage iii. Ovulation occurs at end of proliferative phase on day 14 © 2016 Pearson Education, Inc.

c. Days 15–28: secretory (postovulatory) phase
i. Uterine wall prepares for embryo to implant ii. Thickened mucus to form cervical mucus plug that blocks entry of more sperm, pathogens, or debris iii. If fertilization does not occur: Blood vessels fragment, and functional layer sloughs off Uterine cycle starts all over again on first day of menstruation © 2016 Pearson Education, Inc.

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