The Reproductive System: Part A

The Reproductive System: Part A
27 The Reproductive System: Part A

Primary sex organs (gonads) - testes and ovaries
Reproductive System Primary sex organs (gonads) - testes and ovaries Produce gametes (sex cells ) – sperm & ova Secrete steroid sex hormones Androgens (males) Estrogens and progesterone (females) Accessory reproductive organs - ducts, glands, and external genitalia © 2013 Pearson Education, Inc.

Sex hormones play roles in
Reproductive System Sex hormones play roles in Development and function of reproductive organs Sexual behavior and drives Growth and development of many other organs and tissues © 2013 Pearson Education, Inc.

Male Reproductive System
Testes (within scrotum) produce sperm Sperm delivered to exterior through system of ducts Epididymis  ductus deferens  ejaculatory duct  urethra © 2013 Pearson Education, Inc.

Male Reproductive System
Accessory sex glands Seminal glands Prostate Bulbo-urethral glands Empty secretions into ducts during ejaculation © 2013 Pearson Education, Inc.

Figure 27.1 Reproductive organs of the male, sagittal view.
Peritoneum Seminal gland (vesicle) Ampulla of ductus deferens Ejaculatory duct Rectum Prostate Bulbo-urethral gland Anus Bulb of penis Ductus (vas) deferens Epididymis Testis Scrotum Ureter Urinary bladder Prostatic urethra Pubis Intermediate part of the Urogenital diaphragm Corpus cavernosum spongiosum Spongy Glans penis Prepuce (foreskin) External urethral orifice © 2013 Pearson Education, Inc.

Sac of skin and superficial fascia
The Scrotum Sac of skin and superficial fascia Hangs outside abdominopelvic cavity Contains paired testes 3C lower than core body temperature Lower temperature necessary for sperm production © 2013 Pearson Education, Inc.

Temperature kept constant by two sets of muscles
The Scrotum Temperature kept constant by two sets of muscles Dartos muscle - smooth muscle; wrinkles scrotal skin; pulls scrotum close to body Cremaster muscles - bands of skeletal muscle that elevate testes © 2013 Pearson Education, Inc.

Superficial inguinal ring (end of inguinal canal) Testicular artery
Figure 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 Septum of scrotum Pampiniform venous plexus Cremaster muscle Epididymis Tunica vaginalis (from peritoneum) External spermatic fascia Superficial fascia containing dartos muscle Tunica albuginea of testis Scrotum Internal spermatic fascia Skin © 2013 Pearson Education, Inc.

Each surrounded by two tunics
The Testes Each surrounded by two tunics Tunica vaginalis – outer layer derived from peritoneum Tunica albuginea – inner layer; fibrous capsule Septa divide testis into ~250 lobules, each containing 1–4 seminiferous tubules - site of sperm production © 2013 Pearson Education, Inc.

Produce androgens, e.g., testosterone
Seminiferous Tubules Interstitial endocrine cells in soft tissue surrounding seminiferous tubules Produce androgens, e.g., testosterone Secrete it into interstitial fluid © 2013 Pearson Education, Inc.

The Testes Blood supply
Testicular arteries arise from abdominal aorta Testicular veins arise from pampiniform venous plexus surrounding each testicular artery Cooler; absorb heat from testicular arteries Keep testes cool Spermatic cord encloses nerve fibers, blood vessels, and lymphatics that supply testes © 2013 Pearson Education, Inc.

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 Cavity of tunica vaginalis Duct of epididymis Tail of epididymis © 2013 Pearson Education, Inc.

The Penis Penis consists of Root and shaft that ends in glans penis
Prepuce, or foreskin—cuff of loose skin covering glans Crura Proximal ends of corpora cavernosa surrounded by ischiocavernosus muscle; anchors penis to pubic arch © 2013 Pearson Education, Inc.

Surgical removal of foreskin 60% newborn boys in US circumcised
Circumcision Surgical removal of foreskin 60% newborn boys in US circumcised 15% in other parts of world Some claim medically unnecessary Studies show 60% reduction in HIV risk Reduced risk for other reproductive system infections © 2013 Pearson Education, Inc.

The Penis: Internally Spongy urethra and three cylindrical bodies of erectile tissue (spongy network of connective tissue and smooth muscle with vascular spaces) Corpus spongiosum - surrounds urethra and expands to form glans and bulb Corpora cavernosa - paired dorsal erectile bodies Erection - erectile tissue fills with blood, causing penis to enlarge and become rigid © 2013 Pearson Education, Inc.

Figure 27.5 Male reproductive structures.
Ureter Urinary bladder Ampulla of ductus deferens Seminal gland Prostate Prostatic urethra Ejaculatory duct Orifices of prostatic ducts Bulbo-urethral gland and duct Intermediate part of the urethra (membranous urethra) 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 © 2013 Pearson Education, Inc.

Ducts carry sperm from testes to body exterior
The Male Duct System Ducts carry sperm from testes to body exterior Epididymis Ductus deferens Ejaculatory duct Urethra © 2013 Pearson Education, Inc.

Epididymis Head - contains efferent ductules; superior aspect of testis; body and tail on posterolateral area of testis Duct of the epididymis ~ 6 m in length Microvilli (stereocilia) absorb testicular fluid and pass nutrients to stored sperm Nonmotile sperm enter, pass slowly through (~ 20 days), become motile; can be stored several months During ejaculation epididymis contracts, expelling sperm into ductus deferens © 2013 Pearson Education, Inc.

Ductus Deferens and Ejaculatory Duct
Ductus deferens (vas deferens) ~ 45 cm Passes through inguinal canal to pelvic cavity Expands to form ampulla; joins duct of seminal vesicle to form ejaculatory duct Smooth muscle in walls propels sperm from epididymis to urethra Vasectomy - cutting and ligating ductus deferens; nearly 100% effective form of birth control © 2013 Pearson Education, Inc.

Conveys both urine and semen (at different times) Has three regions
Urethra Conveys both urine and semen (at different times) Has three regions Prostatic urethra – surrounded by prostate Intermediate part of the urethra (membranous urethra) – in urogenital diaphragm Spongy urethra – runs through penis; opens at external urethral orifice © 2013 Pearson Education, Inc.

The Male Accessory Glands
Paired seminal glands (seminal vesicles) Paired bulbo-urethral glands Prostate Produce bulk of semen Remainder - sperm from testes © 2013 Pearson Education, Inc.

Accessory Glands: Seminal Glands
On posterior bladder surface; smooth muscle contracts during ejaculation Produces viscous alkaline seminal fluid Fructose, citric acid, coagulating enzyme (vesiculase), and prostaglandins Yellow pigment fluoresces with UV light 70% volume of semen Duct of seminal gland joins ductus deferens to form ejaculatory duct © 2013 Pearson Education, Inc.

Accessory Glands: Prostate
Encircles urethra inferior to bladder; size of peach pit; smooth muscle contracts during ejaculation Secretes milky, slightly acid fluid Contains citrate, enzymes, and prostate-specific antigen (PSA) Role in sperm activation Enters prostatic urethra during ejaculation 1/3 semen volume © 2013 Pearson Education, Inc.

Prostatitis – inflammatory disorders
Prostate Disorders Prostatitis – inflammatory disorders Bacterial infection; acute and chronic; treated with antibiotics Benign prostatic hyperplasia May be age-related; distorts urethra; treated with surgery, microwaves, drugs, balloon compression, radio-frequency radiation © 2013 Pearson Education, Inc.

Prostate Disorders Prostate cancer
Second most common cause of cancer death in males Digital exam screening, PSA levels Biopsy if abnormal Treated with surgery and sometimes radiation; castration; drugs In clinical trials - cryosurgery, chemotherapy, ultrasound, proton beam therapy © 2013 Pearson Education, Inc.

Accessory Glands: Bulbo-Urethral Glands (Cowper's Glands)
Pea-sized glands inferior to prostate Produce thick, clear mucus during sexual arousal Lubricate glans penis Neutralize traces of acidic urine in urethra © 2013 Pearson Education, Inc.

Milky-white mixture of sperm and accessory gland secretions
Semen Milky-white mixture of sperm and accessory gland secretions 2–5 ml semen ejaculated, contains 20–150 million sperm/ml Contains fructose for ATP production; protects and activates sperm; facilitates sperm movement Alkaline  neutralizes acidity of male urethra and female vagina  enhanced motility © 2013 Pearson Education, Inc.

Semen Functions Prostaglandins decrease viscosity of mucus in cervix; stimulate reverse peristalsis in uterus Hormone relaxin, enzymes  sperm motility Contains ATP for energy Suppresses female immune response Antibacterial action Clotting factors coagulate semen initially to prevent draining out; then liquefied by fibrinolysin  sperm begin journey © 2013 Pearson Education, Inc.

Male Sexual Response Erection Arterioles normally constricted
Sexual excitement causes CNS activation of parasympathetic neurons  nitric oxide (NO) release  local vascular smooth muscle relaxation  arterioles dilate  corpora cavernosa expands, retards venous drainage  engorgement of erectile tissues with blood  enlargement and stiffening of penis © 2013 Pearson Education, Inc.

Male Sexual Response Ejaculation
Propulsion of semen from male duct system Sympathetic spinal reflex Bladder sphincter muscle constricts, preventing expulsion of urine Ducts and accessory glands contract and empty their contents Bulbospongiosus muscles undergo rapid series of contractions  expulsion of semen at ~ 500 cm/s (close to 11 mph) Ejaculatory event – climax (orgasm) © 2013 Pearson Education, Inc.

Homeostatic Imbalance
Erectile dysfunction Parasympathetic nerves of penis release too little NO Causes – alcohol, drugs, hormones, blood vessel or nervous system problems, incompetent venous valves fail to retain blood in penis New drugs (Viagra, Cialis) potentiate existing NO effects © 2013 Pearson Education, Inc.

Sperm (spermatozoa) production in seminiferous tubules
Spermatogenesis Sperm (spermatozoa) production in seminiferous tubules Most body cells have 46 chromosomes - diploid chromosomal number (2n) Two sets (23 pairs) of chromosomes One maternal, one paternal – homologous chromosomes Gametes have 23 chromosomes - haploid chromosomal number (n) Only one member of homologous pair © 2013 Pearson Education, Inc.

Figure 27.6 Comparison of mitosis and meiosis in a mother cell with a diploid number (2n) of 4.
(before chromosome replication) Chromosome replication Chromosome replication 2n = 4 MITOSIS MEIOSIS Replicated chromosome Tetrad formed by synapsis of replicated homologous chromosomes Prophase Prophase I Chromosomes align at the metaphase plate Tetrads align randomly at the metaphase plate Metaphase Metaphase I Sister chromatids separate during anaphase Homologous chromosomes separate but sister chromatids remain together during anaphase I Daughter cells of mitosis Daughter cells of Meiosis I 2n 2n No further chromosomal replication; sister chromatids separate during anaphase II Meiosis II n n n n Daughter cells of meiosis II (usually gametes) MITOSIS MEIOSIS Number of divisions One, consisting of prophase, metaphase, anaphase, and telophase. Two, each consisting of prophase, metaphase, anaphase, and telophase. DNA replication does not occur between the two nuclear divisions. Synapsis of homologous chromosomes Does not occur. Occurs during prophase I; tetrads form, allowing crossovers. Daughter cell number and genetic composition Two. Each diploid (2n) cell is identical to the mother cell. Four. Each haploid (n) cell contains half as many chromosomes as the mother cell and is genetically different from the mother cell. Roles in the body For development of multicellular adult from zygote. Produces cells for growth and tissue repair as multicellular adult develops. Ensures genetic makeup of all body cells is constant. Produces cells for reproduction (gametes). Introduces genetic variability in the gametes and reduces chromosomal number by half so that when fertilization occurs, the normal diploid chromosomal number is restored (in humans, 2n = 46). © 2013 Pearson Education, Inc.

Figure 27.7 Meiosis. © 2013 Pearson Education, Inc. Interphase cell
MEIOSIS I Prophase I Prophase events occur, as in mitosis. Additionally, synapsis occurs: Homologous chromosomes come together along their length to form tetrads. During synapsis, the “arms” of homologous chromatids wrap around each other, forming several crossovers. The nonsister chromatids trade segments at points of crossover. Crossover is followed through the diagrams below. Nuclear envelope Centromere Centriole pairs Crossover Spindle Sister chromatids Chromatin Nuclear envelope fragments late in prophase I 2n = 4 Interphase events As in mitosis, meiosis is preceded by DNA replication and other preparations for cell division. Metaphase I The tetrads align randomly on the spindle equator in preparation for anaphase. Tetrad Dyad Anaphase I Unlike anaphase of mitosis, the centromeres do not separate during anaphase I of meiosis, so the sister chromatids (dyads) remain firmly attached. However, the homologous chromosomes do separate from each other and the dyads move toward opposite poles of the cell. Chromosomes uncoil Telophase I The nuclear membranes re-form around the chromosomal masses, the spindle breaks down, and the chromatin reappears as telophase and cytokinesis end. The 2 daughter cells (now haploid) enter a second interphase-like period, called interkinesis, before meiosis II occurs. There is no second replication of DNA before meiosis II. Nuclear envelopes re-form Cleavage furrow MEIOSIS II Prophase II Meiosis II begins with the products of meiosis I (2 haploid daughter cells) and undergoes a mitosis-like nuclear division process referred to as the equational division of meiosis. Metaphase II Anaphase II After progressing through the phases of meiosis and cytokinesis, the product is 4 haploid cells, each genetically different from the original mother cell. (During human spermatogenesis, the daughter cells remain interconnected by cytoplasmic extensions during the meiotic phases.) Telophase II and cytokinesis Products of meiosis: haploid daughter cells © 2013 Pearson Education, Inc.

Spermatogenic cells give rise to sperm
Spermatogenesis Spermatogenic cells give rise to sperm Mitosis of spermatogonia (stem cell) forms two spermatocytes Meiosis Spermatocytes  secondary spermatocytes  spermatids Spermiogenesis Spermatids become sperm © 2013 Pearson Education, Inc.

Figure 27.8a Spermatogenesis.
Scanning electron micrograph of a cross-sectional view of a seminiferous tubule (165x) © 2013 Pearson Education, Inc.

Figure 27.8c Spermatogenesis.
Tight junction between sustentocytes Cytoplasm of adjacent sustentocytes Spermatogonium (stem cell) Sustentocyte cell nucleus Basal lamina Type A daughter cell remains at basal lamina as a precursor cell compartment Basal Type B daughter cell Primary spermatocyte Secondary spermatocytes Early spermatids Late spermatids Adluminal compartment Cytoplasmic bridge Lumen of seminiferous tubule Spermatozoa A portion of the seminiferous tublule wall, showing the spermatogenic cells surrounded by sustentocytes (colored gold) © 2013 Pearson Education, Inc.

Mitosis of Spermatogonia
Spermatogenesis begins at puberty Spermatogonia Stem cells in contact with epithelial basal lamina Each mitotic division  one type A daughter cell and one type B daughter cell © 2013 Pearson Education, Inc.

Mitosis of Spermatogonia
Type A cells maintain germ cell line at basal lamina Type B cells move toward lumen and develop into primary spermatocytes © 2013 Pearson Education, Inc.

Figure 27.8b 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 spermatogenesis) Meiosis (early Meiosis I completed n n Secondary spermatocytes Meiosis ll Spermatogenesis n n n n Early spermatids n n n n Late spermatids Spermiogenesis (late spermatogenesis) n n n n Spermatozoa Events of spermatogenesis, showing the relative position of various spermatogenic cells © 2013 Pearson Education, Inc.

Approximately 24 days Golgi apparatus Acrosomal vesicle Mitochondria
Figure Spermiogenesis: transformation of a spermatid into a functional sperm. Slide 1 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 © 2013 Pearson Education, Inc.

Takes 64 – 72 days if conditions hospitable
Spermatogenesis Takes 64 – 72 days if conditions hospitable Pressure of testicular fluid pushes immotile sperm into epididymis  motility and fertilizing power © 2013 Pearson Education, Inc.

Infertility Gradual decline in male fertility past 50 years Xenobiotics (alien molecules) may be cause Environmental toxins, PVCs, phthalates, pesticides, herbicides, compounds with estrogenic effects, antibiotics, radiation, lead, marijuana Also, lack of selenium, excessive alcohol, lack of specific Ca2+ channel, anatomical obstructions, hormonal imbalances, oxidative stress, fevers, hot tubs © 2013 Pearson Education, Inc.

Hormonal Regulation of Male Reproductive Function
Sequence of hormonal regulatory events involving hypothalamus, anterior pituitary gland, and testes Hypothalamic-pituitary-gonadal (HPG) axis Regulates production of gametes and sex hormones through 3 interacting sets of hormones GnRH indirectly stimulates testes via FSH & LH FSH & LH directly stimulate testes Testosterone & inhibin – negative feedback on hypothalamus and anterior pituitary © 2013 Pearson Education, Inc.

HPG Axis Testosterone  sex organ maturation, development/maintenance secondary sex characteristics, libido Rising testosterone levels  feedback inhibition on hypothalamus to inhibit GnRH and on pituitary to inhibit gonadotropin release Inhibin (released when sperm count high) – inhibits GnRH and FSH release © 2013 Pearson Education, Inc.

1 GnRH Anterior Via portal pituitary blood 7 7 6 Inhibin 2 LH FSH
Figure Hormonal regulation of testicular function, the hypothalamic-pituitary-gonadal (HPG) axis. Slide 1 1 GnRH Anterior pituitary Via portal blood 7 7 6 Inhibin 2 FSH LH Interstitial endocrine cells 3 3 4 Testosterone Somatic and psychological effects at other body sites; maintenance of secondary sex characteristics Sustentocyte 5 Spermatogenic cells Spermatogenesis Seminiferous tubule Stimulates Inhibits © 2013 Pearson Education, Inc.

Adult Fertilization Birth 100 Puberty 50 3 6 9 1 10 20 60 Months Years
Figure Plasma testosterone and sperm production levels versus age in male humans. Adult Fertilization Birth 100 Puberty Plasma testosterone level Sperm production (% of maximal) 50 3 6 9 1 10 20 60 Months Years Age © 2013 Pearson Education, Inc.

Female Reproductive Anatomy
Ovaries - female gonads Produce female gametes (ova) Secrete female sex hormones, estrogen (estradiol, estrone, estriol) and progesterone Accessory ducts include Uterine tubes Uterus Vagina © 2013 Pearson Education, Inc.

Female Reproductive Anatomy
Internal genitalia – in pelvic cavity Ovaries Uterine tubes Uterus Vagina External genitalia External sex organs © 2013 Pearson Education, Inc.

Suspensory ligament of ovary Infundibulum Uterine tube Ovary Fimbriae
Figure Internal organs of the female reproductive system, midsagittal section. Suspensory ligament of ovary Infundibulum Uterine tube Ovary Fimbriae Peritoneum Uterus Uterosacral ligament Round ligament Vesicouterine pouch Perimetrium Rectouterine pouch Urinary bladder Pubic symphysis Rectum Mons pubis Posterior fornix Cervix Urethra Anterior fornix Clitoris Vagina External urethral orifice Anus Urogenital diaphragm Hymen Labium minus Greater vestibular gland Labium majus © 2013 Pearson Education, Inc.

Figure 27.14 Internal reproductive organs of a female, posterior view.
Suspensory ligament of ovary Uterine (fallopian) tube Ovarian blood vessels Fundus of uterus Lumen (cavity) of uterus Uterine tube Broad ligament Ovary • Ampulla • Mesosalpinx • Isthmus • Infundibulum • Mesovarium • Fimbriae • Mesometrium Round ligament of uterus Ovarian ligament Wall of uterus • Endometrium Body of uterus • Myometrium Ureter • Perimetrium Uterine blood vessels • Internal os Isthmus • Cervical canal Uterosacral ligament • External os Cardinal (lateral cervical) ligament Lateral fornix Vagina Cervix © 2013 Pearson Education, Inc.

Cortex Medulla Primary follicles
Figure Photomicrograph of a mammalian ovary showing follicles in different developmental phases. Germinal epithelium Tunica albuginea Cortex Medulla Primary follicles Secondary follicle Antrum of a vesicular (antral) follicle © 2013 Pearson Education, Inc.

Ducts have no contact with ovary
Female Duct System Ducts have no contact with ovary Oocyte cast into peritoneal cavity; some lost there Uterine (fallopian) tubes or oviducts Uterus Vagina © 2013 Pearson Education, Inc.

Ectopic pregnancy Oocyte fertilized in peritoneal cavity or distal uterine tube begins developing there Normally abort naturally with substantial bleeding Pelvic inflammatory disease (PID) Spread of infection from reproductive tract to peritoneal cavity May cause scar tissue  infertility © 2013 Pearson Education, Inc.

Cervical cancer 450,000 women worldwide each year – killing half Most common between 30 – 50 Risks – frequent cervical inflammations, STIs, multiple pregnancies Papanicolaou (Pap) smear for detection Every two years 21 – 30; every year > 30; discontinue at 65 if negative for 10 years © 2013 Pearson Education, Inc.

Pap smear results inconclusive Test for human papillomavirus – cause of most cervical cancers Gardasil – three-dose vaccine; protects against HPV Recommended for 11- and 12-year-old girls © 2013 Pearson Education, Inc.

Vagina Layers of wall Fibroelastic adventitia Smooth muscle muscularis Stratified squamous mucosa with rugae Dendritic cells in mucosa may provide route for HIV transmission Mucosa near vaginal orifice forms incomplete partition called hymen – ruptures with intercourse Vaginal fornix - upper end of vagina surrounding cervix © 2013 Pearson Education, Inc.

Figure 27.16a The external genitalia (vulva) of the female.
Mons pubis Labia majora Prepuce of clitoris Labia minora Clitoris (glans) External urethral orifice Vestibule Hymen (ruptured) Vaginal orifice Anus Opening of the duct of the greater vestibular gland © 2013 Pearson Education, Inc.

External Genitalia (Vulva or Pudendum)
Mons pubis - fatty area overlying pubic symphysis Labia majora - hair-covered, fatty skin folds Counterpart of male scrotum Labia minora - skin folds lying within labia majora Join at posterior end of vestibule  fourchette Vestibule - recess within labia minora © 2013 Pearson Education, Inc.

Greater vestibular glands
External Genitalia Greater vestibular glands Flank vaginal opening Homologous to bulbo-urethral glands Release mucus into vestibule for lubrication © 2013 Pearson Education, Inc.

Clitoris – anterior to vestibule
External Genitalia Clitoris – anterior to vestibule Glans of the clitoris - exposed portion Prepuce of the clitoris – hoods glans Counterpart of penis Perineum Diamond-shaped region between pubic arch and coccyx Bordered by ischial tuberosities laterally © 2013 Pearson Education, Inc.

Figure 27.16b The external genitalia (vulva) of the female.
Clitoris Labia minora Labia majora Anus Pubic symphysis Inferior ramus of pubis Body of clitoris, containing corpora cavernosa Clitoris (glans) Crus of clitoris External urethral orifice Vaginal orifice Greater vestibular gland Bulb of vestibule Fourchette © 2013 Pearson Education, Inc.

Modified sweat glands consisting of 15–25 lobes
Mammary Glands Modified sweat glands consisting of 15–25 lobes Function in milk production Areola - pigmented skin surrounding nipple Suspensory ligaments – attach breast to underlying muscle Lobules within lobes contain glandular alveoli that produce milk © 2013 Pearson Education, Inc.

Breast size due to amount of fat deposits
Mammary Glands Milk  lactiferous ducts  lactiferous sinuses  open to outside at nipple Breast size due to amount of fat deposits © 2013 Pearson Education, Inc.

Figure 27.17 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 © 2013 Pearson Education, Inc.

13% will develop condition
Breast Cancer Invasive breast cancer most common malignancy, second most common cause of cancer death in U.S. women 13% will develop condition © 2013 Pearson Education, Inc.

70% of women with breast cancer have no known risk factors
Usually arises from epithelial cells of smallest ducts; eventually metastasize Risk factors include Early onset of menstruation and late menopause No pregnancies or first pregnancy late in life No or short periods of breast feeding Family history of breast cancer 70% of women with breast cancer have no known risk factors © 2013 Pearson Education, Inc.

Breast Cancer: Treatment
Radical mastectomy – removes breast, all underlying muscles, fascia, associated lymph nodes Lumpectomy – excises only cancerous lump Simple mastectomy – removes only breast tissue, sometimes some axillary lymph nodes Some have breast reconstruction © 2013 Pearson Education, Inc.

Film of breast with tumor
Figure Mammograms. Malignancy Mammogram procedure Film of normal breast Film of breast with tumor © 2013 Pearson Education, Inc.

Physiology of the Female Reproductive System
Always assumed females total supply of eggs determined at birth New evidence stem cells can arise from epithelial cells at ovary surface May overturn previous assumption © 2013 Pearson Education, Inc.

Figure 27.19 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) In absence of fertilization, ruptured follicle becomes a corpus luteum and ultimately degenerates. Polar bodies (all polar bodies degenerate) n n n n Second polar body Ovum Degenerating corpus luteum © 2013 Pearson Education, Inc.

Comparison of Oogenesis and Spermatogenesis
Spermatogenesis  4 viable sperm Spermatogenesis – error rate of 3-4% Oogenesis  1 viable gamete; 3 polar bodies Oogenesis – error rate of 20% Unequal divisions ensure oocyte has ample nutrients for 6-7 day journey to uterus Polar bodies degenerate and die © 2013 Pearson Education, Inc.

Monthly series of events associated with maturation of egg
Ovarian Cycle Monthly series of events associated with maturation of egg Two consecutive phases (in 28-day cycle) Follicular phase - period of follicle growth (days 1–14) Ovulation occurs midcycle Luteal phase - period of corpus luteum activity (days 14–28) © 2013 Pearson Education, Inc.

Only 10 – 15% women have 28-day cycle Follicular phase varies
Ovarian Cycle Only 10 – 15% women have 28-day cycle Follicular phase varies Luteal phase constant – always 14 days from ovulation to end of cycle © 2013 Pearson Education, Inc.

Figure Schematic and microscopic views of the ovarian cycle: development and fate of ovarian follicles. Slide 1 1 Primordial follicles 2 Primary follicle Theca folliculi 3a Secondary follicle Theca folliculi 3a 3b 3b Late secondary follicle Forming antrum 2 Primary oocyte 7 Zona pellucida Antrum Secondary oocyte 4 5 Secondary oocyte 6 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 4 © 2013 Pearson Education, Inc.

The Reproductive System: Part C
27 The Reproductive System: Part C

Figure 27.21 Regulation of the ovarian cycle.
Slide 1 Hypothalamus Hypothalamus GnRH Positive feedback exerted by large in estrogen output by maturing follicle. 4 4 GnRH 6 Travels via portal blood 1 Anterior pituitary 1 4 Progesterone Estrogens Inhibin LH surge FSH LH Ruptured follicle 5 2 2 6 Thecal cells Slightly elevated estrogen and rising inhibin levels inhibit FSH secretion. 2 3 Androgens 5 Granulosa cells 2 Mature vesicular follicle Inhibin Convert androgens to estrogens Ovulated secondary oocyte Corpus luteum 2 Estrogens Early and midfollicular phases Late follicular and luteal phases Stimulates Inhibits © 2013 Pearson Education, Inc.

Plasma hormone level LH FSH
Figure 27.22a Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus. LH Plasma hormone level FSH Fluctuation of gonadotropin levels: Fluctuating levels of pituitary gonadotropins (follicle-stimulating hormone and luteinizing hormone) in the blood regulate the events of the ovarian cycle. © 2013 Pearson Education, Inc.

Primary follicle Secondary follicle Vesicular follicle Ovulation
Figure 27.22b Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus. Primary follicle Secondary follicle Vesicular follicle Ovulation Corpus luteum Degenerating corpus luteum Follicular phase Luteal phase Ovulation (Day 14) 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. © 2013 Pearson Education, Inc.

The Uterine (Menstrual) Cycle
Cyclic changes in endometrium in response to fluctuating ovarian hormone levels Three phases Days 1–5 - menstrual phase Days 6–14 - proliferative (preovulatory) phase Days 15–28 - secretory (postovulatory) phase (constant 14-day length) © 2013 Pearson Education, Inc.

Menstrual phase (Days 1 - 5)
Uterine Cycle Menstrual phase (Days 1 - 5) Ovarian hormones at lowest levels Gonadotropins beginning to rise Stratum functionalis shed; menstrual flow (blood and tissue) days By day 5 growing ovarian follicles produce more estrogen © 2013 Pearson Education, Inc.

Proliferative phase (Days 6 - 14)
Uterine Cycle Proliferative phase (Days ) Rising estrogen levels prompt generation of new stratum functionalis layer; increased synthesis of progesterone receptors in endometrium; glands enlarge and spiral arteries increase in number Normally thick, sticky cervical mucus thins in response to rising estrogen (allows sperm passage) Ovulation occurs at end of proliferative phase © 2013 Pearson Education, Inc.

Estrogens Progesterone
Figure 27.22c Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus. Plasma hormone level Estrogens Progesterone 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). © 2013 Pearson Education, Inc.

Blood vessels Basal layer Days 1 5 10 15 20 25 28
Figure 27.22d Correlation of anterior pituitary and ovarian hormones with structural changes of the ovary and uterus. Endometrial glands Blood vessels Menstrual flow Functional layer Basal layer Days 1 5 10 15 20 25 28 Menstrual phase Proliferative phase Secretory phase The three phases of the uterine cycle: • Menstrual: The functional layer of the endometrium is shed. • Proliferative: The functional layer of the endometrium is rebuilt. • Secretory: Begins immediately after ovulation. Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo. Both the menstrual and proliferative phases occur before ovulation, and together they correspond to the follicular phase of the ovarian cycle. The secretory phase corresponds in time to the luteal phase of the ovarian cycle. © 2013 Pearson Education, Inc.

Promote oogenesis and follicle growth in ovary
Effects of Estrogens Promote oogenesis and follicle growth in ovary Exert anabolic effects on female reproductive tract Support rapid but short-lived growth spurt at puberty © 2013 Pearson Education, Inc.

Induce secondary sex characteristics
Effects of Estrogens Induce secondary sex characteristics Growth of breasts Increased deposit of subcutaneous fat (hips and breasts) Widening and lightening of pelvis © 2013 Pearson Education, Inc.

Metabolic effects (not true secondary sex characteristics)
Effects of Estrogens Metabolic effects (not true secondary sex characteristics) Maintain low total blood cholesterol and high HDL levels Facilitate calcium uptake © 2013 Pearson Education, Inc.

Effects of Progesterone
Progesterone works with estrogen to establish and regulate uterine cycle Promotes changes in cervical mucus Effects of placental progesterone during pregnancy Inhibits uterine motility Helps prepare breasts for lactation © 2013 Pearson Education, Inc.

Sexually Transmitted Infections (STIs)
Also called sexually transmitted diseases (STDs) or venereal diseases (VDs) U.S. – highest rates of infection among developed countries Latex condoms help prevent spread Single most important cause of reproductive disorders © 2013 Pearson Education, Inc.

Commonly called "the clap"
Gonorrhea Commonly called "the clap" Bacterial infection of mucosae of reproductive and urinary tracts Spread by contact with genital, anal, and pharyngeal mucosae Number of cases in U.S. declining © 2013 Pearson Education, Inc.

Treatment - antibiotics, but resistant strains becoming prevalent
Gonorrhea Signs and symptoms Males Urethritis, painful urination, discharge of pus Females 20% display no signs or symptoms Abdominal discomfort, vaginal discharge, or abnormal uterine bleeding Can result in pelvic inflammatory disease and sterility Treatment - antibiotics, but resistant strains becoming prevalent © 2013 Pearson Education, Inc.

Bacterial infection transmitted sexually or contracted congenitally
Syphilis Bacterial infection transmitted sexually or contracted congenitally Infected fetuses stillborn or die shortly after birth Infection asymptomatic for 2–3 weeks Painless chancre appears at site of infection; disappears in few weeks © 2013 Pearson Education, Inc.

Treatment - penicillin
Syphilis If untreated, secondary signs appear several weeks later for 3–12 weeks, then disappear Pink skin rash, fever, and joint pain Latent period may or may not progress to tertiary syphilis, characterized by gummas (lesions of CNS, blood vessels, bones, and skin) Treatment - penicillin © 2013 Pearson Education, Inc.

Chlamydia Most common bacterial STI in United States
Responsible for 25–50% of all diagnosed cases of pelvic inflammatory disease Symptoms - urethritis; penile and vaginal discharges; abdominal, rectal, or testicular pain; painful intercourse; irregular menses Can cause arthritis and urinary tract infections in men; sterility in women; newborns contract in birth canal  trachoma (painful eye infection), respiratory tract inflammation Treatment - tetracycline © 2013 Pearson Education, Inc.

Most common curable STI in active young women in U.S.
Trichomoniasis Most common curable STI in active young women in U.S. Parasitic infection; easily, inexpensively treated Yellow-green vaginal discharge with strong odor; some symptomless © 2013 Pearson Education, Inc.

Viral Infections Genital warts Caused by human papillomavirus (HPV)
Second most common STI in United States Increased risk of cancers in infected body regions Linked to 80% cases of invasive cervical cancer; most strains do not cause cancer Treatment difficult; controversial © 2013 Pearson Education, Inc.

Viral Infections Genital herpes Caused by herpes simplex virus 2
Characterized by latent periods and flare-ups Congenital herpes can cause malformations of fetus Treatment - acyclovir and other antiviral drugs © 2013 Pearson Education, Inc.

Urethral fold Anus Tail (cut) Urethral groove
Figure 27.24a Development of homologous structures of the external genitalia in both sexes. Genital tubercle Urethral fold Labioscrotal swelling Anus Tail (cut) Urethral groove Sexually indifferent stage © 2013 Pearson Education, Inc.

Glans penis Urethral folds Anus Glans penis Penis Scrotum Anus
Figure 27.24b Development of homologous structures of the external genitalia in both sexes. Approximately 5 weeks Glans penis Urethral folds Labioscrotal swellings (scrotum) Anus Glans penis Penis Scrotum Anus Male development © 2013 Pearson Education, Inc.

Glans clitoris Anus Glans clitoris Labia majora Anus
Figure 27.24c Development of homologous structures of the external genitalia in both sexes. Approximately 5 weeks Glans clitoris Urogenital sinus Labioscrotal swellings (labia majora) Urethral folds (labia minora) Anus Glans clitoris Labia majora Labia minora Anus Female development © 2013 Pearson Education, Inc.

Development Aspects: Descent of the Gonads
About two months before birth Testosterone stimulates migration of testes toward scrotum Gubernaculum - fibrous cord from each testis to scrotum or from ovary to labium majus; guides descent Ovaries also descend, but stopped by broad ligament at pelvic brim © 2013 Pearson Education, Inc.

Figure 27.23 Development of the internal reproductive organs.
Mesonephros Mesonephric (Wolffian) duct Gonadal ridge Paramesonephric (Müllerian) duct Metanephros (kidney) Cloaca 5- to 6-week embryo: sexually indifferent stage Testes Efferent ductules Ovaries Epididymis Paramesonephric duct forming the uterine tube Paramesonephric duct (degenerating) Mesonephric duct (degenerating) Mesonephric duct forming the ductus deferens Fused paramesonephric ducts forming the uterus Urinary bladder Seminal gland Urinary bladder (moved aside) Urogenital sinus forming the urethra Urogenital sinus forming the urethra and lower vagina 7- to 8-week male 8- to 9-week female Urinary bladder Uterine tube Seminal gland Ovary Prostate Bulbo-urethral gland Uterus Ductus deferens Urethra Urinary bladder (moved aside) Efferent ductules Vagina Epididymis Urethra Testis Hymen Penis Vestibule At birth: male development At birth: Female development © 2013 Pearson Education, Inc.

Development Aspects: Puberty
FSH and LH elevated at birth but drop and remain low during prepubertal years Reproductive organs grow to adult size and become functional – puberty Occurs in response to rising levels of gonadal hormones Secondary sex characteristics appear Earliest time that reproduction is possible © 2013 Pearson Education, Inc.

Has occurred when menses have ceased for an entire year
Menopause Has occurred when menses have ceased for an entire year No equivalent to menopause in males Males continue to produce sperm well into eighth decade of life, though numbers and motility decrease © 2013 Pearson Education, Inc.

Declining estrogen levels 
Menopause Declining estrogen levels  Atrophy of reproductive organs and breasts Irritability and depression in some Hot flashes as skin blood vessels undergo intense vasodilation Gradual thinning of skin and bone loss Increased total blood cholesterol levels and falling HDL © 2013 Pearson Education, Inc.

Treatment with estrogen-progesterone preparations given for years
Menopause Treatment with estrogen-progesterone preparations given for years Women's Health Initiative research reported increased risk of heart disease (51%), invasive breast cancer (24%), stroke (31%), dementia (risk doubled) Smallest does for shortest time alright to reduce symptoms if no breast cancer or mutated BRCA gene © 2013 Pearson Education, Inc.

Sperm Major regions Head - genetic region; nucleus and helmetlike acrosome containing hydrolytic enzymes that enable sperm to penetrate egg Midpiece - metabolic region; mitochondria  ATP to move tail Tail - locomotor region; flagellum © 2013 Pearson Education, Inc.

Large supporting cells (Sertoli cells)
Role of Sustentocytes Large supporting cells (Sertoli cells) Extend through wall of tubule and surround developing cells Provide nutrients and signals to dividing cells Move cells along to lumen Secrete testicular fluid into lumen for sperm transport Phagocytize faulty germ cells and excess cytoplasm Produce chemical mediators to regulate spermatogenesis © 2013 Pearson Education, Inc.

Mechanism and Effects of Testosterone Activity
Synthesized from cholesterol Transformed to exert its effects on some target cells Dihydrotestosterone (DHT) in prostate Estradiol in some neurons in brain © 2013 Pearson Education, Inc.

Held in place by several ligaments
Ovaries Held in place by several ligaments Ovarian ligament - anchors ovary medially to uterus Suspensory ligament - anchors ovary laterally to pelvic wall Mesovarium - suspends ovary Suspensory ligament and mesovarium part of broad ligament – supports uterine tubes, uterus, and vagina © 2013 Pearson Education, Inc.

Breast Cancer: Diagnosis
Early detection via self-examination and mammography X-ray examination American Cancer Society recommends screening every year for women 40 and over U.S. Prevention Services Task Force on Breast Cancer Screening recommends 50 and over © 2013 Pearson Education, Inc.

Breast Cancer: Treatment
Treatment depends upon characteristics of lesion Radiation; chemotherapy; surgery, often followed by radiation or chemotherapy to destroy stray cells Drugs for estrogen-responsive cancers Trastuzumab – for aggressive cancer cells Tamoxifen – improves outcome for premenopausal women with early- or late-stage Letrozole – reduces recurrence © 2013 Pearson Education, Inc.

Developmental Aspects: Determination of Genetic Sex
Of 46 chromosomes in fertilized egg, two (one pair) are sex chromosomes Two sex chromosomes – X chromosome (large); Y chromosome (quite small) Females are XX; each ovum always has an X chromosome Males are XY, so ~50% of sperm contain X, ~50% contain Y © 2013 Pearson Education, Inc.

Developmental Aspects: Determination of Genetic Sex
X egg + X sperm  XX (female offspring) X egg + Y sperm  XY (male offspring) The SRY gene on Y chromosome initiates testes development and maleness © 2013 Pearson Education, Inc.

Developmental Aspects: Sexual Differentiation
Sexually indifferent stage Gonads begin development in fifth week as gonadal ridges Paramesonephric (Müllerian) ducts (future female ducts) form lateral to mesonephric (Wolffian) ducts (future male ducts); sexually indifferent stage - embryo could develop into male or female Primordial germ cells migrate to gonadal ridges to provide germ cells destined to become spermatogonia or oogonia Gonads begin development in seventh week in males, eighth week in females © 2013 Pearson Education, Inc.

Developmental Aspects: Development of External Genitalia
Genital tubercle  penis of male; clitoris of female Urethral fold  spongy urethra of male; labia minora of female Labioscrotal swellings  scrotum of male: labia majora of female If testosterone absent, all embryos develop into females © 2013 Pearson Education, Inc.

The Reproductive System: Part A

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The Reproductive System: Part A

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