document27

PowerPoint® Lecture Slides prepared by Janice Meeking, Mount Royal College

C H A P T E R

Copyright © 2010 Pearson Education, Inc.

27

The Reproductive System: Part A


Reproductive System

• Primary sex organs (gonads): testes and ovaries

• Produce sex cells (gametes)

• Secrete steroid sex hormones

• Androgens (males)

• Estrogens and progesterone (females)

• Accessory reproductive organs: ducts, glands, and external genitalia


Reproductive System

• Sex hormones play roles in

• Development and function of the reproductive organs

• Sexual behavior and drives

• Growth and development of many other organs and tissues


Male Reproductive System

• Testes (within the scrotum) produce sperm

• Sperm are delivered to the exterior through a system of ducts

• Epididymis vas deferens ejaculatory duct urethra


Male Reproductive System

• Accessory sex glands: seminal vesicles, prostate, and bulbourethral glands

• Empty secretions into the ducts during ejaculation

Copyright © 2010 Pearson Education, Inc. Figure 27.1

PeritoneumSeminalvesicle Ampulla ofductus deferensEjaculatoryduct

RectumProstateBulbourethralgland

AnusBulb of penis

Epididymis

UreterUrinary bladderProstaticurethra

Pubis

Membranousurethra

Urogenitaldiaphragm

Corpuscavernosum Corpusspongiosum

Glans penisPrepuceExternalurethral orifice

TestisScrotum

Ductus (vas)deferens


The Scrotum

• Sac of skin and superficial fascia

• Hangs outside the abdominopelvic cavity

• Contains paired testes

• 3C lower than core body temperature (temperature necessary for sperm production)

• Sperm would die/be malformed at internal body temperature


The Scrotum

• Temperature is kept constant by two sets of muscles

• Smooth muscle that wrinkles scrotal skin (dartos muscle)

• Bands of skeletal muscle that elevate the testes (cremaster muscles)


Penis

Internal spermaticfascia

Superficial inguinalring (end of inguinal canal)

Urinary bladder

Spermatic cord Ductus (vas) deferensAutonomicnerve fibers

Testicular artery

Epididymis

Pampiniformvenous plexus

Tunica vaginalis(from peritoneum)Tunica albugineaof testis

Middle septumof scrotum

Cremaster muscleExternal spermaticfascia

Superficial fasciacontaining dartos muscle

Skin

Scrotum


The Testes

• Each is surrounded by two tunics

• Tunica vaginalis, derived from peritoneum

• Tunica albuginea, the fibrous capsule

• Septa extend inward and form ~250 lobules

• Each contains 4 seminiferous tubules, which produce sperm

Copyright © 2010 Pearson Education, Inc. Figure 27.3a

Head of epididymis

Body of epididymis

Tail of epididymis

Efferent ductule

Rete testis

Straight tubule

Duct of epididymis


Lobule

Testis

SeptumTunica albuginea

Tunica vaginalis

Cavity oftunica vaginalis

Spermatic cord

Seminiferoustubule

Blood vesselsand nerves

(a)


The Penis

• Spongy urethra and three cylindrical bodies of erectile tissue (spongy network of connective tissue and smooth muscle with vascular spaces)

• Corpus spongiosum surrounds the urethra and expands to form the glans and bulb

• Corpora cavernosa are paired dorsal erectile bodies

• Erection: erectile tissue fills with blood, causing the penis to enlarge and become rigid


Urinary bladder

Dorsal vesselsand nerves

Skin

Deep arteries(b)

(a)

Bulbourethral gland and duct

Urogenital diaphragm

Bulb of penis

Corpora cavernosa

Corpus spongiosum

Section of (b)

Spongy urethra

Glans penis

Prepuce (foreskin)

External urethral orifice

Corpora cavernosa

Urethra

Tunica albuginea of erectile bodies

Corpus spongiosum

Crus of penisBulbourethral duct openingDuctus deferens

Ampulla of ductus deferens

Prostatic urethraOrifices of prostatic ducts

Prostate

Membranous urethra

Root of penis

Shaft (body) of penis

Ejaculatory duct

Seminal vesicle

Epididymis

Testis

Ureter


The Male Duct System

• Epididymis

• Vas deferens

• Ejaculatory duct

• Urethra


Epididymis

• Head: contains the efferent ductules

• Duct of the epididymis

• Microvilli (stereocilia) absorb testicular fluid and pass nutrients to stored sperm

• During ejaculation the epididymis contracts, expelling sperm into the vas deferens


Vas Deferens and Ejaculatory Duct

• Vas deferens

• Passes through the inguinal canal

• Propels sperm from the epididymis to the urethra

• Vasectomy: cutting and ligating the vas deferens, which is a nearly 100% effective form of birth control


Urethra

• Conveys both urine and semen (at different times)

• Has three regions

1. Prostatic urethra

2. Membranous urethra

3. Spongy (penile) urethra


Accessory Glands: Seminal Vesicles

• Produces viscous alkaline seminal fluid

• Fructose, ascorbic acid, coagulating enzyme (vesiculase), and prostaglandins

• 70% of the volume of semen

• Duct of seminal vesicle joins the vas deferens to form the ejaculatory duct


Accessory Glands: Prostate

• Encircles part of the urethra inferior to the bladder

• Secretes milky, slightly acid fluid:

• Contains citrate, enzymes, and prostate-specific antigen (PSA)

• Plays a role in the activation of sperm


Accessory Glands: Bulbourethral Glands (Cowper’s Glands)

• Pea-sized glands inferior to the prostate

• Prior to ejaculation, produce thick, clear mucus

• Lubricates the glans penis

• Neutralizes traces of acidic urine in the urethra


PeritoneumSeminalvesicle Ampulla ofductus deferensEjaculatoryduct

RectumProstateBulbourethralgland

AnusBulb of penis

Epididymis

UreterUrinary bladderProstaticurethra

Pubis

Membranousurethra

Urogenitaldiaphragm

Corpuscavernosum Corpusspongiosum

Glans penisPrepuceExternalurethral orifice

TestisScrotum



Semen

• Mixture of sperm and accessory gland secretions

• Contains nutrients (fructose), protects and activates sperm, and facilitates their movement (e.g., relaxin)

• Prostaglandins in semen

• Decrease the viscosity of mucus in the cervix

• Stimulate reverse peristalsis in the uterus


Semen

• Alkalinity neutralizes the acid in the male urethra and female vagina

• Antibiotic chemicals destroy certain bacteria

• Clotting factors coagulate semen just after ejaculation, then fibrinolysin liquefies it


Male Sexual Response

• Erection:

• Parasympathetic reflex promotes release of nitric oxide (NO)

• NO causes erectile tissue to fill with blood

• Expansion of the corpora cavernosa

• Compresses drainage veins and maintains engorgement

• Corpus spongiosum keeps the urethra open

• Impotence: the inability to attain erection


Male Sexual Response

• Ejaculation

• Propulsion of semen from the male duct system

• Sympathetic spinal reflex causes

• Ducts and accessory glands to contract and empty their contents

• Bladder sphincter muscle to constrict, preventing the expulsion of urine

• Bulbospongiosus muscles to undergo a rapid series of contractions


Mitosis of Spermatogenesis

• Begins at puberty

• Spermatogenesis

• Stem cells in contact with the epithelial basal lamina

• Each mitotic division a type A daughter cell and a type B daughter cell

Copyright © 2010 Pearson Education, Inc. Figure 27.7b

Basal lamina

Spermatogonium(stem cell)

Mitosis

Growth

Late spermatids

Early spermatids

Secondaryspermatocytes

Primaryspermatocyte

Spermatozoa

Type B daughter cell

Enters meiosis I and moves toadluminalcompartmentMeiosis Icompleted

Meiosis II

Type A daughter cellremains at basal laminaas a stem cell

(b) Events of spermatogenesis, showing the relative position of various spermatogenic cells


Sperm

• Major regions

1. Head: genetic region; nucleus and helmetlike acrosome containing hydrolytic enzymes that enable the sperm to penetrate an egg

2. Midpiece: metabolic region; mitochondria

3. Tail: locomotor region; flagellum


HPG Axis

1. Hypothalamus releases gonadotropin-releasing hormone (GnRH)

2. GnRH stimulates the anterior pituitary to secrete FSH and LH

3. FSH causes sustentacular cells to release androgen-binding protein (ABP), which makes spermatogenic cell receptive to testosterone

4. LH stimulates interstitial cells to release testosterone


HPG Axis

5. Testosterone is the final trigger for spermatogenesis

6. Feedback inhibition on the hypothalamus and pituitary results from

• Rising levels of testosterone

• Inhibin (released when sperm count is high)


Anteriorpituitary

Inhibin

GnRH

Testosterone

Via portalblood

Interstitialcells

SustentacularcellSpermatogeniccells

Seminiferoustubule

Somatic andpsychologicaleffects atother bodysites

LHFSH

1

2

2

3 4

5

6

78

Stimulates

Inhibits


Mechanism and Effects of Testosterone Activity

• Testosterone

• Synthesized from cholesterol (steroid hormone)

• Transformed to exert its effects on some target cells

• Dihydrotestosterone (DHT) in the prostate

• Estrogen in some neurons in the brain


Mechanism and Effects of Testosterone Activity

• Prompts spermatogenesis

• Targets all accessory organs; deficiency leads to atrophy

• Has multiple anabolic effects throughout the body

• Is the basis of the sex drive (libido) in males


Male Secondary Sex Characteristics

• Features induced in the nonreproductive organs by male sex hormones (mainly testosterone)

• Appearance of pubic, axillary, and facial hair

• Enhanced growth of the chest and deepening of the voice

• Skin thickens and becomes oily

• Bones grow and increase in density

• Skeletal muscles increase in size and mass


Female Reproductive Anatomy



• Ovaries: female gonads

• Produce female gametes (ova)

• Secrete female sex hormones (estrogen and progesterone)

• Accessory ducts include

• Uterine tubes

• Uterus

• Vagina



• Internal genitalia

• Ovaries

• Uterine tubes

• Uterus

• Vagina

• External genitalia

• The external sex organs


Peritoneum

InfundibulumUterine tubeOvary

UterusRound ligamentVesicouterine pouch

Urinary bladderPubic symphysisMons pubis

UrethraClitoris

External urethralorificeHymenLabium minusLabium majus

Suspensoryligament of ovary

UterosacralligamentPerimetriumRectouterinepouch

RectumPosterior fornixCervixAnterior fornixVaginaAnusUrogenital diaphragmGreater vestibular(Bartholin’s) gland

Fimbriae


Ovaries

• Held in place by several ligaments

• Ovarian ligament: anchors ovary medially to the uterus

• Suspensory ligament: anchors ovary laterally to the pelvic wall

• Mesovarium: suspends the ovary

• Broad ligament: supports the uterine tubes, uterus, and vagina; also contains the suspensory ligament and the mesovarium


Vagina

External osCervical canalInternal os

Wall of uterusPerimetriumMyometriumEndometrium

Round ligament of uterus

Uterinetube

InfundibulumFimbriae

IsthmusAmpulla

Lumen (cavity)of uterus

Suspensoryligament of ovary Uterine (fallopian) tubeOvarian bloodvessels

MesosalpinxMesovarium

Broadligament

Mesometrium

Ovary

Ovarian ligamentBody of uterusUreterUterine blood vesselsIsthmusUterosacral ligamentLateral cervical(cardinal) ligamentLateral fornixCervix

(a)

Fundusof uterus


Ovaries

• Blood supply: ovarian arteries and the ovarian branch of the uterine artery

• Surrounded by a fibrous tunica albuginea

• Two poorly defined regions

• Cortex: ovarian follicles

• Medulla: large blood vessels and nerves


Ovaries

• Follicle

• Immature egg (oocyte) surrounded by

• Follicle cells (one cell layer thick)

• Granulosa cells (when more than one layer is present)


Follicles

• Several stages of development

• Primordial follicle: squamouslike follicle cells + oocyte

• Primary follicle: cuboidal or columnar follicle cells + oocyte

• Secondary follicle: two or more layers of granulosa cells + oocyte

• Late secondary follicle: contains fluid-filled space between granulosa cells; coalesces to form a central antrum


Ovaries

• Vesicular (Graafian) follicle

• Fluid-filled antrum forms; follicle bulges from ovary surface

• Ovulation

• Ejection of the oocyte from the ripening follicle

• Corpus luteum develops from ruptured follicle after ovulation


Medulla

Tunicaalbuginea

Germinalepithelium

Cortex

Oocyte Granulosa cellsLate secondary follicle

Antrum

Primaryfollicles

Oocyte

Zonapellucida

Thecafolliculi

Ovulatedoocyte

Mesovarium andblood vessels

Vesicular(Graafian)follicle

Coronaradiata

Developingcorpus luteum

Corpus luteum

Ovarianligament

Degenerating corpusluteum (corpus albicans)

(a) Diagrammatic view of an ovary sectioned to reveal the follicles in its interior


Female Duct System

• Uterine (fallopian) tubes or oviducts

• Uterus

• Vagina


Uterine Tubes

• Ampulla

• Distal expansion with infundibulum near ovary

• Usual site of fertilization

• Ciliated fibriae of infundibulum create currents to move oocyte into uterine tube

• Isthmus: constricted region where tube joins uterus


Uterine Tubes

• Oocyte is carried along by peristalsis and ciliary action

• Nonciliated cells nourish the oocyte and the sperm

• Mesosalpinx: mesentery that supports the uterine tubes


Vagina




Uterinetube


IsthmusAmpulla




Broadligament

Mesometrium

Ovary


(a)

Fundusof uterus


Uterus

• Body: major portion

• Fundus: rounded superior region

• Isthmus: narrowed inferior region


Uterus

• Cervix: narrow neck, or outlet; projects into the vagina

• Cervical canal communicates with the

• Vagina via the external os

• Uterine body via the internal os

• Cervical glands secrete mucus that blocks sperm entry except during midcycle


Supports of the Uterus

• Mesometrium—lateral support: portion of the broad ligament

• Lateral cervical (cardinal) ligaments: from the cervix and superior part of the vagina to the walls of the pelvis

• Uterosacral ligaments secure uterus to the sacrum

• Round ligaments bind to the anterior wall


Vagina




Uterinetube


IsthmusAmpulla




Broadligament

Mesometrium

Ovary


(a)

Fundusof uterus


Peritoneal Pouches

• Sacs of peritoneum exist around the uterus

• Vesicouterine pouch is between bladder and uterus

• Rectouterine pouch is between rectum and uterus


Uterine Wall

• Three layers

1. Perimetrium: serous layer (visceral peritoneum)

2. Myometrium: interlacing layers of smooth muscle

3. Endometrium: mucosal lining


Endometrium

• Stratum functionalis (functional layer)

• Changes in response to ovarian hormone cycles

• Is shed during menstruation

• Stratum basalis (basal layer)

• Forms new functionalis after menstruation

• Unresponsive to ovarian hormones


Uterine Vascular Supply

• Uterine arteries: arise from internal iliacs

• Arcuate arteries: in the myometrium

• Radial branches in the endometrium branch into

• Spiral arteries stratum functionalis

• Straight arteries stratum basalis

• Spasms of spiral arteries leads to shedding of stratum functionalis


Lumen of uterus

Uterine glands

Smooth muscle fibers

Straight artery

Radial artery

Arcuate arteryUterine artery

Endometrial vein

Capillaries

Venous sinusoids

Epithelium

Spiral (coiled) artery

Lamina propria ofconnective tissue

(b)


Vagina

• Birth canal

• Extends between the bladder and the rectum from the cervix to the exterior

• Urethra embedded in the anterior wall


Vagina

• Layers of wall

1. Fibroelastic adventitia

2. Smooth muscle muscularis

3. Stratified squamous mucosa with rugae

• Mucosa near the vaginal orifice forms an incomplete partition called the hymen

• Vaginal fornix: upper end of the vagina surrounding the cervix


Monspubis

Prepuceof clitoris

Clitoris(glans)

Vestibule

Anus

(a)

LabiamajoraLabiaminoraUrethralorificeHymen(ruptured)

Opening of the ductof the greater vestibular gland

Vaginalorifice


External Genitalia (Vulva or Pudendum)

• Mons pubis: fatty area overlying pubic symphysis

• Labia majora: hair-covered, fatty skin folds

• Labia minora: skin folds lying within labia majora

• Vestibule: recess between labia minora


External Genitalia

• Greater vestibular glands

• Houses bulbourethral glands

• Release mucus into the vestibule for lubrication


External Genitalia

• Clitoris

• Erectile tissue hooded by a prepuce

• Glans clitoris: exposed portion

• Perineum

• Diamond-shaped region between the pubic arch and coccyx

• Bordered by the ischial tuberosities laterally


Pubic symphysis

Labia minora

Clitoris

Labia majora

Anus Body of clitoris,containing corporacavernosa

Clitoris (glans)

Crus of clitoris

Urethral orifice

Vaginal orifice

Greatervestibulargland

Fourchette

Bulb ofvestibule

Inferior ramus of pubis

(b)


Mammary Glands

• Modified sweat glands consisting of 15–25 lobes

• Areola: pigmented skin surrounding the nipple

• Suspensory ligaments: attach the breast to underlying muscle

• Lobules within lobes contain glandular alveoli that produce milk


Mammary Glands

• Milk lactiferous ducts lactiferous sinuses open to the outside at the nipple


Skin (cut)

Pectoralis major muscleSuspensory ligament

Adipose tissueLobeAreolaNipple

Opening oflactiferous duct Lactiferous sinus

Lactiferous duct

Hypodermis(superficial fascia)Intercostal muscles

Lobule containingalveoli

(a) (b)

First rib


Breast Cancer

• Usually arises from the epithelial cells of small ducts

• Risk factors include:

• Early onset of menstruation and late menopause

• No pregnancies or first pregnancy late in life

• Family history of breast cancer

• 10% are due to hereditary defects, including mutations to the genes BRCA1 and BRCA2


Breast Cancer: Detection and Treatment

• 70% of women with breast cancer have no known risk factors

• Early detection via self-examination and mammography

• Treatment depends upon the characteristics of the lesion:

• Radiation, chemotherapy, and surgery followed by irradiation and chemotherapy


(b) Film of normal breast

(a) Mammogram procedure

(c) Film of breast with tumor

Malignancy


Oogenesis

• Production of female gametes

• Begins in the fetal period

• Oogonia (2n ovarian stem cells) multiply by mitosis and store nutrients

• Primary oocytes develop in primordial follicles

• Primary oocytes begin meiosis but stall in prophase I


Oogenesis

• Each month after puberty, a few primary oocytes are activated

• One is selected each month to resume meiosis I

• Result is two haploid cells

• Secondary oocyte

• First polar body


Oogenesis

• The secondary oocyte arrests in metaphase II and is ovulated

• If penetrated by sperm the second oocyte completes meiosis II, yielding

• Ovum (the functional gamete)

• Second polar body


Meiotic events Follicle developmentin ovaryBefore birth

Infancy andchildhood(ovary inactive)

Primary oocyte

Primary oocyte (stillarrested in prophase I)

Vesicular (Graafian)follicle

Primary follicle

Primordial follicle

Primordial follicle

Oocyte

Ovulated secondaryoocyte

In absence offertilization, ruptured follicle becomes a corpus luteum andultimately degenerates.Degenating

corpus luteum

Secondary follicle

Primary oocyte(arrested in prophase I;present at birth)

Oogonium (stem cell)

Each month frompuberty to menopause

Meiosis I (completed by one primary oocyte each month in response to LH surge)

First polar body

Mitosis

Growth

Meiosis II of polarbody (may or may not occur)

Polar bodies(all polar bodiesdegenerate)

OvumSecondpolar body

Meiosis IIcompleted(only if spermpenetration occurs)

SpermOvulation

Secondary oocyte(arrested in metaphase II)

Follicle cells

Spindle


Ovarian Cycle

• Monthly series of events associated with the maturation of an egg

• Two consecutive phases (in a 28-day cycle)

• Follicular phase: period of follicle growth (days 1–14)

• Ovulation occurs midcycle

• Luteal phase: period of corpus luteum activity (days 14–28)


Ovulation

• Ovary wall ruptures and expels the secondary oocyte with its corona radiata

• Mittelschmerz: twinge of pain sometimes felt at ovulation

• 1–2% of ovulations release more than one secondary oocyte, which, if fertilized, results in fraternal twins

Copyright © 2010 Pearson Education, Inc. Figure 27.18 (5 of 7)

Theca folliculi

Primary oocyteZona pellucidaAntrum

Secondaryoocyte

Secondary oocyteCorona radiata

12

3 4

5

6

7

8

Mature vesicularfollicle carries out meiosis I; ready to be ovulated

5


Theca folliculi


Secondaryoocyte


12

3 4

5

6

7

8Follicle ruptures;secondary oocyte ovulated

6


Luteal Phase

• Ruptured follicle collapses

• Granulosa cells and internal thecal cells form corpus luteum

• Corpus luteum secretes progesterone and estrogen (progesterone dominant)


Luteal Phase

• If no pregnancy, the corpus luteum degenerates into a corpus albicans in 10 days

• Stops producing hormones, body begins to shed endometrial lining

• If pregnancy occurs, corpus luteum produces hormones until the placenta takes over at about 3 months


Theca folliculi


Secondaryoocyte


12

3 4

5

6

7

8Corpus luteum(forms from ruptured follicle)

7


Establishing the Ovarian Cycle

• During childhood, ovaries grow and secrete small amounts of estrogens that inhibit the hypothalamic release of GnRH

• As puberty nears, GnRH is released; FSH and LH are released by the pituitary, and act on the ovaries

• These events continue until an adult cyclic pattern is achieved and menarche occurs


Hormonal Interactions During a 28-Day Ovarian Cycle

• Day 1: GnRH release of FSH and LH

• FSH and LH growth of several follicles, and estrogen release

• estrogen levels

• Inhibit the release of FSH and LH

• Stimulate synthesis and storage of FSH and LH

• Enhance further estrogen output



• Estrogen output by the vesicular follicle increases

• High estrogen levels have a positive feedback effect on the pituitary at midcycle

• Sudden LH surge at day 14



• Effects of LH surge

• Completion of meiosis I (secondary oocyte continues on to metaphase II)

• Triggers ovulation

• Transforms ruptured follicle into corpus luteum



• Functions of corpus luteum

• Produces inhibin, progesterone, and estrogen

• These hormones inhibit FSH and LH release

• Declining LH and FSH ends luteal activity and inhibits follicle development



• Days 26–28: corpus luteum degenerates and ovarian hormone levels drop sharply

• Ends the blockade of FSH and LH

• The cycle starts anew


Hypothalamus

Late follicular andluteal phases

1

1

2 2

2

3

4

5

5

6

8

8

7 Slightlyelevated estrogen and rising inhibin levels.

Positivefeedback exerted by large inestrogen output.

Mature follicleCorpus luteum

Ovulatedsecondaryoocyte

Rupturedfollicle

LH surgeProgesteroneEstrogenInhibin

Hypothalamus

Early and midfollicular phases

Travels viaportal blood

Granulosacells

Inhibin

Androgens

Convertandrogens toestrogens

Thecalcells

Anterior pituitary

GnRH

FSH LH


(a) 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.

FSH

LH


(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.

Primaryfollicle

Secondaryfollicle

Vesicularfollicle

Ovulation

Corpusluteum Degenerating

corpus luteum

Follicularphase

Ovulation(Day 14)

Lutealphase


Uterine (Menstrual) Cycle

• Cyclic changes in endometrium in response to ovarian hormones

• Three phases

1. Days 1–5: menstrual phase

2. Days 6–14: proliferative (preovulatory) phase

3. Days 15–28: secretory (postovulatory) phase (constant 14-day length)


Uterine Cycle

• Menstrual phase

• Ovarian hormones are at their lowest levels

• Gonadotropins are beginning to rise

• Stratum functionalis is shed and the menstrual flow occurs


Uterine Cycle

• Proliferative phase

• Estrogen levels prompt generation of new functional layer and increased synthesis of progesterone receptors in endometrium

• Glands enlarge and spiral arteries increase in number


Uterine Cycle

• Secretory phase

• Progesterone levels prompt

• Further development of endometrium

• Glandular secretion of glycogen

• Formation of the cervical mucus plug

Copyright © 2010 Pearson Education, Inc. Figure 27.20c

(c) Fluctuation of ovarian hormone levels: Fluctuating levels of ovarian hormones (estrogens and progesterone) cause the endometrial changes of the uterine cycle. The high estrogen levels are also responsible for the LH/FSH surge in (a).

Progesterone

Estrogens

Copyright © 2010 Pearson Education, Inc. Figure 27.20d

(d) The three phases of the uterine cycle: • Menstrual: Shedding of the functional layer of the endometrium. • Proliferative: Rebuilding of the functional layer of the endometrium. • Secretory: Begins immediately after ovulation. Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo.Both the menstrual and proliferative phases occur before ovulation, and together they correspond to the follicular phase of the ovarian cycle. Thesecretory phase corresponds in time to the luteal phase of the ovarian cycle.

Menstrualphase

Menstrualflow

Endometrialglands

Blood vessels

Functional layer

Basal layer

Proliferativephase

Secretoryphase

Days


Uterine Cycle

• If fertilization does not occur

• Corpus luteum degenerates

• Progesterone levels fall

• Spiral arteries kink and spasm

• Endometrial cells begin to die

• Spiral arteries constrict again, then relax and open wide

• Rush of blood fragments weakened capillary beds and the functional layer sloughs


Effects of Estrogens

• Promote oogenesis and follicle growth in the ovary

• Exert anabolic effects on the female reproductive tract

• Support the rapid but short-lived growth spurt at puberty



• Induce secondary sex characteristics

• Growth of the breasts

• Increased deposit of subcutaneous fat (hips and breasts)

• Widening and lightening of the pelvis



• Metabolic effects

• Maintain low total blood cholesterol and high HDL levels

• Facilitates calcium uptake


Effects of Progesterone

• Progesterone works with estrogen to establish and regulate the uterine cycle

• Effects of placental progesterone during pregnancy

• Inhibits uterine motility

• Helps prepare the breasts for lactation


Female Sexual Response

• The clitoris, vaginal mucosa, and breasts engorge with blood

• Vestibular gland secretions lubricate the vestibule

• Females do not have a refractory period after orgasm and can experience multiple orgasms in a single sexual experience


STIs


Sexually Transmitted Infections (STIs)

• Also called sexually transmitted diseases (STDs) or venereal diseases (VDs)

• The single most important cause of reproductive disorders


Gonorrhea

• Bacterial infection of mucosae of reproductive and urinary tracts

• Spread by contact with genital, anal, and pharyngeal mucosae


Gonorrhea

• Signs and symptoms

• Males

• Urethritis, painful urination, discharge of pus

• Also can have no s/sxs depending on infx

• Females

• 20% display no signs or symptoms

• Abdominal discomfort, vaginal discharge, or abnormal uterine bleeding

• Can result in pelvic inflammatory disease and sterility


Syphilis

• Bacterial infection transmitted sexually or contracted congenitally

• Infected fetuses are stillborn or die shortly after birth

• Infection is asymptomatic for 2–3 weeks

• A painless chancre appears at the site of infection and disappears in a few weeks


Syphilis

• If untreated, secondary signs appear several weeks later for 3–12 weeks, and then disappear: pink skin rash, fever, and joint pain

• The latent period may or may not progress to tertiary syphilis, characterized by gummas (lesions of the CNS, blood vessels, bones, and skin); causes death


Chlamydia

• Most common bacterial STI in the 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, and sterility in women


Viral Infections

• Genital warts

• Caused by human papillomavirus (HPV)

• Second most common STI in the United States

• Increase the risk of cancers in infected body regions


Viral Infections

• Genital herpes

• Caused by human herpes virus type 2

• Characterized by latent periods and flare-ups

• Congenital herpes can cause malformations of a fetus

• Treatment: acyclovir and other antiviral drugs

• Lysine and avoidance of arginine


Development Aspects: Puberty

• In response to rising levels of gonadal hormones

• Reproductive organs grow to adult size and become functional

• Secondary sex characteristics appear

• Earliest time that reproduction is possible


Menopause

• Has occurred when menses have ceased for an entire year (12 months); generally occurs between age 45-55

• Perimenpause = the time before menstrual cycles have ceased for 12 months, but cycles are becoming more erratic

• Andropause occurs in males roughly 10 years later (decline in testosterone)


Menopause

• Declining estrogen levels

• Atrophy of reproductive organs

• Irritability and depression in some

• Hot flashes as skin blood vessels undergo intense vasodilation

• Gradual thinning of the skin and bone loss

• Increased total blood cholesterol levels and falling HDL


QUESTIONS TO TEST WHAT YOU NOW KNOW!!!


What is the primary function of the reproductive system?

• To produce gametes

• To produce reproductive hormones

• To promote growth

• To promote maturation


The testes are housed in the ______, which __________.

• testicle; elevates sperm development temperature

• epididymis; provides energy to the sperm

• scrotum; lowers sperm development temperature

• dartos muscle; lowers the scrotum


What metabolic effect would you expect if someone developed an autoimmune disease in which the person’s interstitial cells were destroyed?

• Testosterone production would plummet.

• Estrogen levels would decrease.

• Testosterone levels would soar.

• Estrogen levels would increase.


The ________ of the penis fill(s) with blood during sexual arousal, causing an erection.

• corpus spongiosum

• corpora cavernosa

• urethra

• glans penis


The _______ is (are) the main sperm-carrying duct that deposits sperm into the female reproductive tract.

• epididymis

• ductus deferens

• seminiferous tubules

• urethra


The ______ is (are) responsible for producing semen.

• testes

• seminal vesicles

• prostate gland

• b and c


Which of the following components in semen stimulates the uterus to contract in reverse peristalsis?

• Fructose

• Seminalplasmin

• Alkaline fluid

• Prostaglandins


A man and his wife have been unable to conceive a child. When examined, the man’s sperm are viable, swim unidirectionally, and are present in higher than average quantities. Which of the following could explain the inability of his sperm to penetrate an egg?• The sperm may have the improper chromosome

number.

• The midpiece contains too many mitochondria.

• The acrosomal cap is deficient in the enzymes necessary to penetrate the egg.

• The tail is longer than average.


Which of the following hormones do males secrete?

• Testosterone

• FSH

• LH

• All of the above


If testosterone were ineffective during development of a male’s brain, what might be the outcome?

• The brain would develop without any noticeable difference from other males.

• The brain might have a female orientation.

• Gender identity may be ambiguous.

• Both b and c are possible.


In a female, which of the following structures houses the oocytes?

• Ovarian medulla

• Fallopian tubes

• Uterus

• Ovarian cortex


Female reproductive hormones are produced by the ________.

• primary oocytes

• uterus

• follicle cells

• ovarian medulla


Ovulated oocytes enter the fallopian tubes:

• directly, from contact with the ovary.

• via undulations of the fimbriae that draw in the oocyte.

• via diffusion.

• via muscular contractions of the infundibulum expelling the oocyte at a rate of 200 m/sec.


The _______ of the uterus receives the embryo and provides nourishment until the placenta is formed.

• endometrium

• myometrium

• perimetrium

• epimetrium


The pH of the vagina is normally acidic, which keeps bacterial growth in check, but the vagina is still home to many bacteria and yeast in balance with each other. Occasionally, when a female takes antibiotics for a bacterial infection, a secondary yeast infection results. Why might this happen?• Yeast flourish and grow in the presence of antibiotics.

• Yeast use the antibiotics as nutrient.

• The removal of bacteria from the vagina allows yeast to grow at a faster rate than normal.

• Yeast infections are a normal circumstance during a woman’s monthly cycle.


In females, the _______ is (are) the homologous structure to the glans penis in males.

• vagina

• labia majora

• cervix

• clitoris


What might happen in a nonpregnant woman who began taking high levels of progesterone and estrogen supplements followed by high doses of prolactin supplements?• The woman would spontaneously become pregnant.

• There would be no detectable change in the woman’s body.

• The woman’s mammary glands would begin lactating.

• The woman’s vagina and uterus would atrophy.


Which of the following are risk factors for the development of breast cancer?

• History of no, or short periods of, breast-feeding

• Early onset of menses and late menopause

• Family history of breast cancer

• All of the above


What is the major difference between spermatogenesis and oogenesis?• Spermatogenesis begins while the male fetus

is in the uterus.

• Oogenesis results in the formation of one viable oocyte whereas spermatogenesis results in the formation of four viable sperm.

• Oogenesis is the result of several mitotic divisions.

• Oogenesis is complete before ovulation occurs.


LH stimulates the production of ______ by the follicle thecal cells.

• estrogen

• progesterone

• an oocyte

• androgens


A woman who wants to ensure conception might buy an “ovulation predictor” kit. Which of the following hormones, when detected by the kit, would be the best indicator of imminent ovulation?

• Estrogen

• GnRH

• LH

• FSH


From a hormonal standpoint, why is the first day of menstrual bleeding counted as the first day of a new cycle rather than as the end of the previous cycle?

• Hormone secretion from the pituitary peaks at day 1 and causes menstruation.

• Without feedback from a fertilized zygote, the corpus luteum degenerates and pituitary hormones are no longer under ovarian negative feedback.

• The cycle is coordinated with ovulation, so each time ovulation occurs, the cycle resets.

• Menstrual flow is necessary to allow implantation of a fertilized zygote.


Which of the following is a secondary sexual characteristic promoted by estrogen?

• growth of the mammary glands

• enlargement of the external genitalia

• stimulation of oogenesis

• thickening of cervical mucus


In females, _______ is the stage of life when reproductive hormones first begin surging and reproduction is first possible.

• menopause

• amenorrhea

• mittelschmerz

• puberty


________ is the stage of life in females when reproductive hormones decline and menstrual cycles become erratic.

• Menopause

• Menarche

• Mittelschmerz

• Puberty

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