·         primary sex organs

o   Testes in males

o   Ovaries in females

o   Sperm—male gametes

o   Ova (eggs)—female gametes

SCROTUM

·         Temperature

·         Optimal for sperm development is 3°C below body temp (~91 F)

·         Controlled by muscles

·         Spermatic cord

·         Testicular artery

·         Plexus of veins

·         Nerves

·         Vas deferens

TESTES

·         Covering

·         Tunica albuginea—capsule

·         Septa—extensions of the capsule that divide it into lobules

·         Each lobule contains one to four seminiferous tubules

·         Tightly coiled structures

·         Form sperm

·         Sperm travels through rete testis to epididymis

·         Interstitial cells in the seminiferous tubules produce testosterone

SEMINIFEROUS TUBULES

Spermatogenic cells

Spermatogenesis begins at puberty

~400 million sperm/day

INTERSTITIAL (Leydig)CELLS

Secretes testosterone

sER for steroid production

Controlled by LH from pituitary

TESTOSTERONE

—  The most important hormone of the testes

—  Produced in interstitial cells

—  During puberty, luteinizing hormone (LH) activate the interstitial cells

—  Functions of testosterone

—  Stimulates reproductive organ development

—  Underlies sex drive

—  Causes secondary sex characteristics

—  Deepening of voice

—  Increased hair growth

—  Enlargement of skeletal muscles

—  Thickening of bones

SPERMATOGENESIS

·         Production of sperm cells

·         Begins at puberty and continues throughout life

·         Occurs in the seminiferous tubules

·         Nurse cells

·         Connected to each other by tight junctions

·         Nourish spermatogenic cells

·         Transport spermatogenic cells

·         Phagocytize excess cytoplasm

·         Secretions regulate spermatogenesis

SPERM

—  The only human flagellated cell

—  Head

—  Contains DNA

—  Acrosome—“helmet” on the nucleus, similar to a large lysosome

—  Breaks down and releases enzymes to help the sperm penetrate egg

—  Midpiece

—  Base of tail

—  Mitochondria

—  Tail

—  Long flagellum

EPIDIDYMIS

·         Located in scrotum

·         ~6 m long

·         Comma-shaped, tightly coiled tube

·         Functions to mature and store sperm cells (at least 20 days)

·         Expels sperm with the contraction of muscles in the epididymis walls to the vas deferens

DUCTUS DEFERENS(Vas Deferens)

·         Ejaculation—smooth muscle in the walls of the ductus deferens create peristaltic waves to squeeze sperm forward

·         Forms ejaculatory duct with seminal vesicle duct

·         Vasectomy—cutting of the ductus deferens at Carries sperm from the epididymis to the ejaculatory duct

·         Propels sperm during ejaculation

·         the level of the testes to prevent transportation of sperm

PENIS

·         Delivers sperm into the female reproductive tract

·         Shaft

·         Glans penis (enlarged tip)

·         Prepuce (foreskin)

·         Folded cuff of skin around proximal end

·         Often removed by circumcision

·         Spongy urethra

o   Erectile bodies

o   Corpus spongiosum

o   2 corpora cavernosa

·         Extends from the base of the urinary bladder to tip of penis

·         Carries both urine and sperm

·         Regions of the urethra

PROSTATE GLAND

—  Prostate gland

—  Encircles the upper part of the urethra

—  Enters the urethra through several small ducts

—  Secretes a milky fluid

—  Helps to activate sperm

—  30% of semen

As men age, the prostate may get bigger and block the urethra or bladder = benign prostatic hyperplasia (BPH)

Symptoms of BPH may be similar to symptoms of prostate cancer

prostate cancer

Symptoms and Diagnosis

·         Weak or interrupted flow of urine.

·         Frequent urination (especially at night).

·         Trouble urinating.

·         Pain or burning during urination.

·         Blood in the urine or semen.

·         A pain in the back, hips, or pelvis that doesn't go away.

·         Painful ejaculation.

SEMINAL VESICLES

·         Located at the base of the bladder

·         Produces a thick, yellowish secretion (60% of semen)

·         Fructose (sugar)

·         Vitamin C

·         Prostaglandins

·         Other substances that nourish and activate sperm

BULBOURETHRAL GLANDS (Cowper’s Glands)

·         Pea-sized gland inferior to the prostate

·         Produces a thick, clear mucus

·         Cleanses the urethra of acidic urine

·         Serves as a lubricant during sexual intercourse

SEMEN

·         Mixture of sperm and accessory gland secretions

·         Advantages of accessory gland secretions

·         Fructose provides energy for sperm cells

·         Alkalinity of semen helps neutralize the acidic environment of vagina

·         Semen inhibits bacterial multiplication

·         Elements of semen enhance sperm motility

ERECTION

·         Erections occur when erectile tissue in penis fills with blood during sexual excitement

·         Sexual excitement (parasympathetic)

­    up    blood flow to erectile bodies

·         Squeezes veins shut

­     up   blood pressure in erectile bodies

EJACULATION

·         Sympathetic activation

·         Peristaltic contraction of smooth muscles in ducts and glands - ejaculation

·         Constriction of arteries

down      blood pressure in erectile bodies

o  OVARIES

o   Functions:

§  Production of gametes

§  Production of hormones

·         Progesterone

·         Estrogens

o  OVARY SUPPORT

o   Suspensory ligaments—lateral pelvis walls

o   Ovarian ligaments— uterus

o   Broad ligament—a fold of the peritoneum, encloses suspensory ligament

o  OVARIES

o   A_ Outer capsule = tunica albuginea

o   B_ Cortex (outer portion) – site of germ cell development

§  The cortex contains many ovarian follicles that consists of:

§  An immature egg (oocyte)

§  Follicle/granulosa cells

o   C_ Medulla (inner portion) – contains mostly    arteries, veins, nerves, and lymphatics

o  UTERINE TUBE

o   = Fallopian tubes or oviducts

o   Functions:

§  Receives the ovulated oocyte

§  Provides a site where fertilization can occur

o   Anatomical regions of the uterine tubes

§  Isthmus

§  Ampulla – typically where fertilization occurs

§  Infundibulum

§  Fimbriae

o   The walls of the uterine tubes contain ciliated cells, microvili, and smooth muscle

o  UTERUS

o   Located between the urinary bladder and rectum

o   Functions:

§  Receives a fertilized egg

§  Retains the fertilized egg

§  Nourishes the fertilized egg

o   UTERUS REGIONS

§  Body—main portion

§  Fundus—superior rounded region above where uterine tube enters

§  Cervix—narrow outlet that protrudes into the vagina

o   UTERUS WALL

§  Endometrium

·         Inner layer

·         Allows for implantation of a fertilized egg

·         Sloughs off if no pregnancy occurs (menses)

§  Myometrium—middle layer of smooth muscle

§  Perimetrium (visceral peritoneum)—outermost serous layer of the uterus

o  VAGINA

o   Functions:

§  Passageway for fetus = birth canal

§  Passageway for menstrual flow

§  Organ of copulation

o   Vaginal environment – acidic

o   Hymen—partially closes the vagina until it is ruptured

o    

o  EXTERNAL GENITALIA (VULVA)

o   MONS PUBIS

§  Fatty area overlying the pubic symphysis

§  Covered with pubic hair after puberty

o   LABIA

§  Labia—skin folds

·         Labia majora—hair-covered skin folds

o   Homologous to the male scrotum

·         Labia minora—delicate, hair-free folds of skin

o   VESTIBULE AND GLANDS

§  Vestibule - Contains the external opening of the urethra and the vagina

§  Vestibular glands – secrete mucus and keep the vestibule moist

§  Homologous to the bulbourethral glands

o   CLITORIS

§  Corresponds to the male penis

§  Hooded by a prepuce

§  Composed of sensitive erectile tissue

§  Contains erectile tissue - swells with blood during sexual excitement

o  MAMMARY GLAND

o   Function = Milk production

o   Anatomy

§  Areola - Contains sebaceous glands that keep the nipple from cracking or chapping

§  Nerve endings and smooth muscle fibers cause the nipple to become erect when stimulated

§  Nipple

§  Alveoli – milk-producing ducts

o  OOGENESIS

o   2 x 10⁶ at birth

o   Undergo a process of degeneration = atresia

o   400,000 left at puberty

o   Release of eggs begins at puberty

o   Only one oocyte is ovulated each 28-day cycle

o   ~ 300-400 total

o   Reproductive ability ends at menopause

o   PRE - OVULATION

o   OVULATION

o   POST OVULATION

§  After ovulation, remains of the follicle develops into the corpus luteum (yellow body)

§  LH from pituitary gland initiates this luteinization and stimulates the granulosa cells to secrete progesterone 

§  If no pregnancy it disintegrates into the corpus albicans  

o  OVARIAN CYCLE

o   Typically a 28 day cycle

o   The Follicular Phase

§  Period of follicle growth

§  Days 1 - 13

o   Ovulation

§  Occurs at midcycle

§  Day 14

o   The Luteal Phase

§  Period of corpus luteum activity

§  Days 15 – 28

§  Corpus luteum secretes estrogen and progesterone, but ceases if pregnancy does not occur

o  UTERINE CYCLE

o   Repeating series of changes in the endometrium

o   Continues from menarche to menopause

o   Menses

o   Degeneration of the endometrium

o   Menstruation

o   Proliferative phase 

§  Restoration of the endometrium

o   Secretory phase

o   Endometrial glands enlarge and accelerate their rates of secretion

o  FEMALE REPRODUCTIVE HORMONES

o   FSH

§  Stimulates follicular development

o   LH

§  Maintains structure and secretory function of corpus luteum

o   Estrogens

§  Have multiple functions

o   Progesterones

§  Stimulate endometrial growth and secretion

§   

o  MENOPAUSE

o   The time when a woman is nearing menopause is called perimenopause.

o   estrogen levels begin to drop

o   may experience irregular periods, skip some periods, or have very light periods

o   When a woman has stopped having monthly menstrual cycles for 1 year and is not pregnant, she is said to be in menopause.

o   45 and 55 years

o   follicles stop maturing, and significant amounts of estrogen and progesterone are no longer being secreted

o  ENDOMETRIOSIS

n  Common cause of dysmennorrhea, dyspareunia, and infertility

n  Endometrium fragments and lodges in other parts of the pelvic cavity

n  Causes inflammation, bleeding, scarring, and adhesions

n  Causes are still being studied

n  Treated through hormonal therapy, laparoscopic surgery, or major surgical management

o  DYSMENORRHEA

n  Painful menstrual cramps

n  Painful menses without evidence of a physical abnormality

n  Believed to be normal body response to uterine contractions

n  Other symptoms :

o  Nausea, vomiting, gastrointestinal disturbances, and fainting

o  Prostaglandins cause forceful, frequent uterine contractions called cramps

o  Fibroids, polyps, IUD, PID, or endometriosis

Egg viable ~ 24 hrs

Sperm viable ~ 48 hrs

= 3 day window for fertilization

Sperm undergo a functional change in the female tract – called capacitation

membrane around the acrosome becomes fragile

and enzymes are released

It requires the combined action of many sperm to allow one sperm to penetrate the oocyte

Zygote undergoes rapid mitotic cell divisions

But these do not increase the size of the zygote – called cleavage divisions

MORULA

= a solid sphere of cells, still surrounded by zona pellucida

~100 cells

BLASTULA

4.5 to 5 days

Hollow ball of cells – blastocyst

Outer layer of cells = trophoblast – helps form membranes and fetal part of placenta

Inner cell mass and fluid filled cavity = blastocele – forms the embryo

Enters and implants (day 6-7) into the uterus

Nourished by glycogen from glands of the endometrium

BLASTOCYST

IMPLANTATION

 Begins 6–7 days after ovulation

Trophoblast adheres to a site with the proper receptors and chemical signals

The implanted blastocyst is covered over by endometrial cells

Implantation is completed by the twelfth day after ovulation

HORMONE CONTROL

8 -12 days after fertilization blastocyst begins to secrete human chorionic gonadotropin or hCG

hCG keeps the corpus luteum active until the placenta can produce estrogens and progesterone

hCG is basis for pregnancy tests

PLACENTA

= site of nutrient, gas, and waste exchange

Secretes hormones that maintain pregnancy

Trophoblast cells release human chorionic gonadotropin (hCG) which signals the corpus luteum to enlarge and produce progesterone

The placenta develops from the embryonic chorion and maternal uterine tissue

Chorionic villi are formed from the chorion, and project into endometrium of the uterus

The umbilical cord, containing two umbilical arteries and one umbilical vein connects the embryo and the placenta

EMBRYONIC MEMBRANES

TRAITS:

Protect and nourish the embryo

Develop from the germ layers,

Not part of the embryo

Lost at birth

EMBRYONIC MEMBRANES

Chorion

Amnion

Allantois

Yolk sac

CHORION

CHORION

Surrounds the entire embryo

Chorionic villi invade the endometrium, and allow transfer of nutrients from maternal blood to fetal blood

Eventually helps form the placenta

AMNION

= a membrane that forms the amniotic sac that surrounds and protects the embryo

Amniotic fluid (liquor amnii) also allows free movements of the fetus

ALLANTOIS

YOLK SAC

yolk aids in formation of red blood cells              

= a membranous sac attached to an embryo, providing early nourishment

It functions as the developmental circulatory system of the human embryo, before internal circulation begins.

ORGANOGENESIS

GESTATION

1^st – 8^th week = embryo

8^th week = fetus

By day 35 the heart is beating, and eye and limb buds are present

3rd month - placenta is functioning

4^th month the rudiments of all organ systems are formed and functioning 

4^th month + = primarily growth

First Month

Two Months

4 months

QUICKENING

The first movement of the fetus felt by the mother, usually 4-5^th month

By month seven the fetus is quite active

Last month fetus becomes less active

6 Months

LABOR STAGE ONE

From onset of true labor contractions until the cervix is completely dilated at 10 cm

The uterine contractions cause the cervix to dilate, and the amniotic sac may rupture

Usually lasts 6 – 24 hours depending on the number of previous deliveries

LABOR STAGE TWO

Period from maximal cervical dilation until the birth of the baby

Lasts minutes to an hour

Contractions become more intense and frequent

LABOR STAGE THREE

The expulsion of the placenta

Usually occurs within  15 minutes after the birth of the baby, but can range from 5 to 60 minutes