ch 14 reproductive structures

areola

Location:

• Breast (female and male)

Description:

• Pigmented skin encircling nipple

• Pigmentation varies

Function:

• Female: contains openings of sebaceous glands that lubricate nipple and areola

Comment:

• Permanent increase in pigmentation occurs during first pregnancy

Body of breast

Location:

• Anterior thoracic wall

Description:

• Conical structure with wide range of size and shape

• Base on deep fascia of pectoralis major muscle; apex includes areola and nipple

• Upper lateral quadrant extends toward axilla as axillary process

• Composed primarily of fat (in superficial fascia) and mammary gland (active during lactation)

Function:

• Fat storage

• Mammary gland in breast produces milk during lactation

Comment:

• Size and shape influenced by genetics, diet, and hormones

Breast

Location:

• Anterior thoracic wall

• Axilla

Description:

• Pyramidal structure

• Composed of skin with areola and nipple; fat and connective tissue; mammary gland, and associated ducts

• Base located over pectoralis major muscle

• Extends into axilla (armpit) as "tail"

• Divided into lobes by suspensory ligaments (connective tissue septae)

Function:

• Milk production

• Fat storage (determines breast size and shape in non-lactating female)

Comment:

• Amount of fat determined by genetics, hormones, and dietary habits

• Fat partially replaced by glandular tissue during pregnancy and lactation

Lactiferous ducts

Location:

• Breast

Description:

• 10-20 ducts connect milk-producing (mammary) glands with nipple

• Wider (lactiferous sinus) near nipple

Function:

• Transfer milk from mammary glands to nipple

Comment:

• Each duct opens independently on nipple

Nipple

Location:

• Breast

Description:

• Elevation of skin near apex of breast

• Contains openings of 15-20 lactiferous ducts

• Contains smooth muscle

Function:

• Transfers milk from mammary gland (milk-producing part of breast) to nursing infant

Comment:

• Enlarges and becomes more prominent during nursing and in response to cold

Suspensory ligaments of breast

Location:

• Upper part of breast

Description:

• Well-developed condensations of fibrous connective tissue septae

• Connect to dermis

Function:

• Divide upper portion of breast into lobes

• Supports breast tissue

Also known as:

• Cooper's ligaments

Comment:

• Stretch with age due to weight of breast

Body of uterus

Location:

• Uterus

Description:

• Pear-shaped, muscular portion

• Has narrow cavity lined by endometrium

• Contacts urinary bladder (anterior) and intestines (posterior)

• Fundus is superior part

• Continuous with cervix inferiorly

Function:

• Conducts sperm

• Implantation site for blastocyst

• Supplies nutrients and oxygen, via placenta, to embryo and fetus

• Contracts to expel fetus and placenta during parturition (childbirth)

• Endometrium sloughed (shed) under hormonal influence to form menstrual fluid

Comment:

• Position varies with fullness of urinary bladder and rectum

• In late pregnancy in contact with diaphragm

Cervical canal

Location:

• Cervix of uterus

Description:

• Narrow canal continuous with uterine cavity at internal os

• Opens into vagina at external os

Function:

• Connects vaginal canal to uterine cavity

• Duct for menstrual fluid

• Conducts sperm

• Part of birth canal

Comment:

• Lining (endometrium) not shed during menstruation

• Dilation is standard measure for timing parturition (childbirth)

Cervix of uterus

Location:

• Uterus

Description:

• Short, cylindrical, fibrous part of uterus

• Supravaginal and vaginal parts

• Pierces anterior vaginal wall

• Contains cervical canal with internal os and external os

Function:

• Secretes mucus barrier between vaginal canal and uterine cavity, and lubricates vagina during sexual response

Comment:

• Dilation is standard measure for timing parturition (childbirth)

Clitoris

Location:

• Perineum (urogenital triangle)

Description:

• Erectile tissue

• Has paired crura, body, and glans (distal expansion)

• Prepuce covers glans clitoris

Function:

• Organ for female sexual response

Comment:

• Erectile tissue engorges with blood during sexual response

• Has dense network of sensory nerve endings

Fundus of uterus

Location:

• Uterus (body)

Description:

• Dome-shaped, muscular portion superior to entry of uterine tubes

Function:

• Contracts to expel fetus and placenta during parturition (childbirth)

Labium majus

Location:

• Perineum (urogenital triangle)

Description:

• Paired elevations of skin created by subcutaneous fat

• Hair on lateral and inferior surfaces

• Between mons pubis and anus

Function:

• Protection of external genitalia

Labium minus

Location:

• Perineum (urogenital triangle)

Description:

• Paired fold of thin skin medial to labium majus

• Hairless and fat-free

• Unite anteriorly to form prepuce of clitoris

Function:

• Contains sebaceous glands that lubricate vestibule

• Help direct stream of urine

Comment:

• Vestibule is region between labia minora

Mons pubis

Location:

• Anterior to pubic symphysis and bodies of pubic bones

Description:

• Part of female external genitalia

• Subcutaneous fat pad

• Continuous with fat in labia majora

• After puberty, covered with pubic hair

Comment:

• Fat increases during puberty and decreases at menopause

Ovary

Location:

• Pelvis (lateral wall)

• Near distal end of uterine tube

• Extends into lower abdominal quadrants

Description:

• Paired, female gonad

• Almond shape and size

• Contains oocytes (egg)

Function:

• Maturation (oogenesis) and release (ovulation) of oocytes

• Produces the female sex hormones progesterone, estrogen, and inhibin

Comment:

• Suspended by mesovarium of broad ligament (a peritoneal fold)

• Suspensory ligament of ovary (a peritoneal fold) contains ovarian vessels and nerves

• Size decreases after menopause

Recto-uterine pouch

Location:

• Pelvis (female)

Description:

• Blind recess in peritoneal cavity of female

• Between rectum and uterus

• Closely related to vagina (posterior fornix)

Also known as:

• Pouch of Douglas or cul-de-sac

Comment:

• Most inferior region of female peritoneal cavity

• Size varies with volume of rectum and position of uterus

Uterine cavity

Location:

• Uterus

Description:

• Slit-like cavity in body of uterus

Function:

• Receives sloughed endometrium during menstruation

• Transports sperm toward uterine tube

• Contains embryo and fetus during pregnancy

Comment:

• Between cervical canal and lumen of uterine tubes

• Junction with cervical canal is internal os

Uterine tube

Location:

• Pelvis

• Between lateral aspect of body of uterus and ovary

• Extends into lower abdominal quadrants

Description:

• Part of female reproductive tract

• Paired, muscular tube

• Four parts (proximal to distal): interstitial (uterine), isthmus, ampulla, and infundibulum

• Infundibulum has fimbriae (finger-like processes)

• Approximately 10 cm in length

Function:

• Conduit for movement of germ cells (oocyte and sperm)

• Site of fertilization (ampulla)

Uterus

Location:

• Pelvis

Description:

• Part of female reproductive tract

• Pear-shaped organ with narrow cavity

• Divided into body and cervix

• Body has thick, smooth muscle layer (myometrium)

• Cervix pierces superior, anterior wall of vagina

Function:

• Conducts sperm

• Implantation site for blastocyst

• Supplies nutrients and oxygen, via placenta, to embryo and fetus

• Contracts to expel fetus and placenta during parturition (childbirth)

Comment:

• Position varies with fullness of urinary bladder and rectum

• Contacts diaphragm in late pregnancy

• Hysterectomy (surgical removal of the uterus) performed for treatment of cancer, fibroids, or endometriosis

Vagina

Location:

• Perineum (urogenital triangle)

• Pelvis

Description:

• Smooth muscle sheath (anterior and posterior walls in contact)

• About 9 cm in length

• Receives cervix of uterus (superiorly) and opens into vestibule (inferiorly)

• Has annular fornix at upper end

Function:

• Female organ of copulation

• Lower birth canal

• Duct for menstrual fluid

Comment:

• Vaginal walls contain no glands

Vesico-uterine pouch

Location:

• Pelvis (female)

• Between uterus and urinary bladder

Description:

• Recess in peritoneal cavity

Comment:

• Size varies with position of uterus and size (i.e., amount of urine) in urinary bladder

Bulb of penis

Location:

• Penis

Description:

• Midline erectile body

• Attached to perineal membrane

• Contains spongy urethra

• Covered by bulbospongiosus muscle

Function:

• Engorged with blood during sexual response

• Helps establish and maintain erection

Comment:

• Enters body of penis to become corpus spongiosum

Bulbospongiosus m. - male

Action:

• Compresses erectile tissue of bulb of penis during sexual response

• Compresses spongy urethra

Origin:

• Perineal body

• Median raphe on bulb of penis

Insertion:

• Perineal membrane

• Fascia of bulb of penis and corpus spongiosum

Innervation:

• Pudendal nerve

Comment:

• Compresses spongy urethra to help expel urine or semen

• Compresses bulb of penis to help establish and maintain erection

Corpus cavernosum penis

Location:

• Penis (body)

Description:

• Paired, erectile bodies on dorsal aspect

• Continuation of crus of penis

• Distal end capped by glans penis

• Surrounded by tunica albuginea (thick, fibrous coat)

Function:

• Engorged with blood during sexual response

• Helps establish and maintain erection

Comment:

• Responsible for most of increased size and rigidity of penis during erection

Corpus spongiosum penis

Location:

• Body of penis

Description:

• Single erectile body on ventral aspect

• Continuation of bulb of penis

• Distal expansion forms glans penis

• Contains spongy urethra

• Surrounded by tunica albuginea (thick, fibrous coat)

Function:

• Engorged with blood during sexual response

• Helps establish and maintain erection

• Conducts urine and semen via spongy urethra

Comment:

• Contains less erectile tissue than corpora cavernosa

Epididymis

Location:

• Scrotum

Description:

• Convoluted muscular tube along posterolateral surface of testis

• Between efferent ducts of testis and vas deferens

• Divided into head, body, and tail

Function:

• Site for maturation and storage of sperm

Comment:

• Plural of epididymis is epididymides

• Sperm can be stored in epididymis for 5-6 weeks

Glans penis

Location:

• Penis (body)

Description:

• Expanded distal end (tip) of corpus spongiosum

• Erectile tissue

• Contains terminal part of spongy urethra and external urethral orifice

Function:

• Contains dense network of sensory nerve endings important in sexual response

• Spongy urethra transmits urine and semen

Comment:

• Hooded by prepuce (fold of skin) in uncircumcised male

Membranous urethra

Location:

• Perineum (deep perineal pouch of urogenital triangle)

Description:

• Passes through pelvic floor (urogenital diaphragm)

• Between prostatic and spongy urethra (male)

• 3-5 cm in length

Function:

• Transmits urine and semen (male)

• Transmits urine only (female)

Comment:

• Can be closed voluntarily by external urethral sphincter muscle

Pelvic part of ductus deferens

Location:

• Pelvis

Description:

• Muscular tube

• Between deep inguinal ring on anterior abdominal wall and ejaculatory duct

• Terminal part distended (ampulla)

Function:

• Transport sperm and fluid from epididymis during emission

Comment:

• Ejaculatory duct formed by union of vas deferens with duct of seminal vesicle

• Emission is stage of male sexual response when components of semen brought together in prostatic urethra

• Ductus deferens also known as vas deferens

Penis

Location:

• Perineum (urogenital triangle)

Description:

• Attached part composed of erectile bodies (paired crura and unpaired bulb) covered by muscle

• Unattached part (body of penis) composed of erectile bodies (paired corpora cavernosa and unpaired corpus spongiosum)

• Expanded distal end (tip) of corpus spongiosum forms glans

Function:

• Male organ of copulation

• Body of penis contains dense network of sensory nerve endings important in sexual response

• Transmits urine and semen

Comment:

• Dorsal surface directed anteriorly when penis is flaccid (non-erect)

Prostate

Location:

• Pelvis (posterior to pubic symphysis)

Description:

• Glandular and muscular regions

• Contains prostatic urethra, ejaculatory ducts, and 15-20 prostatic ducts

• Dense outer capsule

Function:

• Accessory reproductive gland

• Contributes 30% of semen volume

• Secretes thin, milky, slightly acidic fluid that contains citric acid, seminal plasmin, and prostate-specific antigen (PSA)

Comment:

• Benign enlargement of prostate (benign prostatic hyperplasia, or BPH) is common from middle age

Prostatic urethra

Location:

• Prostate

Description:

• Passes through prostate

• Between preprostatic and membranous urethra

• Receives two ejaculatory ducts and 15-20 prostatic ducts

Function:

• Transmits urine

• Semen formed here by combining secretions from epididymides, seminal vesicles, and prostate

Recto-vesical pouch

Location:

• Pelvis (male)

Description:

• Blind recess in peritoneal cavity of male

• Between urinary bladder and rectum

Comment:

• Most inferior region of male peritoneal cavity

• Size varies with volume of urinary bladder and rectum

Scrotal part of ductus deferens

Location:

• Scrotum

Description:

• Muscular tube

• Between tail of epididymis and superficial inguinal ring

• Within spermatic cord

Function:

• Transport sperm and fluid from epididymis during emission

Comment:

• Emission is stage of male sexual response when components of semen brought together in prostatic urethra

• Site for voluntary sterilization (vasectomy)

• Ductus deferens also known as vas deferens

Scrotum

Location:

• Perineum (urogenital triangle)

• Between upper medial thighs

Description:

• Pouch of skin with sparse distribution of hair

• Wall contains dartos (smooth) muscle

• Septum divides into right and left parts

• Midline raphe is surface indication of septum

• Contains testes and first part of male reproductive tract

Function:

• Contraction of dartos muscle changes size of scrotum to regulate temperature of testes for sperm development and maturation

Comment:

• Size varies with age and temperature

• Scrotal temperature ~3° degrees Celsius lower than body cavity

Seminal vesicle

Location:

• Pelvis (between bladder and rectum)

Description:

• Paired, sacculated, contorted muscular tube

• Duct connects to vas deferens

Function:

• Accessory reproductive gland

• Contributes 60% of semen volume

• Secretes thick, alkaline fluid that contains fructose and prostoglandins

Also known as:

• Seminal gland

Comment:

• Duct of seminal vesicle and vas deferens unite to form ejaculatory duct

Spermatic fascia

Location:

• Scrotum

• Inguinal canal

Description:

• Outer layers of spermatic cord

• Three layers: external, cremasteric, and internal

• Derived from layers of anterior abdominal wall during migration of testis through inguinal region

Function:

• Encloses contents of spermatic cord and testis

Comment:

• Cremasteric layer contains cremaster muscle (important in regulating position of testis in scrotum)

Spongy urethra

Location:

• Penis

Description:

• Longest part of male urethra (approximately 15 cm in length)

• Within bulb and corpus spongiosum of penis

• Ends at external urethral orifice

Function:

• Conducts urine and semen

Also known as:

• Penile urethra

Testis

Location:

• Scrotum

Description:

• Paired, oval, male gonad

• Dense outer capsule (tunica albuginea testis)

• Interior divided into 200-300 lobules

• Each lobule contains up to three seminiferous tubules

Function:

• Produces sperm cells

• Produces androgens (male sex hormones) such as testosterone

Comment:

• Plural: testes

• The testis begins development near the kidney, and later descends along the posterior abdominal wall to the scrotum

• Development of sperm cells is temperature dependent (scrotal temperature ~3° lower than body cavity)

• Temperature of testis regulated by: (1) distance from body cavity, and (2) heat exchange between testicular artery and pampiniform venous plexus

• Testosterone regulates hair pattern, sperm production, skeletomuscular growth, and libido

Body of epididymis

Location:

• Epididymis

Description:

• Convoluted muscular tube along posterolateral surface of testis

• Between head and tail of epididymis

Function:

• Site for maturation and storage of sperm

Body of penis

Location:

• Penis

Description:

• Part of male urinary and reproductive tracts

• Unattached portion of penis

• Formed by three cylinders of erectile tissue (paired corpora cavernosa and corpus spongiosum)

• Corpus spongiosum contains spongy urethra and has distal expansion (glans penis)

Function:

• Male organ of copulation

• Spongy urethra transmits urine and semen

Comment:

• Dorsal surface directed anteriorly when penis is flaccid (non-erect)

Corpus cavernosum penis

Location:

• Penis (body)

Description:

• Paired, erectile bodies on dorsal aspect

• Continuation of crus of penis

• Distal end capped by glans penis

• Surrounded by tunica albuginea (thick, fibrous coat)

Function:

• Engorged with blood during sexual response

• Helps establish and maintain erection

Comment:

• Responsible for most of increased size and rigidity of penis during erection

Corpus spongiosum penis

Location:

• Body of penis

Description:

• Single erectile body on ventral aspect

• Continuation of bulb of penis

• Distal expansion forms glans penis

• Contains spongy urethra

• Surrounded by tunica albuginea (thick, fibrous coat)

Function:

• Engorged with blood during sexual response

• Helps establish and maintain erection

• Conducts urine and semen via spongy urethra

Comment:

• Contains less erectile tissue than corpora cavernosa

Epididymis

Location:

• Scrotum

Description:

• Convoluted muscular tube along posterolateral surface of testis

• Between efferent ducts of testis and vas deferens

• Divided into head, body, and tail

Function:

• Site for maturation and storage of sperm

Comment:

• Plural of epididymis is epididymides

• Sperm can be stored in epididymis for 5-6 weeks

Glans penis

Location:

• Penis (body)

Description:

• Expanded distal end (tip) of corpus spongiosum

• Erectile tissue

• Contains terminal part of spongy urethra and external urethral orifice

Function:

• Contains dense network of sensory nerve endings important in sexual response

• Spongy urethra transmits urine and semen

Comment:

• Hooded by prepuce (fold of skin) in uncircumcised male

Head of epididymis

Location:

• Scrotum

Description:

• Series of convoluted muscular tubes along posterosuperior surface of testis

• Between efferent ductules of testis and body of epididymis

Function:

• Site for maturation and storage of sperm

Scrotum

Location:

• Perineum (urogenital triangle)

• Between upper medial thighs

Description:

• Pouch of skin with sparse distribution of hair

• Wall contains dartos (smooth) muscle

• Septum divides into right and left parts

• Midline raphe is surface indication of septum

• Contains testes and first part of male reproductive tract

Function:

• Contraction of dartos muscle changes size of scrotum to regulate temperature of testes for sperm development and maturation

Comment:

• Size varies with age and temperature

• Scrotal temperature ~3° degrees Celsius lower than body cavity

Septum of scrotum

Location:

• Scrotum (midline)

Description:

• Incomplete, vertical fascial partition

Function:

• Separates scrotum into right and left cavities

Comment:

• Midline raphe in scrotal skin is surface indication of septum

• Latin: raphe = seam

Spermatic cord

Location:

• Scrotum

• Inguinal canal

Description:

• Paired bundle of vessels, nerves, lymphatics, and vas deferens

• Extends from deep inguinal ring to testis

• Three (spermatic) fascial layers derived from anterior abdominal wall

Function:

• Conducts vasculature and nerve supply to testis

• Conducts vas deferens from scrotum to pelvis

Comment:

• Middle fascial layer contains cremaster muscle (important in regulating position of testis in scrotum)

Spermatic fascia

Location:

• Scrotum

• Inguinal canal

Description:

• Outer layers of spermatic cord

• Three layers: external, cremasteric, and internal

• Derived from layers of anterior abdominal wall during migration of testis through inguinal region

Function:

• Encloses contents of spermatic cord and testis

Comment:

• Cremasteric layer contains cremaster muscle (important in regulating position of testis in scrotum)

Suspensory ligament of penis

Location:

• Perineum (urogenital triangle)

Description:

• Sling of deep fascia

• Between body of pubic bones and penis

Function:

• Suspends body of penis

Tail of epididymis

Location:

• Scrotum

Description:

• Convoluted muscular tube near lower pole of testis

• Between body of epididymis and vas deferens

Function:

• Site for maturation and storage of sperm

Testis

Location:

• Scrotum

Description:

• Paired, oval, male gonad

• Dense outer capsule (tunica albuginea testis)

• Interior divided into 200-300 lobules

• Each lobule contains up to three seminiferous tubules

Function:

• Produces sperm cells

• Produces androgens (male sex hormones) such as testosterone

Comment:

• Plural: testes

• The testis begins development near the kidney, and later descends along the posterior abdominal wall to the scrotum

• Development of sperm cells is temperature dependent (scrotal temperature ~3° lower than body cavity)

• Temperature of testis regulated by: (1) distance from body cavity, and (2) heat exchange between testicular artery and pampiniform venous plexus

• Testosterone regulates hair pattern, sperm production, skeletomuscular growth, and libido

Testis with spermatic fascia

Location:

• Scrotum

Description:

• Paired, oval, male gonad

• Dense outer capsule (tunica albuginea testis)

• Interior divided into 200-300 lobules

• Each lobule contains up to three seminiferous tubules

Function:

• Produces sperm cells

• Produces androgens (male sex hormones) such as testosterone

Comment:

• Plural: testes

• The testis begins development near the kidney, and later descends along the posterior abdominal wall to the scrotum

• Development of sperm cells is temperature dependent (scrotal temperature ~3° lower than body cavity)

• Temperature of testis regulated by: (1) distance from body cavity, and (2) heat exchange between testicular artery and pampiniform venous plexus

• Testosterone regulates hair pattern, sperm production, skeletomuscular growth, and libido

Ductus deferens

Location:

• Scrotum

• Inguinal canal

• Pelvis

Description:

• Muscular tube between epididymis and ejaculatory duct

Function:

• Transport sperm and fluid from epididymis during emission

Also known as:

• Vas deferens

Comment:

• Emission is stage of male sexual response when components of semen brought together in prostatic urethra

• Scrotal part bisected during vasectomy (voluntary sterilization)

Body of epididymis

Location:

• Epididymis

Description:

• Convoluted muscular tube along posterolateral surface of testis

• Between head and tail of epididymis

Function:

• Site for maturation and storage of sperm

Epididymis

Location:

• Scrotum

Description:

• Convoluted muscular tube along posterolateral surface of testis

• Between efferent ducts of testis and vas deferens

• Divided into head, body, and tail

Function:

• Site for maturation and storage of sperm

Head of epididymis

Location:

• Scrotum

Description:

• Series of convoluted muscular tubes along posterosuperior surface of testis

• Between efferent ductules of testis and body of epididymis

Function:

• Site for maturation and storage of sperm

Lobule of testis

Location:

• Testis

Description:

• Cone-shaped subdivision (200-300 in each testis) of variable size

• Oriented perpendicular to long axis of testis, with base facing tunica albuginea and apex directed toward mediastinum testis

• Separated by connective tissue septae

• Each contains up to three seminiferous tubules

Description:

• Mediastinum of testis is area where vessels and nerves enter testis and efferent tubules of rete testis exit testis

Tail of epididymis

Location:

• Scrotum

Description:

• Convoluted muscular tube near lower pole of testis

• Between body of epididymis and vas deferens

Function:

• Site for maturation and storage of sperm

Testis

Location:

• Scrotum

Description:

• Paired, oval, male gonad

• Dense outer capsule (tunica albuginea testis)

• Interior divided into 200-300 lobules

• Each lobule contains up to three seminiferous tubules

Function:

• Produces sperm cells

• Produces androgens (male sex hormones) such as testosterone

Comment:

• Plural: testes

• The testis begins development near the kidney, and later descends along the posterior abdominal wall to the scrotum

• Development of sperm cells is temperature dependent (scrotal temperature ~3° lower than body cavity)

• Temperature of testis regulated by: (1) distance from body cavity, and (2) heat exchange between testicular artery and pampiniform venous plexus

• Testosterone regulates hair pattern, sperm production, skeletomuscular growth, and libido

Ductus deferens

Location:

• Scrotum

• Inguinal canal

• Pelvis

Description:

• Muscular tube between epididymis and ejaculatory duct

Function:

• Transport sperm and fluid from epididymis during emission

Also known as:

• Vas deferens

Comment:

• Emission is stage of male sexual response when components of semen brought together in prostatic urethra

• Scrotal part bisected during vasectomy (voluntary sterilization)