TBL 31

Question 1

Define perineum.

Answer 1

the perineum is a shallow, subcutaneous space inferior to the pelvic diaphragm.

Question 2

Discuss the perineum when the lower limbs are ABducted.

Answer 2

when the lower limbs are abducted, the perineum is diamond-shaped extending from the pubic symphysis to the tip of the coccyx and between the ischial tuberosities.

Question 3

Define the areas formed with an imaginary line between the ischial tuberosities.

Answer 3

an imaginary line between the ischial tuberosities forms the anterior urogenital (UG) triangle and posterior anal triangle.

Question 4

Define perineal body.

Answer 4

the perineal body (star) is the central point of the perineum

Question 5

Discuss the relative position of the perineal body.

Answer 5

the perineal body resides at the site of convergence of the external sphincter with the transverse perineal and bulbospongiosus muscles

Question 6

Why resides in the UG/anal triangle.

Answer 6

the genitalia and urethra occupy the UG triangle and the anal canal and anus reside in the anal triangle.

Question 7

Discuss the urogenital hiatus.

Answer 7

the urogenital hiatus is a gap formed by the puborectal sling that allows the urethra and vagina in females to pass from the pelvic cavity into the UG triangle.

Question 8

Define the perineal membrane- what it spans and divides.

Answer 8

the perineal membrane is a sheet of deep fascial that stretches between the ischiopubic rami and spans the urogenital hiatus to cover the UG triangle.

the perineal membrane divides the UG triangle into deep and superficial pouches (i.e., the urethra traverses the urogenital hiatus into the deep pouch and perforates the perineal membrane to enter the superficial pouch).

Question 9

Discuss the superficial fascia below the umbilicus.

Answer 9

below the umbilicus the superficial fascia consists of Camper’s and Scarpa’s fasciae.

Question 10

Define the origin of the Colles fascia- also where may it be found and what does it cover?

Answer 10

the membranous Scarpa’s fascia continues as Colles fascia in the female UG triangle

envision Colles fascia covers the superficial pouch of the UG triangle.

Question 11

Discuss the origin of the dartos fascia- what it covers, where?

Answer 11

Scarpa’s fascia continues as the dartos fascia on the penis and scrotum in the male UG triangle.

the dartos (smooth) muscle joins the dartos fascia in the scrotum.

Question 12

Discuss the deep pouch of the UG triangle- define and what does it contain.

Answer 12

the deep pouch of the UG triangle is the shallow space between the pelvic diaphragm and perineal membrane.

it contains the urethra, voluntary external urethral sphincter, and deep transverse perineal muscle, a slip of involuntary smooth muscle from the muscularis externa of the anal canal.

the deep pouch in females contains the compressor urethrae, a slip of skeletal muscle from the pubococcygeus.

Question 13

perineal membrane is the foundation for (2).

Answer 13

the perineal membrane is the foundation for the bulb and crura of the penis and the body of the clitoris that occupy the superficial pouch.

Question 14

Wha tissue type cover the erectile tissues?

Define the superficial transverse perineal muscle.

Answer 14

thin sheets of skeletal muscle cover the erectile tissues

the superficial transverse perineal muscle is a slip of smooth muscle from the muscularis externa of the anal canal.

Question 15

Discuss the differences with the Camper’s fascia in females and males.

Answer 15

Camper’s fascia continues as the fatty superficial fascial layer in the female UG triangle but the fatty layer is greatly diminished in males and replaced by the dartos muscle in the scrotum.

Question 16

Discuss the terminating point o the voluntary external anal sphincter.

Answer 16

the voluntary external anal sphincter surrounds the anal canal that terminates at the anus in the anal triangle.

Question 17

Define the origin of the ischioanal fat pad.

Answer 17

Camper’s fascia continues into the anal triangle as the ischioanal fat pad.

Question 18

What forms the pudendal canal and discuss the structural purpose of the pudendal canal.

Answer 18

the obturator fascia covering the medial surface of the obturator internus muscle forms the pudendal canal that provides a horizontal passageway for the internal pudendal artery and pudendal nerve (S2-S4).

Question 19

Discuss the origin and route taken by the pudendal nerve and internal pudendal artery.

Discuss the route taken and origin of the inferior rectal nerve and innervation.

Answer 19

the pudendal nerve (and internal pudendal artery) emerge from the greater sciatic foramen in the gluteal region and hook around the sacrospinous ligament to traverse the lesser sciatic foramen and descend to the pudendal canal.

the inferior rectal nerve arises from the pudendal nerve and courses through ischioanal fat pad to innervate the external anal sphincter, inferior anal canal, and anus.

Question 20

Discuss the structural function of the urorectal septum.

Discuss what the tip of the urorectal septum forms and what forms the cloacal membrane.

Answer 20

the urorectal septum divides the cloaca into the anterior urogenital sinus and posterior anorectal canal.

the tip of the septum forms the perineal body, and ascertain fusion of the cloacal endoderm and surface ectoderm forms the cloacal membrane.

Question 21

Discuss cell migration and cloacal membrane.

Answer 21

mesenchymal cells migrate onto the surface of the cloacal membrane to form a pair of elevated cloacal folds that join at the genital tubercle.

Question 22

Discuss the origin of the ANTerior URETHRAL folds and POSTerior ANAL fold.

Answer 22

caudal to the genital tubercle, the cloacal folds separate into the anterior urethral folds and posterior anal fold (anus).

Question 23

What goes into creating the lateral walls of the urethral groove.

Answer 23

testosterone stimulates rapid elongation of the genital tubercle to form the phallus that pulls the urethral folds forward to create the lateral walls of the urethral groove.

Question 24

What forms the penile urethra.

Answer 24

closure of the urethral groove forms the penile urethra.

Question 25

Discuss what forms the scrotal swellings.

Answer 25

the bilateral genital swellings on the sides of the urethral folds.

the genital swellings become the scrotal swellings with pigmented skin overlying the dartos fascia and muscle.

Question 26

Discuss the cascade necessary to form the scrotal septum.

Answer 26

descension of the testis and spermatic cord from the superficial ring of the inguinal canal pushes the scrotal swellings caudally and their midline fusion forms the scrotal septum.

Question 27

Innervation from the posterior and anterior surfaces of the scrotum.

Answer 27

somatic afferent fibers of the pudendal nerves convey sensations from the posterior of the scrotum.

somatic afferent fibers of the ilioinguinal nerve convey sensations from the anterior surfaces of the scrotum.

Question 28

Discuss the darts muscle in response to cold and discuss scrotal temperature.

Answer 28

postsynaptic sympathetic fibers of the spinal nerves involuntarily contract the dartos muscle in response to cold thus decreasing the surface area of the scrotum (i.e., scrotal temperature is maintained a few degrees below body temperature to insure normal spermatogenesis).

Question 29

Discuss what the prostatic urethra becomes in the DEEP perineal pouch. What surrounds said structure?

Answer 29

the prostatic urethra becomes the membranous urethra in the deep perineal pouch where it is surrounded by the external urethral sphincter.

Question 30

Discuss the spatial course taken by the membranous urethra and what it becomes.

Answer 30

the membranous urethra perforates the perineal membrane to become the penile urethra in the superficial pouch where it courses through the root, body, and glans of the penis.

Question 31

the bulb of the penile root continues (structure) that surrounds (structure).

Discuss the origin of the corpus cavernosa.

Answer 31

the bulb of the penile root continues as the corpus spongiosum that surrounds the penile urethra

the bilateral crura of the penile root continue as the corpus cavernosa that parallel the spongiosum in the root and body of the penis.

Question 32

Discuss the thin bulbospongiosus and ischiocavernosus muscles.

Answer 32

the thin bulbospongiosus and ischiocavernosus muscles cover the bulb and body of the penis and the bilateral crura.

Question 33

Discuss the constituents of the corpus spongiosum and corpus cavernosa.

Discuss the supply of the muscular helicine arteries.

Answer 33

the corpus spongiosum and corpus cavernosa consist of venous sinuses surrounded by dense connective tissue.

the venous sinuses are supplied by the muscular helicine (convoluted) arteries.

Question 34

the helicine arteries are branches of the (artery).

Answer 34

the helicine arteries are branches of the internal pudendal artery.

Question 35

What nerve fibers maintain tonic convolution of the helicon arteries?

What nerves inhibit the tonic convolutions?- discuss origin of said nerves.

Answer 35

postsynaptic sympathetic fibers of the pudendal nerve maintain tonic convolution of the helicon arteries

the cavernous nerves, which arise from the pelvic splanchnic nerve in the prostatic plexus, inhibit the tonic convolutions.

Question 36

Discuss the period before (blood flow limitation) and the events leading to penile erection (blood flow and nerves).

Answer 36

the tonic convolutions of the helicine arteries normally limit blood flow into the venous sinuses but after activation of the cavernous nerves, uncoiling of the arteries results in engorgement of the venous sinuses and penile erection.

Question 37

Discuss embryological origins of the testis cords and further course of development action surrounding the testis cords.

Answer 37

germ cells stimulate proliferation of the primitive sex cords that subsequently transform into the testis cords that become separated from the genital ridge epithelium by the tunica albuginea, a layer of dense connective tissue.

Question 38

What form the short rete testis? The rete testis unite with (structure)

Answer 38

portions of the testis cords near the mesonephric duct form the short rete testis that unites with the mesonephric duct-derived efferent ductules.

Question 39

DISTAL to the efferent ductules, the mesonephric duct becomes (describe)

Answer 39

distal to the efferent ductules, the mesonephric duct becomes the highly convoluted epididymis and vas deferens.

Question 40

What structures occupy the spermatic cord (3)?

Answer 40

the vas deferens, the testicular artery, and the pampiniform venous plexus occupy the spermatic cord

Question 41

What forms the testicular vein (from a superior vantage point).

Answer 41

the pampiniform plexus converges superiorly as the testicular vein.

Question 42

Discuss what transforms into the seminiferous tubules and when does this occur (time).

Answer 42

the solid testis cords acquire lumens and transform into seminiferous tubules at puberty.

Question 43

What cell type lines the seminiferous tubules?

Discuss what structure is in involved to accommodate the rete testes?

Answer 43

stratified epithelium lines the seminiferous tubules and the tunica albuginea thickens along the posterior border of the testis to accommodate the rete testes.

Question 44

spermatogenic cells of the seminiferous epithelium are derivatives of the (cells)

Sertoli cells of the seminiferous epithelium are derivatives of the (tissue).

Answer 44

spermatogenic cells of the seminiferous epithelium are derivatives of the germ cells.

Sertoli cells of the seminiferous epithelium are derivatives of the genital ridge epithelium.

Question 45

Spermatogonia are (cell) derived and reside on (structure).

Discuss what generates spermatocytes and their nuclear morphology.

(cell shaped) Sertoli cells- discuss their nature and spatial layout.

Answer 45

germ cell-derived spermatogonia reside on the basement membrane and their continuous renewal generates spermatocytes with dark spherical nuclei that become smaller as the cells move toward the tubular lumen.

the columnar- shaped Sertoli cells are nonproliferating and extend from the basement membrane to the lumen.

Question 46

Discuss the relation of spermatocytes and Sertoli cells.

Answer 46

developing spermatocytes are embedded in crypt-like recesses of the Sertoli cells that secrete factors (e.g., androgen binding protein) essential for spermatocyte survival.

Question 47

Discuss what completes spermatogenesis.

Answer 47

transformation of small spermatocytes near the lumen into spermatozoa completes spermatogenesis.

Question 48

What provides energy to the mobile spermatozoa?

Answer 48

mitochondria in the middle piece provide energy to the mobile cilium that forms the tail.

Question 49

Discuss the acrosome and how it relates to fertilization.

Answer 49

acrosome surrounds the condensed nucleus in the head contains proteolytic enzymes, which allow the spermatozoa to penetrate the corona radiata at fertilization.

Question 50

Under LH stimulation relate to the essential nature for spermatogenesis.

Discuss testosterone and relation to prostate and seminal glands.

Answer 50

under LH stimulation, the intermediate mesoderm-derived Leydig cells secrete testosterone into the seminiferous epithelium where it is essential for spermatogenesis.

Leydig cell-derived testosterone that enters the bloodstream maintains normal functioning of the prostate and seminal glands.

Question 51

Discuss the nerve and tissue involvement for propelling spermatozoa through its course and the specific result of ejaculation.

Answer 51

sympathetic-mediated contraction of the bundles of smooth muscle that surround the mucosa of the vas deferens propels spermatozoa into the ejaculatory ducts and prostatic urethra, and sympathetic-mediated contraction of the prostatic fibromuscular stroma and pudendal nerve-mediated contraction of the thin bulbospongiosus muscle results in ejaculation.

Question 52

What is involved in the formation of the clitoris.

What peculiar tissue is in the body of the clitoris?

Answer 52

estrogen from the developing ovaries stimulates slight elongation of the genital tubercle to form the clitoris.

recognize erectile tissue of the corpus cavernosa in body of the clitoris.

Question 53

Discuss the formation/differentiation into the THIN labia minor and THICK labia majora.

Answer 53

the urethral folds form the thin labia minora that demarcate the open vestibule and the genital swellings differentiate into the thick labia majora that surround the labia minora.

Question 54

Discuss spatial relation of the vaginal orifice and what forms the mons pubis?

The urethra is derived from (structure).

Answer 54

the vaginal orifice is posterior to the external urethral orifice in the vestibule and the labia majora merge anteriorly to form the mons pubis.

the urethra is derived from the inferior portion of the urogenital sinus.

Question 55

Define what the bulbospongiosus covers.

When does the bulbospongiosus contract and why?

Answer 55

the bulbospongiosus covers the bulbs of the vestibule (homologous with bulb of the penis) and the vestibular glands in the superficial perineal pouch.

the bulbospongiosus contracts during sexual arousal to expedite mucus secretion by the vestibular glands into the vestibule.

Question 56

What forms the FATTY cores of the labia MAJORA and mons pubis?

Answer 56

the fatty layer of the superficial pouch thickens to form the fatty cores of the labia majora and mons pubis.

Question 57

What are the main constituents of the valva?

Answer 57

the clitoris, labia minora, vestibule, labia majora, and mons pubis are main constituents of the valva (aka female genitalia).

Question 58

Discuss lymph drainage from the valva.

Answer 58

lymph from the valva drains into the superficial inguinal lymph nodes.

Question 59

What forms the uterine canal (embryologically)?

Answer 59

midline fusion of the paramesonephric ducts forms the uterine canal.

Question 60

Discuss the area where the uterine canal terminates.

What forms the vagina and the vaginal fornix?

Answer 60

the uterine canal terminates at the wall of the urogenital sinus where a solid tissue wedge forms between them.

vacuolization of the tissue wedge forms the vagina and the vaginal fornix.

Question 61

How long is the vagina and discuss the vaginal fornix.

Answer 61

the vagina is 8-10 cm long and the vaginal fornix surrounds the exocervix where it protrudes into the vagina.

Question 62

Discuss what account for vaginal distensibility- and is it found?

Answer 62

elastic fibers fill the thick lamina propria and account for vaginal distensibility.

Question 63

Discuss the significance of PALE cytoplasm of the nonkeratinized stratified squamous epithelial cells of the vagina.

Answer 63

pale cytoplasm of the nonkeratinized stratified squamous epithelial cells depicts estrogen-stimulated glycogen accumulation that occurs during the proliferative phase.

Question 64

What nerves are involved with the distention of the superior half of the vagina.

Answer 64

distension of the superior half of the vagina activates visceral afferent fibers of the pelvic splanchnic nerves.

Question 65

(fibers) convey sensations of touch, pain, and temperature from the inferior half of the vagina.

Answer 65

somatic afferent fibers of the pudendal nerve convey sensations of touch, pain, and temperature from the inferior half of the vagina.

Question 66

Which levator ani muscles are most commonly torn during childbirth and what are the consequences?

Answer 66

pubococcygeus and puborectalis,
the main and most medial parts of the levator ani, are the
muscles torn most often.

These changes may cause urinary stress incontinence, characterized by dribbling of urine when intra-abdominal pressure is raised during coughing and lifting, for instance, or lead to the prolapse of one or more pelvic organs

Question 67

What clinical consequences can occur if the perineal body is damaged during childbirth?

Answer 67

Stretching or tearing the attachments of perineal
muscles from the perineal body can occur during
childbirth, removing support from the pelvic floor. As a result, prolapse of pelvic viscera, including prolapse of the bladder (through the urethra) and prolapse of the uterus and/or vagina (through the vaginal orifice) may occur.

Question 68

What is hypospadias and where is it likely to occur?

Answer 68

fusion of the urethral folds is incomplete, and abnormal openings of the urethra occur along the inferior aspect of the penis, usually near the glans, along the shaft or near the base of the penis.

Question 69

Why do injection sites differ for anesthetizing the anterior and posterior surfaces of the scrotum?

Answer 69

Since the anterolateral surface of the scrotum is supplied
by the lumbar plexus (primarily L1 fi bers via the
ilio-inguinal nerve) and the postero-inferior aspect is
supplied by the sacral plexus (primarily S3 fi bers via the pudendal nerve), a spinal anesthetic agent must be injected more superiorly to anesthetize the anterolateral surface of the scrotum than is necessary to anesthetize its postero- inferior surface.

Question 70

How do the sites of urine extravasation differ after injury to the penile and membranous urethrae?

Answer 70

Rupture of membranous urethra results in the extravasation (escape) of urine and blood into the deep perineal pouch; the fluid may pass superiorly through the urogenital hiatus and distribute extra peritoneally around the prostate and bladder.

Rupture of the penile urethra- the common site of rupture and extravasation of urine is in the bulb of the penis. results in urine passing from it (extravasating) into the superfi cial perineal space.

Question 71

Why can radical prostatectomy cause erectile dysfunction?

Answer 71

A lesion of the prostatic plexus or cavernous nerves results in an inability to achieve an erection.

Question 72

What is the function of the Sertoli cell-derived blood-testis barrier?

Answer 72

The resulting blood-testis permeability barrier separates spermatogonia and primary spermatocytes
from more apical secondary spermatocytes and spermatids. Contents in the seminiferous tubule lumen are thus isolated from circulating antigens, thereby protecting spermatocytes and spermatids from autoimmune reactions and bloodborne substances.

Question 73

What is the potential for surgical reversal of a vasectomy?

Answer 73

Microsurgery can reverse a vasectomy and restore fertility but is successful in only about 70% of cases.

Question 74

Why is torsion of the spermatic cord a surgical emergency?

Answer 74

Torsion of the spermatic cord is a surgical emergency
because necrosis (pathologic death) of the
testis may occur.

Question 75

How do urorectal and rectovaginal fistulas develop?

Answer 75

May be due to abnormalities in formation of cloaca and/or urorectal septum.

Opening of the hindgut shifts anteriorly leading to an opening of the hindgut into the urethra or vagina.

Question 76

Why is a mediolateral episiotomy preferable to a median episiotomy?

Answer 76

Recent studies indicate median episiotomies are
associated with an increased incidence of severe lacerations, associated in turn with an increased incidence of long-term incontinence, pelvic prolapse, and anovaginal fi stulae.

Mediolateral episiotomies appear to result
in a lower incidence of severe laceration and are less likely to be associated with damage to the anal sphincters and canal.

Question 77

Why do epithelial cells shed into the vaginal lumen contribute to the mobility of spermatozoa?

Answer 77

Near the time of ovulation, estrogen stimulates an

increased glycogen content. When the cells are shed, they discharge glycogen into the vaginal lumen.

Question 78

How does pain relief differ after local pudendal or ilioinguinal nerve blocks during childbirth?

Answer 78

entire perineum UG and post anal triangle- pudendal

only anterior UG triangle- ilioinguinal

Question 79

Why is a caudal epidural block the popular choice for participatory childbirth?

Answer 79

The caudal epidural block is a popular choice for participatory childbirth. It must be administered
in advance of the actual delivery, which is not possible with a precipitous birth. The anesthetic agent is administered using an in-dwelling catheter in the sacral canal, enabling administration of more anesthetic agent for a deeper or more prolonged anesthesia, if necessary.