4-External Genitalia
Terms
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copy deck
- What is contained in the scrotum?
- testis, epididymis, vas or ductus deferens, testicular and epididymal arteries, and pampiniform plexus of veins
- What is the purpose of the pampiniform plexus of veins?
- countercurrent heat exchange system, keeps testis cooler than body temp
- What are the parts of the epididymis?
- head (caput); body (corpus); tail (cauda)
- Name 5 functions of the epididymis.
-
sperm maturation
sperm storage
sperm disposal
absorption
secretion - What surrounds the vas deferens?
- 3 layers of SM
- What does the vas deferens form?
- ejaculatory ducts
- What is the position of the vas deferens with respect to the seminal vesicles?
- it is just superior to seminal vesicles
- After a vasectomy where is it thought that sperm are broken down?
- within the epididymis
- What is cryptorchidism? What else can be affected?
-
retention of the testes anywhere along the route of descent
fertillity - What is the insufficient or congenital absence of valves with the spermatic vein? What can this cause? Which side is this more common on? Why?
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-varicocele
-blood reflux within pampiniform plexus
-more common on L side
-L testicular vein returns to renal vein which has a higher pressure than the R testicular vein which drains into the IVC - Discuss a congenital hydrocele of the testis.
- congenital-processes vaginalis remains open to peritoneal cavity
- Discuss an acquired hydrocele of the testis.
- abnormal accumulation of serous fluid in the sac of the tunica vaginalis
- What is torsion of testis.
- twisting of spermatic cord causing strangulation of the blood vessels serving testis and epididymis
- Name the layers of the anterior abdominal wall.
- skin, Camper's (fatty) & Scarpa's (membranous) fascia, external oblique, internal oblique, transverse abd, transversalis fascia, extraperitoneal fatty tissue, peritoneum
- Name the layers of the scrotum. (starting from skin)
- skin, dartos fascia (membranous), external spermatic fascia, cremasteric m & fascia, internal spermatic fascia, areolar tissue w/ localized collections of fat, tunica vaginalis
- Name the layers of the spermatic cord.
- external spermatic fascia, cremasteric muscle & fascia, internal spermatic f, obliterated processus v
- What are the 3 parts of the urethra?
- prostatic, membranous (intermediate), penile (spongy)
- What surrounds the internal urethral orifice as it penetrates the wall of the bladder. What type of muscle is it composed of?
- internal urethral sphincter made up of smooth muscle
- The midline ridge of the urethral crest rises up to form the seminal colliculus. What embryonic homolgue to the females is this? What functional structure is located here?
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prostatic utricle, a blind pouch, equiv to vagina in females
two openings for the ejaculatory ducts - What does the membranous urethra pass through? What is it surrounded by?
-
passes through levator ani of pelvic diaphragm and perineal membrane
surrounded by muscular fibers - What do the muscular fibers that surround the membranous urethra form?
- external urethral sphincter formed of striated muscle of the urogenital diaphragm
- Name the least distensible portion of the urethra in males and females. What can be used to forcefully open the urethra?
-
membranous portion of urethra for both
catheter - Where does the bulbourethral gland lie? Where do its ducts open to?
-
deep to perineal membrane
ducts open into proximal portion of penile urethra - Name the 3 cylinders of erectile tissue.
- 2 corpora cavernosa on dorsal surface, a single corpus spongiosum
- Which cylinder of erectile tissue contains the urethra?
- corpus spongiosum
- What surrounds each cylinder of erectile tissue?
- tunica albuginea
- The corpus spongiosum expands diatally to form the _____ and proximally to form the ______.
-
glans
bulb of the penis - Name the layers of the penis.
- skin, superficial fascia of penis, deep f (Buck's) of penis, tunica albuginea of corpus cavernosum erectile tissue
- What is the superficial (dartos) fascia of the penis continuous with?
- Scarpa's fascia of ant abdomen and Colle's fascia of perineum
- Name the blood vessels associated w/ the penis.
- superficial dorsal veins, deep dorsal arteries and veins, and deep corpus cavernosum artery
- Name the 2 ligaments of the penis.
- fundiform and suspensory ligament
- Which of the ligaments of the penis is more superficial? What does this ligament attach to?
- fundiform ligament-attaches from deep f. (Buck's) to linea alba superiorly
- What does the suspensory ligament attach to?
- from deep f. of penis to pubic symphysis
- If the foreskin is retracted what is exposed?
- corona of the glans
- The _____ body of the penis is skin, fascia, erectile tissue, blood, blood vessels and nerves.
- pendulous
- The ventral surface of the penis has a penile raphe, an embryological remnant of what?
- fusion of left and right tissue masses (urogenital folds) that join to form the penis
- At the base or root of the penis, each corpora cavernosae attaches where? What does this form?
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along inferior ramus of the pubic bone towards the ischial tuberosities
forms the R&L crura of penis - What attach to the superficial surface of the perineal membrane of the penis?
- bulb of the penis and crura
- What muscles cover the base of the bulb of the penis and the two crura? What type of muscle is this?
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bulbospongiosus & ischiocavernosus muscles
both are skeletal muscles - What is the only part of the penis that contains muscle? What is the purpose of the muscle here?
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the root
helps restrict venous blood flow out from the penis causing increase in internal penile pressure above arteriolar pressure - What does the bulbospongiosus muscle do in addition to restricting blood flow?
- expels both semen and urine from the base of the penile urethra
- What is the major artery that supplies the penis? Name the branches of this artery.
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internal pudendal A
dorsal penile arteries, deep penile arteries, artery of the bulb of the penis - What do the dorsal penile arteries supply?
- area btwn the corpora cavernosa, and mainly to skin and fascia
- What do the deep penile arteries supply?
- each corpora cavernosa, to erectile tissue
- What does the artery of the bulb of th penis supply? (2 things)
- the bulb of the penis and the bulbourethral glands
- Afferent sensations (GSA) are carried in _____ nerve of the penis, which is a branch of the _____ nerve. Name the corresponding spinal levels.
-
dorsal
pudendal N
S2,3,4 - Parasympathetic fibers (GVE) travel along the _____ nerve and _____ nerves to the deep arteries of the penis.
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pudenal
pelvic splanchnic - Sympathetic fibers innervating the penis come from spinal level(s) _____ and innervate arterial blood vessel walls.
- L1-2
- Motor innervation is from the deep branch of the _____ N, which is a branch of the _____ nerve. What is innervated?
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perineal
pudendal
bulbospongiosus and ischiocavernosus muscles - Erection of the penis requires (sympathetic or parasympathetic) stimulation? What does this allow for?
-
parasympathetic
vasodilation - What type of innervation is needed for ejaculation? What spinal levels? Name the nerves.
-
sympathetic
L1&2
sacral splanchnic N - What is detumescence?
- loss of an erection
- During ejaculation the internal urethral sphincter must remain closed and the external urethral sphincter must stay open otherwise what can occur?
- retroejaculation of seminal contents into bladder
- What may be the cause of the refractory period in which men cannot have a second orgasm?
- sympathetic discharge
- What is the name of the female external genitalia?
- vulva
- What is anterior to the pubic synphysis in females?
- mons pubis
- What contains the round ligament of the uterus?
- labia majora
- What are the two parts of the labia majora?
- anterior and posterior labial commissure
- Where is the anterior labial commissure located?
- anterior to the prepuce of the clitoris
- Where is the posterior labial commissure located?
- posterior to the vestibule, partially on top of the perineal body
- What immediately surrounds the vestibule of the vagina?
- labia minora
- What can the anterior commissure of the labia minora also be called?
- frenulum of clitoris
- What female tissue is homologous to the penis? What is the function of this tissue?
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clitoris
sexual arousal - Where are the R&L crus of the clitoris located?
- along the inferior pubic rami
- Name the 3 parts of the clitoris.
- angle, body and glans
- Where is the angle of the clitoris?
- superiorly attached to pubic symphysis
- What is the most distal end of the clitoris called?
- glans
- What is the most innervated part of the clitoris? What is the nerve that innervates it?
-
glans (distal end)
dorsal nerve of clitoris - What is the partially covered angle and body of the clitoris called?
- prepuce of clitoris
- What ist he space between the labia minora?
- vestibule
- About how far away is the external urethral orifice from the clitoris?
- 2 cm
- What are the thin folds of mucus membrane that may partially surround the vaginal orifice? What does this demarcate?
-
hymen
vulva from vaginal orifice - What is the name of the erectile tissue on either side of the vaginal orifice?
- bulbs of vestibule
- Name the muscle that covers the bulbs of vestibule.
- bulbospongiosus muscles
- What are the mucus secreting glands that of the vulva? Where are the openings of the glands located?
- greater vestibular (Bartholin's) glands, openings are in the posterior lateral portion of the vestibule
- Compare the mucus secreting glands of males and females.
- in females the glands are superficial to the urogenital diaphragm
- What else is located by the fourchette or posterior commissure of the vulva?
- the frenulum of the labia minora inferior to the vaginal opening
- Glans of the clitoris may be connected to what?
- vestibular bulb
- In females, what does the bulbospongiosus muscle attach to?
- attaches from perineal body, runs on top of vestibular bulb
- In females, what does the ischiocavernosus muscle attach to?
- from ischial ramus and partially covers crura of clitoris
- In females, what does the superficial transverse perineal muscle attach to?
- from ischial ramus to perineal body
- Contraction of what muscle forces blood into the clitoris glans and body?
- superficial transverse perineal muscle
- What is the fibromuscular structure in the midline between the vaginal opening and anal opening? What does it connect?
-
perineal body
perineal structures to pelvic diaphragm - What part of the nervous system is throught to control desire and arousal phase in women?
- CNS and PSNS
- Orgasmic muscle contraction includes what muscles?
-
the superficial perineal skeletal muscles-ischiocavernosus, bulbocavernosus, superficial transverse perineal muscles
smooth muscles of vaginal wall and muscles of pelvic floor or levator ani-pubococcygeus and iliococcygeus - What may actually be located in the G spot?
- erectile tissue of the bulb of the clitoris that surrounds the urethra or Skene's glands (mucus secreting glands) that surround the urethra
- What type of cut may be done during labor in order to prevent tearing of the vagina and perineal body?
- episiotomy
- What are the main nerves that innervate the vulva? (2)
- pudendal and ilioinguinal
- name the branches of the pudendal nerve.
- dorsal nerve of the clitoris, posterior labial nerves, superficial and deep perineal nerves
- What does the ilioinguinal N provide some innervation to?
- mons pubis and anterior labia majors
- What is the purpose of a pudendal N block? How can this be done?
-
provide some relief from the pain of childbirth
the pudendal nerve wraps around the ischial spine so it can be palpated and injects near this location