External Genitalia, Vasculature, Innervation and Lymphatics

Question 1

Describe the structure of the clitoris

Answer 1

Clitoral glans at an angle pointing downwards
Long corpus cavernosum separated by the pars intermedia
Corpus cavernosum splits into 2 crus clitoris
In between there is the bulb of vestibule where the urethral and vaginal opening are found

Question 2

Describe the structure of the penis

Answer 2

Glans penis, most distal
Corpus cavernosum over the corpus spongiosum
Most proximal part of the corpus spongiosum, bulb of penis
Corpus cavernosa splits into 2 crura penis

Question 3

Innervation of pelvic organs
Somatic (afferent and efferent)
SNS
PNS

Answer 3

Somatic
-Pudendal nerve (S2-4)

SNS
-Sacral sympathetic chains (L10-S2) => Superior and inferior hypogastric plexus

PNS
-Pelvic splanchnic (S2-4) => Inferior hypogastric plexus

Question 4

Innervation of the pelvic organs
Autonomic (afferent visceral)
Referred pain
Reflexes

Answer 4

For reflexive sensations, fibres travel with P fibres

For pain sensation, fibres travel with S above pelvic pain line and P below it

Question 5

Pudendal nerve route in perineum from anterior rami (S2-4 sacral plexus)

Answer 5

from anterior rami (S2-4 sacral plexus)
Pudendal nerve pass out of the greater sciatic notch in pelvis, enter via the lesser sciatic notch into the gluteal region

In the pelvis, splits into 3
2 branches enter pudendal canal, 1 branches into the superficial perineum, forms the inferior anal nerve

1 branch that enters the pudendal canal enters the deep perineal pouch and then the dorsal of the penis. Forms the dorsal penis nerve

The other branch in the pudendal canal splits into 2, 1 passes into the deep perineal pouch into the dorsum of the penis, forms the dorsal penis nerve
The other branch enters the superficial perineum, forms the deep and superficial perineal nerves and then the posterior scrotal nerves

Question 6

Structure of the nerves in the pelvis around the common iliac and sacrum

Answer 6

Superior hypogastric plexus (S) around the common iliacs and external, internals and forms periarterial plexus

Sacral splanchnic nerves (SVS) (S) surrounds sacrum

Somatic sciatic nerves passes under internal iliac

Inferior hypogastric plexus (S and P), leads into pelvic splanchnic nerves (P)

Question 7

Locations of the pelvic nerves in relation to the pain lines

Answer 7

Pain lines along the bottom of the peritoneum in both sexes

Question 8

Distribution of lymphatics in a pelvis

Answer 8

From the bottom of the internal iliac upwards,
Deep inguinal
Superficial inguinal
External iliac
Internal iliac joins the external
Common iliac
Lumbar, surround inferior mesenteric artery

Question 9

Blood supply from the common iliac

Answer 9

External and internal iliac

From the internal iliac
Iliolumbar
Branching off branches in the internals PA
Lateral sacral
Superior, inferior gluteal
Uterine (males have inferior vesical artery and a prostate branch instead), internal pudendal

Medial umbilical ligament
Branches of the most anterior vessel form the superior vesicle arteries and obturator

Middle rectal branches off internal pudendal

Uterine arteries lead to the vaginal arteries

Branching off the external iliac
Deep circumflex iliac
Inferior epigastric

Question 10

How do the testes descend

3 key steps

Answer 10

Regression of the testes
-Initially above the kidneys which are in the pelvis

Transabdominal phase
-Testes move down from abdomen to pelvis

Transinguinal phase

• Testes move from pelvis into scrotum
• Outside body as spermatogenesis occurs at 2C lower than body temp

Question 11

Movement of the testes out of the pelvis

Answer 11

Travels down gubernaculum between transversals fascia and peritoneum

Travels through gap in transversus abdominis and pushes transversals fascia, internal and external obliques with it. Infolding of peritoneum also follows, forming a processes vaginalis.

Question 12

Movement of the ovaries in the pelvis

Answer 12

Ovaries descend too but they stay in the true pelvis

Question 13

Contents of the inguinal canal and spermatic cord

Answer 13

3 fascia

• external spermatic fascia
• cremasteric
• internal spermatic fascia

3 veins

• Pampiniform plexus
• testicular vein
• cremasteric vein
• deferential vein

3 arteries
-testiular
cremasteric
-deferential

3 nerves

• genital branch of genitofemorla
• ilioinguinal
• autonomic nerves

Lymphatics

Question 14

Contents of the inguinal canal in females

Answer 14

Round ligament of uterus
Genital branch of genitofemoral nerve
Ilioinguinal nerve

Question 15

Structure of the testis and functions of the cells
What are the 2 main cells found here
What are the 2 main structures found here

Answer 15

Leydig cells adjacent to seminiferous tubules
-produce testosterone in presence of LH

Sertoli cells in seminiferous tubules, essential for testis formation and spermatogenesis
-secretes androgen binding proteins in lumen under FSH action

Seminiferous tubules lead to rete testes into epididymus

Epididymus allows passage for the sperm cells to join ducts from the seminal vesicals

Question 16

Relations of the prostate, seminal vesicles, bulbourethral glands

Answer 16

Vas deferent comes from testes, in front of bladder and comes over and behind the ureters into the seminal vesicles

Seminal vesicle ducts travel through the prostate and join the urethra

Bulbourethral glands sit inferior to the prostate

Question 17

Areas of the prostate

Answer 17

Transitional zone surrounds the urethra, common site for prostate cancers

Central zone, posterior to urethra and prostate and surrounds the ejaculatory duct surrounded by prostatic sinus

Peripheral zone inferior and posterior to central zone, small part is below transitional zone

Question 18

Parts of the male urethra

Answer 18

Preprostatic urethra
Prostatic urethra
Membranous urethra
Spongy urethra

Question 19

Penis structure at dorsum

Answer 19

Prepuce surrounds distal part of penis

Glans penis at the most distal

Question 20

Cross section of a penis, structure

Answer 20

Skin and superficial fascia surrounds loose areolar tissue. Superficial dorsal vein found here between superficial and deep fascia.

Deep to the deep fascia, deep dorsal vein, arteries and nerves found here

Tunica albuginea deep to deep fascia, surrounds 2 corpus cavernous and 1 corpus spongiosum

Spongy urethra found in corpus spongiosum

Deep artery found in both corpus cavernosum

Question 21

The nervous innervation in erection

Answer 21

On stimulation, P fibres (S2-4) => vasodilation, increased blood flow into cavernosum and spongiosum

Tunica albuginea and deep fascia surrounds erectile tissue, restricts venous drainage

Question 22

The nervous innervation in emission

Answer 22

Sympathetic fibres (L1-2) via pelvic plexus => contraction of ductus deferent and seminal vesicles

Sperm expelled, secretion into urethra

Question 23

The nervous innervation in ejaculation

Answer 23

Caused by rhythmic contraction of bulbospongiosus muscle and opening of external urethral sphincter

Controlled by pudendal branches

Question 24

Structure of the female reproductive system

Answer 24

Ovaries kept in place by ligaments

Fimbriae lead to fallopian tube into uterine cavity in uterus

Uterine body made up of fundus down to the ureter

Uterine neck made up of the portion of the uterus below the ureter

Cervical canal between both os

Internal os, at opening of the uterus

External os, at opening of the vagina from the uterus

Invagination of the vagina at the uterine opening, lateral vaginal fornix

Vagina is most distal

Question 25

Sagittal section of broad ligament (mesentery of the uterus)

Answer 25

Mesovarium surrounds ovaries, anterior to uterine tubes

Mesosalpinx surrounds uterine tube, posterior to ovaries

Uterine artery between 2 mesenteries above ureter

Question 26

Passage of an egg from the ovary into the uterus

Answer 26

Egg released from follicle
Fertilization in the fallopian tube
Egg pushed through tube by cilia
Egg buries itself in the endometrium in the uterus

Question 27

What is an ectopic pregnancy and why is it bad

Answer 27

Pregnancy not in the uterus
Egg can fall out, grow elsewhere
If fallopian tube ruptures, v vascular, can be fatal

Question 28

Angles of the uterus

Answer 28

Angle of uterine flexion (internal angle )greater than angle of uterine version (external angle)

Question 29

External genitalia structure in females

Answer 29

Prepuce and glans clitoris
Most anterior is the crus
Medial structure is the labia minora
Urethra anterior to 2 lesser vestibular glands
Vagine anterior to 2 greater vestibular glands
Fourchette posterior in labia minora

Question 30

Innervation and mechanism of erection in females

Structure

Answer 30

Clitoris made up of corpora cavernosa
Cavernosa made up of trabecular and sinusoidal spaces
Clitoris enclosed in tunica albuginea (dense fibrous sheath)
Glans clitoris innervated by sensory nerve endings, cap on ends of corporal bodies
Venous plexus of Kobelt that communicates to the venous circulation of bulb to cavernosa under clitoris angle

Question 31

Innervation and mechanism of erection in females

Arousal

Answer 31

Increase in blood flow to erectile tissue
Engorgement with erection by P fibres (S2-4) via pelvic splanchnic and NO

Tunica albuginea restricts further erection of corpora cavernosa, shuts venous drainage
Due to engorgement with blood, labia minora => turgid, doubles, triples in thickness
Continuous involuntary reflex hypertonic contraction, maintains erection