External Genitalia, Vasculature, Innervation and Lymphatics Flashcards
Describe the structure of the clitoris
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
Describe the structure of the penis
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
Innervation of pelvic organs
Somatic (afferent and efferent)
SNS
PNS
Somatic
-Pudendal nerve (S2-4)
SNS
-Sacral sympathetic chains (L10-S2) => Superior and inferior hypogastric plexus
PNS
-Pelvic splanchnic (S2-4) => Inferior hypogastric plexus
Innervation of the pelvic organs
Autonomic (afferent visceral)
Referred pain
Reflexes
For reflexive sensations, fibres travel with P fibres
For pain sensation, fibres travel with S above pelvic pain line and P below it
Pudendal nerve route in perineum from anterior rami (S2-4 sacral plexus)
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
Structure of the nerves in the pelvis around the common iliac and sacrum
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)
Locations of the pelvic nerves in relation to the pain lines
Pain lines along the bottom of the peritoneum in both sexes
Distribution of lymphatics in a pelvis
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
Blood supply from the common iliac
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
How do the testes descend
3 key steps
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
Movement of the testes out of the pelvis
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.
Movement of the ovaries in the pelvis
Ovaries descend too but they stay in the true pelvis
Contents of the inguinal canal and spermatic cord
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
Contents of the inguinal canal in females
Round ligament of uterus
Genital branch of genitofemoral nerve
Ilioinguinal nerve
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
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
Relations of the prostate, seminal vesicles, bulbourethral glands
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
Areas of the prostate
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
Parts of the male urethra
Preprostatic urethra
Prostatic urethra
Membranous urethra
Spongy urethra
Penis structure at dorsum
Prepuce surrounds distal part of penis
Glans penis at the most distal
Cross section of a penis, structure
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
The nervous innervation in erection
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
The nervous innervation in emission
Sympathetic fibres (L1-2) via pelvic plexus => contraction of ductus deferent and seminal vesicles
Sperm expelled, secretion into urethra
The nervous innervation in ejaculation
Caused by rhythmic contraction of bulbospongiosus muscle and opening of external urethral sphincter
Controlled by pudendal branches
Structure of the female reproductive system
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
Sagittal section of broad ligament (mesentery of the uterus)
Mesovarium surrounds ovaries, anterior to uterine tubes
Mesosalpinx surrounds uterine tube, posterior to ovaries
Uterine artery between 2 mesenteries above ureter
Passage of an egg from the ovary into the uterus
Egg released from follicle
Fertilization in the fallopian tube
Egg pushed through tube by cilia
Egg buries itself in the endometrium in the uterus
What is an ectopic pregnancy and why is it bad
Pregnancy not in the uterus
Egg can fall out, grow elsewhere
If fallopian tube ruptures, v vascular, can be fatal
Angles of the uterus
Angle of uterine flexion (internal angle )greater than angle of uterine version (external angle)
External genitalia structure in females
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
Innervation and mechanism of erection in females
Structure
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
Innervation and mechanism of erection in females
Arousal
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
