Anatomy 3: Pelvic Organs - General Viscera and Male Pelvic Organs Flashcards
Describe the peritoneum’s relationship with the rectum
- Covers the anterir and lateral walls of the superior 1/3 of the rectum
- Covers only the anteior surface of the middle 1/3
- The inferior 1/3 is sub-peritoneal
Describe the muscle layers around the rectum
- Outer longitudinal
- Inner circular
Functio nof puborectalis muscle
Acts as a muscular sling that kinks the anorectal junction. Functions in the maintenance of fecal continence
Artery from which the superior rectal artery originates
Inferior mesenteric artery
Artery from which the middle rectal artery originates
Internal iliac artery
Artery from which the inferior rectal artery originates, and the artery from what that originates
Internal iliac artery –> internal pudendal artery –> inferior rectal artery
Where does the inferior mesenteric vein empty into?
Portal System
5 main vessels of the portal system
- Portal vein
- Superior mesenteric vein
- Superior rectal vein
- Inferior mesenteric vein
- Splenic vein
Define the ureter
Retroperitoneal muscular ducts ~25-30 cm long
What crosses the ureters anteriorly
Gonadal vessels
What does the ureter cross to enter the pelvis
Bifurcation of the common iliac artery
3 places where the ureters are normally constricted
- Junction of the ureters and the renal pelvis
- Where the ureters cross the brim of the pelvic inlet
- During their passage through the wall of the bladder
Label these 7 internal features of the bladder
See image
FUnction of parasympathetic fibers with respect to micturation
Contraction of the detrusor muscle and are inhibitory to the internal involuntary sphincter (allows voiding)
Function of sympathetic fibers with respect to micturation (3)
- Induce relaxation of the bladder walla nd constrict the internal sphincter (inhibit emptying)
- Prevents semen from entering the bladder in males during ejaculation
- Make you unable to void from self-consciousness
Full bladder volume
300 mL or more
Describe how voiding occurs physiologically (6 steps)
- Bladder full and stretched
- Visceral afferent fibers are stimulated
- Impulses enter S2-4 via pelvic splanchnicnerve (parasympathetic)
- Efferent fibers transmit impulses back to the bladder
- Recontractio nof the detrusor muscle reflexively
- Internal sphincter relaxes
NOTE: Can suppress this reflex by voluntary control of the external urethral sphincter
Describe the trajectory of the vas deferens
- Continuation of the epididymis
- Passes through the inguinal canal within the spermatic cord to enter the abdomen
- Descends into the true pelvic along its lateral walls just deep to the peritoneum
- Crosses over the ureter and travels to the posterior surface of the bladder
- Enlarges posterior to the bladder into the ampulla of the vas
What forms the ejaculatory duct?
- Duct of the ampulla
- Duct of the seminal vesicle
Location of the seminal vesicles
- Paired organs
- Lie on the posterior surface of the bladder between the bladder and the rectum
- Lateral to the terminal parts of the vas deferens
Where do the seminal vesicles empty into
Short duct at the inferior end that fuses with the duct of the ampulla of the vas
Where do the ejaculatory ducts open into?
The prostatic part of the urethra (prostatic urethra) near the orifice of the prostatic utricle
Define the prostatic utricle
The tiny vesitgial development homologue of the uterus
5 lobes of the prostate
- Ventral/anterior lobe
- Lateral lobes (2)
- Posterior lobe
- Middle lobe
Location of ventral/anterior lobe of prostate
Anterior to the urethra
Location of lateral lobes of the prostate
Lateral to the ejaculatory ducts
Location of the posterior lobe of the prostate
Between the ejaculatory ducts
Location of the middle lobe of the prostate
Above the ejaculatory ducts
5 functional zones of the prostate
- Anterior fibromuscular zone
- Preprostatic sphincter
- Transitional zone
- Central zone
- Peripheral zone
Location of the central zone of the prostate
Posterior to the urethra and surrounds the two ejaculatory ducts
Location of the transitional zone of the prostate
Mainly anterior and superior to the prostatic colliculus
Location of the preprostatic sphincter
Surrounds the proximal prostatic urethra and is surrounded by the transitional zone
Location of the peripheral zone of the prostate
Extends over the posterior and lateral surfacees of the prostates
Location of the anterior fibromuscular zone
Anterior part of the prostate
Function of the prostate
Generate ~20% of the seminal fluid which enters the prostatic urethra through 20-30 ducts that open into the prostatic sinus
