Anatomy 3: Pelvic Organs - General Viscera and Male Pelvic Organs

Question 1

Describe the peritoneum’s relationship with the rectum

Answer 1

• 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

Question 2

Describe the muscle layers around the rectum

Answer 2

• Outer longitudinal
• Inner circular

Question 3

Functio nof puborectalis muscle

Answer 3

Acts as a muscular sling that kinks the anorectal junction. Functions in the maintenance of fecal continence

Question 4

Artery from which the superior rectal artery originates

Answer 4

Inferior mesenteric artery

Question 5

Artery from which the middle rectal artery originates

Answer 5

Internal iliac artery

Question 6

Artery from which the inferior rectal artery originates, and the artery from what that originates

Answer 6

Internal iliac artery –> internal pudendal artery –> inferior rectal artery

Question 7

Where does the inferior mesenteric vein empty into?

Answer 7

Portal System

Question 8

5 main vessels of the portal system

Answer 8

• Portal vein
• Superior mesenteric vein
• Superior rectal vein
• Inferior mesenteric vein
• Splenic vein

Question 9

Define the ureter

Answer 9

Retroperitoneal muscular ducts ~25-30 cm long

Question 10

What crosses the ureters anteriorly

Answer 10

Gonadal vessels

Question 11

What does the ureter cross to enter the pelvis

Answer 11

Bifurcation of the common iliac artery

Question 12

3 places where the ureters are normally constricted

Answer 12

• 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

Question 13

Label these 7 internal features of the bladder

Answer 13

See image

Question 14

FUnction of parasympathetic fibers with respect to micturation

Answer 14

Contraction of the detrusor muscle and are inhibitory to the internal involuntary sphincter (allows voiding)

Question 15

Function of sympathetic fibers with respect to micturation (3)

Answer 15

• 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

Question 16

Full bladder volume

Answer 16

300 mL or more

Question 17

Describe how voiding occurs physiologically (6 steps)

Answer 17

1. Bladder full and stretched
2. Visceral afferent fibers are stimulated
3. Impulses enter S2-4 via pelvic splanchnicnerve (parasympathetic)
4. Efferent fibers transmit impulses back to the bladder
5. Recontractio nof the detrusor muscle reflexively
6. Internal sphincter relaxes

NOTE: Can suppress this reflex by voluntary control of the external urethral sphincter

Question 18

Describe the trajectory of the vas deferens

Answer 18

1. Continuation of the epididymis
2. Passes through the inguinal canal within the spermatic cord to enter the abdomen
3. Descends into the true pelvic along its lateral walls just deep to the peritoneum
4. Crosses over the ureter and travels to the posterior surface of the bladder
5. Enlarges posterior to the bladder into the ampulla of the vas

Question 19

What forms the ejaculatory duct?

Answer 19

• Duct of the ampulla
• Duct of the seminal vesicle

Question 20

Location of the seminal vesicles

Answer 20

• 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

Question 21

Where do the seminal vesicles empty into

Answer 21

Short duct at the inferior end that fuses with the duct of the ampulla of the vas

Question 22

Where do the ejaculatory ducts open into?

Answer 22

The prostatic part of the urethra (prostatic urethra) near the orifice of the prostatic utricle

Question 23

Define the prostatic utricle

Answer 23

The tiny vesitgial development homologue of the uterus

Question 24

5 lobes of the prostate

Answer 24

• Ventral/anterior lobe
• Lateral lobes (2)
• Posterior lobe
• Middle lobe

Question 25

Location of ventral/anterior lobe of prostate

Answer 25

Anterior to the urethra

Question 26

Location of lateral lobes of the prostate

Answer 26

Lateral to the ejaculatory ducts

Question 27

Location of the posterior lobe of the prostate

Answer 27

Between the ejaculatory ducts

Question 28

Location of the middle lobe of the prostate

Answer 28

Above the ejaculatory ducts

Question 29

5 functional zones of the prostate

Answer 29

• Anterior fibromuscular zone
• Preprostatic sphincter
• Transitional zone
• Central zone
• Peripheral zone

Question 30

Location of the central zone of the prostate

Answer 30

Posterior to the urethra and surrounds the two ejaculatory ducts

Question 31

Location of the transitional zone of the prostate

Answer 31

Mainly anterior and superior to the prostatic colliculus

Question 32

Location of the preprostatic sphincter

Answer 32

Surrounds the proximal prostatic urethra and is surrounded by the transitional zone

Question 33

Location of the peripheral zone of the prostate

Answer 33

Extends over the posterior and lateral surfacees of the prostates

Question 34

Location of the anterior fibromuscular zone

Answer 34

Anterior part of the prostate

Question 35

Function of the prostate

Answer 35

Generate ~20% of the seminal fluid which enters the prostatic urethra through 20-30 ducts that open into the prostatic sinus