Ch.61 Penis and Prepuce

Question 1

Which of the following statements is true?

a. dorsally located corpus cavernosum penis (ccp), is responsible for erection

b. dorsally located corpus spongiosum penis (csp), is responsible for erection

c. ventrally located corpus cavernosum penis (ccp),
surrounds the urethra

d. dorsally located corpus cavernosum penis (ccp),
surrounds the urethra

Answer 1

a. dorsally located corpus cavernosum penis (ccp), which is responsible for erection

ventrally located corpus spongiosum penis (cSp), formerly termed the corpus cavernosum urethrae
surrounds the urethra

Question 2

Which of the following statements is correct?

a. Sexual excitement stimulates parasympathetic outflow from the sacral portion of the spinal cord and results in dilation and straightening of the helicine arteries, coiled branches of the deep artery of the penis

b. contraction of the ischiocavernosus muscles from stimulation of the pudendal nerves occludes arterial and venous flow against the ischium, making the ccp a closed system during peak erection

c. Arterial flow to the penis is supplied by terminal branches of the internal pudendal (or internal pudic),
obturator, and external pudendal (or external pudic) arteries

d. All of the above

Answer 2

d. all of the above

Question 3

a. The internal pudendal artery supplies the cranial (or dorsal) artery of the penis, a major source of blood for erectile tissue

b. Deep arteries of the penis originate from the obturator arteries and supply the ccp

c. External pudendal artery supplies the pelvic portion of the urethra

d. All of the above

Answer 3

b. deep arteries of the penis originate from the obturator arteries and supply the ccp

The external pudendal artery supplies the cranial (or dorsal) artery of the penis, a major source of blood for erectile tissue

The internal pudendal artery supplies the pelvic portion of the urethra

Question 4

a. The external pudendal artery supplies a branch to the scrotum and continues as the caudal superficial epigastric artery, which provides branches to the prepuce

b. Deep perineal and caudal rectal nerves supply the bulbospongiosus, ischiocavernosus, and retractor penis muscles

c. The venous plexus is emptied by the external pudendal and obturator veins

d. All of the above

Answer 4

All of the above

Question 5

What lines the cavernous spaces

Answer 5

Endothelial cells

Longitudinally orientated smooth muscle

Question 6

What maintains the non erect penis in the prepuce

Answer 6

Tonus of the muscular trabeculae and retractor penis muscles

Question 7

Mechanism of erection

Answer 7

1. Sexual arousal - Parasympathetic
   outflow from sacral portion of spinal
   cord
2. Dilation and straightening of the
   helicon arteries
3. Relaxation of the sinusoidal smooth
   muscles

• Enabling blood to flow into the
  sinusoidal spaces
• Engorgement of the cavernous spaces
  is controlled and stopped by tunica
  albuginea and trabeculae lengthens
  and stiffens the penis

Question 8

Contraction of what muscles causes the CCP to become a closed system

Answer 8

Ischiocavernosus muscles

Compression of the crura by the ischiocavernosus m forces blood into the CCP to produce high pressures

Question 9

Innervation of the ischiocavernosum m

Answer 9

Pudenadal n

Question 10

What muscle is essential for increasing pressures in the CSP

Answer 10

Bulbospongious

Question 11

Is the CSP an open or closed system during erection

Answer 11

Open

Question 12

Contraction of what muscles elevates the penis

Answer 12

Ischiocavernosus

Question 13

How is blood flow out of the penis impeded

Answer 13

Ischiocavernosus compresses penis against the ischium preventing venous flow from CCP

Question 14

What muscle forces release of seminal fluid during ejaculation and also urine during urination

Answer 14

Urethralis muscle

Question 15

How do ischiourethral mm assist in erection

Answer 15

Compress dorsal veins of the penis

Question 16

Arteries supplying the penis

Answer 16

Internal pudendal - pelvic urethra
Obturator - deep aa
External pudendal - cranial aa

Question 17

Innervation of the penis

Answer 17

Pudendal n
Pelvic plexus

Deep perineal and caudorectal supply the bulbospongiosus, ischiocavernosus and retractor penis mm

Question 18

What are the accessory genital glands

Answer 18

Paired seminal vesicles
Prostate
Paired ampullae of ductus def

Question 19

What its the function of the bulbourethral glands

Answer 19

Produce alkaline, mutinous secretion that clears the urethra of urine before ejaculation and lubricates the urethra for passage of seminal fluid.

Question 20

Function of the prostate

Answer 20

Produces watery alkaline secretion that neutralises the acidity of fluid entering the urethra from the ductus def

Question 21

What glands secretion makes up the majority of the ejaculate volume

Answer 21

Seminal vesicles

Question 22

What is the ejaculatory duct

Answer 22

Combined terminal portion of the ampulla and excretory duct of seminal vesicle