Lecture 40: Comparative Penile Anatomy

Question 1

penis function

Answer 1

external reproductive organ
semen delivery and urination

Question 2

2 types of penises

Answer 2

musculocavernous penis
fibroelastic prenis

Question 3

what type of penis do dogs/horses/cats have

Answer 3

musculocavernous

Question 4

what type of penis do bulls/rams/bucks/boars have

Answer 4

fibroelastic

Question 5

what do both types of penis have in common

Answer 5

fibroelastic and membranous/erectile tissue

Question 6

musculocavernous vs fibroelastic penis

Answer 6

musculocavernous: greater content of erectile tissue, lower content of fibroelastic tissue
fibroelastic: greater content of fibroelastic tissue, lower content of erectile tissue

Question 7

penis structure: 3 regions

Answer 7

glans
body
base

Question 8

unique feature of fibroelastic penis

Answer 8

sigmoid flexure

Question 9

how many cavernous bodies make up penis

Answer 9

2

Question 10

how many spongy bodies make up penis

Answer 10

1

Question 11

4 muscles of penis base

Answer 11

-ischiourethralis
-ischiocavernosus
-bulbospongiosis
-retractor penis

Question 12

which muscle of penis pulls the penis backwards

Answer 12

retractor penis

Question 13

which muscle of penis expels semen during ejaculation (+ urine)

Answer 13

bulbospongiosis

Question 14

2 locations of fibroelastic tissue: musculocavernous penis

Answer 14

tunica albuginea and trabeculae

Question 15

os penis

Answer 15

free floating bone in musculocavernous penis

Question 16

cavernous bodies are eventually replaced by what structure

Answer 16

os penis

Question 17

what structure contributes to tying during mating: musculocavernous penis (dogs)

Answer 17

bulbus glandis

Question 18

musculocavernous penis in cats: specialization, function

Answer 18

keratinized glans spikes
induced ovulation by stimulus of spikes

Question 19

function of spongy body in musculocavernous penis

Answer 19

enclose urethra

Question 20

body and glans: bulls vs rams/bucks

Answer 20

bulls: urethral process attached to glans
ram/buck: urethral process not attached to glans

Question 21

blood supply to cavernous bodies

Answer 21

artery of the penis

Question 22

blood supply to spongy bodies

Answer 22

artery of the bulb

Question 23

innervation of penis

Answer 23

pudendal nerve

Question 24

blood supply to bulbus glandis

Answer 24

dorsal artery of penis

Question 25

main blood supply to penis: general arteries

Answer 25

artery of penis + branches continuation of internal pudendal

Question 26

artery of the penis: 3 branches

Answer 26

artery of the bulb deep artery of penis dorsal artery of penis

Question 27

venous drainage of penis: pathway

Answer 27

bulbus glandis --> deep vein of the glans --> dorsal vein of the glans --> internal pudendal vein

Question 28

erection: musculocavernous penis

Answer 28

results from positive balance in blood flow --> higher blood filling of cavernous and spongy bodies more blood accumulates in penis as venous drainage is interrupted

Question 29

what penile muscles are involved in erection (and what do they do)

Answer 29

proximal to base of penis: constriction by ischiourethralis and ischiocavernosus distal to base of penis: constriction by vestibular bulb, constrictor vestibuli and constrictor vulvae

Question 30

erection: fibroelastic penis

Answer 30

stimulated by temperature lower blood filling of cavernous and spongy bodies extension of sigmoid flexure

Question 31

erected penis shape in bulls/boars

Answer 31

corkscrew spiraling

Question 32

prepuce definition and function

Answer 32

musculocutaneous shield that covers and protects the penis

Question 33

what muscle protracts the prepuce in dogs

Answer 33

preputialis

Question 34

2 muscles in prepuce: bull (and what they do)

Answer 34

preputial caudalis: retractor preputial cranialis: protractor

Question 35

specialized structure in prepuce of boar

Answer 35

preputial diverticulum

Question 36

function of preputial diverticulum in boar

Answer 36

gland --> pheromones

Question 37

blood supply of prepuce

Answer 37

external pudendal artery and vein

Question 38

3 nerves that innervate prepuce

Answer 38

pudendal iliohypogastric ilioinguinal

Question 39

lymphatic drainage of penis and prepuce

Answer 39

penile: superficial inguinal node prepuce: deep inguinal node