Lecture 40: Comparative Penile Anatomy Flashcards
penis function
external reproductive organ
semen delivery and urination
2 types of penises
musculocavernous penis
fibroelastic prenis
what type of penis do dogs/horses/cats have
musculocavernous
what type of penis do bulls/rams/bucks/boars have
fibroelastic
what do both types of penis have in common
fibroelastic and membranous/erectile tissue
musculocavernous vs fibroelastic penis
musculocavernous: greater content of erectile tissue, lower content of fibroelastic tissue
fibroelastic: greater content of fibroelastic tissue, lower content of erectile tissue
penis structure: 3 regions
glans
body
base
unique feature of fibroelastic penis
sigmoid flexure
how many cavernous bodies make up penis
2
how many spongy bodies make up penis
1
4 muscles of penis base
-ischiourethralis
-ischiocavernosus
-bulbospongiosis
-retractor penis
which muscle of penis pulls the penis backwards
retractor penis
which muscle of penis expels semen during ejaculation (+ urine)
bulbospongiosis
2 locations of fibroelastic tissue: musculocavernous penis
tunica albuginea and trabeculae
os penis
free floating bone in musculocavernous penis
cavernous bodies are eventually replaced by what structure
os penis
what structure contributes to tying during mating: musculocavernous penis (dogs)
bulbus glandis
musculocavernous penis in cats: specialization, function
keratinized glans spikes
induced ovulation by stimulus of spikes
function of spongy body in musculocavernous penis
enclose urethra
body and glans: bulls vs rams/bucks
bulls: urethral process attached to glans
ram/buck: urethral process not attached to glans
blood supply to cavernous bodies
artery of the penis
blood supply to spongy bodies
artery of the bulb
innervation of penis
pudendal nerve
blood supply to bulbus glandis
dorsal artery of penis
main blood supply to penis: general arteries
artery of penis + branches
continuation of internal pudendal
artery of the penis: 3 branches
artery of the bulb
deep artery of penis
dorsal artery of penis
venous drainage of penis: pathway
bulbus glandis –> deep vein of the glans –> dorsal vein of the glans –> internal pudendal vein
erection: musculocavernous penis
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
what penile muscles are involved in erection (and what do they do)
proximal to base of penis: constriction by ischiourethralis and ischiocavernosus
distal to base of penis: constriction by vestibular bulb, constrictor vestibuli and constrictor vulvae
erection: fibroelastic penis
stimulated by temperature
lower blood filling of cavernous and spongy bodies
extension of sigmoid flexure
erected penis shape in bulls/boars
corkscrew
spiraling
prepuce definition and function
musculocutaneous shield that covers and protects the penis
what muscle protracts the prepuce in dogs
preputialis
2 muscles in prepuce: bull (and what they do)
preputial caudalis: retractor
preputial cranialis: protractor
specialized structure in prepuce of boar
preputial diverticulum
function of preputial diverticulum in boar
gland –> pheromones
blood supply of prepuce
external pudendal artery and vein
3 nerves that innervate prepuce
pudendal
iliohypogastric
ilioinguinal
lymphatic drainage of penis and prepuce
penile: superficial inguinal node
prepuce: deep inguinal node
