C O M PA R AT I V E A N AT O M Y O F T H E M A L E R E P R O D U C T I V E S Y S T E M

• which nerves is the penis innervated by?

  -pudendal nerve (somatic motor+sensory fibres)

  -pelvic nerves (parasympathetic)

  -hypogastric nerves (sympathetic)
• which artery of the internal pudendal artery supplies the glans?

  dorsal artery of the penis
• which artery of the internal pudendal artery supplies the corpus cavernosum?

  deep artery of the penis
• which artery of the internal pudendal artery supplies the corpus spongiosum?

  artery of the bulb of the penis
• what is supplied by branches of the internal pudendal artery?

  urethra, accessory sex glands+penis
• what is the ischiocavernous muscle?

  -paired

  -enclose the crura

  -upon contraction, blocks venous return from corpus cavernosum
• what is the bulbospongiosus muscle?

  -continuation of urethralis muscle

  -expel urethral contents
• what is the retractor muscle?

  -paired

  -origin from caudal vertebrae

  -smooth muscle

  -important in ruminants/swine with sigmoid flexure
• what is the glans like in horses?

  -mushroom shaped with fossa

  -exaggerated durinng erection

  -corpus spongiosum expands over apex of penis

  -widest part=corona

  -prepuce has 2 layers allowing telescopic lengthening

  -urethral process sits within fossa glandis

  -glands of prepuce produce solid smegma (bean of urethral sinus)
• what is the glans like in small ruminants?

  urethral process continues beyond end of penis
• what is the glans like in bulls?

  -small

  -asymmetrical

  -slightly spiralled
• what is the glans like in pigs?

  corkscrew with small clapping glans
• what is the glans like in cats?

  -keratinised papillae barbs

  -stimulate ovulation in female
• what is the glans like in dogs?

  -long distal part

  -expanded proximal part (bulbis glandis)

  -contributes to copulatory lock (knotting during mating)
• what is the baculum/os penis

  -dogs+mammals

  -penis bone

  -after termination of corpus cavernosum

  -contributes stiffness

  -ventral groove contains urethra (narrowing at distal end risks obsrtruction)
• what is a fibroelastic penis?

  -ruminants+pigs

  -more tough fibroelastic tissue so penis inherently stiff

  -small blood spaces so little blood flow to corpus cavernosum+spongiosum

  -elongation by relaxation of retractor penis muscle+straightening of sigmoid flexure
• what is a musculocavernous penis?

  -horse,dog,cat,human

  -erection achieved by blood filling blood spaces (corpus cavernousm+spongiosum)
• what are the 2 types of penis?

  musculocavernous+fibroelastic
• what is the unpaired corpus spongiosum?

  -surrounds urethra

  -originates at pelvic outlet (start of penile urethra)

  -continues along length of urethra
• what are the paired corpus cavernosum?

  -speatrate at base/root

  -divided by a septum

  -can converge later in body/shaft
• what does the penis contain?

  -3 columns of cavernous erectile tissue (spaces filled with blood)

  -paired corpus cavernosum

  -unpaired corpus spongiosum
• what is the glans?


  -distal

  -free portion

  -shaped by expansion of corpus spongiosum
• what is the body?

  -corpus cavernosum combine

  -run alongside corpus spongiosa
• what is the root?

  -originates from ischial arch

  -wrapped in tunica albuginea

  -paired crura separate structures (contains corpus cavernosum)

  -expansion of corpus spongiosum around penile urethra (bulb)
• what makes up the penis?

  root, body+glans
• what is the penis

  -contained within fold of skin (prepuce) to protect from trauma+drying

  -varies between species
• what are the bulbourethral glands?

  -all domestic

  -not dogs

  -near urethra's exit from pelvis
• what is the prostate?

  -all domestic

  -body+disseminate part
• what is the vesicular?

  -stallions, ruminats,boar

  -not cats+dogs

  -near opening of deferent duct
• what is the ampulla?

  -ruminants, horses+dogs

  -not cats or pigs

  -enlargement at end of deferent duct
• what is the purpose of the glands?

  -clear urethra

  -lubrication

  -nourish spermatozoa

  -transport spermatozoa
• what additionally joins the urethra?

  -accessory sex glands at various lvels
• what is the urethra?

  -made of pelvic+penile part

  -deferent duct joins uretha as leaves bladder

  -carries semen+urine
• what happens if the testes get too cold?

  -cremaster muscle contracts+pulls testes closer to body

  -dartos muscle in scrotum contracts+reduces exposed SA+elevates scrotum
• how do the testes keep cool?

  -pampiniform plexus precools blood

  -in scrotum outside of body

  -many sweat glands in scrotal skin
• what temperature are the testes kept at?

  lower than body temp
• what is the cremaster muscle?

  -portion of internal abdominal oblique (body wall)

  -runs alongside spermatic fascia

  -inserts onto cranial pole of testes
• what binds the structures of the spermatic cord?

  spermatic fascia
• what is the spermatic cord made of?

  -testicular vein/artery/nerves/lymphatic vessels

  -defernt duct/artery/vein

  -visceral+parietal vaginal tunic
• what is the testicular artery a direct branch of?

  -abdominal aorta

  -leave aorta at L4

  -high blood pressure