Animal / Dairy Science 434Animal / Dairy Science 434Lec 4: Comparative Male AnatomyLec 4: Comparative Male Anatomy

TestisSpecies Testis Wt. % Of Orientation

(grams) Body Wt.

bull 300+ .03 vertical

ram 250 .3 vertical

boar 350 .2 oblique

stallion 200 .03 horizontal

dog 25 .2 oblique

rabbit 2.5 .1 vertical

human 25 .03 vertical

Reproductive Organs of the

Bull

Cowpers Gland

Caput Epididymis

Cauda EpididymisTestis

Scrotum

GlansPenis

Bladder

Ampulla

Seminal Vesicles

ProstateRectum

Vas Deferens

Gubernaculum

SigmoidFlexure

Retractor Penis

Muscle

Prepuce

Reproductive Organs of the

Bull

Vertical

RamVertical

Boar

Oblique

Dog

Oblique

Stallion

Horizontal

HumanVertical

Testis Orientation

Tail Head

Bull

TestisSpecies Testis Wt. % Of Orientation

(grams) Body Wt.

bull 300+ .03 vertical

ram 250 .3 vertical

boar 350 .2 oblique

stallion 200 .03 horizontal

dog 25 .2 oblique

rabbit 2.5 .1 vertical

human 25 .03 vertical

Ram

No Body of the Prostate

Ampulla

SeminalVesicles

Prostate

BulbospongiosusMuscle

Cowper’s

Gland

Bladder

Vas Defere

ns

Pelvic Urethral Muscle

No AmpullaLarge Cowper’s

SeminalVesicles

BulbospongiosusMuscle

Cowper’s Gland

Vas Deferens

Pelvic Urethral Muscle

Prostate

No DisseminateProstate

SeminalVesicles

BulbospongiosusMuscle

Cowper’s Gland

Vas Deferens Pelvic Urethral Muscle

Prostate

Ampulla

Human

No DisseminateProstate

Dog Pelvic Tract

Prostate

Vas Defere

ns

Bladder

Pelvic Urethral Muscle

BulbospongiosusMuscle

No Seminal Vesicles or Disseminate Prostate

Cat (Tom) Reproductive Tract

ProstateCowper’s Gland

Glans Penis

Corpus Cavernosum

Crus Penis

Vas Deferens

AmpullaNo Seminal Vesicles or Disseminate Prostate

Cat (Tom) Reproductive

Tract

Note how close the cowper’s gland is to the penis in the cat.

Cat Glans Penis

Feline Anatomy: Erection and

Mating

Accessory GlandsSpecies Seminal Prostate Cowper's

Vesicles body disseminate

bull ++ + + +

ram + - + ++

boar +++ + + +++

stallion +++ ++ - (+) +

dog - ++ - -

Cat - ++ - ++

human + ++ - +

Accessory Gland SecretionsSpecies Seminal

VesiclesProstate

Body+ DisseminateCowper’s

bull 30 6ram 8 6boar 30 40 30

stallion 30dog 70

human 70 25

GelGel

Clot Clot Enzyme

Penis TypesMuscular-Vascular Fibroelastic

Human Penis Cross Section

Corpus Cavernosum

Corpus SpongiosumUrethra

Blood Vessels

Large Veins

InternalPrepuce Raphe

UrethralProcess

Free End of Penis GlansPenis

FiliformAppendage

Bull

Ram

Boar

Stallion

Human

Cat

Comparison of Penis Types

Human

Sigmoid Flexure

Bull

Boar

Fibroelastic Penis

Muscular-Vascular

Penis Type

Stallion

The Penis

Erection and Ejaculation Characteristics

Species Speed of Ejaculate Semen Sperm SpermErection Time Volume Conc. Number

bull rapid short medium medium- mediumhigh

ram rapid short small high medium

boar rapid long large low high

stallion slow moderate large low medium

dog slow long large low low

human slow moderate medium low low

Large Testes = high sperm numbersLarge accessory glands = large volume of the ejaculate with lower concentration of sperm

»Support spermatogenesis

»Testosterone synthesis

PrimarySpermatocyte

Sertoli Cells

Leydig Cells

Capillary

BasementMembrane

Spermatids

Round Spermatids

SecondarySpermatocyte

Myoid Cells

SeminiferousTubule

SeminiferousTubule

Spermatogonium

Seminiferous Tubules

Seminiferous Tubule

Sertoli CellSertoli Cell

Leydig Cell

Capillary

Interstitial Tissue (space)

Capillary

LeydigCells

Basal CellPrincipal Cell Stereo-Cillia

Epididymis

Cauda Epididymis near Vas Deferens

Vas Deferens

Smooth Muscle

Sperm