AnimalDairy Science 434 Male Reproductive Tract Anatomy Learning

Animal/Dairy Science 434 Male Reproductive Tract Anatomy

Learning Objectives • To be able to describe the male reproductive system in the stallion. – Structure – Function

Testis Factory • <1 - 25 X 109 sperm/day • “Plant” must be air conditioned Penis Delivery System • Erection • Protrusion • Ejaculation Epididymis Finishing School • Fluid Absorption • 8 -25 X 109 sperm – membrane changes – nuclear & flagellar stabilization – motility, fertility – cytoplasmic droplet translocation Tail of Epididymis Warehouse and Delivery Accessory Sex Glands Alterations & Packaging • Metabolic substrates • Surface coatings • Transport for sperm • Storage 10 -50 X 109 sperm • Sperm for 5 -10 ejaculates • Smooth muscle contractions upon sexual stimulation

Stallion Reproductive Tract Pelvic Tract Testes Penis

Reproductive Organs of the Stallion

Reproductive Organs of the Stallion Testis Primary Sex Organ

Tunica Vaginalis Parietal Visceral

Tunica Albuginea

Scrotum • • • Thermosensor Radiator Protective sac Scrotum

Scrotal Cross Section - Stallion

Scrotal Cross Section

Scrotal Longitudinal Section

Equine Testis and Spermatic Chord

a. b. c. d. e. f. g. h. i. Varner and Johnson, 2007 Tunica Albuginea Seminiferous tubule Efferent Ducts Initial Segment Caput (head) Rete testis Corpus (body) Cauda (Tail) Vas Deferens

Mediastinum Rete Testis Seminiferous Tubule Interstitial Tissue Tunica Albuginea The Testis

Primary Sex Organ • Testes o Testosterone o Sperm Secondary Sex Organs • Efferent Ducts • Epididymis o Caput o Corpus o Cauda • Vas Deferens Varner and Johnson, 2007

Spermatic Chord Testicular Artery Vas Deferens TV TA Testicular Vein Pampiniform Plexus EC VD External Cremaster Muscle

Spermatic Chord • Vascular, lymphatic and nerves • Heat exchanger • Houses cremaster muscle Pampiniform Plexus • Counter Current Exchange Ø Arterial Blood 39 C, 4. 8 ng T/ml Ø Venus blood 34 C, 70 ng T/ml

Testis Arterial Pulse Testicular Artery In Spermatic Chord Testicular Artery In Testes

Spermatic Chord External Cremaster Muscle

Reproductive Organs of the Stallion Tunica Dartos

Contraction of the Tunica Dartos Testis Tunica Dartos • Smooth muscle • Androgen dependent (Testosterone)

Reproductive Organs of the Stallion Gubernaculum

Reproductive Organs of the Stallion Pelvic Genitalia

Pelvic Genitalia of the Stallion Seminal Vesicles Body of Prostate Cowper’s Gland Bulbospongiosus Muscle Urethra Ampulla Colliculus Seminalis Vas Deferens No Disseminate Prostate Pelvic Urethral Muscle

The Stallion Seminal Vesicles Vas Deferens Bladder Cowper’s Gland Bulbospongiosus Muscle Ampulla Body of Prostate Crus Penis Pelvic Urethral Muscle Retractor Penis Muscle Ischiocavernosus Muscle

Bulb of the Penis

Reproductive Organs of the Stallion Seminal Vesicles Ampulla Prostate Cowpers Gland Rectum Bladder Vas Deferens Retractor Penis Muscle Gubernaculum Caput Glans Penis Testis Scrotum Cauda

Cross Section of Stallion Penis Corpus Cavernosum Tunica Albuginea Urethra Bulbospongiosus Muscle Corpus Spongiosum Retractor Penis Muscle

Equine Penis Free Part of Penis Urethral Process Glans Penis Prepuce (Retracted)

Glans Penis Urethral Process Fossa Glandis (urethral sinus)