Animal/Dairy Science 434 Learning Objectives Male Reproductive Tract Anatomy • To be able to describe the male reproductive system in the stallion. – Structure – Function Testis Epididymis Factory Finishing School Stallion Reproductive Tract • <1 - 25 X 109 sperm/day • Fluid Absorption • “Plant” must be air • 8-25 X 109 sperm Pelvic Tract conditioned – membrane changes – nuclear & flagellar stabilization – motility, fertility Penis – cytoplasmic droplet translocation Delivery System • Erection • Protrusion • Ejaculation Tail of Epididymis Warehouse and Delivery • Storage 10-50 X 109 sperm • Sperm for 5-10 ejaculates Testes • Smooth muscle contractions Accessory Sex Glands upon sexual stimulation Alterations & Packaging • Metabolic substrates • Surface coatings • Transport for sperm Penis Reproductive Organs of the Stallion Reproductive Organs of the Stallion Testis Primary Sex Organ Tunica Vaginalis Tunica Albuginea Parietal Visceral Scrotum Scrotal Cross Section - Stallion • Thermosensor • Radiator • Protective sac Scrotum Scrotal Cross Section Scrotal Longitudinal Section Equine Testis and Spermatic Chord a. Tunica Albuginea b. Seminiferous tubule c. Efferent Ducts d. Initial Segment e. Caput (head) f. Rete testis g. Corpus (body) h. Cauda (Tail) i. Vas Deferens Varner and Johnson, 2007 Primary Sex Organ Mediastinum Rete Testis • Testes o Testosterone o Sperm Seminiferous Secondary Sex Organs • Tubule Efferent Ducts • Epididymis o Caput o Corpus Interstitial Tunica Albuginea o Cauda Tissue • Vas Deferens The Testis Varner and Johnson, 2007 Spermatic Chord Spermatic Chord Testicular Vas Deferens TV TA • Vascular, lymphatic and nerves Artery • Heat exchanger Testicular Vein • Houses cremaster muscle Pampiniform Plexus EC VD Pampiniform Plexus • Counter Current Exchange Ø Arterial Blood 39C, 4.8 ng T/ml Ø Venus blood 34C, 70 ng T/ml External Cremaster Muscle Spermatic Chord Testis Arterial Pulse External Cremaster Muscle Testicular Artery Testicular Artery In Spermatic Chord In Testes Reproductive Organs of the Stallion Contraction of the Tunica Dartos Testis Tunica Dartos • Smooth muscle Tunica Dartos • Androgen dependent (Testosterone) Reproductive Organs of the Stallion Reproductive Organs of the Stallion Pelvic Genitalia Gubernaculum Pelvic Genitalia of the Stallion The Stallion Bladder Seminal Cowper’s Body of Cowper’s Vesicles Gland Prostate Gland Seminal Bulbospongiosus Bulbospongiosus Vesicles Urethra Muscle Muscle Ampulla Vas Deferens Ampulla Crus Colliculus Seminalis Body of Penis Prostate Retractor Penis Muscle Pelvic Urethral No Disseminate Muscle Ischiocavernosus Vas Prostate Deferens Pelvic Urethral Muscle Muscle Bulb of the Penis Reproductive Organs of the Stallion Seminal Vesicles Ampulla Prostate Rectum Cowpers Bladder Gland Vas Deferens Retractor Penis Muscle Gubernaculum Cauda Caput Testis Glans Penis Scrotum Cross Section of Stallion Penis Equine Penis Free Part Urethral Process Tunica Albuginea of Penis Corpus Cavernosum Urethra Glans Penis Bulbospongiosus Corpus Spongiosum Prepuce (Retracted) Muscle Retractor Penis Muscle Glans Penis Urethral Process Fossa Glandis (urethral sinus).