Veterinary Anatomy I: CVM 710 Fall 2023 PDF

Reproductive tract: Male gender Dog & Cat Veterinary Anatomy I: CVM 710: Fall 2023 Lec # 28 Abdomen & pelvis Male repro organs Dr. Ismael Concha-Albornoz [email protected] www.anato.cl Learning Objectives 1. List, identify, and describe the components of the male reproductive system in...

Reproductive tract: Male gender Dog & Cat Veterinary Anatomy I: CVM 710: Fall 2023 Lec # 28 Abdomen & pelvis Male repro organs Dr. Ismael Concha-Albornoz [email protected] www.anato.cl Learning Objectives 1. List, identify, and describe the components of the male reproductive system including their features, relationships, position/location, orientation, divisions, subcomponents, and/or functions. List, in order, the parts of the reproductive tract that a spermatozoa would encounter from the testicle to the end of the penile urethra. Describe any relevant differences between the dog and the cat. 2. Identify and describe the components of the spermatic cord. Be able to draw and label a schematic representation of the spermatic cord in transverse section. 3. Describe the mechanisms and structures involved in temperature regulation and protection of the testes. 4. Describe the spatial relationship between the ductus deferens and the ureter near the neck of the urinary bladder. 5. Identify and describe the muscles associated with the penis, including their anatomical relationships and functions. 6. Describe the role of the os penis in urinary tract obstruction due to urethral calculi. 7. Describe the function of the bulbus glandis during coitus. 8. Identify and describe the components of the prepuce. During the erect state, which part of the prepuce normally reflects onto the penis? Male reproductive organs: Accessory sex glands. (Pelvic cavity) Ductus deferent (Spermatic cord, inguinal canal, abdomen, pelvic cavity & prostate) Scrotum. (perineum & inguinal) Prepuce (inguinal & umbilical) Penis Testes and epididymis (perineum, inguinal & umbilical) (Inguinal) Spermatic Cord (Inguinal) Descent of the Testes: Dyce Figs. 5-17 & 5-18 Analogy to Inguinal canal: Similar to collapse tunnel in an Agility course for dogs. As dog passes through, the canal opens and Allows passage. Similarly, as testis descends from peritoneal cavity Into scrotum, the inquinal allows passage. Testicle (testiculus) Male gonad: Produce spermatozoids & hormones Rete testis Efferent ductules Epididymis Tunica albuginea Testicular parenchyma Seminiferous tubules Testicle & epididymis: • Epididymis – Head • Positioned craniodorsally – Body – Tail • Ligament of the tail of the epididymis • Proper ligament of the testis • Scrotal ligament • Scrotum Lateral view Testicle & epididymis: • Lateral view Epididymis – Head • Positioned craniodorsally – Body – Tail • • Ligament of the tail of the epididymis Proper ligament of the testis Left testis – medial view Budras Pg. 69 Scrotum: ◼ Scrotal position ❑ Dog – inguinal position ◼ Scrotal covering ❑ Scrotum of dog has little hair Constantinescu Fig. 7.49 & 7.51 Layers of the Scrotum: • • • • • Skin – Epidermis – Dermis Tunica dartos: Subcutaneous tissue, form the scrotal septum. Help to regulate the internal temperature according with the external temperature External spermatic fascia Internal spermatic fascia Parietal vaginal tunic Miller’s Fig. 9-14 Vaginal tunics: Parietal vaginal tunic Visceral vaginal tunic Vaginal cavity Vaginal ring Testicular a., v., l, & n. Vaginal ring Ductus deferents Parietal peritoneum Transversalis fascia Transverse abdominis m. Deep inguinal ring External & internal abd. Oblique mm. Superficial inguinal ring Vaginal process Cremaster m. Testicular vessels Mesorchium Mesofuniculum Mesoductus deferens Cremaster muscle: • • • • Originates from the caudal free border of the internal abdominal oblique m. Inserts on the spermatic fascia and parietal vaginal tunic Acts to pull the testis closer to the body in response to a cremasteric reflex. Innervated by genitofemoral n. (L3-L4) Spermatic Cord Components: • • • • • Testicular artery Testicular vein & pampiniform plexus Testicular nerve Testicular lymphatics • • Ductus deferens Deferent artery & vein • Internal cremaster m. (artery and vein of the ductus deferens) (smooth muscle) Mesofuniculum Budras Pg. 71 Testicular vein & pampiniform plexus Accessory sex glands in male dog: -Prostate -Ampullary glands Functions 1. 2. 3. 4. Adds volume to ejaculate to provide a vehicle for sperm Provides a source of energy for sperm Acts as a buffer for sperm by neutralizing the pH in urine and the CO2 produced by sperm Production of prostaglandins that cause smooth muscle contraction of female reproductive tract ampulla deferent duct urinary bladder deferent duct Accessory sex glands in male dog: Prostate normal abnormal Prostate gland Enlarged Prostate gland Hill’s Plate 72 & 73 Millers Fig. 9-22 Male K9 urethra: Urethra: *Pelvic part *Penile part (spongy) Evans Fig. 168 B Male K9 urethra: • Colliculus seminalis – Located on dorsal surface of prostatic urethra – Continuation of the urethral crest – Deferent ducts open on each side of the colliculus seminalis • Prostatic openings Evans Fig. 168 B Millers Fig. 9-22 Regions of the canine penis: Body Glans Root Erectile tissue of the penis: • Dense collagenous tissue with many elastic fibers and sinuses – Corpus cavernosum penis (#10) – Corpus spongiosum penis (#11) – Corpus spongiosum glandis of the bulbus glandis (#14) – Corpus spongiosum glandis of the pars longa glandis (#15) Millers Fig. 9-22 Root of the penis (dog): • Crura (6) (right and left) – Composed of: • Corpus cavernosum penis • Tunica albuguinea – Surrounded by ischiocavernosus m. • Bulb of the penis (7) (urethral bulb) – Expansion of corpus spongiosum penis – Surrounded by bulbospongiosus m. • Urethra (8): Surrounded by bulb of the penis(7) (Corpus spongiosum) • Muscles assoc. w/ the canine penis: • Bulbospongiosus muscle Arround the bulb of the penis • Ischiocavernosus muscle From ischiatic tuberosities to the crura (right & left )of the penis • Retractor penis muscle From the external annal sphincter to the gland, caudal and ventral position Pasquini Fig. VIII-49 Body of the penis (dog): • Corpus cavernosum (10) Surrounded by tunica albuginea • Urethra (5) the pelvic portion is surrounded by the urethralis muscle. The penile portion is surrounded by the corpus spongiosum • Corpus spongiosum (11). In the root of the penis the corpus spongiosum form the bulb of the penis (9) • Proximal part of os penis (13) • (Retractor penis m.) Body of the penis Millers Fig. 9-22 Glans of the penis (dog): • Bulbus glandis (3) – Corpus spongiosum glandis • Pars longa glandis (2) – Corpus spongiosum glandis • Os penis (4) Around the penile urethra • Urethra (8) Surrounded by the corpus spongiosum and the os penis • Corpus spongiosum penis (7) in the root form the bulbus of the penis and surround the penile urethra all the way toward the external urethral orifice Glans Dyce Fig. 15-13 Os penis (dog): • • • Adds rigidity for intromission Deforms apex of the penis in the vagina Urethra passes through the urethral groove on ventral surface Millers Fig. 9-27 Canine spp. Penis: Transverse section of the glans I? II? III? IV? V? VI? Canine prepuce: • • • Prepuce – External lamina (haired skin) – Internal lamina – Penile lamina Preputial orifice (ostium) Preputial fornix (fundus) Canine prepuce: • • • Prepuce – External lamina (haired skin) – Internal lamina – Penile lamina Preputial orifice (ostium) Preputial fornix (fundus) Canine prepuce: Prepuce opened Glans penis Retractor penis mm. Retractor penis mm. Ischiocavernosus mm. Bulbospongiosus m. Blood supply to the penis: Internal pudendal a. (and Vein) Branch of internal iliac a. Ventral perineal a. Artery of the penis (and Vein) (and Vein) Artery of the bulb (and Vein) Dorsal a. of the penis (and Vein) Corpus spongiosum (bulb of the penis) Bulbus glandis Deep a. of the penis (and Vein) Corpus cavernosum Corpus spongiosum Millers Fig. 9-35 Blood supply to penis: Dorsal a. of the penis (and Vein) Superficial veins of glans Bulbus glandis Millers Fig. 9-35 Non-erect penis: • Blood flow to the penis bypasses the vascular spaces of the erectile tissue • Vascular spaces of penile erectile tissue contain only a small amount of blood Erect penis: • Results from filling of cavernous bodies with blood • Stimulation of the pelvic nerve causes relaxation of smooth muscles of the arteries of the penis allowing an increase in blood flow to the penis • Blood is directed into the helical arteries of the erectile tissue • The penis enlarges and becomes turgid Millers Fig. 9-35 Maintenance of erection: • Neurogenic (male) – Parasympathetic stimulation, retractor penis muscle relaxed • Preputial orifice (male) – Compresses dorsal veins of the penis • Ischial arch (male) – Compresses dorsal veins of the penis • Ischiourethralis m. (male) – Restricts venous return • Penis twists on long axis during dismount (male) – Restricts venous return • Constrictor vulvae and vestibuli mm. (female) – Inhibits venous return Dyce Plate 20 Erection and Ejaculation: • Erection – Parasympathetic function • Ejaculation – Secretion of accessory sex glands • Sympathetic function – Bulbospongiosus muscle contracts causing expulsion of semen • Somatic function Scrotum in the cat: Male cat ◼ Scrotal position ❑ Dog – inguinal position ❑ Cat – perineal position ◼ Scrotal covering ❑ Scrotum of dog has little hair ❑ Scrotum of cat is covered with hair Male dog Constantinescu Fig. 7.49 & 7.51 Accessory sex glands: male cat: • Prostate • Bulbourethral gland Constantinescu Fig. 7.46 Hudson/Hamilton Plate 9-3 Feline penis: Understanding feline penis anatomy: Critical when placing an urinary catheter to unblock blocked tomcat! • • • Apex: directed caudoventrally os penis-present Glans penis: small • • • Keratinized spines on glans penis: Domestic cats: induced ovulators – Stimulation of vagina results in ovulation Glans penis orifice Nickel Fig. 471 Feline behavioral postures: Modified “kill bite” during coitus in cat spp. Hudson/Hamilton Plate 9-4 Questions ????? Questions ????? Cape Hunting dog = Painted Wolf (Lycaon pictus)