C23 - Scrotum, testis, epididymis, ductus deferens, accessory male genital glands, their blood supply and innervation

Question 1

Structures to mention

Answer 1

Scrotum:

• Cutis scroti
• Raphe scroti
• Tunica dartos
  
  • Septum scroti

Testis:

• Extremitas capitata
• Extremitas caudata
• Facies lateralis
• Facies medialis
• Margo liber
• Margo epididymalis
• Tunica albuginea
• Mediastinum testis (Ø eq)
  
  • Septula testis
• Lobuli testis
• Parenchyma testis
  
  • Tubuli seminiferi contorti
  • Tubuli seminiferi recti
  • Rete testis
• Appendix testis (eq)

Epididymis:

• Caput epididymidis
  
  • Ductuli efferentes testis
• Corpus epididymidis
• Cauda epididymidis
• Lobuli epididymidis
• Ductus epididymidis
• Paradidymis

Funiculus spermaticus:

• Fascia spermatica externa
• M. cremaster
• Fascia cremasterica
• Fascia spermatica interna
• Tunica vaginalis
  
  • Lamina parietalis
  • Lamina visceralis
  • Anulus vaginalis
  • Canalis vaginalis
  • Cavum vaginale
• Mesofuniculus
  
  • Mesorchium
    
    • Mesorchium proximale [= Plica vasculosa]
    • Mesorchium distale
  • Mesoductus deferens [= Plica ductus deferentis]
  • Mesepididymis
• Lig. testis proprium
• Lig. caudae epididymidis
• Lig. scroti
• Bursa testicularis

Question 2

Scrotum

Location

Answer 2

• Located behind the penis, and in front of the anus
• External sac of skin (continous with the lower abdomen)
• Divided into 2 compartments, each compartment contains:
  
  • Testes
  • Glands that produce sperm (which one???)
  • Epeididymis
• Horse and dog: Located in regio inguinalis
• Ruminants: Located below regio inguinalis
• Pig: Perineal
• Cat: Subanal

Question 3

Scrotum

Function

Answer 3

• Protect the testes and keep them at a temperature lower normal body temperature
  
  • Cold: contracts (conserves heat)
  • Warm: relax (permitting circulation of air)

Question 4

Scrotum

Give the layers of the scrotum

Answer 4

1. Cutis scroti (skin)
   
   • Contains many sweat gland and sebaceous gland
   • Hairless skin (ø fe)
2. Tunica dartosa
   
   • ​Can not be separated from the skin
   • Consists of smooth muscle bundles
   • Forms septum scroti, marked externally by raphe scroti
     
     • ​Continued cranially with raphe preputalis
3. Fascia spermatica externa
   
   • ​Detached from deep and superficial fascia of the abdomen at the scrotum
   • Adherent with cauda epididymis → lig. scroti
4. M. cremaster
   
   • Derived from m. obliquus interna
   • Cremaster reflex: raises the tunica vaginalis and brings testis and epididymis closer to the external inguinal ring
5. Fascia spermatica interna
   
   • ​​Detached from deep and superficial fascia of the abdomen at the scrotum
   • ​Fused with tunica vaginalis
6. Tunica/processus vaginalis
   
   • Formed by transvers fascia and peritoneum
     
     • ​An evagination of pariteal peritoneum→ passing through canalis inguinalis → scrotum
   • Distal part surrounds: testis and epididimys
   • Proximal part surrounds: spermatic cord
   • The vaginal cavity communicates with the abdominal cavity through ostium vaginae located within the internal opening of canalis inguinalis

Question 5

Scrotum

Ligaments

Answer 5

Ligaments of spermatic cord:

• Lig. scroti
  
  • ​Connective tissue between tunica dartos and:
    
    • Un: lig. caudae epididymis
    • Car: cauda epididymis
• Mesorchium
  
  • ​Suspension of testis
  • Mesorchium proximale: from origin of a/v. testicularis → mesoepididymis
  • Mesorchium distale: from mesepididymis → testis
• Lig. testis proprium: from testis → epididymis
• Lig. caudalis epididymis: between cauda epididymis →
  
  • Un: l**amina parietalis
  • Car: fascia spermatica interna

Question 6

Testis

Location

Answer 6

• Contained in the scrotum
  
  • ​Together with epididymis

Question 7

Testis

1. List the strucutres of the testis
2. Draw the testis

Answer 7

• Extremitas capitata (Related to caput epididymis, cranial directed)
• Extremitas caudata (Related to cauda epididymis, caudal directed)
• Facies lateralis (Ru: caudal)
• Facies medialis (Ru: cranial)
• Margo liber (Ventral directed)
• Margo epididymalis (Dorsal directed)
• Tunica albuginea (Dense with capsule)
• Mediastinum testis (Ø eq) (Axial strand of connective tissue from which the septula radiate)
  
  • Septula testis (Interlobular partitions extending from the mediastinum testis → tunica albuginea)
• Lobuli testis
• Parenchyma testis (Semiferous tubules)
  
  • Tubuli seminiferi contorti (Convoluted seminiferous tubules)
  • Tubuli seminiferi recti (Straight seminiferous tubules, from the convoluted tubules to the rete testis)
  • Rete testis (Network of ducts in the mediastinum testis connecting the tubuli semiferi recti to the ductuli efferents)
• Appendix testis (eq) (Near caput epididymis)

Question 8

Testis

Give the axis of the testis

Answer 8

• Horse:
  
  • Horizontal orientation
  • Extremitas capitata points cranially
  • Extremitas caudata points caudally
• Ruminant:
  
  • Vertical orientation
  • Extremitas capitata points dorsally
  • Extremitas caudata points ventrally
• Ca, sus:
  
  • Oblique orientation

Question 9

Epididymis

Structures

Answer 9

• Consists of coils of the elongated convoluted tubules
  
  • Held together by connective tissue
• Can be divived into:
  
  • Caput epididymis (head)
    
    • Attached to testicular capsule
    • Receives efferent ducts of the testis
  • Corpus epididymis (body)
  • Cauda epididymis (tail)
    
    • The epididymal duct continues as cauda epididymis
    • Attached to:
      
      • *Extremitas caudalis* bylig. testis proprium**
      • Processus vaginalis by lig. caudae epididymis
        
        • ​Fibers of this ligament extends fibers into deep layer of scrotum
• Ductus epeididymis: where spermatazoa mature

Structures:

• Caput epididymidis (Contains the lobulis epididymis)
  
  • Ductuli efferentes testis (Efferent ductules, lead from the rete testis → ductus epididymis. Coiled to form lobuli epididymis)
• Corpus epididymidis (Consists of the coiled duct)
• Cauda epididymidis (Continuous with the ductus deferens)
• Lobuli epididymidis (Containing the coiled ductuli efferents testis in the caput epididymisia)
• Ductus epididymidis (Convoluted to form the epididymis)
• Paradidymis (Detached mesoneprhic tubules in the spermatic cord just proximal to caput epididymidis)

Question 10

Epididymis

Location

Answer 10

• Firmly attached along the testis

Question 11

Name the area between the testis and corpus epididymis

Answer 11

Bursa testicularis

Question 12

Spermatic cord (funiculus spermaticus)

Answer 12

• Formed by ductus deferens and surrounding tissue
• Runs from deep inguinal ring → to each testicle
• The spermatic cord can be divided into 3 layers of tissue:
  
  • Fascia spermatica externa
    
    • ​Continuous with fascia m. oblqui externi abdominis
  • M. cremasterica and fascia
    
    • ​Continous with m. obliqui interna abdominalis and its fascia
  • Fascia spermatica interna
    
    • ​Continuous with fascia transversalis
• Content:
  
  • A. testicularis
  • A. ductus deferentis
  • A. cremasterica
  • N. genitofemoralis → r. genitalis
  • N. testicularis
  • Ductus deferens
  • Plexus pampiniformis
  • Lymphatic vesses
  • Tunica vaginalis (remains of processus vaginalis)
• Tunica vaginalis: extension of peritoneum, passing through transversalis fascia

Structures

• Fascia spermatica externa (Continuous with fascia m. oblqui externi abdominis)
• M. cremaster (Muscle on tunica vaginalis. Lies between the internal and external spermatic fascia and draws the testis towards canalis inguinalis)
• Fascia cremasterica (Cremasteric fascia on the m. cremaster)
• Fascia spermatica interna (Continuous with fascia transversalis)
• Tunica vaginalis (Serous membranes covering the spermatic cord and testis)
  
  • Lamina parietalis (Continuous with the parietal peritoneum)
  • Lamina visceralis (Adherent to the testis, epididymis and spermatic cord)
  • Anulus vaginalis (Vaginal ring. Where the peritoneum is evaginated to form lamina parietalis on tunica vaginalis)
  • Canalis vaginalis (Potential space between lamina parietalis of the tunica vaginalis)
  • Cavum vaginale (Between lamina parietalis and lamina visceralis around the testis)
• Mesofuniculus (Strip of mesorchium between origin of mesoductus deferens and lamina parietalis)
  
  • Mesorchium (Peritoneal fold containing vessels and nerves of testis)
    
    • Mesorchium proximale [= Plica vasculosa] (Extends from the origin of the testicular vessels → mesepididymis)
    • Mesorchium distale (Extends from mesepididymis to the testis)
  • Mesoductus deferens [= Plica ductus deferentis] (Attaches the ductus deferens to the mesorchium and to the abdominal and pelvic walls)
  • Mesepididymis (Attaches the epididymis)
• Lig. testis proprium (From testis → cauda epididymis)
• Lig. caudae epididymidis (Betwen the cauda epididymis → lamina parietalis (Un))
• Lig. scroti (Between tunica dartos and lig. caudae epididymis (Un) or the caudae epididymis (Car))
• Bursa testicularis (Formed by mesorchium distale, testis and epididymis)

Question 13

Ductus deferens

Answer 13

• Ductus deferens is the direct continuation of the ductus epididymis
• Pathway:
  
  • Originates at the underlying part of cauda epididymis
  • Passes along the medial border of the testis
  • Ascends within the spermatic cord
  • Enters the abdominal cavity through canalis inguinalis
  • Forms a cranial convex loop within mesoducutus deferens (a fold of peritoneum)
  • Opens in the proximal part of urethra at the colliculus seminalis
  • The terminal part of ductus deferens is thickened to form ampulla ducuts deferens (ø su)
• Horse & ruminants: Ductus ejaculatorius: ductus deferens is joined by ductus excretorius of gl. vesicularis

Structures:

• Ampulla ductus deferentis (Ø su)
• Ductus ejaculatorius
• Plica genitalis

Question 14

Accessory male genital glands

Name the accessory male genital glands with their structures

Answer 14

• Ampulla ductus deferens (ø su)
• Gl. vesicularis (ø car)
  
  • Ductus excretorius
• Gl. prostatae
  
  • Facies ventralis
  • Facies dorsalis
  • _​_Corpus prostatae
  • Pars disseminata prostatae
  • Lobus dexter et sinister
  • Isthmus prostatae (eq)
  • Parenchyma
  • Ductuli prostatici
  • Capsula prostatae
• Gl. bulbourethralis (ø ca)
  
  • Ductus gl. bulbourethralis

Question 15

Accessory male genital glands

Where are the accessory male genital glands located in general?

Answer 15

Located along pelvic portion of urethra

Question 16

Accessory male genital glands

Gl. vesicularis

Answer 16

• Ø car
• Paired
• Location: dorsolateral to cervix vesicae
• Ductus excretorius (Opens on the colliculus seminalis, sometimes via a ductus ejaculatiorius)
• Eq, ru: Ductus ejaculatorius: ductus excretorius joins ductus deferens just before its termination
• Sus: Gl. vesicularis opens separately into urethra next to the seminal colliculus
• Ru, su: lobulated surface

Question 17

Accessory male genital glands

Gl. prostatae

Answer 17

• Secreting into the pelvic part of urethra
• Consists of 2 parts (ø eq)
  
  • Pars disseminata prostatae: spread within the wall of the pelvic urethra
  • Corpus prostatae: external to the urethra

Structures:

• Facies ventralis
• Facies dorsalis
• Corpus prostatae (ø small ru)
• Pars disseminata prostatae (ø eq) (Forms a glandular layer in the wall of the pelvic urethra)
• Lobus dexter et sinister (Eq: right and left lobes are connected by an isthmus. Car: they are partially divided by a groove)
• Isthmus prostatae (eq) (Lies between the lobes, across the dorsal surface of cervix vesicae)
• Parenchyma (Glandular substance)
• Ductuli prostatici (Numerous excretory ductules open into urethra)
• Capsula prostatae (Containing smooth muscle)

Interspecies differences:

• Corpus prostatae (ø small ru)
• Pars disseminata prostatae (ø eq)
• Isthmus prostatae (eq)
• Ru: corpus prostatae is small and flat
• Car:
  
  • Pars disseminata prostatae is vestigal
  • Pars compacta is large
  • Entirely surrounds the urethra (ca), or partly (fe)
• Lobus dexter et sinister:
  
  • ​Dog: prostata is divided by a median groove, completely surrounds the urethra
  • Eq: right and left lobes are connected by isthmus prostatae
• Pars disseminata prostatae:
  
  • ​Ca: a few scattered lobes on urethral wall
  • Eq: ø
  • Ru, su: covered by m. rethralis

Location:

• Ca: completely surrounds urethra
• Fe: does not cover ventral surface of urethra
• Eq: dosolateral of urethra
• Ru: dorsal of urethra
• Su: dorsal of urethra

Question 18

Accessory male genital glands

Gl. bulbourethralis

Answer 18

• Ø ca (small in fe)
• Paired
• Location: dorsal surface of the caudal end of the pelvic urethra
  
  • ​Closely related to bulbus penis
• Ductus gl. bulbourethralis
• Interspecies:
  
  • Eq:
    
    • Cylindrical
    • 3 excretory ducts
  • Ru:
    
    • Spherical
      
      • Small ru: round
    • Each L/R lobe has 1 excretory duct
  • Su:
    
    • 2 large cylindrical lobes on both sides of urethra, covered by M. Bulboglandularis
    • Each L/R lobe has 1 excretory duct

Question 19

Accessory male genital glands

Draw the accessory male genital glands

Answer 19

Question 20

Blood supply

Answer 20

Scrotum:

• A. pudenda externa → r. scrotalis → a. cremasterica (to m. cremaster)

Testis:

• A. abdominalis → a. testicularis (forms numerous of coils)
• V. testicularis → plexus pampiniformis (surrounds the coil of the artery

Epididymis:

• A. testicularis
• Rr. epididymales

Ductus deferens:

• A. pudenda interna → a. ductus deferens

Prostatae gland:

• A. pudenda interna → a. prostatica

Question 21

Innervation

Answer 21

Scrotum:

• Motor, sensory and parasympathetic:
  
  • N. pudendus from plexus sacralis → nn. scrotales dorsales
• N. genitofemorale → r. genitalis (goes through canalis inguinalis)
  
  • ​Supply:
    
    • M. cremaster
    • Scrotum
    • Tunica vaginalis
    • Preputium
    • Mammae

Testis, epididymis & ductus deferens:

• Sympathetic
  
  • Plexus testicularis (accompanies a/v. testicularis)​