Anatomy of Male Reproductive organs

1. Male Reproductive System
Anatomy
Testis, Epididymis, Penis, Scrotum and Male Urethra

2. Testis:
 Located within scrotum which hangs below the penis, between the legs.
 Is a firm, mobile organ lying within the scrotum. Left is slightly lower than the right testis.
 Covered by multi-layered(3) tunica:
 Tunica Vasculosa-consists of blood vessels & connective tissue.
 Tunica Albuginea-create partitions b/w seminiferous tubules.
 Tunica Vaginalis-2 layered:visceral & parietal: Hydrocele-excess fluid in b/w the 2 layers.
 Divided into lobules which contain tubes called Seminiferous Tubules (abt. 800 in testis).
 The tubules open into a network of channels called the Rete Testis.
 Small Efferent Ductules connect the rete-testis to the upper end of the Epididymis.
 The Seminiferous tubules are lined by Sertoli cells-aid the maturation process of the spermatozoa.
 In the interstitial tissue lie the Leydig cells that are primarily responsible for testosterone production.

3. Testis (Cont’d):
 The Testicular artery is a branch of the abdominal aorta.
 The testicular veins emerge from the testis & Epididymis as a venous network, the Pampiniform Plexus.
This becomes reduced to a single vein as it ascends through the inguinal canal.
 The right testicular vein drains the Inferior Vena Cava.
 The left testicular vein joins the left renal vein.
 Lymph vessels ascend in the spermatic cord & end in the lymph nodes on the side of the aorta
(lumbar/para-aortic) nodes at the level of 1st lumbar vertebrae.(Retroperitoneal LN)
 This is because during development the testis has descended from high up on the post. abdominal wall,down
through inguinal canal, & into the scrotum, dragging its blood supply & lymph vessels after it.
 The testes & Epiphysis receive innervation from the Testicular Plexus-a network of nerves derived from the
renal & aortic plexi. They receive autonomic & sensory fibres.

4. Testis Illustration:

5. Epididymis:
 Is a firm structure lying posterior to the testis, with the vas deferens lying on its medial side.
 Has an expanded upper end, the Head, a Body, and a pointed Tail inferiorly.
 Laterally, a distinct groove lies b/w the testis & the epididymis, which is lined by the inner visceral layer
of the tunica vaginalis & is called the SINUS OF THE EPIDIDYMIS.
 Functions as a storage & maturation site for sperm.

6. PENIS:
 Is an external organ of male reproductive system. Has 2 main funtions:
 Sexual Intercourse
 Micturition
 The penis can be anatomically divided into 3 parts:
 Root-most proximal, fixed part of penis. Not visible externally.
-contains 3 erectile tissues(2 crura & bulb of penis), & 2 muscles (ischiocavernosus &
bulbospongiosus).
 Body-free part of the penis. Suspended from the pubic symphysis.
-Composed of 3 cylinders of erectile tissue-2 corpora cavernosa, & the corpus spongiosum.
 Glans-most distal part formed by the distal expansion of the corpus spongiosum
-contains the opening of urethra (external urethral orifice).

7. Penis (Cont’d):
 Arterial supply is from 3 sources:
 Dorsal arteries of the penis All are branches of the Internal Pudendal Artery. This vessel arises from
 Deep arteries of the penis the anterior division of the Internal Iliac artery.
 Bulbourethral artery
 Venous drainage:
 Superficial structures e.g. skin & cutaneous tissues drained by Superficial Dorsal Veins.
 Cavernous spaces drained by the Deep Dorsal vein of the penis.
 Innervation:
 Supplied by S2-S4 spinal cord segments & spinal ganglia.
 Sensory & Sympathetic innervation to the skin & glans penis-Dorsal nerve of penis (br. of Pudendal n.)
 Parasympathetic innervation carried by Cavernous nerves from the Peri-Prostatic nerve plexus, & is responsible
for the vascular changes which cause erection.
 Lymph drainage:
 Skin-drained into the medial group of superficial inguinal nodes.
 Deep structures-drained into the internal iliac nodes.

8. Scrotum:
 Is an out-pouching of the lower part of the anterior abdominal wall. Contains the testes, the
epididymides, & the lower ends of the spermatic cords.
 Wall has the following layers:
 Skin-is relatively thin & wrinkled, & pigmented and forms a single pounch.
 Superficial fascia- continuous w/the fatty & membranous layers of the ant. abdominal wall; the fat is
however replaced by Dartos muscle(smooth m.)
Membranous(Colle’s) fascia is continuous infront w/Scarpa’s fascia & behind attached to the
Ischiopubic rami.
 Spermatic fascia-3 layers derived from 3 layers of anterior abdominal wall.
 External spermatic fascia derived from aponeurosis of external oblique muscle.
 Cremasteric fascia derived from internal oblique muscle.
 Internal spermatic fascia derived from fascia transversalis.
 Cremaster muscle-raises the scrotum & testis upward for warmth & protection against injury.
 Tunica vaginalis-lies within spermatic fascia & covers anterior, medial, & lateral surfaces of each testis.

9. Scrotum ILLustration:

10. Urethra
 Male urethra is approx. 15-20cm long. NB: Female(approx. 4cm)
 In addition to urine, it also provides an exit for semen.
 Anatomically can be divided into 3 parts:
 Prostatic: -Passes through the prostate gland.
-The Ejaculatory ducts & the Prostatic ducts drain into the urethra here.
 Membranous: -Passes through the pelvic floor & the deep perineal pouch.
-Surrounded by external urethral sphincter (voluntary control of micturition).
 Spongy: Passes through the Bulb and Corpus Spongiosum of the penis, ending at external
urethral orifice.
In the glans penis, the urethra dilates, forming the Navicular Fossa.
 Clinical relevance: Male Urinary Catheterization.

11. Male Urethra:

12. Spermatic Cord
 Is a collection of structures that pass through the inguinal canal to & from the testis.
 Begins at the deep inguinal ring lateral to the inferior epigastric artery & ends at testis.
 Structures include:
 Vas deferens-directs spermatozoa from epididymis to the urethra
 Testicular artery
 Testicular Vein (Pampiniform Plexus)
 Testicular Lymph vessels
 Autonomic nerves
 Remains of Processus Vaginalis
 Genital br. Of Genitofemoral nerve, which supplies the cremaster muscle.

13. The End
MARAU JIKO TACI…