The male reproductive system includes the testes, epididymis, penis, scrotum, and urethra. The testes produce sperm and testosterone and are held in the scrotum outside of the body. The epididymis is a coiled structure where sperm mature after leaving the testes. The penis is made up of erectile tissues and is used for both reproduction and urination. During an erection, blood flows into the tissues of the penis. The urethra passes through the penis and is the channel through which both urine and semen exit the body.

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…