Male Anatomy

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Male Anatomy
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When you have completed this study you should be
able to

• Recognize and identify the various parts of the
  male reproductive system
• Relate function to structure of each part
• Distinguish differences between species
• Recognize the internal structures of the male
  reproductive system
• Relate function to the internal structures

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Anatomy of the Male Reproductive System

• Functions to produce and deliver viable gametes
  to the female reproductive tract.
• Scrotum
• Testes
• Epididymis
• Spermatic cords
• Accessory sex glands
• Muscles
• Penis

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Scrotum

• Two-lobed pouch that houses the testes
• Aids in protection
• Temperature regulation
• Movement
• Concentric layers Consisting of
• Skin
• Tunica Dartos muscle
• Fascia
• Tunica Vaginalis

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Testes

• Male gonads
• Function to produce male gametes
• Spermatozoa
• Produce male hormones (androgens)
• Testosterone

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Testicular Descent

• Important for proper development of spermatozoa
  and for temperature control
• Abdominal cavity
• Gubernaculum
• Inguinal ring
• Scrotum

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Cryptorchidism

• Failure of one or both of the testes to
  descend into the scrotum (heritable trait)
• Unilateral When one testis does not descend
  into the scrotum. The testis that descends into
  the scrotum is fertile, however, reduced sperm
  concentrations usually result.
• Bilateral When neither testes descend into the
  scrotum. Results in sterility due to the
  elevated temperature.

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Thermoregulation of the Testes
Testes should be 4- 6C cooler than body
temperature
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Epididymis

• Highly convoluted duct attached to the tunica
  albuginea that functions in
• Sperm transport
• Spermatozoa maturation
• Concentration of spermatozoa
• Storage reservoir

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Epididymis

• Three segments
• Caput
• Contains efferent ducts
• Fluid resorption
• Corpus
• Maturation
• Cauda
• Storage

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Accessory Sex Glands

• Ampullae
• Vesicular Glands
• Seminal vesicles
• Prostate
• Bulbourethral glands
• Cowpers glands

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Penis

• Organ of copulation (3 parts)
• 1. Root (crus penis) 2. Body (corpus)
  3. Glans penis

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Penis

• Corpus cavernosum
• Majority of interior penile shaft
• Spongy erectile tissue
• Smooth muscle
• Corpus spongiosum
• Surrounds urethra
• Extends to glans
• Very prominent in stallion - belling

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Histology of the Penis
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Muscles of the Penis

• Retractor penis
• Contracted/relaxed state
• Ischiocavernosus
• Inserts on crus penis
• Important in erection
• Compresses crus penis
• Bulbospongiosus
• Overlaps root of penis
• Covers bulbourethral glands
• Urethralis
• Encloses pelvic urethra
• Covers bulbourethral glands

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Fibroelastic Penis Vs. Vascular Penis

• Fibroelastic composed of a fiberous elastic type
  tissue that extends in length to create an
  erection rather than in diameter (as does the
  vascular type penis).
• Vascular composed of corpus cavernosum (dorsal)
  and corpus spongiosum (ventral) erectile tissues.
  During an erection, the corpus cavernosum and
  the corpus spongiosum fill with blood causing the
  penis to become turgid/erect.

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Spermatogenesis

• Formation of spermatozoa
• Seminiferous tubules
• Interstitial space
• Requires hormones (FSH, LH)
• Cell types
• Peritubular myoid, Leydig, Sertoli,
  Spermatogonia, Spermatocytes, Spermatids,
  Spermatozoa

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Sperm develop in the seminiferous tubules with
direct interactions from the Sertoli cells. The
most immature cell is the spermatogonia and the
most mature is the round spermatid. The
completion of spermatogenesis is marked by the
release of mature sperm into the lumen of the
tubule termed spermiation.
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Anatomy of a Spermatozoa
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Sperm Transport
Seminiferous Tubules ? Rete Testis ? Vas
Efferens ? Epididymis Head Body Tail ? Vas
Deferens ? Urethra ? Female Tract