Male Reproductive System

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Male Reproductive System

• Veterinary anatomy

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Male Reproductive System

• The male reproductive system consists of the
• Scrotum
• Testes
• Spermatic cord
• Excurrent duct system
• Epididymis
• Ductus deference
• Urethra
• Accessory sex glands
• Penis

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Scrotum

• Functions
• Thermoregulation
• Sweat glands
• Thermosensetive nerves
• Protection and support of testis

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• The scrotum is a two lobed sack. It protects and
  supports the testes and is required for proper
  temperature regulation.
• The scrotum consists of four major layer. They
  are
• 1) the skin.
• 2) the tunica dartos
• Smooth muscle
• Elevate testes for a sustained period of time in
  response to temperature or stress
• 3) the scrotal fascia
• 4) parietal tunica vaginalis
• - The scrotal skin is heavily populated with
  sweat glands. These sweat glands are required for
  maintenance of proper testicular temperature.
  Sweating allows the scrotum to be cooled by
  evaporative heat transfer.

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Scrotum

• Descent of testes into scrotum
• Timing
• Sheep / cattle midgestation
• Humans / horses just before or after
• birth

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Testes

• Functions
• Produce male germ cells (spermatozoa)
• Produce testosterone, inhibin and estrogen

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Testes

• Structure
• Testicular capsule
• Parenchyma
• Mediastinum
• Rete tubules (rete testis)
• Efferent ductules

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Testes - Structure

• 1- Testicular capsule
• 1)Tunica vaginalis
• Visceral
• Parietal
• 2) Tunica albuginea

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Testis
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Testes - Structure

• 2- Parenchyma
• A- Tubular compartment
• Seminiferous tubules
• B- Interstitial compartment
• Leydig cells
• Capillaries
• Lymphatic vessels
• Connective tissue

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Testes - Structure

• 3- Mediastinum
• Central connective tissue core that houses rete
  tubules
• 4- Rete tubules (rete testis)
• Tiny channels thru which spermatozoa transported
  out of testis

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Testes - Structure

• 5. Vasa efferentia (efferent ductules)
• a. Collect sperm from rete testis
• b. Carry sperm out of testis proper

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Testes

• Seminiferous tubules
• Site of sperm production
• Consists of 2 cell types
• Germ cells (eventual sperm cells)
• Sertoli or nurse cells

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Testes

• Sertoli cells
• Surround developing germ cells
• Provide structural metabolic support to
  spermatogenic cells
• Produces
• Androgen binding protein (ABP)
• Inhibin
• Sulfated glycoprotein

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Testes

• Blood-testis Barriers
• a. Cells surrounding seminiferous tubules
• b. Prevent autoimmune reaction from destroying
  developing germ cells

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Testes

• Leydig cells
• Located between seminiferous tubules
• Produce androgens (testosterone)

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Epididymis

• Three parts
• Head (caput)
• Body (corpus)
• Tail (cauda)

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Epididymis - Functions

• Sperm
• Transport
• Maturation
• Motility
• Concentration
• Storage
• Gains ability of fertilization

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Vas Deferens

• Ductus deferens or deferent duct
• Paired ducts
• Ampulla
• Wide end of vas deferens
• Function
• Sperm transport from epididymis to pelvic urethra

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Spermatic Cord

• spermatic cord extends from the inguinal ring to
  its attachment on the dorsal pole of the testis.
  It suspends the testis in the scrotum.
• The function of the spermatic cord is provides
  the pathway to and from the body for testicular
  vasculature, Lymphatic and nerves.

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Spermatic Cord

• The spermatic cord also houses the ductus
  deferent, cremaster muscle and specialized
  vascular network called the pampiniform plexus.
• The pampiniform plexus is a vascular structure
  consisting of an intimately intertwined artery
  and vein and this structure is important for
  proper temperature control of the testis

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Spermatic Cord - Functions

• Suspends testis in scrotum
• Pathway to blood vessels, lymphatics, nerves
• Thermoregulation mechanism
• Pampiniform plexus
• Cremaster muscle
• Pulse pressure eliminator

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Spermatic Cord
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Accessory Sex Glands

• Vesicular glands (seminal vesicles)
• Prostate gland
• Bulbourethral glands (Cowpers gland)
• Ampulla of ductus deference

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Vesicular Glands

• Paired glands
• Located at junction of urethra vas deferens
• Rough structure
• Contribute large amount of fluid
• Fructose sorbitol energy sources
• Phosphate bicarbonate buffers

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Seminal vesicle

• Absent in camel, dog and cat.
• Lobulated type in ox and pig
• Vesicular type in horse.
• Shape
• Pyramidal in pig
• Elongated and lobulated in ox, sheep and goat
• Elongated sac in horse

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Prostate Gland

• Located caudal to seminal vesicles and close
  proximity to pelvic urethra
• Bilobed in bull
• Diffuse in ram
• Surrounds urethra in dogs humans
• Function cleanse lubricate and secretes just
  prior during ejaculation
• Only accessory gland in dog

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Prostate Gland

• The prostate gland of the dog is spherical,
  smooth and divided into right and left lobes
  which completely surrounded the urethra.
• In the cat the prostate gland has an uneven
  surface and covers the urethra dorsally and
  laterally only.

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Bulbourethral Glands

• Paired glands
• Buried under bulbospongiosus muscle
• Function
• Cleanse urethra prior to ejaculation
• Produce gel fraction
• Adds considerable volume

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Colliculus Seminalis

• Region of urethra where sperm mixes with
• seminal vesicle secretions
• Mixing incomplete in stallion
• Sperm-free fraction Sperm-rich fraction

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Comparative of accessory sex gland
Ampulla Bulbourethral Int. prostate Ext. prostate Seminal vesicle Animals
- Horse
Ox
- Sheepgoat
- Camel
- - - Dog
- Cat
- Pig
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Penis

• Male copulatory organ
• Consists of
• Base
• Shaft
• Glans penis

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Penis

• Cavernous bodies
• Corpus spongiosum
• Corpus cavernosum

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Penis

• Sigmoid flexure
• Ram, buck, bull
• Allows penis to be retracted inside body until
  erection occurs

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Penis

• Retractor penis muscle
• Pair of smooth muscle
• Dorsally attached to tail vertebrae
• Holds penis inside sheath
• Glans
• Distal end of penis, contains sensory nerves
• Sheath
• Covers penis

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Penis

• Two Types
• 1. Fibroelastic
• Bull, buck, ram, dog
• 2. Vasomuscular
• Stallion, human

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