Reproduction: Male

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Reproduction Male

• PA 481 C
• Anatomy Physiology
• Dr. Tony Serino
• Misericordia University
• Biology Dept.

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Reproduction

• Function
• Survival of species
• Production of sex cells (gametes)
• Transport the gametes toward each other
• Allow gametes to meet (fertilization)
• Promote the generation, maintenance and rearing
  of progeny

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Human Life Cycle
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Gonadsundergo Meiosis to produce gametes

• Meiosis (divided into Meiosis I and II)
• Meiosis I
• Assorts chromosomes by homologous pairs
• Then separates the pairs randomly
• Reduces the number of chromosomes by half
  Diploid to Haploid (2n ? n)
• Meiosis II
• Separates sister chromatids
• Progeny cells now have one DNA per chromosome

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Mitosis vs. Meiosis
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Male Reproduction

• Gonads Testis
• Gamete Spermatozoa (sperm)
• Duct system to store and transport sperm from
  gonad to external environment
• Supporting structures
• Allow sperm maturation
• Allow survival of sperm in ext. environment
• Deposit sperm into female vagina
• Sensory functions

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Male Reproductive Anatomy
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Spermatogenesis
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Sperm Anatomy
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Sperm on Ovum
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Testis Anatomy
Spermatic cord
Septum dividing testis into lobules
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Seminiferous Tubule
Sertoli Cell
(Leydig Cells)
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Sertoli and Leydig cells
Leydig cells
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Sperm leave tubules by ducts and proceed to
epididymis
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Ductus Deferens carries sperm from epididymis
to ejaculatory duct
Passes through inguinal canal back into
peritoneal cavity
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Accessory Sex Glands

• Add seminal fluid to sperm to form semenseminal
  fluid accounts for 90-95 of semen volume
• Seminal fluid will include water, alkaline
  buffers, mucous, fructose, prostaglandins and
  enzymes (clotting and de-clotting,
  anti-bacterial)
• Three glands
• Seminal Vesicle 60 of semen volume
• Prostate Gland 30 of semen volume
• Bulbourethral (Cowpers) Gland lt5

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Accessory glands (medial view)
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Accessory Sex Glands (posterior view)
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Prostate
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Male Urethra
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Scrotum and Spermatic Cord
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Inferior abdominal wall
Transverse abdominal
Transversalis fascia
Parietal Peritoneum
Conjoint tendon
Internal oblique
External oblique
Scarpas fascia
Campers fascia
Superficial inguinal ring
Tunica vaginalis
Int. spermatic fascia
Cremasteric pouch
Ext. spermatic fascia
Dartos tunic
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Inguinal canal
Deep inguinal ring
Superficial inguinal ring
In males contains spermatic cordIn females
contains round ligament
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Descent of Testes

• Begins at 7 months gestational
• The testes are attached at their inferior margin
  to the scrotal swelling by the gubernaculum
• Growth of the individual and retraction of the
  gubernaculum allow the testes to descend into the
  scrotum
• An extension of the parietal peritoneum (Vaginal
  process) maintains an opening into the scrotum
  and forms the inguinal canal and tunica vaginalis
• In female, gubernaculum becomes the ovarian and
  round ligaments

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Adult scrotum
Obliterated vaginalis process
Tunica vaginalis
Skin ad Dartos tunic
Int. spermatic fascia
Cremasteric pouch
Ext. spermatic fascia
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Scrotum and Spermatic cord

• Provide physical support to testes
• Regulate testicular temperature
• Cremaster muscle position can change tesits temp.
• Pampiniform plexus acts as heat counter current
  exchanger with testicular artery

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Penis Erectile Tissue and support
Penis suspensory lig.
(Crura)
Root of Penis (Bulb)
Corpus Spongiosum
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Penis Anatomy
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Smegma
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Penis (X.S.)
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Male Hormones
ABP
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Male Sexual Response

• Arousal Sexual excitement
• Triggered by
• Touching of genital skin
• Mechanical stimulation of pressure receptors in
  penis
• Erotic sights, sounds, and smells
• Thoughts and memories
• Increased myotonia (muscle tension) throughout
  body, BP, breathing and HR
• Sexual stimulation leads to erection of penis
• Plateau
• Increased accumulation of blood in erectile
  tissues
• Bulbourethral gland secretes small amount of
  mucoid fluid to neutralize male urethra and
  lubricate glans
• The testes are drawn upward by increased
  contractions vas deferens and cremaster muscles
• Orgasm
• Ejaculation rhythmic contractions propel semen
  out of the penis

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Sexual Excitation Erection

• Enlargement and stiffening of the penis
• Parasympathetic (through the local release of NO)
  vasodilation of arterioles leading to the
  erectile tissue of penis
• As corpora cavernosa enlarge they reduce blood
  flow through the penile veins this increases
  engorgement
• Erection reflex controlled by both the brain and
  the sacral spinal cord

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Male Orgasm

• Begins when stimulation reaches a critical point
  (accompanied by feelings of inevitability)
• 2 part spinal reflex
• Emission movement of semen into the urethra
• Vas deferens, ejaculatory duct, prostate and
  seminal vesicle contract and push their fluids
  into the urethra through sympathetic stimulation
• The external sphincter of the urethra remains
  closed as pressure builds
• The bladder sphincter muscle constricts
  preventing urine and semen from mixing
  (sympathetic control)
• Ejaculation expulsion of semen from the urethra
• The external sphincter relaxes as a second spinal
  reflex triggers rapid rhythmic contractions of
  the bulbospongiosus and ischiocavernosus muscles
  and urogenital diaphragm propels semen out
  (200in/sec)
• Contractions of muscles throughout body
• Accompanied with intense pleasure, increased HR,
  BP, respirations
• Followed by a quick relaxation and refractory
  period