1. Misericordia University
Reproduction: Male
PA 544
Clinical Anatomy
Dr. Tony Serino
Misericordia University
Biology Dept.

2. 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

3. Human Life Cycle

4. Gonads: undergo 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

5. 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

6. Male Reproductive Anatomy

7. Spermatogenesis

8. Human Sperm

9. Sperm on Ovum

10. Testis Anatomy
Spermatic cord
Septum dividing testis into lobules

11. Seminiferous Tubule
Sertoli Cell
(Leydig Cells)

12. Sertoli and Leydig cells

13. Sperm leave tubules by ducts and proceed to epididymis

14. Ductus Deferens: carries sperm from epididymis to ejaculatory duct
Passes through inguinal canal back into peritoneal cavity

15. Accessory Sex Glands
Add seminal fluid to sperm to form semen; seminal 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 (Cowper’s) Gland <5%

16. Accessory glands (medial view)

17. Accessory Sex Glands (posterior view)

18. Prostate

19. Male Urethra

20. Scrotum and Spermatic Cord

21. Inferior abdominal wall
Transverse abdominal
Transversalis fascia
Parietal Peritoneum
Conjoint tendon
Internal oblique
External oblique
Scarpa’s fascia
Camper’s fascia
Superficial inguinal ring
Tunica vaginalis
Int. spermatic fascia
Cremasteric pouch
Ext. spermatic fascia
Dartos tunic

22. Inguinal canal Deep inguinal ring Superficial inguinal ring
In males: contains spermatic cord In females: contains round ligament

23. 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

24. Adult scrotum Obliterated vaginalis process Tunica vaginalis
Skin ad Dartos tunic
Int. spermatic fascia
Cremasteric pouch
Ext. spermatic fascia

25. 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

26. Penis: Erectile Tissue and support
Penis suspensory lig.
Root of Penis (Bulb)
(Crura)
Corpus Spongiosum

27. Penis Anatomy

28. Smegma

29. Penis (X.S.)

30. Male Hormones
ABP

31. Male Sexual Response Arousal –Sexual excitement Plateau Orgasm
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

32. 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

33. 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