Animal Reproduction/Theriogenology https://www.youtube.com/channel/UCHzZhYqMy10vsVRZdddEkUg

1. Western College of Veterinary Medicine

3. Westgen Research Suite

4. Sperm Production and Fate
May 09, 2008

5. Human Sperm
(Hartsoeker, 1694)

6. Mammalian Sperm
(Leeuwenhoek, 1679)
Rabbit sperm Dog sperm

7. Spermatozoa of Different Species

8. Bull Reproductive Tract
Testis
Tail of epididymis
Retractor penis
Sigmoid flexure
Body of prostateVesicular gland
Ampulla
Ductus deferens
Cremester
muscle
Penile shaft
Glans penis

9. Testis
• Composition of testis:
– Testicular capsule
– Parenchyma:
• Tubular compartment:
– Adluminal
– Basal
• Interstitial compartment
– Mediastinum testis
– Rete testis

10. Seminiferous Tubule: Histology
Spermatogonia
Sertoli cell
Junctional complex
Primary spermatocyte
Spermatids
Connective tissue
Leydig cell
Blood
vessel
Lymphatic
vessel
Adlumninal
compartment
Basal
compartment
Interstitial
compartment

11. Spermatogenesis
Spermatogonia A1
Spermatogonia A2
Spermatogonia A3
Spermatogonia A4
Spermatogonia I
Spermatogonia B
Primary spermatocyte
Secondary spermatocyte
Spermatids (round)
Spermatids (elongated)
Spermatocytogensis
(Mitosis)
Meiosis
Spermio-
genesis
Basement membrane
Lumen
Basal
Adluminal

12. Male Endocrinology

13. Male Endocrinology

14. Hormonal Regulation of Spematogenesis
Hypothalamus
GnRH
Ant. Pit.
LH FSH
Leydig cell
Sertoli
cell
Inhibin
ABP
-ive feedback
of androgen
-ive feedback
of inhibin
Seminiferous tubule
Blood vessel
Testosterone

17. Testis, Epididymis & Ductus Deferens
Testis
Cremester
muscle Ductus deferens
Epididymal body
Epididymal
tail

18. Epididymis
Head (Caput)
8-25 x 109
Spermatozoa
Body (Corpus)
8-25 x 109
Spermatozoa
Tail (Cauda)
10-50 x 109
Spermatozoa
Ducuts
Deferens
Sperm characteristics
•Non motile
•Non fertile
•Little motility
•Little fertility
•Translocation
of cytoplasmic
droplet
•Nomral motility
•Normal fertility
•No cytoplasmic
droplet
To Pelvic
Urethra

19. Semen
• Sperm:
– Head - Nucleus, Acrosome, Post-nuclear
cap
– Tail - Middle piece, Principal piece, terminal
piece
• Seminal plasma:
– Secretions from accessory sex gland
– Functions - Vehicle and Nutrition

20. Sperm Morphology
Head
Middle
piece
Principal
piece
End
piece
Acrosome:
Hyaluronidase
Acrosin

21. Semen Characteristics
Man Bull Ram Boar Stallion Cock
Volume
(ml)
1.5 –
5.0
5.0-8.0 0.8-1.2 150-300 60-100 0.2-0.5
Sperm
Conc.
(million/ml)
40-250 800-
2000
2000-
3000
200-300 150-300 3000-
7000
Motility
(%)
60-70 40-75 60-80 50-80 40-75 60-80
pH 7.2-7.8 6.4-7.8 5.9-7.3 7.3-7.8 7.2-7.8 7.2-7.6
Fructose
(mg/100 ml)
150-600 400-600 250 9 2 4

22. Thank you

23. Sperm Transport in Female Tract
• Barriers:
– Cervix
– Uterotubal junction
• Phases:
– Rapid - Not understood
– Sustained - Trickle-like effect
• Transport:
– Sperm motility
– Uterine motility ( E2 during estrus)

25. Phagocytosis

26. Capacitation

27. Acrosome Reaction
Acrosomal
contents
Outer acr.
membrane
Inner acr.
membrane
Nucleus
Fusion of plasma
& outer acr. membrane
Plasma
membrane
Release of acrosomal
contents (hyaluronidase
and acrosin)
Equatorial
segment
Before acrosome
reaction
During acrosome
reaction
After acrosome
reaction

28. Fertilization
Corona
radiata
Zona pellucida
Ovum
Acrosome with
enzymes Nucleus
Sperm cell nucleus
inside ovum

29. Sperm Production

30. Sperm Binding

31. Acrosome Reaction

32. Sperm Penetration

33. Thank You

34. Male Reproductive Tract
• Testes: Production of:
– Sperm - 1-25x109 sperm/day
– Hormones (testosterone) and proteins (ABP)
– Fluid - Vehicle for sperm suspension
• Duct System:
– Efferent ducts - from rete testis to epididymis
– Epididymis (head, body and tail)
• Sperm maturation and storage
– Ductus deferens
• Delivery from cauda epididymis to pelvic urethra
• Accessory Sex Organs:
– Ampulla, seminal vesicles, prostate, bulbourethral
• Secretion - Seminal plasma, a vehicle for sperm suspension
• Delivery System: Penis

35. Penile Erection
Flacid penis
Arousal
Artery
dilation
Blood flow to
cavernous muscle
Venous
outflow
Time (sec)
Vein
Artery
Artery
Vein
CC
Urethra CS
CC - Corpus cavernosum
CS - Corpus spongiosum

36. Sexual Behavior
• Pre-copulatory stage:
– Search for sexual partner
– Courtship
– Sexual arousal
– Erection
– Penile protrusion
• Copulatory stage:
– Mounting
– Intromission
– Ejaculation
• Post-copulatory stage:
– Dismount
– Refractory period
– Memory

37. Female Sexual Behavior
Species Search Courtship Arousal
Cow Increased locomotion,
vocalization, twitching
& elevation of tail
Increased grooming,
mounting attempts
with other females
Homosexual
mounting & standing
to be mounted
Mare Increased locomotion,
tail erected (“flagging”)
Urination stance,
urination in presence
of stallion
Presents hindquarters
to male, clitoral
exposure by labial
eversion, pulsatile
contraction of labia
Ewe Restlessness Urination in
presence of ram
Immobile stance
Sow Mild restlessness Immobile stance Immobile stance

38. Male Sexual Behavior
Specie Search Courtship Arousal
Bull Chin resting, testing for
lordosis
Flehmen, nuzzling,
and licking of
perineal region
Penile protrusion
with dribbling of
seminal fluid,
erection, mouning
attempts
Horse Visual search Flehmen, excitement Penile protrusion
with no dribbling
Ram Neck stretched, head
held horizontally
Lehmen, sniffing
and licking of vulva,
nudging
Penile protrustion, no
dribbling
Boar Moving among female Nuzzling, grinding
of teeth, foams at
mouth
Penile protrusion,
shallow pelvic thrust

39. Sperm Transport in Male
Reproductive Tract
• Sensory stimulation (Optic, olfactory,
tactile and auditory)  Spinal cord 
Hypothalamus
• Stimulation of SON and PVN neurons
• Release of oxytocin from posterior
pituitary
• Contraction of of epididymis and vas
deferens
• Transport of spermatozoa in ejaculatory
duct

40. Ejaculation: A Neural Reflex
Sensory stimulation of glans penis
(temperature and pressure of vagina)
spinal cord
Powerful contraction of urethralis,
bulbospongiosus and ischiocavernous
muscles (motor neurons)
Expulsion of semen

41. Ferilization: A Cascade of Events
Capacitation
Hyperactive motility
Sperm binding to zona pellucida
Acrosome reaction
Penetration of zona pellucida
Sperm-oocyte membrane fusion
Entry of sperm DNA in oocyte
Decondensation of sperm nucleus
Formation of male pronucleus

42. Events During Sperm Transport
in Female Tract
• Vagina:
– Loss of spermatozoa - Retrograde flow
– Phagocytosis
• Cervix:
– Sperm selection
– Major reservoir
• Uterus:
– Initiation of capacitation
– Phagocytosis
• Oviduct:
– Completion of capacitation
– Acrosome reaction
– Oocyte penetration