1. Reproductive system
physiology
By
Khorrami Ph.D.
khorrami4@yahoo.com
http://khorrami1962.spaces.live.com

5. Testis
• Seminiferous tubules
– 900*50cm …..450m
– 80% volume of testis
• Rete testis(anastomosing tubule)
• Efferent ductules
• Epididymis
– 5m long
– Head …immature sperm
– Body….sperm maturation
– Tail ….sperm maturation
• Vas deferens …. Decapacitation
• Ejaculatory duct

7. Spermatogenesis needs
• Sertoli
• Leydig
• Germ cells
• Myoepithelial cells
• Epithelial cells

8. Spermatogenesis
• Mitosis
• Miosis
• Spermiogenesis
• spermiation

9. Spermatogenesis
• Spermatogenesis: The production of
spermatozoa in the sertoli cells
• Spermiogenesis: Conversion of the
spermatids into spermatozoa
• Spermiation: Release of the
spermatazoon into the lumen
• Capacitation: Final maturation of the
spermatazoon in the female genital tract

10. Spermatogenesis
• Stem cells
• Mitosis
• Spermatogonia
• First spermatocyte
• First miosis
• Second spermatocyte
• Second miosis
• Spermatid
• sperm

12. SPERMATOGENESIS
SPERMATOGONIA (DIPLOID)
MITOSIS
PRIMARY
SPERMATOCYTES
(DIPLOID)
12

13. SPERMATOGENESIS
PRIMARY SPERMATOCYTES
MEIOSIS I
SECONDARY SPERMATOCYTES
(HAPLOID)
MEIOSIS II
SPERMATIDS (HAPLOID)
SPERMIOGENESIS
SPERMATOZOA (HAPLOID)
13

15. FROM SPERMATID TO SPERM
15

16. 16

17. SERTOLI CELL
17

18. Spermatogenesis
• Inhibited by:
• Toxiphole
• Hypokalemia

22. Functions of Sertoli cells
• Blood-testis barrier(sertoli-cell barrier) by
tight junction
– Adluminal compartment
– Basal compartment
• Supportive effects on germ cells
• Nutritive effects on germ cells
• Secretions

23. FUNCTIONS OF SERTOLI CELLS
• Secrete ANDROGEN BINDING PROTEIN &
LUMINAL FLUID.
• Secrete PARACRINE AGENTS Stimulating
proliferation & differentiation.
23

24. FUNCTIONS OF SERTOLI CELLS
• Secrete the regulatory protein INHIBIN.
• Secrete paracrine agents: FACILITATING
LEYDIG CELL FUNCTION.
• PHAGOCYTOSIS of defective sperm
• Secrete MULLERIAN INHIBITING
HORMONE(MIH)
24

25. Secretions of Sertoli cells
• Mullerian inhibitory factor (MIF)
• Aromatase
• Androgen binding protein (ABP)
• Inhibin
• Estrone/estradiol
• DHT
• GnRH-like peptide
• Ceruloplasmin
• Plasminogen activator
• Follistatin
• IGF-1
• TGF
• Transferrin
• Cytokines

26. Functions of leydig cells
• Steroidogenesis …8-18th week of gest.
• LH receptor/PRL(potentiate LH function)
• Testosteron ..5-7mg/day
• Androstenedione
• Relaxin-like factor
• A good marker for fully differentiated adult-
type Leydig cells
• Weakly expressed in prepubertal
• Immature Leydig cells
– By insulin-like factor 3 gene

27. Relaxin-like factor 3(RLF)
• In estrogen-induced cryptorchidism, RLF
levels in the testis are significantly reduced
• RLF secreted by theca cells of small antral
follicles
• RLF secreted by the corpus luteum of the
cycle and pregnancy

28. Testicular steroidogenesis

29. MALE REPRODUCTION: HORMONAL REGULATION
HYPOTHALAMUS
- ve feedback
GONADOTROPIN RELEASING HORMONE
ANTERIOR PITUITARY
- ve feedback
FSH LH
TESTES
S
E LEYDIG CELL
R
T
O TESTOSTERONE
L
I REP.TRACT
CELL SPERMATOGENESIS
& OTHER ORGANS
INHIBIN 29

30. SEMEN ANALYSIS
• A test for infertility
• Semen contain:
– Sperms
– Secretions:
• Seminal vesicles
• Prostate
• Cowper’s glands
• Bulbo-urethral glands
30

31. SEMEN ANALYSIS
• Volume: 2.5 to 3.5 ml/ejaculate
• Sperm count: 100 M/ml.
• <20% abnormal.
• <20 M/ml, sterile
• Sperm speed: 3mm/min.
• Reach fallopian tube 30- 40 min after coitus.
31

32. SEMEN: COMPOSITION
• Color: white, opalescent
• Specific gravity: 1.028
• Ph : 7.35 – 7.50
32

33. SEMEN
• Liquid when ejaculated
• Coagulates:
– In vitro
– In vagina
• Undergoes secondary liquefaction after
15 min.
33

34. SPERMATOZOA
• Fertile up to 24 to 48 hrs after deposition.
• Motile, for 48 – 60 hrs.`
34

35. Semen production
• Seminal vesicle (60%)
• Prostate (30%)
• Bulbouretral gland (cowper)
• Seminiferous tubule

36. Semen composition
• Fructose (for anaerobic metabolism of sperm )….sem.ves
• Glucose, A.A. and sorbitol (for aerobic metabolism of sperm ) ….sem.ves
• Hormones (androgens, estrogens, progesterone)
• Decapacitation factors (cholesterol/esterol) ….sem.ves
• Prostoglandins ….sem.ves
• Citrate
• Ascorbic acid ….sem.ves
• Lecithin ….sem.ves
• Phosphoryl choline ….sem.ves
• Potassium
• Acid phosphatase
• Phosphate
• HCO3-
• Acrosin inhibitor
• Spermine (odor- coagulation) .....prostate
• Sperm coating proteins.....prostate
• Fibrinolysin .....prostate
• Zinc .....prostate

42. Testosterone & other steroids in
man
• Testis 95%
• Adrenal 5%
• Total: 5-7mg/day
• DHT 50-100µg/day
• 17α-OH-progesterone 1-2mg/day
• Estradiol 10-15µg/day

43. Testosterone & other steroids
• Castration →increase in LH & FSH
• Castration+ androgen →increase in FSH only
• Role of inhibin

44. Androgen in plasma
• SHBG 40%
• Albumin 47%
• Other proteins

45. Metabolism of androgens
• By urine
• Excreted as 17KS 50%
• Gluco & sulphoconjugation in liver
• ↓
• Urinary 17-KS
– Testis 30%
– Adrenal 70%

50. FUNCTION OF PENIS IN COITUS
(SEXUAL INTERCOURSE)
• Erection
• Ejaculation
50

51. ERECTION
• VASCULAR:
– SMALL ARTERIAL DILATATION
– VENOCONSTRICTION
• PARASYMPATHETIC FACILITATION
• SYMPATHETIC INHIBITION
– SMOOTH MUSCLES RELAX
51

52. PENILE ERECTION: REFLEX PATHWAYS
INPUT FROM
THOUGHTS MECHANORECEPTORS
EMOTIONS OF PENIS
SIGHT, SMELL
NEURONS TO PENIS
NEURONS RELEASE nonCholinergic
NEUROTRANSMITTER (NO)
INHIBITION ON SYMPATHETIC NEURONS
PENIS
ARTERIAL DILATATION + VENOCOMPRESSION
= ERECTION
52

53. EJACULATION
• Sympathetic facilitation
• Skeletal muscles contract
• Two events:
1. EMISSION: Smooth muscles contract &
semen sent into urethra
2. EXPULSION: Rapid contraction of
urethral smooth muscles.
53

54. MALE REPRODUCTIVE
ABNORMALITIES
• CRYPTORCHIDISM (UNDESCENDED
TESTES)
– THE DESCENT OF TESTES IS INCOMPLETE IN
10% OF NEONATES
– SPONTANEOUS DESCENT OCCURS LATER
– INCIDENCE: 2% AT INFANCY & 0.3% AFTER
PUBERTY
– COMPLICATIONS: INCREASED INCIDENCE OF
TESTICULAR MALIGNANCIES & INFERTILITY.
54

57. Testosterone /effects

58. Synthesis of the male sex hormones in Leydig
cells of the testis. P450SSC, 3b-DH, and
P450c17 are the same enzymes as those
needed for adrenal steroid hormone
synthesis. 17,20-desmolase is the same as
17,20-lyase of adrenal hormone synthesis..

66. LH & FSH during life of a woman

67. HL: FSH>LH

68. Follicles
• At 20th week …..20mil
• At birth …………1-2 mil
• At puberty ……..300-400k
• During reproductive period..400-500

69. Uterine cycle
• Proliferative
• Secretory
• Ischemic
• Bleeding

71. Estrogen in proliferation phase
• Cell proliferation in endometrium
• Growth of ER & mitochondria in endometrium
• Increase glycogen storage
• Endometrial glands
• Dilation of arteries and coiled
• Increase in progesterone receptors
• Increase sensitivity & contractility of myometrium

72. Secretory phase
• Secretion of mucus
• Continue to proliferation
• Edema of endometrium
• Decrease contraction of myometrium

74. Menstrual cycle

75. Ovarian cycle
• Follicular phase
• Preovulatory phase
• Ovulatory phase
• Luteal phase
• Luteolysis phase

76. Steroidogenesis in ovary

77. Follicle graaf
• Theca interna is rich in Scc450(desmolase)
• Theca interna cells have LH receptors
• Granulosa cells are rich in aromatase
• Granulosa cells have LH & FSH receptors

79. Synthesis of the major female sex hormones in the ovary. Synthesis of testosterone and
androstenedione from cholesterol occurs by the same pathways as indicated for
synthesis of the male sex hormones.

82. Hohlweg effect
• Critical plasma concentration for estrogen
– 200pg/ml
– For 36 hrs
– No response to 100pg/ml
• Increase GnRH receptor on gonadotrops (est &
PGE2)
• Increase the enzymatic activity of
gonadotrops(est)
• Increase amplitude & frequency of GnRH(est &
PGE2)

83. PGs & follicular rupture

86. Ovulation
• Androgen to estrogen microenvironment
• More FSH receptors
• Hohlweg effect
• Less OMI concentration
• Plasminogen activator
• Plasmin
• Fibrinolysin
• Collagenase
• Inhibin
• FSH & LH…..increase in cAMP
• Prostaglandin F2α( 2-5 hrs before ovulation)
– Completion of first miosis
– Contraction of ovarian smooth muscles
• Oxytocin

87. Ovulation

89. Luteal phase
• Progesterone secretion
• Negative Fern test
• LH support
• Maximum activity: 6-8 days after ovulation

90. Luteolysis
• PGF2α:
– Reduction in blood flow of corpus luteum
– Increase estrogen secretion
– Reduce response of corpus luteum to LH
– Increase OT secretion from CL

91. Menstrual cycle

93. Capacitation
• Remove of HMW glycoprotein (polylactoseamine) &
peptides
• Whiplash-like pattern of hyperactivation of sperm
• Removing sterol & cholesterol from the surface
• Rearrangement of surface molecules
• Increase permeability to calcium
• Hyaloronidase activity
• Galactosyl-transferase activity

95. Acrosome reaction
• Calcium entrance- Ca-cal
• Increase cAMP
• Activation of phospholipaseA2
• Increasing lysophospholipids
• Adhesion
• pH: 5.2 to 7:00
• Segmentation of acrosome

99. Syngamy
• After enter the sperm, 2nd polar body
• After 30 min, disperse of sperm nucleus
• After 6-8 hrs, pronucleus & syngamy
• After 27-43 hrs, first division

105. Origin of testosterone in women

106. Factors affecting SHBG
Stimulator Inhibitors
• Estrogen • Progestins (except OH-
• Hyperthyroidism prog)
• Ageing • GH
• Glucocorticosteroids
• Hypothyroidism

107. Relation of MCR of steroids & affinity to SHBG

108. DHEA-S concentration versus age

109. Distribution of plasma testosterone &
estadiol

110. Aromatase activity in
• Muscle (25-30% in normal conditions)
• Adipose tissue
• Skin fibroblasts
• Hair follicles
• Brain
• Aromatase has more affinity to androstenedione than
testosterone

111. Sources of estrone in women
Aromatase

112. Strogens
• Estradiol; 95% by ovary
• Estrone; peripheral conversion
• In normal women: E2/E1 >1