Skip to main content

Normal Erectile Physiology

  • Chapter
  • First Online:
Contemporary Treatment of Erectile Dysfunction

Abstract

The human male penis is composed of the paired dorsal corpora cavernosa and the ventral corpus spongiosum each of which is encased within a fibrous sheath, the tunica albuginea. Together, these are enclosed within Buck’s fascia, Colles’ fascia, and the skin. The spongiosum contains the urethra and is contiguous with the glans distally. The arterial supply to the penis is from the four terminal branches of the paired penile arteries, which are branches of the internal pudendal arteries. The external iliac, obturator, vesical, and femoral arteries can provide accessory arterial supply to the penile artery in some cases. Venous outflow originates from postcavernous venules that coalesce to form emissary veins. These veins empty into the cavernous vein, the deep dorsal vein, and the superficial dorsal vein depending on their origin within the penis. Efferent innervation arises from parasympathetic, sympathetic, and somatic sources. Somatosensory afferents course from the penis to central sites. The maintenance of penile flaccidity and the erectile response are controlled via intercommunicating supraspinal and spinal reflex pathways. During the flaccid state, antierectile neural input, primarily via sympathetic efferents, acts to limit blood flow to the penis to a quantity sufficient to meet physiologic needs but insufficient for erection. Following either physical or psychological sexual stimulation, proerectile neural signals are sent to the penis primarily via parasympathetic tracts. These inputs initiate the erectile response via neurotransmitter release onto postsynaptic smooth muscle cells within the corporal bodies. Nitric Oxide (NO) is the main proerectile neurotransmitter. The resultant molecular cascade leads to a decrease in intracellular Ca2+ and arteriolar smooth muscle relaxation. This relaxation allows for increased blood flow and subsequent corporal engorgement with increasing penile rigidity. As the corpora become engorged, the emissary veins are compressed by within the tunica albuginea limiting venous outflow. The increased arterial inflow and limited venous outflow increases intracorporal pressure and leads to erection. As proerectile input ceases, the secondary molecular messenger cGMP is hydrolyzed allowing for a rise in intracellular Ca2+, subsequent smooth muscle contraction, decreased penile blood flow, and a return to flaccid state physiology.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 79.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 99.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 139.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  1. Andersson KE, Wagner G. Physiology of penile erection. Physiol Rev. 1995;75(1):191–236.

    CAS  PubMed  Google Scholar 

  2. Hoznek A, Rahmouni A, Abbou C, Delmas V, Colombel M. The suspensory ligament of the penis: an anatomic and radiologic description. Surg Radiol Anat. 1998;20(6):413–7.

    Article  CAS  PubMed  Google Scholar 

  3. Bitsch M, Kromann-Andersen B, Schou J, Sjontoft E. The elasticity and the tensile strength of tunica albuginea of the corpora cavernosa. J Urol. 1990;143(3):642–5.

    CAS  PubMed  Google Scholar 

  4. Droupy S, Benoit G, Giuliano F, Jardin A. Penile arteries in humans. Origin–distribution–variations. Surg Radiol Anat. 1997;19(3):161–7.

    Article  CAS  PubMed  Google Scholar 

  5. Newman HF, Northup JD. Mechanism of human penile erection: an overview. Urology. 1981;17(5):399–408.

    Article  CAS  PubMed  Google Scholar 

  6. Hanyu S. Morphological changes in penile vessels during erection: the mechanism of obstruction of arteries and veins at the tunica albuginea in dog corpora cavernosa. Urol Int. 1988;43(4):219–24.

    Article  CAS  PubMed  Google Scholar 

  7. Lue TF, Takamura T, Schmidt RA, Palubinskas AJ, Tanagho EA. Hemodynamics of erection in the monkey. J Urol. 1983;130(6):1237–41.

    CAS  PubMed  Google Scholar 

  8. Giuliano F, Rampin O, Bernabe J, Rousseau JP. Neural control of penile erection in the rat. J Auton Nerv Syst. 1995;55(1–2):36–44.

    Article  CAS  PubMed  Google Scholar 

  9. Giuliano F, Rampin O. Neural control of erection. Physiol Behav. 2004;83(2):189–201.

    Article  CAS  PubMed  Google Scholar 

  10. Lepor H, Gregerman M, Crosby R, Mostofi FK, Walsh PC. Precise localization of the autonomic nerves from the pelvic plexus to the corpora cavernosa: a detailed anatomical study of the adult male pelvis. J Urol. 1985;133(2):207–12.

    CAS  PubMed  Google Scholar 

  11. Giuliano F, Bernabe J, Jardin A, Rousseau JP. Antierectile role of the sympathetic nervous system in rats. J Urol. 1993;150(2 Pt 1):519–24.

    CAS  PubMed  Google Scholar 

  12. Steers WD. Neural pathways and central sites involved in penile erection: neuroanatomy and clinical implications. Neurosci Biobehav Rev. 2000;24(5):507–16.

    Article  CAS  PubMed  Google Scholar 

  13. Janig W, McLachlan EM. Organization of lumbar spinal outflow to distal colon and pelvic organs. Physiol Rev. 1987;67(4):1332–404.

    CAS  PubMed  Google Scholar 

  14. Whitelaw GP, Smithwick RH. Some secondary effects of sympathectomy; with particular reference to disturbance of sexual function. N Engl J Med. 1951;245(4):121–30.

    Article  CAS  PubMed  Google Scholar 

  15. Schmidt MH, Schmidt HS. The ischiocavernosus and bulbospongiosus muscles in mammalian penile rigidity. Sleep. 1993;16(2):171–83.

    CAS  PubMed  Google Scholar 

  16. Halata Z, Munger BL. The neuroanatomical basis for the protopathic sensibility of the human glans penis. Brain Res. 1986;371(2):205–30.

    Article  CAS  PubMed  Google Scholar 

  17. McKenna KE. Central control of penile erection. Int J Impot Res. 1998;10 Suppl 1:S25–34.

    PubMed  Google Scholar 

  18. Christ GJ, Lue T. Physiology and biochemistry of erections. Endocrine. 2004;23(2–3):93–100.

    Article  CAS  PubMed  Google Scholar 

  19. Dean RC, Lue TF. Physiology of penile erection and pathophysiology of erectile dysfunction. Urol Clin North Am. 2005;32(4):379–95.

    Article  PubMed  PubMed Central  Google Scholar 

  20. Saenz de Tejada I, Angulo J, Cellek S, et al. Physiology of erectile function. J Sex Med. 2004;1(3):254–65.

    Article  CAS  PubMed  Google Scholar 

  21. Fournier Jr GR, Juenemann KP, Lue TF, Tanagho EA. Mechanisms of venous occlusion during canine penile erection: an anatomic demonstration. J Urol. 1987;137(1):163–7.

    Google Scholar 

  22. Andersson KE. Neurophysiology/pharmacology of erection. Int J Impot Res. 2001;13 Suppl 3:S8–17.

    Article  PubMed  Google Scholar 

  23. Saenz de Tejada I, Kim N, Lagan I, Krane RJ, Goldstein I. Regulation of adrenergic activity in penile corpus cavernosum. J Urol. 1989;142(4):1117–21.

    CAS  PubMed  Google Scholar 

  24. Lue TF. Erectile dysfunction. N Engl J Med. 2000;342(24):1802–13.

    Article  CAS  PubMed  Google Scholar 

  25. Berridge MJ. Inositol trisphosphate and calcium signalling. Nature. 1993;361(6410):315–25.

    Article  CAS  PubMed  Google Scholar 

  26. Cellek S, Rees RW, Kalsi J. A Rho-kinase inhibitor, soluble guanylate cyclase activator and nitric oxide-releasing PDE5 inhibitor: novel approaches to erectile dysfunction. Expert Opin Investig Drugs. 2002;11(11):1563–73.

    Article  CAS  PubMed  Google Scholar 

  27. The WMP, Lecture AA. The Ayerst award lecture 1990. Calcium-dependent mechanisms of regulation of smooth muscle contraction. Biochem Cell Biol. 1991;69(12):771–800.

    Article  Google Scholar 

  28. Rees RW, Ziessen T, Ralph DJ, Kell P, Moncada S, Cellek S. J., Kell P, Moncada S, Cellek S. Human and rabbit cavernosal smooth muscle cells express Rho-kinase. Int J Impot Res. 2002;14(1):1–7.

    Article  CAS  PubMed  Google Scholar 

  29. Somlyo AP, Somlyo AV. Signal transduction by G-proteins, rho-kinase and protein phosphatase to smooth muscle and non-muscle myosin II. J Physiol. 2000;522(Pt 2):177–85.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Wang H, Eto M, Steers WD, Somlyo AP, Somlyo AV. RhoA-mediated Ca2+ sensitization in erectile function. J Biol Chem. 2002;277(34):30614–21.

    Article  CAS  PubMed  Google Scholar 

  31. Ignarro LJ, Bush PA, Buga GM, Wood KS, Fukuto JM, Rajfer J. Nitric oxide and cyclic GMP formation upon electrical field stimulation cause relaxation of corpus cavernosum smooth muscle. Biochem Biophys Res Commun. 1990;170(2):843–50.

    Article  CAS  PubMed  Google Scholar 

  32. Saenz de Tejada I, Goldstein I, Azadzoi K, Krane RJ, Cohen RA. Impaired neurogenic and endothelium-mediated relaxation of penile smooth muscle from diabetic men with impotence. N Engl J Med. 1989;320(16):1025–30.

    Article  CAS  PubMed  Google Scholar 

  33. Bors E, Comarr AE. Neurological disturbances in sexual function with special reference to 529 patients with spinal cord injury. Urol Surv. 1960;10:191–222.

    Google Scholar 

  34. Comarr AE. Sexual concepts in traumatic cord and cauda equina lesions. J Urol. 1971;106(3):375–8.

    CAS  PubMed  Google Scholar 

  35. Chapelle PA, Durand J, Lacert P. Penile erection following complete spinal cord injury in man. Br J Urol. 1980;52(3):216–9.

    Article  CAS  PubMed  Google Scholar 

  36. Luiten PG, ter Horst GJ, Karst H, Steffens AB. The course of paraventricular hypothalamic efferents to autonomic structures in medulla and spinal cord. Brain Res. 1985;329(1–2):374–8.

    Article  CAS  PubMed  Google Scholar 

  37. Sawchenko PE, Swanson LW. Immunohistochemical identification of neurons in the paraventricular nucleus of the hypothalamus that project to the medulla or to the spinal cord in the rat. J Comp Neurol. 1982;205(3):260–72.

    Article  CAS  PubMed  Google Scholar 

  38. Wagner CK, Clemens LG. Projections of the paraventricular nucleus of the hypothalamus to the sexually dimorphic lumbosacral region of the spinal cord. Brain Res. 1991;539(2):254–62.

    Article  CAS  PubMed  Google Scholar 

  39. Argiolas A, Gessa GL. Central functions of oxytocin. Neurosci Biobehav Rev. 1991;15(2):217–31.

    Article  CAS  PubMed  Google Scholar 

  40. Argiolas A, Melis MR. Oxytocin-induced penile erection. Role of nitric oxide. Adv Exp Med Biol. 1995;395:247–54.

    CAS  PubMed  Google Scholar 

  41. MacLean PD, Ploog DW. Cerebral representation of penile erection. J Neurophysiol. 1962;25:29–55.

    Google Scholar 

  42. Liu YC, Salamone JD, Sachs BD. Impaired sexual response after lesions of the paraventricular nucleus of the hypothalamus in male rats. Behav Neurosci. 1997;111(6):1361–7.

    Article  CAS  PubMed  Google Scholar 

  43. Yanagimoto M, Honda K, Goto Y, Negoro H. Afferents originating from the dorsal penile nerve excite oxytocin cells in the hypothalamic paraventricular nucleus of the rat. Brain Res. 1996;733(2):292–6.

    Article  CAS  PubMed  Google Scholar 

  44. Giuliano F, Rampin O. Central neural regulation of penile erection. Neurosci Biobehav Rev. 2000;24(5):517–33.

    Article  CAS  PubMed  Google Scholar 

  45. MacLean PD, Denniston RH, Dua S. Further studies on cerebral representation of penile erection: caudal thalamus, midbrain, and pons. J Neurophysiol. 1963;26:274–93.

    Google Scholar 

  46. Paredes RG, Baum MJ. Role of the medial preoptic area/anterior hypothalamus in the control of masculine sexual behavior. Annu Rev Sex Res. 1997;8:68–101.

    CAS  PubMed  Google Scholar 

  47. Courtois FJ, Macdougall JC. Higher CNS control of penile responses in rats: the effect of hypothalamic stimulation. Physiol Behav. 1988;44(2):165–71.

    Article  CAS  PubMed  Google Scholar 

  48. Oomura Y, Yoshimatsu H, Aou S. Medial preoptic and hypothalamic neuronal activity during sexual behavior of the male monkey. Brain Res. 1983;266(2):340–3.

    Article  CAS  PubMed  Google Scholar 

  49. Liu YC, Salamone JD, Sachs BD. Lesions in medial preoptic area and bed nucleus of stria terminalis: differential effects on copulatory behavior and noncontact erection in male rats. J Neurosci. 1997;17(13):5245–53.

    CAS  PubMed  Google Scholar 

  50. Stefanick ML, Davidson JM. Genital responses in noncopulators and rats with lesions in the medical preoptic area or midthoracic spinal cord. Physiol Behav. 1987;41(5):439–44.

    Article  CAS  PubMed  Google Scholar 

  51. McKenna KE. Some proposals regarding the organization of the central nervous system control of penile erection. Neurosci Biobehav Rev. 2000;24(5):535–40.

    Article  CAS  PubMed  Google Scholar 

  52. Chang AY, Kuo TB, Chan JY, Chan SH. Concurrent elicitation of electroencephalographic desynchronization and penile erection by cocaine in the rat. Synapse. 1996;24(3):233–9.

    Article  CAS  PubMed  Google Scholar 

  53. Chen KK, Chan JY, Chang LS, Chen MT, Chan SH. Elicitation of penile erection following activation of the hippocampal formation in the rat. Neurosci Lett. 1992;141(2):218–22.

    Article  CAS  PubMed  Google Scholar 

  54. Marson L, McKenna KE. The identification of a brainstem site controlling spinal sexual reflexes in male rats. Brain Res. 1990;515(1–2):303–8.

    Article  CAS  PubMed  Google Scholar 

  55. Tang Y, Rampin O, Giuliano F, Ugolini G. Spinal and brain circuits to motoneurons of the bulbospongiosus muscle: retrograde transneuronal tracing with rabies virus. J Comp Neurol. 1999;414(2):167–92.

    Article  CAS  PubMed  Google Scholar 

  56. Veronneau-Longueville F, Rampin O, Freund-Mercier MJ, et al. Oxytocinergic innervation of autonomic nuclei controlling penile erection in the rat. Neuroscience. 1999;93(4):1437–47.

    Article  CAS  PubMed  Google Scholar 

  57. Melis MR, Spano MS, Succu S, Argiolas A. The oxytocin antagonist d(CH2)5Tyr(Me)2-Orn8-vasotocin reduces non-contact penile erections in male rats. Neurosci Lett. 1999;265(3):171–4.

    Article  CAS  PubMed  Google Scholar 

  58. Bjorklund A, Lindvall O, Nobin A. Evidence of an incerto-hypothalamic dopamine neurone system in the rat. Brain Res. 1975;89(1):29–42.

    Article  CAS  PubMed  Google Scholar 

  59. Skagerberg G, Lindvall O. Organization of diencephalic dopamine neurones projecting to the spinal cord in the rat. Brain Res. 1985;342(2):340–51.

    Article  CAS  PubMed  Google Scholar 

  60. Pehek EA, Thompson JT, Eaton RC, Bazzett TJ, Hull EM. Apomorphine and haloperidol, but not domperidone, affect penile reflexes in rats. Pharmacol Biochem Behav. 1988;31(1):201–8.

    Article  CAS  PubMed  Google Scholar 

  61. Hull EM, Eaton RC, Markowski VP, Moses J, Lumley LA, Loucks JA. Opposite influence of medial preoptic D1 and D2 receptors on genital reflexes: implications for copulation. Life Sci. 1992;51(22):1705–13.

    Article  CAS  PubMed  Google Scholar 

  62. Warner RK, Thompson JT, Markowski VP, et al. Microinjection of the dopamine antagonist cis-flupenthixol into the MPOA impairs copulation, penile reflexes and sexual motivation in male rats. Brain Res. 1991;540(1–2):177–82.

    Article  CAS  PubMed  Google Scholar 

  63. Argiolas A, Collu M, D’Aquila P, Gessa GL, Melis MR, Serra G. Apomorphine stimulation of male copulatory behavior is prevented by the oxytocin antagonist d(CH2)5 Tyr(Me)-Orn8-vasotocin in rats. Pharmacol Biochem Behav. 1989;33(1):81–3.

    Article  CAS  PubMed  Google Scholar 

  64. Tang Y, Rampin O, Calas A, Facchinetti P, Giuliano F. Oxytocinergic and serotonergic innervation of identified lumbosacral nuclei controlling penile erection in the male rat. Neuroscience. 1998;82(1):241–54.

    Article  CAS  PubMed  Google Scholar 

  65. Bitran D, Hull EM. Pharmacological analysis of male rat sexual behavior. Neurosci Biobehav Rev. 1987;11(4):365–89.

    Article  CAS  PubMed  Google Scholar 

  66. Bancila M, Verge D, Rampin O, et al. 5-Hydroxytryptamine2C receptors on spinal neurons controlling penile erection in the rat. Neuroscience. 1999;92(4):1523–37.

    Article  CAS  PubMed  Google Scholar 

  67. Chen KK, Chan SH, Chang LS, Chan JY. Participation of paraventricular nucleus of hypothalamus in central regulation of penile erection in the rat. J Urol. 1997;158(1):238–44.

    Article  CAS  PubMed  Google Scholar 

  68. Melis MR, Argiolas A. Role of central nitric oxide in the control of penile erection and yawning. Prog Neuropsychopharmacol Biol Psychiatry. 1997;21(6):899–922.

    Article  CAS  PubMed  Google Scholar 

  69. Sato Y, Christ GJ, Horita H, Adachi H, Suzuki N, Tsukamoto T. The effects of alterations in nitric oxide levels in the paraventricular nucleus on copulatory behavior and reflexive erections in male rats. J Urol. 1999;162(6):2182–5.

    Article  CAS  PubMed  Google Scholar 

  70. Sato Y, Horita H, Kurohata T, Adachi H, Tsukamoto T. Effect of the nitric oxide level in the medial preoptic area on male copulatory behavior in rats. Am J Physiol. 1998;274(1 Pt 2):R243–7.

    CAS  PubMed  Google Scholar 

  71. Melis MR, Succu S, Iannucci U, Argiolas A. Oxytocin increases nitric oxide production in the paraventricular nucleus of the hypothalamus of male rats: correlation with penile erection and yawning. Regul Pept. 1997;69(2):105–11.

    Article  CAS  PubMed  Google Scholar 

  72. Melis MR, Succu S, Mauri A, Argiolas A. Nitric oxide production is increased in the paraventricular nucleus of the hypothalamus of male rats during non-contact penile erections and copulation. Eur J Neurosci. 1998;10(6):1968–74.

    Article  CAS  PubMed  Google Scholar 

  73. Argiolas A, Melis MR, Murgia S, Schioth HB. ACTH- and alpha-MSH-induced grooming, stretching, yawning and penile erection in male rats: site of action in the brain and role of melanocortin receptors. Brain Res Bull. 2000;51(5):425–31.

    Article  CAS  PubMed  Google Scholar 

  74. Wikberg JE. Melanocortin receptors: perspectives for novel drugs. Eur J Pharmacol. 1999;375(1–3):295–310.

    Article  CAS  Google Scholar 

  75. Argiolas A, Melis MR. Central control of penile erection: role of the paraventricular nucleus of the hypothalamus. Prog Neurobiol. 2005;76(1):1–21.

    Article  CAS  PubMed  Google Scholar 

  76. Wessels H. Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II. Int J Impot Res. 2000;12(4):74–9.

    Article  Google Scholar 

  77. Giuliano F, Rampin O, Brown K, Courtois F, Benoit G, Jardin A. Stimulation of the medial preoptic area of the hypothalamus in the rat elicits increases in intracavernous pressure. Neurosci Lett. 1996;209(1):1–4.

    Article  CAS  PubMed  Google Scholar 

  78. Melis MR, Stancampiano R, Argiolas A. Nitric oxide synthase inhibitors prevent N-methyl-d-aspartic acid-induced penile erection and yawning in male rats. Neurosci Lett. 1994;179(1–2):9–12.

    Article  CAS  PubMed  Google Scholar 

  79. Melis MR, Stancampiano R, Argiolas A. Penile erection and yawning induced by paraventricular NMDA injection in male rats are mediated by oxytocin. Pharmacol Biochem Behav. 1994;48(1):203–7.

    Article  CAS  PubMed  Google Scholar 

  80. de Groat WC, Booth AM. Neural control of penile erection. In: Maggi CA, editor. The autonomic nervous system. London: Harwood Academic Publishers; 1993. p. 465–524.

    Google Scholar 

  81. Bozkurt M, Gocmez C, Soylemez H, Daggulli M, Em S, Yildiz M, Atar M, Bozkurt Y, Ozbey I. Association between neuropathic pain, pregabalin treatment, and erectile dysfunction. J Sex Med. 2014;11(7):1816–22.

    Article  CAS  PubMed  Google Scholar 

  82. Melis MR, Succu S, Spano MS, Argiolas A. Morphine injected into the paraventricular nucleus of the hypothalamus prevents noncontact penile erections and impairs copulation: involvement of nitric oxide. Eur J Neurosci. 1999;11(6):1857–64.

    Article  CAS  PubMed  Google Scholar 

  83. Jain NK, Singh A, Kulkarni SK. Sildenafil-induced peripheral analgesia and activation of the nitric oxide–cyclic GMP pathway. Brain Res. 2001;909(1-2):170–8.

    Article  CAS  PubMed  Google Scholar 

  84. Yoon MH, Park KD, Lee HG, Kim WM, An TH, Kim YO, Huang LJ, Hua CJ. Additive antinociception between intrathecal sildenafil and morphine in the rat formalin test. J Korean Med Sci. 2008;23(6):1033–8.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  85. Mixcoatl-Zecuatl T, Aguirre-Bañuelos P, Granados-Soto V. Sildenafil produces antinociception and increases morphine antinociception in the formalin test. Eur J Pharmacol. 2000;400(1):81–7.

    Article  CAS  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Joseph J. Pariser MD .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2016 Springer International Publishing Switzerland

About this chapter

Cite this chapter

Auffenberg, G.B., Pariser, J.J., Helfand, B.T. (2016). Normal Erectile Physiology. In: Köhler, T., McVary, K. (eds) Contemporary Treatment of Erectile Dysfunction. Contemporary Endocrinology. Humana Press, Cham. https://doi.org/10.1007/978-3-319-31587-4_2

Download citation

  • DOI: https://doi.org/10.1007/978-3-319-31587-4_2

  • Published:

  • Publisher Name: Humana Press, Cham

  • Print ISBN: 978-3-319-31585-0

  • Online ISBN: 978-3-319-31587-4

  • eBook Packages: MedicineMedicine (R0)

Publish with us

Policies and ethics