Male urethra. Penis and erection

1. Male urethra. Penis and erection Anna L.Kiss Department of Anatomy, Histology and Embryology Semmelweis University Budapest 2018

2. The male urethra has three parts Long (about 20cm) musculartube) • Prostatic part: piercestheprostate • Membranous part: theshortest part, passesthroughthepelvicdiaphragm • Spongy part: thelongest part, running in theaxis of thepenis

3. 1.)Prostatic part: • medianlongitudinalridge: urethralcrest • in themiddle of thiscrest: • seminalcolliculus: roundedeminence • aslitlikeorifice, leadinginto a smallvestigealcul-de-sac: prostaticutricule, • oneachside of thisutricle: openings of theejaculatoryducts • 2.)Membranous part: • voluntarysphincterthatcompresstheurethra (fromthepelvicdiaphragm) • 3.)Spongy part: • end: glanspenis • fossa navicularis: proximal: bulbourethralglands • mucus secretingurethralglands

4. Three parts of the male urethra 1 3 2

5. Endoscopy of the urethra • Wheninsertingcatheters and soundsthecurves in theurethra must be considered: • The membranous partrunsinferiorly and anteriorly, The prostatic parttakes a slightcurvethat is concaveanteriorly • The spongy part: wellcoveredinferiorly and posteriorlyerectiletissue Shortsegment of themembranousurethra is unprotected!! • In thenavicular fossa: transversemucosa fold (about 2cm fromtheexternalopening of theurethra)

6. Histological structure of the male urethra • Prostatic part: urothelium (vesicalsphincter m.: smoothmuscle!) • Membranous part: pseudostratifiedorstratifiedcolumnarepithelium theurogenitaldiaphargm: striatedmusclemakes a sphincter: sphincterurethrae m. • Penil (orspongy) part: pseudostratifiedcolumnarepithelium • distal end: stratifiednon-keratinizedsquamousepithelium • attheorifice: stratifiedkeratinized squamous epithelium • Bulbourethralglands and mucus secretingLittreglandsemptyintoit

7. Penis

8. Penis Threecylindricalbodies: • Corpora cavernosa – twoerectilebodiesenclosedby a densewhitefibrouscapsule: tunicaalbuginea. • Corpus spongiosum – ventrally (corpus cavernosumurethrae) containingthespongyurethra, ending in theglanspenis • Crura – attachedtotheconjoint rami of pubis and ischium. body Root: bulb+crura+bulbospongiosus m.)

9. Erectile bodies of the penis and urethra • skin • spffascia: thinsmooth m.+ spf. dorsal v. • fasciapenis: deepdorsal v. + 2!!! dorsal art. • tunicaalbuginea

10. Blood supply of the penis • Twodorsalispenileaa.–terminalbranch of theinternalpudendalartery • Deep arteries (cavernousartery) – paired, principalarterysupplyingthecavernousspaces • Bulbourethralartery–spongyurtethra (internalpudendal)

13. Venous drainage • Superficial– spf. dorsal vein • Deep –deep dorsal vein sinuses – emissary veins - circumflex veins

14. Innervation of the penis • Autonom (vegetative) - sympathetic (T11-L2) fibers - parasymphathetic (S2-S4) fibers:nervuscavernosus (inthepelvis) • Somaticinnervationsensory and motor innervation of theextracorporalstriatedmuscles: nervuspudendus

15. Innervation of the penis • Cavernousnerves posterolaterallytothe prostateentersthe CC and CS, regulatesthe blood flow of the penis. • Dorsal n. of thepenis • (frompudendalnerve) somaticnerve, primary innervatestheskin of thepenis

16. AZ ERECTION

17. Erection is: sexual reponse • Erection(haemodinamiceventregulatedbyneuralmechanism)is resultedinbyvarioussexualstimuli: • Touchand mechanicalstimulation of thepenis(reflexogen) • Erotic view, sound, and smell(centralorpsychogenic) • The erectioncan be causedbutalsoinhibitedbyanyemotionalorhighermentalactivity • The thirdtype of theerection is thesocallednocturnalerectionassociatedtosleepingperiod.

18. view (occipital) smell (rhiencephalon) ERECTIO imagination (limbic systems) touch (thalamus)

19. Relaxation of the smooth muscle in cavernous spaces and arterioles. Sexual stimulus Occlusion of the venous dranaige. Blood inflow to the caveornous spaces. Intracavernous blood pressure>systemic blood pressure ERECTION

20. In erectile stage: relaxationof thetrabecular and arteriolar smooth muscles, vasodilation of aa. helicinae increased blood flow cavernous spaces (sinusoids) are filling in with blood. Expansion of sinusoids press the emissary and circumflex veins. The streches of the tunica albuginea increases this effect significant decrease in venous blodd flow.In flaccid stage: helicine arteries are coiled, arterious blood flow is minimal, venous drainaige is not blocked.

21. Anatomy of the erection

22. Erection of the penis (and the clitoris)

23. Erection of the penis (and the clitoris)

24. Szexual stimulus EAA, OXYTOCIN, DOPAMINE, NO SACRAL PARASYMPATHETIC FIBERS Smooth muscle relaxation! NO cGMP Physiology of the erection ERECTION

25. 2+ Ca SYMPATHETIC NEURON 2+ nNOS PARASYMPATHETIC NEURON Ca NA a1 soluble Guanylyl Cyclase CONTRACTION cGMP RELAXATION Smooth muscle NO NO NO

26. cGMP cAMP NA ET PGF2a TXA2 AngII PGE1 VIP NO NA a1 SMOOTH MUSCLE ETA EP-R VIP-R R sGC b2 AC Intracellular calcium RELAXATIO CONTRACTIO

27. EJACULATION

28. MEDIATORS OF THE EJACULATION DOPAMINE 5-HT SYMPATHETIC NEURONS Smooth muscle contraction! NA EJACULATION

29. Ejaculation • Ejaculation = emission + propulsion (expulsio) • Ejaculation≠ orgasmus • Ejaculatum (~2ml)=10% from the prostate + 10% from vas deferens + 75% a from seminal vesicule + 5% fromCowper’s glands + <0.1% spermatozoa

30. Seminalis emission and ejaculation. Contraction of the reproductiv ducts and accessory organs and release their contant.

31. Seminalis emissio ésejaculation Sphincter of the bladder sontracts, preventing expulsion of the urine. Bulbospongiosus muscles contract fast and serially; The semen is released (ejaculated) form the urethra (propulsion).

32. “My brain is my second favorite organ.” Woody Allen