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2012-12-12 21:46:52
Male Reproductive System

ANAT390 Lecture 35 Male Reproductive System II
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  1. In the vas deferens, how many layers of smooth muscle are there?
    • 3 layers: long/circulatory/long
    • Involved in ejaculatory contraction
  2. Describe the epithelium and lamina propri of the vas deferens.
    • Epl: pseudostratified with basal cells and principal cells with stereocilia 
    • L. Propria:  Core of lamina propria makes the epl folded 
  3. How is the smooth muscle of the vas deferens controlled?
    • Contraction is initiated by sympathetic control
    • Short lived response
    • Powerful rhythmic contractions for active ejaculation of spermatazoa
  4. Where does a vasectomy occur and what are the consequences of this procedure?
    • Occurs at the ductus (vas) deference
    • no hormonal disruption
    • spermatazoa and ejaculate are still produced
    • Principal epl cells of epididymis and ductus deferens become very phagocytic
    • In a small minority, an immune response against spermatazoa is mounted in the wall
  5. Describe the epl/muscle of the ejaculatory ducts.
    • Epl: similar to epididymis- pseudostratifed with basal cells and principal cells
    • Muscle:  no smooth muscle in walls
  6. How do spermatazoa travel through the ejaculatory ducts?
    • Passive flow, driven by the contraction of the vas deferens
    • passes through prostate, delivers spermatazoa and seminal fluid to the urethra
  7. Name the accessory genital glands nd provide their secretory function.
    • Seminal vesicles- secrete fructose-rich seminal fluid (majority of semen volume), provides energy for sperm motility
    • Cowper's (bulbourethral) glands- secrete GAG/Sialic Acid-Rich fluid for lubrication
    • Prostate- Secretes protease/fibrolytic enzyme which liquifies semen
  8. Describe the structure of the prostate.
    • Parenchyma (functional): exocrine, compound tubuloalveolar gland
    • pseudostratified epl including columnar cells for differentiation/secretion and basal cells for proliferation/hyperplasia, both of which are testosterone-responsive
    • Stroma (supportive):  Dense irregular connective tissue + sympathetic-responsive smooth muscle
    • intermingled smooth muscle for sympathetic controlled contraction
  9. How is the prostate histologically stained?
    Stained using a Prostate Specific Antigen-specific stain which appears brown under LM
  10. Compare benign prostate hyperplasia and prostate carcinoma.
    • Benign:  increased epl proliferation, cells remain polarized, still testosterone dependent
    • Carcinoma (malignant):  increase epl proliferation, not polarized, no lumen (appears endocrine instead of exocrine), PSA is released into the stroma and fenestrated capillaries, testosterone-independent
  11. What is the functional role of the urethra?
    Common urine/semen passage
  12. Describe the epithelial transitions in the urethra.
    • Begins as transitional epl (expansion/contraction) in the prostatic urethra.  Then it becomes pseudostratified columnar epithelium (some mucous secretion) in the membranous/bulbar urethra.  Finally it becomes stratified squamous epl (protective, merges with skin externally) in the penile urethra.
    • Since the transition is gradual, there is a lower likelihood of tumour development, and it is protective of infection.
  13. Describe the structure of the penis.
    • Three columns of erectile tissue = corpora (corpus spongiosum and 2 corpora cavernosum)
    • Tissue of corpora is fibroelastic CT
    • Each corpus is surrounded by a dense irregular CT capsule (tunica albuginea)
    • Highly vascular- helicine arteries with prominent smooth muscle
    • Corpora contain venous spaces/sinuses
  14. Compare the flaccid and erect state of erectile tissue.
    • Flaccid state-
    • 1) helicine arterial smooth muscle contracted
    • 2) little blood to venous sinuses in corpora
    • 3) considerable blood shunted directly to non-corporal veins via arteriovenous anastomses (direct path from artery to vein without a capillary bed)
    • Erect state-
    • 1) Helicine arterial smooth muscle relaxed
    • 2)  Increased blood to venous sinuses which fill and expand
    • 3) Decreased drainage to veins from venous sinuses due to pressure against the tunica albuginea (maintains erection)
  15. Name the signals/messengers involved in facilitating erection.
    • Parasympathetic NS- relaxes helicine smooth muscle
    • Nitric oxide signalling- relaxes helicine smooth muscle
    • NO generated 2nd messenger, cGMP - facilitates filling of venous sinuses
  16. How does Viagra work?
    Viagra is a phosphodiesterase inhibitor which prevents the breakdown of cGMP to maintain filling of the venous sinuses