Presentation on physiology of sexual functions


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Presentation on physiology of sexual functions

  1. 1. Presented by : Dr Gopal G HargiPG in FM & T
  2. 2. Ref Prakasam Reddy.Fundamentals of medical physiology .4th edn.p634,645 JG McGeown.Master Medicine Physiology.3rd edn . p275-80 K S N Reddy. 30th edn . p350-53
  3. 3.  Vital organs - survival Reproductive organs – satisfying basic instincts developedpropagation of race functional
  4. 4. Copyright 2008 Allyn & Bacon
  5. 5.  The Testes Male sex glands, suspended in the scrotum Exocrine EndocrineCopyright 2008 Allyn & Bacon
  6. 6. ORGANTestisSeminiferous tubulesInterstitial cellsEpididymisVas deferensSeminal vesicleProstate glandBulbourethral glandScrotumPenisFUNCTIONProduce sperm cellsProduce and secrete male sex hormonesStores sperm cells undergoing maturation, conveyssperm cells to vas deferensConveys sperm cells to ejaculatory ductSecretes an alkaline fluid containing nutrients andprostaglandins that helps neutralize the acidiccomponents of semenSecretes an alkaline fluid that helps neutralize semen’sacidity and enhances sperm cell motijitySecretes fluid that lubricates end of penisEncloses, protects, and regulates temperature of testesConveys semen into vagina during sexual intercourse;glans penis is richly supplied with sensory nerveendings associated with feelings of pleasure duringsexual stimulationSummary of the functions of Male Reproductive Organs
  8. 8.  Testosterone Male steroid sex hormone Interstitial cells(Leydig’s cells) Cells that secrete testosterone1)Responsible for prenatal differentiation of male sexorgans2)Stimulates the development of secondary sexcharacteristicsCopyright 2008 Allyn & Bacon
  9. 9. Popad Rep Physiol MRP 10
  11. 11.  Thought emotion Stimulation of tactile sight, smell & sensory stimuli receptor Parasynthetic activation , stimulation of nervi erigentisrelease of nitric oxideformation of cGMPPenile arterial dilatationBlood flow to erectile tissueerection of penis
  12. 12. Afferents from genitalia & other structurescarried by pudendal nerve & sacral plexusintegrated at L2-L3 & S2-S4Efferents through sacral parasympathetic via nervi erigentisto smooth musclesErectile tissueglands
  13. 13.  .Ejacution The afferents mostly from receptors in glans –spinal cord – internalpudendal (L1 ,S1-S3, motor pathway S1-S2 & pudendal nerve) Emission Sympathetic impulses from T12 to L2 travel via hypogastric and pelvisnerve plexuses to initiate emission Contraction of vas deferens , expels sperm into the internal urethra. Followed by contraction and fluid addition by the prostate, seminalvesicles and Cowper’s glands This is now semen and the formation of this in the internal urethra isemission
  14. 14.  Ejaculation- Orgasm Peak of sexual excitement Release of sexual tension that builds up during arousal 1)Emission phase First phase of ejaculation, which involves contractions of theprostate gland, seminal vesicles, and the upper part of the vasdeferens (the ampulla) Fluid is propelled into the urethral tract 2)Expulsion stage The second stage of ejaculation, during which muscles at thebase of the penis and elsewhere contract, forcing out semen andproviding pleasureCopyright 2008 Allyn & Bacon
  15. 15.  Erectile abnormalities Peyronie’s disease An abnormal condition characterized by an excessivecurvature of the penis that can make erections painful Caused by buildup of fibrous tissue in the penile shaft Priapism Erections that persist for hours or days Causes include leukemia, sickle cell anemia, or diseases ofthe spinal cord Can be dangerous due to loss of oxygen to penile tissues Cantharides (cantharadine )Copyright 2008 Allyn & Bacon
  16. 16.  Erectile dysfunction inability to maintain the degree ofpenile rigidity until ejaculation. hypoglycemic agents (26%), antihypertensive drugs (14%),vasodilators (36%), and cardiac drugs (28%) Vascular insufficiency most common cause of organic malesexual dysfunction
  17. 17.  Erectile dysfunction Psychogenic Drugs (antihypertensives, anticholinergics,psychotropics, cigarette smoking, substance abuse) Systemic diseases (cardiac, hepatic, renal, pulmonary,cancer, metabolic, postorgan transplant, pelvicirradiation) Androgen deficiency (primary or secondary), androgenresistance, other endocrinopathies
  18. 18.  Vascular insufficiency (atherosclerosis, pelvic steal, penileReynauds, venous leakage) Neurological disorder (Parkinson’s, Alzheimer’s, Shy-Drager, encephalopathy, spinal cord or nerve injury) Penile disease (Peyronie’s, priapism, phimosis, smoothmuscle dysfunction, trauma)
  20. 20. ORGANOvaryUterine tubeUterusVaginaLabia majoraLabia minoraClitorisVestibuleVestibular glandsFUNCTIONProduces oocytes and female sex hormonesConveys secondary oocyte toward uterus; site offertilization; conveys developing embryo to uterusProtects and sustains embryo during pregnancyConveys uterine secretions to outside of body;receives erect penis during sexual intercourse;provides open channel for offspring during birthprocessEnclose and protect other external reproductive organsForm margins of vestibule; protect openings of vaginaand urethraProduces feelings of pleasure during sexualstimulation due to abundant sensory nerve endingsin glansSpace between labia minora that contains vaginal andurethral openingsSecrete fluid that moistens and lubricates vestibuleSummary of the functions of Female Reproductive Organs
  21. 21. 3) Regulation of GnRHHypothalamsGnRHPituitaryFSH, LHOvaryE,
  22. 22. Estrogens Produced by follicle cells Cause secondary sex characteristics Enlargement of accessory organs Development of breasts Appearance of pubic hair Increase in fat beneath the skin Widening and lightening of the pelvis Onset of menses
  23. 23.  Function of ovary1. Reproduction(exocrine)development and maturation of follicle; ovulation2. Endocrineestrogens, progesterone, testosterone
  24. 24.  Female reproductive cycle- cyclical fashion - 28days Ovarian cycle - ovum released middle of cycle Uterine cycle - endometrial primed sheds - repeats
  25. 25. Progesterone Produced by the corpus luteum Production continues until LH diminishes in the blood Helps maintain pregnancy
  26. 26.  Female sexual arousal Afferents –pudendal nerve to the spinal cord and further tocerebral cortex Integrated at S2,3,4 & L1,2 Efferents ,the parasympathetic segments travel by nervierigentis
  27. 27. Intercourse Fluid into vaginal walls Upper vagina is sensitive to stretch Tactile stimulation from labia minora & clitoris add During orgasm - pudendal nerves Vaginal contn – aid sperm transportation
  28. 28. sperm deposited in vagina at ejaculation travel to oviduct takes a little over 1/2 hour cervical canal is open due to estrogen being high and remainsopen two to three days sperm enter uterus and are churned around when reach oviduct, smooth muscle contractions propellthem onward mature egg releases a chemotactic agent- fertilin out of several hundred million only a few thousand make it tail of sperm maneuvers it for final penetration Fertilized ovum – 4-7 days to reach uterus
  29. 29.  corpus leuteum degenerates estrogen and progesterone levels fall menstrual phase involves sloughing of preparedendometrium new cycle starts-new follicles develop and begin secretingestrogen
  30. 30.  Medicolegal imp 1)Civil--- a)nullity of marriage b) divorce c) adultery d)disputed paternity & legitimacy e)suits of adoption f)as a result of accident-claim 2) Criminal---- a) adultery b)rape c) impotency as a defence –to plead
  31. 31.  Penile plethysmography Selective investigations for male sexual dysfunction Penile imaging. Penile biopsy. Cavernosal electrical activity. Pharmaco-penile duplex ultrasound (PPDU). Penile angiography. Cavernous oxygen tension
  32. 32. THANK YOU