L12 Flashcards
Slide 3
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Slide 5
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Describe the male sexual response to a sensory stimulation
SENSORY STIMULATION of penile mechanoreceptors -> travels from prudendal nerve -> sacral spinal cord -> either PNS or SNS
Describe the male sexual response to a sensory stimulation
PSYCHIC stimulation (visual, olfactory, emotional) -> travel to cerebral cortex -> through hypothalamus (paraventricular nucleus) (medial preoptic area) -> sacral spinal cord ->
Parasymathetic via cavernous nerve -> vasodilation of penile arteries (Ach, NO, VIP) -> —erection (arousal)—> smooth muscle relaxation (c.cavernosa and c. spongiosum), cavernous sinusoids fill (penile expansion and stiffening, compression of veins (reduced blood drainage)
Parasymathetic via pelvic plexus -> bulbourethral glands/urethra —lubrication—> mucus secretion -> semen to proximal urethra
Sympathetic via hypogastric nerve -> contraction: epidydimis, vas deferens, prostate, and seminal vesicles (NA) -> semen to proximal urethra -> contraction: pelvic floor, ischeo/bulbocavernous, internal urethral sphincter -> forcible semen expulsion
FROM sacro SC via perineal nerve -> contraction: pelvic floor, ischeo/bulbocavernous, internal urethral sphincter -> forcible semen expulsion
Describe the mechanisms of PDE5 inhibitors (viagra)
Ach pathway, release from post-ganglionic sympathetic neuron, acting on M3 muscuarinc Ach receptors. Gq gets u ur calcium, then activation of eNOS. eNOS synthesizes —– during —–. NO diffuses from endothelium where produced into VSM surrounding helicine artieries. — inc lvls of cGMP which activates PKG. PKG will phosphorylate phospholambin (PLB) and when PLB is phorphoylated, removes inhibition on SERCA so more Ca back up into SR. PKG will also phosphorylate MLCK. MLCK required to phorphylte light chains in order
Describe
1) Lesion: Upper motor neuron
a) Reflexogenic erection: Present
b) Psychogenic erection: Absent
c) Effect on ejaculation: Significantly impaired
2) Lesion: Lower motor neuron
a) Reflexogenic erection:
b) Psychogenic erection:
c) Effect on ejaculation
1) Lesion: Upper motor neuron
a) Reflexogenic erection:
b) Psychogenic erection:
c) Effect on ejaculation
2) Lesion: Lower motor neuron
a) Reflexogenic erection: Absent
b) Psychogenic erection: Present
c) Effect on ejaculation: Less impaired
Slide 8
- Erectile capacity usually preserved with lesions of premotor neurons (reflexogenic erection)
- Psychogenic erections do not occur (pathways from brain are blocked)
- Ejaculation is significantly more impaired with upper than with lower lesions, due to loss of psychogenic component
Describe female sexual response if sensory stimulation
Sensory stimulation (vulva, vagina, clitoris) travels via pudendal nerve -> sacral SC ->
Via perineal nerve —orgasm–> contraction: pelvic floor, perineal muscles, cervical dilation
Sympathetic via hypogastric nerve –orgasm–> contraction: pelvic floor, perineal muscles, cervical dilation
Parasympathetic via pelvic plexus -> Bartholin glands (labia minora), Vaginal epithelium —Lubrication—> mucus secretion
Parasympathetic via pelvic nerve -> vasodilation: vaginal wall, labia minora, clitoris. Inc vaginal tone (ACh, NO, VIP) –Arousal–> Smooth muscle relaxation, clitoral and vaginal engorgement, lengthening and dilation of vagina
Describe female sexual response if psychic stimulation (visual, olfactory, emotional)
Psychic stimulation (visual, olfactory, emotional) -> cerebral cortex -> hypothalamus (paraventricular nucleus) (medial preoptic area) ->
Sacral spinal cord
oxytocin -> uterine contraction
Ways female can experience orgasm?
- Vaginal penetration may stimulate other erogenous areas
- Some females achieve orgasm with vaginal penetration (alone)
- Some females achieve orgasm with clitoral stimulation (alone)
- Some females may achieve orgasm with both, or something else entirely
- Female ejaculation is the expulsion of fluid ”from or near” the vagina (likely fluid is uterine)
Describe the human sexual response
William Masters and Virginia Johnson (1957-1990s)
Research on human sexual responses: laboratory evaluation of >10,000 responses in ~700 adults
- Human volunteers (382 M, 312 F) had intercourse or masturbated while under observation
From the 10,000 F and 2,500 M sexual cycles, what 4 cycles were defined
- Excitement phase (arousal phase): increased muscle tone, heart rate, breathing, blood pressure. Flushed skin, erect nipples and breast swelling, engorgement and lubrication of genitals. In males, testes swell and scrotum tightens.
- Plateau phase: intensification of excitement. Increased muscle tension and muscle spasms. Testes withdraw into scrotum. Increased clitoral sensitivity. Vaginal engorgement and swelling.
- Orgasmic phase
climax – several seconds. Involuntary muscle contractions/spasms. Further increases in heart rate, blood pressure (SAP 160 mmHg males; 140 mmHg females), breathing. Rhythmic contractions of vaginal and uterine muscle. Flushed skin. Rhythmic contraction of pelvic floor, bulbo/ischeocavernosus, internal urethral sphincter (prevents retrograde ejaculation). Increased lubrication. Ejaculation. - Resolution phase
Sense of wellbeing, intimacy and fatigue. Return to normal state. Refractory state (males)
Describe female sexual concerns
“Female Sexual Dysfunction”
- Persistent, recurring issues with arousal, desire, sexual response, orgasm
- Can occur at any stage of life
- Can be physiological, hormonal, psychological, psychosocial
- Treatment or therapy based on individual situations
- Persistent pain during sexual activity may indicate a more serious issue and one should seek a physician’s advice
Describe male sexual concerns: erectile dysfxn
Erectile dysfunction (various risk factors) Treatments can be physical aids or therapeutics
Describe male sexual concerns: premature ejaculation
Treatments can be topical (benzocaine, lidocaine) or methodological (e.g. alternating between foreplay and intercourse)
