Sex Flashcards
How to measure penis length
Erect length the same as stretched flaccid
What is the tunica albuginea. what is its function
Only in males
Fibrous sheath
Push against veins when erect
Less blood leaves penis
What happens to vasculature during erection
Vein compression
Artery vasodilation
Sinusoidal spaces fill/engorge
Helicine arteries no longer constricted
Male sexual response sympathetic NS: what nerve, what functions
SHOOT- ejaculation
Hypogastric nerve (NA)
Contraction: epididymis, vas deferens, prostate, seminal vesicles
- semen travels to proximal urethra
Perineal nerve (branch of pudendal)
Contraction: pelvic floor, ischeo/bulbocavernosus, internal urethral sphincter
- forcible semen expulsion
Male sexual response parasympathetic NS: what nerve, what functions
POINT = parasympathetic NS
Cavernous nerve (ACh, NO, VIP)
Vasodilation of penile arteries causes erection:
Smooth muscle relaxation (corpus cavernosa and corpus spongiosa)
Cavernous sinusoids fill- penile expansion and stiffening
Compression of veins- reduced blood drainage
Pelvic plexus
Bulbourethral glands- lube fluid
urethra- sphincter closed
Lubrication
Mucus secretion (sent to semen in proximal urethra- part of SNS)
How can the male sexual response occur
Sensory stimulation- penile mechanoreceptors
Pudendal nerve to sacral spinal cord
Sympathetic and parasympathetic outputs
Psychic stimulation- visual, olfactory, emotional
Cerebral cortex to
Hypothalamus (paraventricular nucleus, medial preoptic area)
To sacral spinal cord
Sympathetic and parasympathetic outputs
Name parasympathetic neurotransmitters and where they bind
Nitric oxide, acetylcholine, vasoactive intestinal peptide
Bind at penile arteries to induce vasodilation
Describe in full the male sexual response
Check pg. 5
What is considered emission
Contraction of vas deferens, seminal vesicles, prostate that propels semen towards ejaculatory duct
What is considered ejaculation
Expulsion of seminal fluid from body
What initiates emission
Hypogastric nerve
What causes ejaculation
fullness near ejaculatory duct (caused by emission) cause pudendal nerve to send sensory stimulus to brain. This initiates rhythmic contractions that lead to ejaculation
What blocks PDE5? What is the function of PDE5
Phosphodiesterase E5
Sildenafil = viagra blocks PDE5
PDE5 (found in reproductive tissue) job to break down cGMP causes PLB (phospholamban) to inhibit SERCA activity therefore less relaxation
So Sildenafil will increase relaxation to allow erection
Function of Sildenafil and the cause of its effect (MBB pathway)
Block PDE5 therefore allows cGMP to activate PKG which phosphorylates PLB (PLB release inhibition on SERCA) causing an increase in SERCA activity (faster relaxation- vasodilation)
Explain NO pathway
Ach from parasympathetic efferent bind to M3 Gq
Gq causes increase Ca levels that activate eNOS
eNOS converts L-arginine to NO
NO diffuse from endothelium to VSM and activate GC- guanylyl cyclase
GC convert GTP to cGMP
cGMP activate PKG which phosphorylates PLB (increasing SERCA)
PDE5 break down cGMP to GMP (Sildenafil block PDE5)
How erection and ejaculation are effected by an upper motor neuron lesion
Reflexogenic erection- present (semen winds up in bladder since urethral sphincter open)
Psychogenic erection- absent (can’t reach pudendal nerve)
Effect of ejaculation- significantly impaired
How erection and ejaculation are effected by a lower motor neuron lesion
Reflexogenic erection- absent
Psychogenic erection- present (must be constant to maintain)
Effect of ejaculation- less impaired
Female sexual response sympathetic and parasympathetic
Sympathetic- Hypogastric nerve
Orgasm
Contractions: pelvic floor, perineal muscles, cervical dilation
Assumption is that uterine contractions propel sperm
Parasympathetic
Pelvic nerve: Ach, NO, VIP
vasodilation- vaginal wall, labia minora, clitoris
Increased vaginal tone
Causes arousal- smooth muscle relaxation, clitoral and vaginal engorgement, lengthening and dilation of vagina
Pelvic Plexus
Bartholin glands (labia minora), vaginal epithelium -> lubrication, mucus secretion
How does female psychic stimulation work
Visual, olfactory, emotional
Cerebral cortex
Hypothalamus (paraventricular nucleus, medial preoptic area)
Oxytocin (secreted by posterior pituitary)
Uterine contractions
Scientists who documented female sexual response
William Masters and Virginia Johnson
What age related changes occur related to sex
Greater stimulation to achieve erection with increasing male age
Less lubrication with increasing female age
Explain 4 phases of human sexual response
Excitement- increased muscle tone, heart rate, breathing, blood pressure. Flushed skin, erect nipples and breast swelling, engorgement and lubrication of genitals. Testes swell and scrotum tightens.
Plateau- intensification of excitement. Increased muscle tension and muscle spasms. Testes withdraw into scrotum. Increased clitoral sensitivity. Vaginal engorgement and swelling.
Orgasm- climax is a few seconds. Involuntary muscle contractions/spasm. Further increases in heart rate, blood pressure, breathing. F: Rhythmic contractions of vagina and uterus (full sperm in). Flushed skin. Rhythmic contraction of pelvic floor, bulbo/isheocavernosus, internal urethral sphincter. Increased lubrication.
Resolution- endorphins, sense of well-being, intimacy, fatigue. Return to normal state. Refractory state in men
Experiment testing orgasm facial expressions proved what
That pain face and sex face are not the same
What are females sexual performance concerns
- sexual dysfunction
- issues with arousal, desire, orgasm
- physical, psychological, hormonal
- pain during sexual activity
What are male sexual performance concerns
- erectile dysfunction
- premature ejaculation
General suggestions for premature ejaculation and erectile dysfunction
Premature- topical = lidocaine, methodological = alternate foreplay and intercourse
Erectile- physical aid (pressure ring) or therapeutics
