Sexual Function after SCI Flashcards
How does a guy get an erection?
1.Vasodilation of the arteries supplying the penis and relaxation of the smooth muscle and the corpus cavernosum and corpus spongiosum (structures in the penis consisting of smooth muscle, connective tissue and vascular spaces)
2. blood fills the vascular spaces of the corpus cavernosum and corpus spongiosum
3. Engorgement of the corpus cavernosum and corpus spongiosum compresses the veins of the penis and the blood gets trapped
- the initial vasodilation of the arteries and the relaxation of the smooth muscle is under neural control from both the parasympathetic and sympathetic nervous systems
What happens during female arousal?
- vaginal lubrication caused by secretions from the greater vestibular glands (on either side of the vaginal opening)
- vascular engorgement (Erection) of the clitoris which also contains erectile tissue (corpus cavernosum but NO corpus spongiosum)
- is under control from both the sympathetic and parasympathetic nervous systems
What happens during male emission?
- Peristaltic contractions in the vas deferens transports sperm from the testis to the end of the vas deferens
- secretions from the seminal vesicles and prostate are added to sperm to form semen
- further contractions of the vas deferens transports semen to the posterior urethra
*under control of sympathetic nervous system
What happens during female emission:
- Peristaltic contractions of the fallopian tubes and further contractions of the uterus
*under control of the sympathetic nervous system
What happens during male ejaculation?
- the propulsion of semen from the posterior urethra involves contractions of the muscles of the pelvic floors
AND
closure of the bladder neck (preventing retrograde ejaculation- into bladder)
*is under the control of somatic motor neurons
What happens during female ejaculation?
occurs as a result of pelvic floor muscle contraction
What is the neural control of erection/vaginal lubrication?
-There are 2 areas in the spinal cord which are associated with the initiation of erections/lubrication (erection centres)
- T11-L2 (thoracolumbar)
-S2-S4 (sacral)
-Outflow from either centre may initiate an erection/lubrication but the maintenance of the erection/lubrication requires outflow from both centres
What is reflexogenic erection/lubrication?
- higher quality
-response to touch
-sensory afferents
-more blood flow
-purely a reflex
-parasympathetic
What is psychogenic erection/lubrication?
-lower quality
-psychological arousal
-brain (thoracolumbar erection centre–> SNS) (Sacral erection centre–> PNS)
-not the same amount of blood flow or lubrication
-sympathetic and parasympathetic
Erection/lubrication after SCI:
-none during spinal shock
-recovery takes days-years (1 or 2)
-incomplete injuries = erection/lubrication very likely
Complete SCI above T11
-no pscyhogenic erections/lubrication
-reflexogenic erection/lubrication intact (occur commonly during body care)
-erection/lubrication maintenance is an issue
-they did not feel the touch, it just causes a reflex
-not necessarily anything sexual about it
Complete SCI between L2-S2:
-preservation of reflexogenic and psychogenic erection/lubrication
-erection/lubrication maintenance is an issue
-some amount of psyschogenic erection and reflexogenic erection is possible, however there is no communication between erection centres (maintaining is an issue)
Complete SCI between T11-L2 or S2-S4:
-varying degrees of preservation of either reflexogenic or psychogenic erection/lubrication
-erection/lubrication maintenance is an issue
-total damage to an erection centre will eliminate the corresponding type of erection/lubrication, as will damage to the LMN’s
Neural control of emission:
- both the thoracolumbar and sacral erection centres are involved, although the thoracolumbar has more influence
Neural control of ejaculation- no sci:
1.First, emission must have occurred
2. semen in posterior urethra
3. afferents to sacral erection centres
4. somatic motor reflex to muscles of pelvis floor and neck of bladder