Sexual reflexes

Question 1

MPOA

Answer 1

medial preoptic area of hypothalamus
projects to:
- hypothalamic paraventricular nucleus
- midbrain (ventral tegmental area)
- brainstem nuclei (raphe and gigantocellular)
then project to autonomic and somatic spinal centres commanding peripheral nerves

Question 2

Sexual hormone function

Answer 2

Estrogen: permissivity
Testosterone: initiation
Progesterone: receptivity

Question 3

Peripheral effects of hormones on sexual function

Answer 3

VIP –> v/c

NPY and substance P –> unknown effect on v/c

Question 4

Serotonin sexual function

Answer 4

inhibits interest, genital arousal and orgasm

Question 5

ACh sexual functions

Answer 5

? effect on interest

facilitates genital arousal and orgasm

Question 6

Noradrenaline sexual functions

Answer 6

facilitates interest and orgasm

inhibits genital arousal

Question 7

Dopamine sexual functions

Answer 7

facilitates interest and genital arousal

? effect on orgasm

Question 8

Psychogenic centre of sexual function

Answer 8

T10-L3

Question 9

Reflexogenic centre of sexual function

Answer 9

sacral afferents and efferents

Question 10

Cervical injury (T11-L3) - sexual function

Answer 10

Reliant on sacral reflex erection/vaginal arousal (need sexual touch)
the higher/more complete the lesion, the better the sacral reflex responses

Question 11

Sacral injury - sexual function

Answer 11

below T9

reliant on mental erection/vaginal arousal

Question 12

Injury between cervical and sacral centres - sexual function

Answer 12

communication between centres disrupted;

get both psychogenic and reflex dysfunction

Question 13

Tx of ED

Answer 13

PDE5 inhibitor
viagra
cialis
levitra

Question 14

Women sexual dysfunction Tx

Answer 14

only erectile tissue will be affected by PDE5i
SCI may help if incomplete
since it only affects erectile tissue, may increase sensation due to vasocongestion –> helps 1/3 women with MS
does not directly influence sexual drive or orgasmic capacity

Question 15

Physiology of ejaculation

Answer 15

spinal cord reflex involving coordination between T10-S4
Central inhibitory control over spinal cord reflex
Ejaculatory inevitability - closure of the bladder neck with seminal emission with concomitant closure of external sphincter, increasing intraprostatic pressure

Question 16

Phases of ejaculation

Answer 16

Seminal emission: sympathetic T10-L1; some voluntary control
Propulsatile ejaculation (expulsion): parasympathetic and somatic, loss of voluntary control

Question 17

Ejaculation centres

Answer 17

T12-L1: sympathetic centres (emission)
L3-L4: lumbar spinothalamic: spinal generator of ejaculation
S1-3: somatic (expulsion); PSNS (secretion)

Question 18

Ejaclation with out orgasm causes

Answer 18

spinal cord injury
MS
Anhedonic ejaculation

Question 19

Orgasm without ejaculation cause

Answer 19

prostate removal
Retrograde ejaculation
Retroperitoneal lymph node dissection

Question 20

Tx of ejaculatory dysfunction

Answer 20

penile vibrostimulation
Reliant on an intact lumbosacral reflex
Reflex erections and +BCR promising signs
higher the lesion - less interference

Electroejaculation: more invasive etc. reliant on efferent component of reflex

Question 21

Bulbocavernosus reflex

Answer 21

squeeze glans penis and watch for responsive pelvic floor contraction
Reflective of intact sensory and motor sacral pathways (not autonomic)
Predictive for: reflex erection/vaginal arousal, ejaculation to VS
Positive is confirmatory

Question 22

Voluntary anal contraction

Answer 22

downgoing CST

rectal insertion for true voluntary anal contraction

Question 23

Testicular squeeze test

Answer 23

positive:
innervation of T9 to brain must still eb intact - injury must be below T9
pain upon squeezing both testes