7. phases of coitus - males (lecture)

Question 1

what are the 4 phases of coitus?

Answer 1

excitement phase
plateau phase
orgasmic phase
resolution phase

Question 2

what causes sexual response (excitement phase) in males?

Answer 2

sensory and psychological stimulation (seeing someone they like) –> limbic system
activation of sacral PARAsympathetic neurons
inhibition of thoracolumbar sympathetic neurons

Question 3

what is the biochemical process which happens during the excitement phase in male sexual response?

Answer 3

ACh –> M3 receptors on endothelial cells –> increase Ca2+ –> activation of eNOS –> NO production

Question 4

why is production of NO necessary in excitement phase of male sexual response?

Answer 4

vasodilator
arteriolar vasodilation in corpora cavernosa
increase penile blood flow

Question 5

what does increase in penile blood flow lead to?

Answer 5

penile filling (latency)

Question 6

what is penile filling called?

Answer 6

latency

Question 7

what does latency (penile filling) lead to?

Answer 7

penile tumescence

Question 8

what is penile tumescence known as?

Answer 8

erection

Question 9

during the excitement phase, what happens to the scrotal skin? (male)

Answer 9

thickens and tenses

Question 10

what happens to the testes during excitement phase? (male)

Answer 10

testes begin to elevate and engorge

Question 11

what happens as the testes begins to elevate and engorge?

Answer 11

the penis enters an erect state (still reversible within the excitement phase)

Question 12

which reflex is activated in the male plateau phase?

Answer 12

sacrospinous reflex

Question 13

what happens during the male plateau phase?

Answer 13

contraction of ischiocavernosus (compresses crus penis and impedes venous return) –> venous engorgement
(blood can get in but not out)
(ischiocavernosus - muscles either side of penis, crus is the side of penis)

Question 14

what does venous engorgement during male plateau phase cause?

Answer 14

rise in intracavernosus pressure, leading to decreased arterial inflow (prevent blood from continuously entering penis)

Question 15

what stimulates secretion in male plateau phase?

Answer 15

stimulation of secretion from accessory glands: Cowper’s and Littre’s glands

Question 16

what is the function of secretion from Cowper’s and Littre’s glands in male plateau phase?

Answer 16

lubricate distal urethra - for ejaculate to flow into vaginal canal
neutralise acidic urine in urethra

Question 17

what percentage of total ejaculate does secretions from Cowper’s and Littre’s glands make up?

Answer 17

5%

Question 18

what happens to Cowper’s glands during plateau phase in males?

Answer 18

cowper’s gland becomes active and gland secretion

Question 19

what happens to the corona during plateau phase in males?

Answer 19

corona may become further engorged

corona - swelling at distal glans penis

Question 20

what happens to the testes during plateau phase in males?

Answer 20

testes become COMPLETELY engorged and elevated

loss of erection unlikely

Question 21

what happens to the scrotum during plateau phase in males?

Answer 21

scrotum maintains its thickened and tensed state

loss of erection unlikely

Question 22

how is the orgasm phase in males subdivided?

Answer 22

into emission and ejaculation

Question 23

what is stimulated during emission of orgasm phase in males?

Answer 23

thoracolumbar sympathetic reflex

Question 24

what happens during emission of orgasm phase in males?

Answer 24

contraction of SM in vas (ductus) deferens, ampulla (of vas deferens), seminal vesicle, prostate

Question 25

what contracts during emission in orgasm phase in males?

Answer 25

internal and external urethral sphincters contract | prevent urine escaping

Question 26

where is semen pooled in emission in orgasm phase in males?

Answer 26

in the urethral bulb (bulbar urethra - before penile urethra) (urethral bulb expands with seminal fluid)

Question 27

list all the physiological changes that occur during emission in orgasm phase in males

Answer 27

contraction of ampulla of vas deferens, seminal vesicle and prostate gland - release semen internal and external urethral sphincter contracts (prevent urine) urethral bulb expands with seminal fluid (temp. store of semen)

Question 28

what is stimulated within ejaculation in orgasm phase in males?

Answer 28

``` spinal reflex (with cortical control) SNS (L1, L2) ```

Question 29

what does the SNS (L1, L2) stimulate within ejaculation in orgasm phase in males?

Answer 29

contraction of glands and ducts (SM) | internal urethral sphincter contracts (prevent urine)

Question 30

what are the physiological changes leading to ejaculation in orgasm phase in males?

Answer 30

filling of internal urethra stimulates pudendal nerve --> contractions of genital organs (ischiocavernosus and bulbocavernosus muscles) --> expulsion of semen (ischiocavernosus lateral to bulbocavernosus)

Question 31

what are the physiological changes that occur during ejaculation in orgasm phase in males?

Answer 31

contraction of penile urethra, muscles around base of penis (maintain erection), anal sphincter (prevent poo) internal urethral sphincter remains contracted external urethral sphincter relaxes

Question 32

what is activated in resolution in male sexual response?

Answer 32

thoracolumbar sympathetic pathway

Question 33

what is contracted in resolution phase in males?

Answer 33

arteriolar SM in corpora cavernosa

Question 34

what happens in resolution phase in males?

Answer 34

``` increased venous return (no longer impede) detumescence and flaccidity refractory period (cannot reach another orgasm) ```

Question 35

what are the physiological changes to the penis in resolution phase in males?

Answer 35

``` erection loss begins unstimulated state (erection loss completed) ```

Question 36

what happens to the testes in resolution?

Answer 36

testes descend and return to unstimulated size

Question 37

what happens to the scrotum in resolution?

Answer 37

scrotum thins and resumes wrinkled appearance