physiology of coitus

Question 1

sexual behaviour

Answer 1

Sexual behaviours are regulated by the brain and spinal cord

Dopaminergic and serotonergic systems play an important role

Question 2

coitus

Answer 2

Coitus and conception are the stages that occur in humans to allow for the fertilisation of an oocyte by sperm

results in the deposition of semen in the vagina at the level of the cervix is known as coitus

Question 3

physiology of erection

Answer 3

In the penis, erection is required to enable coitus

Erection is mediated via the parasympathetic plexus at the level of S2 and S3 in the spinal cord

The penis becomes engorged with blood and the testis and penis both increase in size

These changes are accompanied by systemic effects such as increased skeletal muscle tension, increased heart rate and hyperventilation

Question 4

vagina

Answer 4

the vagina and clitoris engorge with blood

Circumference of the vagina at the level of the pelvis as well as the length of the vagina increase

The labia minora deepen in colour

More secretions in the vagina provide lubrication

The uterus elevates

Respiratory rate, heart rate and blood pressure increases

Question 5

physiology of ejaculation

Answer 5

The stimulation of the penis result in reflex contractions of the bulbocavernosus and ischiocavernosus muscles.

This is a spinal reflex under sympathetic control

Requires contraction of structures such as the ductus deferens, seminal vesicles and prostate

The filling of the urethra stimulates nerves in the genital region which contracts the muscles of the penis resulting in forcible expulsion of semen

The systemic changes of rapid respiration and increased heart rate persist

Question 6

physiology of orgasm

Answer 6

In the vagina, stimulation of the clitoris and the labia result in progression towards orgasm.

Vaginal lubrication increases and the labia become more engorged due to a marked increase in blood flow to the vagina.

During orgasm, the clitoris retracts and a succession of contractions occur in the vaginal walls and the pelvic floor

These last for several seconds

There is an accompanying increase in pulse, respiration rate and blood pressure

Question 7

refraction and resolution

Answer 7

Following ejaculation, penile erection rapidly subsides, as do the other systemic effects

During this period, the penis is refractory to any further stimulation for some time

There is no refractory period in the vagina and clitoris meaning multiple orgasms are possible.