Sexual
intercourse
The
process by which spermatozoa are deposited in the vagina.
A three phase process
Erection
Lubrication
Orgasm
Male
Erection
Initiated by psychic
or physical stimulation
Parasympathetic
impulses from sacral part of spinal cord.
Dilation
of arteries of penis, with venous constriction.
Blood fills cavernous
spaces of spongy bodies, erectile tissue.
Lubrication
Bulbourethral glands produce mucous during sexual stimulation.
Orgasm
Ejaculation
A single experience
A sympathetic spinal
reflex function, L1 and L2
L1 and L2 fibres pass
to the genital organs via the hypogastric plexus to
initiate emission
Peristaltic
contractions of the ducts in the testes, epididymides
and seminal ducts
Sperm propelled into
urethra, a process termed emission
S1 S2 impulses reach
skeletal muscles at base of penis to produce ejaculation
Also
peristaltic contractions of seminal vesicles and prostate.
Female
As in the male sexual
sensory information is transmitted via the sacral segments of the spinal cord
through the pudendal nerve and the sacral plexus.
Erection
Involves the clitoris
and increased blood flow
A parasympathetic
activity
Involvement of
erectile tissue
Lubrication
Parasympathetic
sacral impulses go to greater vestibular glands, (Bartholin`s
gland) beneath the labia minora
Lubrication also
comes from vaginal secretions and a little from the male
Orgasm
May be primarily
vaginal or clitoral
Reflexes from tactile
stimulation of the genitalia
Also a psychic
component
May cause contraction
of the uterus
May cause increased
respiration, pulse and BP
May be multiple and
of varying intensity
Seems to assist
fertilization
After
orgasm
After about 15
minutes seminal fluid liquefies to allow sperm to swim through the cervix
Prostaglandins in
semen and oxytocin from the posterior pituitary
released during female orgasm may stimulate uterine contractions to aid the
journey of the sperm towards the fallopian tube
Female fertility
depends on the stage of the menstrual cycle