Sexual
stimulation and erection begin in the brain where neuronal
testosterone-receptor sites are prompted to ignite a cascade of biochemical
events that involve testosterone-receptor sites in the nerves, blood vessels,
and muscles (Philip, 2003). Libido tends to be
very strong in males of all species and tends to have a low threshold for its
expression. Within the category of sexual behavior, libido would fall under the
appetitive phase where a male or female will usually undergo certain behavior in
order to gain access to the opposite sex (web med).
Libido or sexual desire is key to the process leading to erection. The libido
is not located in the groin but in the brain. Physical stimulation of the penis
is ineffective in producing an erection without engaging the brain and more
specifically the area
such as the medial preoptic area (MPOA) within the brain
responsible for sexual desire (Philip, 2003).
A man with decreased libido thinks less about
sex. He loses interest in sexual fantasy and masturbation and also in sexual
activity. Even sexual stimulation, by sights, words, or touch, may fail to provoke
interest. Sex drive (libido) varies greatly among men. And different men find
different degrees of libido satisfactory. Libido may be decreased temporarily
by conditions such as fatigue or anxiety. Libido also tends to gradually
decrease as a man ages. Occasionally, libido
can be low throughout a man's life. Lifelong low libido can result from
traumatic childhood sexual experiences or from learned suppression of sexual
thoughts. Most often, however, low libido develops after years of normal sexual
desire. Factors of reduced libido can be both psychological and physiological (Nelson,
2005).
i)
Psychological
factors
psychological
factors such as depression, anxiety, or relationship problems, stress or
fatigue, childhood sexual abuse, assault,
trauma,
(Nelson, 2005).
ii)
Physiological factors
Physiological factors that can affect libido include: age,
poor health, such as chronic diabetes mellitus, hypertension, endocrine issues
such as hypothyroidism,
body image issues such as underweight, obese, malnourishment, levels of
available testosterone in the bloodstream, the effect of certain prescription
medications for example proscar
(Finasteride or minoxidil)
(Nelson, 2005) .