4,503
edits
Changes
Erection - Anatomy & Physiology (view source)
Revision as of 11:19, 10 July 2008
, 11:19, 10 July 2008→Sensory Input and Local Vascular Response
* Terminals synapse with neurons in the ''''behaviour centre'''' in the [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology#Hypothalamus|Hypothalamus]].
* Terminals synapse with neurons in the ''''behaviour centre'''' in the [[Endocrine_System_-_Hypothalamus_-_Anatomy_%26_Physiology#Hypothalamus|Hypothalamus]].
* Hypothalamic neurones synapse with parasympathetic and sympathetic efferent neurons that control penile vascular smooth muscle (vascular tone).
* Hypothalamic neurones synapse with parasympathetic and sympathetic efferent neurons that control penile vascular smooth muscle (vascular tone).
* Firing of Nonadrenergic, noncholinergic (NANC) parasympathetic neurones causes erection.
* Firing of '''Nonadrenergic, noncholinergic (NANC) parasympathetic neurones''' causes erection.
** Release nitric oxide (NO) from their terminals.
** Release '''nitric oxide (NO)''' from their terminals.
** NO is the principle neurotransmitter that drives the erectile process.
** NO is the principle neurotransmitter that drives the erectile process.
** NO activates the enzyme guanylate cyclase.
** NO activates the enzyme '''guanylate cyclase'''.
** Guanylate cyclase converts guanylate triphosphate (GTP) into cyclic guanyosine monophosphate (cGMP).
** Guanylate cyclase converts guanylate triphosphate (GTP) into cyclic guanyosine monophosphate (cGMP).
* Causes corporal smooth muscle relaxation (vasodilation) and results in erection.
* Causes corporal smooth muscle relaxation (vasodilation) and results in erection.
* Under nonerotogenic conditions, cGMP is acted upon by PDE5 (phosphodiesterase 5).
* Under nonerotogenic conditions, cGMP is acted upon by '''PDE5 (phosphodiesterase 5)'''.
* PDE5 promotes conversion of cGMP to GMP.
* PDE5 promotes conversion of cGMP to GMP.
* Breakdown causes increased vascular tone.
* Breakdown causes increased vascular tone.