4,503
edits
Changes
Jump to navigation
Jump to search
Erection - Anatomy & Physiology (view source)
Revision as of 10:24, 10 July 2008
, 10:24, 10 July 2008→Vascular and Biochemical Control of Erection
* '''Shaft''' of the Penis consists of two dorso-lateral '''corpora cavernosa''' and the '''corpus spongiosum'''.
* '''Shaft''' of the Penis consists of two dorso-lateral '''corpora cavernosa''' and the '''corpus spongiosum'''.
* Arterial blood is supplied by the '''internal pudendal artery''' that supplies '''dorsal and deep cavernosal arteries'''.
* Arterial blood is supplied by the '''internal pudendal artery''' that supplies '''dorsal and deep cavernosal arteries'''.
* '''Corporal sinuso'''ids are supplied by '''helicine arteries'''.
* '''Corporal sinusoids''' are supplied by '''helicine arteries'''.
* '''Deep dorsal vein''' and '''superficial dorsal vein''' drain the erectile tissues.
* '''Deep dorsal vein''' and '''superficial dorsal vein''' drain the erectile tissues.
'''''Flaccid Penis'''''
'''''Flaccid Penis'''''
* Sinusoids are flattened because adrenergic nerves secrete noradrenaline (norepinephrine).
* Sinusoids are flattened because adrenergic nerves secrete noradrenaline (norepinephrine)that causes '''vasoconstriction'''.
* Blood flow to cavernous tissue is low.
* No eretogenic stimuli present
* Nonadrenergic noncholinergic (NANC) parasympathetic neurons do not fire.
* No release of Nitric Oxide (NO)
* Vasoconstriction takes precedence over vasodilation.
'''''Erect Penis'''''
'''''Erect Penis'''''
* Eretogenic stimuli present
* NANC neurones fire and release NO from their terminals.
* NO activates the enzyme guanylate cyclase.
* Guanylate cyclase converts guanylate triphosphate (GTP) into cyclic guanyosine monophosphate (cGMP).
* Causes smoot muscle of '''corporal sinusoids''' to relax (vasodilation).
* '''Cavernous sinusoids''' engorge with blood.
* Intracorporal pressure increases dramatically.
* Pressure compresses the venules through which blood exits the penis.
* Blood trapped within the penis causing an erection.
----
----
== Sensory Input and Local Vascular Response ==
== Sensory Input and Local Vascular Response ==