Erection and ED Flashcards
List components of the heomdynamic response of the corpora cavernosa that allow for erection
- dilation of arterioles and increased blood flow
- trapping of incoming blood by sinusoids
- compression of subtunical venular plexuses to reduce venous outflow
- stretching of tunica to occlude emissary veins
- increased oxygen tension and intracavernous pressure
- increase in pressure through contraction of ischiocavernosus muscles
The corpus spongiosum achieves a pressure only about 1/2 that of the corpus cavernosa because of lower __________
venous occlusion
Sympathetic and parasympathetic nerves merge to form the _________, which enter the corpora cavernosa and spongiosum to direct erection and detumescence.
cavernous nerves
The somatic nerves of the penis are responsible for sensation and for contraction of the ___________ and _________ muscles
bulbocavernosus and ischiocavernosus
Where do sympathetic nerves to the penis arise from?
T10-T12
Where do parasympathetic nerves to the penis arise from?
S2, 3, 4
The sensory fibers from the penis converge to form the dorsal nerve of the penis then join with other nerves to become the _________
pudendal nerve
What are the supra-spinal centers of penile erection?
pre-optic area, paraventricular nucleus of hypothalamus and hippocampus
Smooth muscle contraction and relaxation in the penis are regulated by cytosolic _______
free caclium
Smooth muscle contraction is required for ______; smooth muscle relaxation is required for ________
contraction= detumescence relaxation= erection
Describe the molecular mechanism of smooth muscle contraction in the penis
- Elevated levels of calcium causes binding to calmodulin and exposes sites of interaction with myosin light-chain kinase
- cycling of myosin crossbridges along actin filaments generates force
- myosin ATPase hydrolyzes ATP to provide energy for contraction
Describe the molecular mechanism of smooth muscle relaxation in the penis
- decrease in sarcoplasmic calcium causes calmodulin dissociation from myosin light-chain kinase
- dephosphorylation of myosin and detachment from the actin filament results in muscle relaxation
Cyclic GMP and cAMP are the secondary messengers involved in smooth muscle relaxation
List general categories of causes of ED
psychogenic neurogenic endocrinologic arteriogenic venogenic
List elements of a history that suggest psychogenic ED
- young, healthy patients
- sudden onset
- situation or partner specific
- nocturnal erections preserved
Describe possible mechanisms of psychogenic ED
Direct inhibition of the spinal erection center as an exaggeration of normal suprasacral inhibition and sympathetic outflow
Elevated peripheral catecholamine levels preventing relaxation of smooth muscle