Regarding male sexual response, which pairing of phase and autonomic control is correct?

• A Erection is sympathetic T10 to L2; emission is parasympathetic S2 to S4
• B Erection is parasympathetic S2 to S4; emission is sympathetic T10 to L2 ✓
• C Both erection and ejaculation are purely somatic via the pudendal nerve
• D Erection is parasympathetic T10 to L2; ejaculation is parasympathetic S2 to S4

Explanation

Erection ('point') depends on parasympathetic pelvic splanchnic nerves from S2 to S4, whose nitric oxide release relaxes cavernosal smooth muscle. Emission and ejaculation ('shoot') depend on sympathetic fibres from T10 to L2 travelling in the hypogastric plexus, with the external sphincter and bulbospongiosus under pudendal somatic control. This 'point and shoot' mnemonic makes options reversing the levels easy to eliminate.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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