ANAT 214 Lecture Notes - Lecture 20: Postganglionic Nerve Fibers, Bulbospongiosus Muscle, Membranous Urethra
25 Jan 2018
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Document Summary
External genitalia is attached to the perineal membrane: development of the male and female genitals is very similar. Starts as one organ in every embryo and then changes depending on the sex chromosomes and hormones present: psuedo-hermaphrodites, genetic female with male external genitalia. Innervation: superior epigastric comes down to the inferior hypogastric plexus (terminal) on the side of the rectum, close to the bladder and prostate, pudendal nerve (s2,3,4) is sensory and motor to perineum. In the posterior triangle, the inferior rectal nerve supplies the external anal sphincter. In the anterior triangle, the perineal branch goes to all the structures above the membrane. Inner lining of the ano-rectal canal is mucosa, but there is smooth muscle: there is an internal anal sphincter under voluntary control that has sympathetic control. In the male the one bulb surrounds the penile urethra. Ischiocavernosus covers the crura: bulbospongiosus covers the bulb. Innervated by the perineal branches of the pudendal nerve.
