1. PELVIC FLOOR

7. PERINEAL BODY is essential for the integrity of the pelvic floor, particularly in females

8. Levator ani- 3 striated muscles: Puborectalis Pubococcygeous
Iliococcygeous

9. Puborectalis is innermost and merges with the external anal sphincter.
Causes 120 deg angulation of anorectum due to the pull against the pubic bones.
Shuts the lumen by apposing the post and the side walls of rectum

11. Puborectalis – from myotome S1-S4 Pubococcygeous and iliococcygeous help to close the urogenital diaphragm

13. EXTERNAL ANAL SPHINCTER: Superficial external sphincter Deep external sphincter – continuous with the puborectalis

14. The external anal sphincter and puborectalis muscles are innervated by the pudendal nerve.

15. INTERNAL ANAL SPHINCTER Circular layer of rectum becomes internal anal sphincter

17. Colon innervation: Intrinsic
Auerbach plexus- segmentation and peristalsis
Plexus of Meissner- secretions and sensation
Extrinsic
Parasympathetic increases and relaxes sphincters
Sympathetic decreases motility and contracts sphincters

18. The muscular wall of the cecum and colon is innervated by: Vagus nerve- cranial nerve X in PNS Superior mesenteric plexus – SNS cord segment T9-L2 The rectum and anal canal innervation: Pelvic splanchnic nerves- parasympathetic S2-4 Hypogastric nerve- sympathetic T11-L2

19. Anal sphincters innervation: Internal anal sphincter- pelvic splanchnic nerves and hypogastric nerves External anal sphincter – pudendal nerve

20. Neural organization of anorectal sphincters:
Somatic from S2,3,4 (pudendal nerve)
to the external anal sphincter
Sympathetic from L2,3,4 (superior hypogastric plexus/pelvic plexus) through hypogastric nerve to the internal anal sphincter
Parasympathetic S2-4 (nervi erigentis or pelvic splanchnic nerves) to the internal anal sphincter

21. ADDITIONAL SLIDES FOR URINARY SYSTEM