Peritoneum Anatomy

• Mesentery = two layers of peritoneum. Attach viscera to body wall. Allow movement. Provide passage for vessels, nerves and lymph.
• Omenta has greater omentum. goes from proximal duodenum, quadruple layer at ileocecal junction, then up to greater curvature of stomach. double sheet of peritoneum. variable amount of fat. lower layers fuse. lesser omentum. lesser curvature of stomach and proximal duodenum. omental foramen is opening to omental bursa
• lesser omentum = hepatoduodenal ligament and hepatogastric ligament
• lymph collects interstitial fluid, pathogens, cell debris, lymphatic cells
• lymphatic vessels contain valves to keep it moving in one direction
• lymphatic movement is aided by proximal muscles and arteries
• Lymph nodes act as filters. contain clusters of lymph cells and macrophages. often site of secondary tumours
• pre-aortic lymph nodes form lumbar trunks that converge at cisterna chyli
• upper end of cisterna chyli becomes thoracic duct
• sympathetic fibres are vasomotor, contract sphincters, inhibit peristalsis. sensory afferent are distinct nerves that travel back to the cns along the same route as the sympathetics
• vagus is motor and secretomotor to gut and glands down to transverse colon. vagus inhibits pyloric sphincter. pelvic splanchnics fulfil parasympathetic role distal to splenic fixture (s2-s4)