27.2
Peritônio
O peritônio é uma membrana vital que reveste a cavidade abdominal e cobre a maioria dos órgãos dentro dela. Ele desempenha um papel crucial na proteçã…
O peritônio é a maior membrana serosa do corpo que envolve a cavidade abdominal.
Tem duas porções - o peritônio parietal e visceral - envolvendo a cavidade peritoneal preenchida com líquido seroso.
O peritônio tem cinco dobras notáveis - o omento maior, o ligamento falciforme, o omento menor, o mesentério e o mesocólon.
Essas dobras unem alguns órgãos abdominais e à cavidade abdominal. Eles também carregam vasos sanguíneos, vasos linfáticos e nervos que atendem aos órgãos abdominais.
A prega peritoneal mais longa é o omento maior. Abrange as bobinas transversais do cólon e do intestino delgado. Também é rico em tecido adiposo.
O ligamento falciforme liga o fígado à parede abdominal frontal e ao diafragma.
O omento menor se desenvolve na serosa do estômago e duodeno e conecta esses órgãos ao fígado.
O mesentério, uma prega peritoneal em forma de leque, liga o jejuno e o íleo à parede abdominal posterior.
Por fim, o mesocólon conecta os cólons transverso e sigmóide à parede abdominal posterior por meio de duas dobras peritoneais.
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Q1: What are the two main layers of the peritoneum and what do they cover?
The peritoneum has two layers: the parietal peritoneum lines the inner surface of the abdominal wall, while the visceral peritoneum covers the abdominal organs. Together, they enclose the peritoneal cavity filled with serous fluid. These layers form the body's largest serous membrane, protecting and supporting abdominal structures.
Q2: How do peritoneal folds support abdominal organs?
Peritoneal folds—including the greater omentum, falciform ligament, lesser omentum, mesentery, and mesocolon—bind abdominal organs together and attach them to the abdominal cavity walls. These folds carry blood vessels, lymphatic vessels, and nerves that supply nutrients and facilitate organ movement while maintaining structural stability.
Q3: What is the greater omentum and what functions does it perform?
The greater omentum is the longest peritoneal fold, hanging from the stomach and wrapping around the small intestines. Rich in adipose tissue, it covers the transverse colon and small intestine coils. It acts as a protective barrier, isolating infections and inflammation within the peritoneal cavity to prevent spread.
Q4: How does peritoneal fluid enable organ movement?
The peritoneal cavity contains a thin layer of peritoneal fluid that acts as a lubricant, reducing friction between organs. This lubrication allows smooth movement and prevents organs from adhering to each other or the abdominal wall, enabling normal physiological function and mechanical and chemical digestion in the small intestine.
Q5: What role do the lesser omentum and mesentery play in digestion?
The lesser omentum connects the stomach and duodenum to the liver, containing blood vessels and bile ducts that aid digestion and nutrient absorption. The mesentery, a fan-shaped fold, attaches the jejunum and ileum to the posterior abdominal wall while carrying blood vessels, nerves, and lymphatics that supply the intestines.
Q6: What is peritonitis and how does it develop?
Peritonitis is severe inflammation of the peritoneum caused by infection-introducing microbes into the peritoneal cavity. It can result from unintentional or surgical injuries to the abdominal wall, or from rupture of hollow organs like the intestine or appendix. People undergoing peritoneal dialysis face elevated peritonitis risk.
Q7: How does the peritoneum contribute to immune defense?
The peritoneal cavity contains immune system cells, such as macrophages, that defend against infections and foreign substances. The peritoneum also provides absorbent and secretory capabilities, allowing it to absorb nutrients and drugs from the gastrointestinal tract while secreting substances for various physiological processes.