27.2
Peritoneo
Il peritoneo è una membrana vitale che riveste la cavità addominale e che copre la maggior parte degli organi al suo interno. Svolge un ruolo cruciale…
Il peritoneo è la membrana sierosa più grande del corpo che avvolge la cavità addominale.
Ha due porzioni - il peritoneo parietale e viscerale - che racchiudono la cavità peritoneale piena di liquido sieroso.
Il peritoneo ha cinque pieghe notevoli: l'omento maggiore, il legamento falciforme, l'omento minore, il mesentere e il mesocolon.
Queste pieghe legano insieme alcuni organi addominali e alla cavità addominale. Trasportano anche vasi sanguigni, vasi linfatici e nervi che si rivolgono agli organi addominali.
La piega peritoneale più lunga è l'omento maggiore. Copre il colon trasverso e le spire dell'intestino tenue. È anche ricco di tessuto adiposo.
Il legamento falciforme collega il fegato alla parete addominale anteriore e al diaframma.
L'omento minore si sviluppa nella sierosa dello stomaco e del duodeno e collega questi organi al fegato.
Il mesentere, una piega peritoneale a forma di ventaglio, attacca il digiuno e l'ileo alla parete addominale posteriore.
Infine, il mesocolon collega il colon trasverso e sigmoideo alla parete addominale posteriore attraverso due pieghe peritoneali.
View the full transcript and gain access to JoVE Core videos
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.