TBL16 - Peritoneum and Peritoneal Cavity Flashcards
What lines the abdominal cavity? What invests most of the abdominal viscera? What is the peritoneal cavity?
1) Parietal peritoneum lines the abdominal cavity
2) Visceral peritoneum invests most of the abdominal viscera
3) The peritoneal cavity (enlarged for illustrative purposes) is the space between the parietal and visceral peritonea
What is the peritoneal cavity normally occupied by? Define the function of the fluid film.
1) The peritoneal cavity is normally occupied by a thin peritoneal fluid film
2) Peritoneal fluid lubricates the peritoneal surfaces, enabling the viscera to move over each other without friction, and allowing the movements of digestion
3) In addition to lubricating the surfaces of the viscera, the peritoneal fluid contains leukocytes and antibodies that resist infection
Why can peritonitis be lethal and why is the linea alba a preferred site for ascites paracentesis?
1) Given the extent of the peritoneal surfaces and the rapid absorption of material, including bacterial toxins, from the peritoneal cavity, when a peritonitis becomes generalized (widespread in the peritoneal cavity), the condition is dangerous and perhaps lethal
2) Treatment of generalized peritonitis includes removal of the ascitic fluid. Surgical puncture of the peritoneal cavity for the aspiration or drainage of fluid is called paracentesis. After injection of a local anesthetic agent, a needle or trocar and a cannula are inserted through the anterolateral abdominal wall into the peritoneal cavity through the linea alba, for example
How can peritoneal adhesions cause emergency complications?
1) Adhesions (scar tissue) may also form after an abdominal operation (e.g., owing to a ruptured appendix) and limit the normal movements of the viscera
2) This tethering may cause chronic pain or emergency complications such as intestinal obstruction when the intestine becomes twisted around an adhesion (volvulus)
Where do all organ primordia form along during development? How are the kidneys different?
1) During development, all organ primordia form along the posterior abdominal wall and protrude to varying degrees into the parietal peritoneum
2) The kidneys do not protrude into the peritoneum and are designated retroperitoneal organs i.e., parietal peritoneum covers their anterior surfaces
How far do the stomach and spleen protrude into the parietal peritoneum and what are these organs known as?
1) The stomach and spleen protrude completely into the parietal peritoneum and this peritoneal investment is defined as visceral peritoneum
2) Organs invested by visceral peritoneum are designated intraperitoneal organs
What are mesenteries? What do they do in the abdomen?
1) Mesenteries are continuities of the visceral and parietal peritonea that result from protrusions of intraperitoneal organs into the parietal peritoneum
2) Mesenteries enclose branches from the retroperitoneal abdominal aorta and IVC that accompany the organs during their protrusion into the parietal peritoneum
What do the nerves that innervate the abdominal wall also innervate? What does distension or irritation of the parietal peritoneum cause?
1) The nerves that provide the regional innervation of the abdominal wall also provide regional somatic sensory fibers to the parietal peritoneum
2) Distension or irritation of the parietal peritoneum activates the sensory fibers causing sharp, localized pain
What creates the lesser omentum and where does it extend to? Describe the four-layered greater omentum.
1) A double-layered extension of visceral peritoneum from the anterior and posterior surfaces of the proximal duodenum and stomach creates the lesser omentum that extends to the liver
2) The greater omentum is a prominent, four-layered peritoneal fold that hangs down like an apron from the greater curvature of the stomach and the proximal part of the duodenum. After descending, it folds back and attaches to the anterior surface of the transverse colon and its mesentery
How does the phrenic nerve provide an exception to the concept that pressure applied to the parietal peritoneum results in sharp, localized pain?
1) Pain from the parietal peritoneum is generally well localized, except for that on the inferior surface of the central part of the diaphragm, where innervation is provided by the phrenic nerves
2) Irritation here is often referred to the C3–C5 dermatomes over the shoulder
How do functions of the greater omentum relate to its common displacement in the peritoneal cavity?
1) The greater omentum, large and fat laden, prevents the visceral peritoneum from adhering to the parietal peritoneum. It has considerable mobility and moves around the peritoneal cavity with peristaltic movements of the viscera. It often forms adhesions adjacent to an inflamed organ, such as the appendix, sometimes walling it off and thereby protecting other viscera from it
2) Thus, it is common when entering the abdominal cavity, in either dissection or surgery, to find the omentum markedly displaced from the “normal” position in which it is almost always depicted in anatomical illustrations
If you make a surgical incision through the anterolateral abdominal wall, what structure do you enter? Where does the omental bursa lie?
1) A surgical incision through the anterolateral abdominal wall enters the greater sac, the largest part of the peritoneal cavity
2) The lesser sac (aka omental bursa) lies posterior to the stomach and lesser omentum
What does the omental foramen connect?
The omental foramen connects the greater and lesser sacs
What does the transverse mesocolon divide the greater sac into? What do the right and left paracolic gutters provide?
1) The transverse mesocolon divides the greater sac into supracolic and infracolic compartments
2) The right and left paracolic gutters provide free communication between the compartments
How do ascites and cancer cells spread within the peritoneal cavity?
1) The paracolic gutters are of clinical importance because they provide pathways for the flow of ascitic fluid and the spread of intraperitoneal infections
2) Purulent material (consisting of or containing pus) in the abdomen can be transported along the paracolic gutters into the pelvis, especially when the person is upright
3) Similarly, the paracolic gutters provide pathways for the spread of cancer cells that have sloughed from the ulcerated surface of a tumor and entered the peritoneal cavity
