The peritoneum is the serous membrane

Serous membrane

In anatomy, serous membrane is a smooth membrane consisting of a thin layer of cells which secrete serous fluid. Serous membranes line and enclose several body cavities, known as serous cavities, where they secrete a lubricating fluid which reduces friction from muscle movement...

 that forms the lining of the abdominal cavity

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

 or the coelom

Coelom

The coelom is a fluid-filled cavity formed within the mesoderm. Coeloms developed in triploblasts but were subsequently lost in several lineages. Loss of coelom is correlated with reduction in body size...

 — it covers most of the intra-abdominal (or coelomic) organs — in amniote

Amniote

The amniotes are a group of tetrapods that have a terrestrially adapted egg. They include synapsids and sauropsids , as well as their fossil ancestors. Amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes...

s and some invertebrate

Invertebrate

An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s (annelid

Annelid

The annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...

s, for instance). It is composed of a layer of mesothelium

Mesothelium

The mesothelium is a membrane that forms the lining of several body cavities: the pleura , peritoneum and pericardium . Mesothelial tissue also surrounds the male internal reproductive organs and covers the internal reproductive organs of women...

 supported by a thin layer of connective tissue

Connective tissue

"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...

.
The peritoneum both supports the abdominal organs and serves as a conduit for their blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 and lymph

Lymph

Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...

 vessels and nerves.

Layers

The abdominal cavity (the space bounded by the vertebrae, abdominal muscles, diaphragm and pelvic floor) should not be confused with the intraperitoneal space (located within the abdominal cavity, but wrapped in peritoneum). For example, a kidney is inside the abdominal cavity, but is retroperitoneal.

Although they ultimately form one continuous sheet, two types or layers of peritoneum and a potential space between them are referenced:

• The outer layer, called the parietal peritoneum, is attached to the abdominal wall.
• The inner layer, the visceral peritoneum, is wrapped around the internal organs that are located inside the intraperitoneal cavity.
• The potential space between these two layers is the peritoneal cavity
  Peritoneal cavity
  The peritoneal cavity is a potential space between the parietal peritoneum and visceral peritoneum, that is, the two membranes that separate the organs in the abdominal cavity from the abdominal wall...
  
  ; it is filled with a small amount (about 50 ml) of slippery serous fluid
  Serous fluid
  In physiology, the term serous fluid is used for various bodily fluids that are typically pale yellow and transparent, and of a benign nature, that fill the inside of body cavities. Serous fluid originates from serous glands, with secretions enriched with proteins and water. Serous fluid may also...
  
   that allows the two layers to slide freely over each other.
• The term mesentery
  Mesentery
  In anatomy, the mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen. Its meaning, however, is frequently extended to include double layers of peritoneum connecting various components of the abdominal cavity.-Mesentery :The...
  
   is often used to refer to a double layer of visceral peritoneum. There are often blood vessels, nerves, and other structures between these layers. The space between these two layers is technically outside of the peritoneal sac, and thus not in the peritoneal cavity.

Subdivisions

There are two main regions of the peritoneum, connected by the epiploic foramen (also known as the Omental Foramen or Foramen of Winslow):

• the greater sac
  Greater sac
  In human anatomy, the greater sac, also known as the general cavity or peritoneum of the peritoneal cavity proper, is the cavity in the abdomen that is inside the peritoneum but outside of the lesser sac....
  
   (or general cavity of the abdomen), represented in red in the diagrams above.
• the lesser sac
  Lesser sac
  The lesser sac, also known as the omental bursa, is the cavity in the abdomen that is formed by the lesser and greater omentum. Usually found in mammals, it is connected with the greater sac via the epiploic foramen...
  
   (or omental bursa), represented in blue. The lesser sac is divided into two "omenta":
  • The lesser omentum
    Lesser omentum
    The lesser omentum is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach and the start of the duodenum.- Structure :...
    
     (or gastrohepatic) is attached to the lesser curvature of the stomach
    Lesser curvature of the stomach
    The lesser curvature of the stomach, extending between the cardiac and pyloric orifices, forms the right or posterior border of the stomach.It descends as a continuation of the right margin of the esophagus in front of the fibers of the right crus of the diaphragm, and then, turning to the right,...
    
     and the liver
    Liver
    The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
    
    .
  • The greater omentum
    Greater omentum
    The greater omentum is a large fold of parietal peritoneum that hangs down from the stomach...
    
     (or gastrocolic) hangs from the greater curve of the stomach and loops down in front of the intestines before curving back upwards to attach to the transverse colon
    Colon (anatomy)
    The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
    
    . In effect it is draped in front of the intestines like an apron and may serve as an insulating or protective layer.

The mesentery

Mesentery

In anatomy, the mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen. Its meaning, however, is frequently extended to include double layers of peritoneum connecting various components of the abdominal cavity.-Mesentery :The...

 is the part of the peritoneum through which most abdominal organs are attached to the abdominal wall and supplied with blood

Blood

Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 and lymph

Lymph

Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...

 vessels and nerves.

Structures include:
| SOURCES >

STRUCTURE

FROM

TO

CONTAINS >- |

OMENTA Omentum Omentum may refer to:* greater omentum* lesser omentum...

>- | dorsal mesentery Dorsal mesentery The portion of mesentery attached to the greater curvature of the stomach is named the dorsal mesentery , and the part which suspends the colon is termed the mesocolon....

* greater omentum Greater omentum The greater omentum is a large fold of parietal peritoneum that hangs down from the stomach...

greater curvature of stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...  (and spleen Spleen The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock... )

transverse colon

>- | dorsal mesentery

** gastrosplenic ligament Gastrosplenic ligament The gastrosplenic ligament is part of the greater omentum.Embryonically the gastrosplenic ligament is derived from the dorsal mesogastrium....

stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

spleen Spleen The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

left gastro-omental artery Left gastro-omental artery The left gastro-omental artery , the largest branch of the splenic artery, runs from left to right about a finger’s breadth or more from the greater curvature of the stomach, between the layers of the greater omentum, and anastomoses with the right gastroepiploic.In its course it distributes:*... >- | dorsal mesentery

** gastrophrenic ligament Gastrophrenic ligament The postero-inferior surface of the stomach is covered by peritoneum, except over a small area close to the cardiac orifice; this area is limited by the lines of attachment of the gastrophrenic ligament, and lies in apposition with the diaphragm, and frequently with the upper portion of the left...

stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

diaphragm Thoracic diaphragm In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...

left inferior phrenic artery Inferior phrenic arteries The inferior phrenic arteries are two small vessels, which supply the diaphragm but present much variety in their origin.They may arise separately from the front of the aorta, immediately above the celiac artery, or by a common trunk, which may spring either from the aorta or from the celiac artery... >- | dorsal mesentery

** gastrocolic ligament Gastrocolic ligament The gastrocolic ligament is a portion of the greater omentum that stretches from the greater curvature of the stomach to the transverse colon. It forms part of the anterior wall of the lesser sac....

stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

transverse colon Transverse colon The transverse colon, the longest and most movable part of the colon, passes with a downward convexity from the right hypochondrium region across the abdomen, opposite the confines of the epigastric and umbilical zones, into the left hypochondrium region, where it curves sharply on itself beneath...

right gastro-omental artery Right gastro-omental artery The right gastro-omental artery is one of the two terminal branches of the gastroduodenal artery. It runs from right to left along the greater curvature of the stomach, between the layers of the greater omentum, anastomosing with the left gastroepiploic branch of the splenic artery.Except at the...  - >- | dorsal mesentery

** splenorenal ligament Splenorenal ligament The splenorenal ligament , is derived from the peritoneum, where the wall of the general peritoneal cavity comes into contact with the omental bursa between the left kidney and the spleen; the lienal vessels pass between its two layers...

spleen Spleen The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

kidney Kidney The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

splenic artery Splenic artery In anatomy, the splenic artery is the blood vessel that supplies oxygenated blood to the spleen. It branches from the celiac artery, and follows a course superior to the pancreas.-Branches:... , tail of pancreas Tail of pancreas The tail of the pancreas, located anatomically left near the hilum of the spleen, is not simply an anatomical distinction. The tail is the only part of the pancreas which contains Pancreatic Polypeptide cells, which are responsible for secreting pancreatic polypeptide to coordinate exocrine and... >- | ventral mesentery Ventral mesentery -Development:The cephalic portion of the septum transversum takes part in the formation of the diaphragm, while the caudal portion into which the liver grows forms the ventral mesentery ....

* lesser omentum Lesser omentum The lesser omentum is the double layer of peritoneum that extends from the liver to the lesser curvature of the stomach and the start of the duodenum.- Structure :...

lesser curvature of the stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...  (and duodenum Duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum... )

Liver

>- | ventral mesentery

** hepatogastric ligament Hepatogastric ligament The cranial part of the lesser omentum is formed by the hepatogastric ligament , extending between the liver and stomach. The ligament itself consists of a dense cranial portion and the caudal portion...

stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

right & left gastric artery Gastric arteries Gastric arteries can refer to:* Right gastric artery* Left gastric artery... >- | ventral mesentery

** hepatoduodenal ligament Hepatoduodenal ligament The hepatoduodenal ligament is the portion of the lesser omentum extending between the porta hepatis of the liver and the superior part of the duodenum.Running inside it are the following:* hepatic artery proper* hepatic portal vein* common bile duct...

duodenum Duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

hepatic artery proper Hepatic artery proper The hepatic artery proper , arises from the common hepatic artery and runs alongside the portal vein and the common bile duct to form the portal triad. The hepatic artery proper gives off a small supraduodenal artery to the duodenal bulb... , hepatic portal vein Hepatic portal vein The hepatic portal vein is not a true vein, because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver... , bile duct Bile duct A bile duct is any of a number of long tube-like structures that carry bile.Bile, required for the digestion of food, is excreted by the liver into passages that carry bile toward the hepatic duct, which joins with the cystic duct to form the common bile duct, which opens into the intestine.The... >- |

MESENTERIES

>- | dorsal mesentery

* Mesentery proper

small intestine Small intestine The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...  – jejunum Jejunum The jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...  and ileum Ileum The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...

posterior abdominal wall

superior mesenteric artery Superior mesenteric artery In human anatomy, the superior mesenteric artery arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies the intestine from the lower part of the duodenum through two-thirds of the transverse colon, as well as the pancreas.-Location... >- | dorsal mesentery

* transverse mesocolon Transverse mesocolon The transverse mesocolon is a broad, meso-fold of peritoneum, which connects the transverse colon to the posterior wall of the abdomen.It is continuous with the two posterior layers of the greater omentum, which, after separating to surround the transverse colon, join behind it, and are continued...

transverse colon Transverse colon The transverse colon, the longest and most movable part of the colon, passes with a downward convexity from the right hypochondrium region across the abdomen, opposite the confines of the epigastric and umbilical zones, into the left hypochondrium region, where it curves sharply on itself beneath...

posterior abdominal wall

>- | dorsal mesentery

* sigmoid mesocolon Sigmoid mesocolon The sigmoid mesocolon is the fold of peritoneum which retains the sigmoid colon in connection with the pelvic wall.Its line of attachment forms a V-shaped curve, the apex of the curve being placed about the point of division of the left common iliac artery....

sigmoid colon

pelvic wall

sigmoid arteries Sigmoid arteries The sigmoid arteries, two or three in number, run obliquely downward and to the left behind the peritoneum and in front of the Psoas major, ureter, and internal spermatic vessels.... >- | dorsal mesentery

* mesoappendix Mesoappendix The mesoappendix is the portion of the mesentery connecting the ileum to the appendix. It may extend to the tip of the appendix. It encloses the appendicular artery and vein, as well as lymphatic vessels, nerves, and often a lymph node....

mesentery of ileum Ileum The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...

appendix Vermiform appendix The appendix is a blind-ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouchlike structure of the colon...

appendicular artery Appendicular artery The appendicular artery, also appendiceal artery, is a terminal branch of the ileocolic artery that descends behind the termination of the ileum and enters the mesoappendix of the vermiform appendix. It runs near the free margin of the mesoappendix and ends in branches which supply the... >- |

OTHER LIGAMENTS AND FOLDS

>- | ventral mesentery

* falciform ligament Falciform ligament The falciform ligament is a ligament that attaches the liver to the anterior body wall.It is a broad and thin antero-posterior peritoneal fold, falciform in shape, its base being directed downward and backward and its apex upward and backward...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

thoracic diaphragm Thoracic diaphragm In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration... , anterior abdominal wall

round ligament of liver Round ligament of liver In anatomy, the round ligament of liver is a degenerative string of tissue that exists in the free edge of the falciform ligament of the liver... , paraumbilical veins Paraumbilical veins In the course of the round ligament of liver and of the median umbilical ligament, small veins are found which establish an anastomosis between the veins of the anterior abdominal wall and the hepatic portal, hypogastric, and iliac veins.... >- | left umbilical vein Umbilical vein The umbilical vein is a vein present during fetal development that carries oxygenated blood from the placenta to the growing fetus.The blood pressure inside the umbilical vein is approximately 20 mmHg.-Development:...

* round ligament of liver Round ligament of liver In anatomy, the round ligament of liver is a degenerative string of tissue that exists in the free edge of the falciform ligament of the liver...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

umbilicus Navel The navel is a scar on the abdomen caused when the umbilical cord is removed from a newborn baby...

>- | ventral mesentery

* coronary ligament Coronary ligament The coronary ligament of the liver refers to parts of the peritoneal reflections that hold the liver to the inferior surface of the diaphragm.-Structure:...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

thoracic diaphragm Thoracic diaphragm In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...

>- | ductus venosus Ductus venosus In the fetus, the ductus venosus shunts approximately half of the blood flow of the umbilical vein directly to the inferior vena cava. Thus, it allows oxygenated blood from the placenta to bypass the liver. In conjunction with the other fetal shunts, the foramen ovale and ductus arteriosus, it...

* ligamentum venosum Ligamentum venosum The ligamentum venosum is the fibrous remnant of the ductus venosus of the fetal circulation. Usually, it is attached to the left branch of the portal vein within the porta hepatis...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

>- |

* phrenicocolic ligament Phrenicocolic ligament A fold of peritoneum, the phrenicocolic ligament, is continued from the left colic flexure to the thoracic diaphragm opposite the tenth and eleventh ribs; it passes below and serves to support the spleen, and therefore has received the name of sustentaculum lienis....

left colic flexure

thoracic diaphragm Thoracic diaphragm In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...

>- | ventral mesentery

* left triangular ligament Left triangular ligament The left triangular ligament is a fold of some considerable size, which connects the posterior part of the upper surface of the left lobe of the liver to the diaphragm; its anterior layer is continuous with the left layer of the falciform ligament.... , right triangular ligament Right triangular ligament The right triangular ligament is situated at the right extremity of the bare area, and is a small fold which passes to the diaphragm, being formed by the apposition of the upper and lower layers of the coronary ligament....

liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

>- |

* umbilical folds Umbilical folds In the urinary bladder, anteriorly there are the following folds:* one median umbilical fold on the median umbilical ligament * two medial umbilical folds on the occluded umbilical artery...

urinary bladder Urinary bladder The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

>- |

* ileocecal fold Ileocecal fold The ileocecal fold or ileocaecal fold is an anatomical structure in the human abdomen. It is formed by a layer of peritoneum. The upper border is fixed to the ileum, opposite its mesenteric attachment, while the lower border passes over the ileocecal junction to join the mesenteriole of the...

ileum Ileum The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum...

cecum Cecum The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...

>- |

* broad ligament of the uterus Broad ligament of the uterus The broad ligament of the uterus is the wide fold of peritoneum that connects the sides of the uterus to the walls and floor of the pelvis.-Subdivisions:The broad ligament may be divided into three subcomponents:...

uterus Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

pelvic wall

mesovarium Mesovarium The mesovarium is the portion of the broad ligament of the uterus that covers the ovaries.At first the mesonephros and genital ridge are suspended by a common mesentery, but as the embryo grows the genital ridge gradually becomes pinched off from the mesonephros, with which it is at first... , mesosalpinx Mesosalpinx The mesosalpinx is part of the lining of the abdominal cavity in higher vertebrates, specifically the portion of the broad ligament that stretches from the ovary to the level of the uterine tube.... , mesometrium Mesometrium The mesometrium is the mesentery of the uterus. It constitutes the majority of the broad ligament of the uterus, excluding only the portions adjacent to the uterine tube and ovary.It is adjacent to the mesosalpinx.... >- |

* ovarian ligament Ovarian ligament The ovarian ligament is a fibrous ligament that connects the ovary to the lateral surface of the uterus....

uterus Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

inguinal canal Inguinal canal The inguinal canal is a passage in the anterior abdominal wall which in men conveys the spermatic cord and in women the round ligament. The inguinal canal is larger and more prominent in men.-Site:...

>- |

* suspensory ligament of the ovary Suspensory ligament of the ovary The suspensory ligament of the ovary, also infundibulopelvic ligament , is a fold of peritoneum that extends out from the ovary to the wall of the pelvis....

ovary Ovary The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

pelvic wall

ovarian artery Ovarian artery In human anatomy, the ovarian artery is a blood vessel that supplies oxygenated blood to the ovary. It arises from the abdominal aorta below the renal artery, and does not pass out of the abdominal cavity. It can be found in the suspensory ligament of the ovary, anterior to the ovarian vein and...

In addition, in the pelvic cavity

Pelvic cavity

-External links:* * *...

 there are several structures that are usually named not for the peritoneum, but for the areas defined by the peritoneal folds:

Name

Location

Genders possessing structure >- | Rectovesical pouch

between rectum Rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...  and urinary bladder Urinary bladder The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

>- | Rectouterine pouch

between rectum Rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...  and uterus Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

>- | Vesicouterine pouch

between urinary bladder Urinary bladder The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...  and uterus Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

>- | Pararectal fossa Pararectal fossa In the male, the peritoneum encircles the sigmoid colon, from which it is reflected to the posterior wall of the pelvis as a fold, the sigmoid mesocolon...

surrounding rectum Rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...

>- | Paravesical fossa Paravesical fossa The peritoneum of the anterior pelvic wall covers the superior surface of the bladder, and on either side of this viscus forms a depression, termed the paravesical fossa, which is limited laterally by the fold of peritoneum covering the ductus deferens....

surrounding urinary bladder Urinary bladder The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...

male and female

Development

The peritoneum develops ultimately from the mesoderm

Mesoderm

In all bilaterian animals, the mesoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and endoderm , with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme , mesothelium, non-epithelial blood corpuscles and...

 of the trilaminar embryo

Trilaminar embryo

A trilaminar embryo is an early stage in the development of triploblastic organisms, which include humans and many other animals....

. As the mesoderm differentiates, one region known as the lateral plate mesoderm

Lateral plate mesoderm

Lateral plate mesoderm is a type of mesoderm that is found at the periphery of the embryo.-Division into layers:It will split into two layers, the somatic layer/mesoderm and the splanchnic layer/mesoderm...

 splits to form two layers separated by an intraembryonic coelom

Intraembryonic coelom

In the development of the human embryo the intraembryonic coelom is a portion of the conceptus forming in the mesoderm. During the second week of development, the lateral mesoderm splits into a dorsal somatic mesoderm and a ventral splanchnic mesoderm...

. These two layers develop later into the visceral and parietal layers found in all serous cavities, including the peritoneum.

As an embryo

Embryo

An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

 develops, the various abdominal organs grow into the abdominal cavity from structures in the abdominal wall. In this process they become enveloped in a layer of peritoneum. The growing organs "take their blood vessels with them" from the abdominal wall, and these blood vessels become covered by peritoneum, forming a mesentery.

Peritoneal dialysis

In one form of dialysis

Dialysis

In medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...

, called peritoneal dialysis

Peritoneal dialysis

Peritoneal dialysis is a treatment for patients with severe chronic kidney disease. The process uses the patient's peritoneum in the abdomen as a membrane across which fluids and dissolved substances are exchanged from the blood...

, a glucose solution is sent through a tube into the peritoneal cavity. The fluid is left there for a prescribed amount of time to absorb waste products, and then removed through the tube. The reason for this effect is the high number of arteries and veins in the peritoneal cavity. Through the mechanism of diffusion

Diffusion

Molecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...

, waste products are removed from the blood.

Classification of abdominal structures

The structures in the abdomen are classified as intraperitoneal, retroperitoneal or infraperitoneal depending on whether they are covered with visceral peritoneum and whether they are attached by mesenteries (mensentery, mesocolon).

Intraperitoneal

Retroperitoneal

Infraperitoneal / Subperitoneal >- | Stomach Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is... , First part of the duodenum [5 cm], jejunum Jejunum The jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum... , ileum Ileum The ileum is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may be used instead of ileum.The ileum follows the duodenum... , cecum, appendix Vermiform appendix The appendix is a blind-ended tube connected to the cecum , from which it develops embryologically. The cecum is a pouchlike structure of the colon... , transverse colon Transverse colon The transverse colon, the longest and most movable part of the colon, passes with a downward convexity from the right hypochondrium region across the abdomen, opposite the confines of the epigastric and umbilical zones, into the left hypochondrium region, where it curves sharply on itself beneath... , sigmoid colon Sigmoid colon The sigmoid colon is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about 40 cm... , Rectum Rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...  (upper 1/3)

The rest of the duodenum Duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum... , ascending colon Ascending colon The ascending colon is smaller in caliber than the cecum.It passes upward, from its commencement at the cecum, opposite the colic valve, to the under surface of the right lobe of the liver, on the right of the gall-bladder, where it is lodged in a shallow depression, the colic impression; here it... , descending colon Descending colon The descending colon of humans passes downward through the left hypochondrium and lumbar regions, along the lateral border of the left kidney.... , Rectum Rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...  (middle 1/3)

Rectum Rectum The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...  (lower 1/3) >- | Liver Liver The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion... , Spleen Spleen The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock... , Pancreas Pancreas The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...  (only tail)

Pancreas Pancreas The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...  (except tail)

>- |

Kidney Kidney The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and... s, adrenal gland Adrenal gland In mammals, the adrenal glands are endocrine glands that sit atop the kidneys; in humans, the right suprarenal gland is triangular shaped, while the left suprarenal gland is semilunar shaped... s, proximal ureters Ureter In human anatomy, the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~3-4 mm in diameter.... , renal vessels Renal artery The renal arteries normally arise off the side of the abdominal aorta, immediately below the superior mesenteric artery, and supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle with the aorta....

Urinary bladder Urinary bladder The urinary bladder is the organ that collects urine excreted by the kidneys before disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor... , distal ureters Ureter In human anatomy, the ureters are muscular tubes that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~3-4 mm in diameter.... >- | In women: Uterus Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species... , Fallopian tube Fallopian tube The Fallopian tubes, also known as oviducts, uterine tubes, and salpinges are two very fine tubes lined with ciliated epithelia, leading from the ovaries of female mammals into the uterus, via the utero-tubal junction... s, ovaries Ovary The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

Gonadal blood vessels Gonadal artery The term gonadal artery is a generic term for a paired artery, with one arising from the abdominal aorta for each gonad. Specifically, it can refer to:* the testicular artery in males* the ovarian artery in females...

>- |

Inferior vena cava Inferior vena cava The inferior vena cava , also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart.... , Aorta Aorta The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...

Structures that are intraperitoneal are generally mobile, while those that are retroperitoneal are relatively fixed in their location.

Some structures, such as the kidneys, are "primarily retroperitoneal", while others such as the majority of the duodenum, are "secondarily retroperitoneal", meaning that structure developed intraperitoneally but lost its mesentery

Mesentery

In anatomy, the mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen. Its meaning, however, is frequently extended to include double layers of peritoneum connecting various components of the abdominal cavity.-Mesentery :The...

and thus became retroperitoneal.

Etymology

Peritoneum is derived from Greek via Latin. Peri- means around, while -ton- refers to stretching. Thus, peritoneum means stretched around or stretched over.

External links

• Overview and diagrams at colostate.edu