Changes

==Introduction==

==Introduction==

The peritoneum is the serous membrane that lines the abdominal cavity. It lies directly beneath the abdominal musculature (rectus abdominis and transverse abdominis). It is a type of '''loose connective tissue''' and is covered by '''mesothelium'''. Extensions of the peritoneum form the mesentries, omenta and ligaments that support the abdominal contents. The peritoneum produces fluid to lubricate abdominal viscera. The peritoneum also enhances immune responses and walls off infection in the abdomen to prevent peritonitis.

The peritoneum is the serous membrane that lines the abdominal cavity. It lies directly beneath the abdominal musculature (''rectus abdominis'' and ''transverse abdominis''). It is a type of '''loose connective tissue''' and is covered by '''mesothelium'''. Extensions of the peritoneum form the mesenteries, omenta and ligaments that support the abdominal contents. The peritoneum produces fluid to lubricate abdominal viscera. The peritoneum also enhances immune responses and walls off infection in the abdomen to prevent [[Peritonitis|peritonitis]].

===Development===

===Development===

In the early embryo, the primitive gut tube is suspended by the dorsal and ventral mesogastria. The mesogastria divide the embryo into two cavities, called the left and right coelomic cavities. The ventral mesogastrium atrophies caudal to the pylorus of the [[Monogastric Stomach - Anatomy & Physiology|stomach]] and cranial to the [[Rectum - Anatomy & Physiology|rectum]]. This gives the entire [[Small Intestine Overview - Anatomy & Physiology|small intestine]] and most of the [[Large Intestine - Anatomy & Physiology|large intestine]] large scope for expansion and rotation. It also allows the left and right coelomic cavities to coalesce. This forms one cavity; '''the peritoneal cavity'''. Peritoneal structures develop from the dorsal and ventral mesogastria.

In the early embryo, the primitive gut tube is suspended by the dorsal and ventral mesogastria. The mesogastria divide the embryo into two cavities, called the left and right coelomic cavities. The ventral mesogastrium atrophies caudal to the pylorus of the [[Monogastric Stomach - Anatomy & Physiology|stomach]] and cranial to the [[Rectum - Anatomy & Physiology|rectum]]. This gives the entire [[Small Intestine Overview - Anatomy & Physiology|small intestine]] and most of the [[Large Intestine - Anatomy & Physiology|large intestine]] large scope for expansion and rotation. It also allows the left and right coelomic cavities to coalesce forming one cavity; '''the peritoneal cavity'''. Peritoneal structures develop from the dorsal and ventral mesogastria.

==Structure & Histology==

==Structure & Histology==

''NB: In reality there are no viscera located in the peritoneal cavity. However the cavity created by the '''serosa''' is also confusingly referred to as the peritoneal cavity, and contains most abdominal contents.''

''NB: In reality there are no viscera located in the peritoneal cavity. However the cavity created by the '''serosa''' is also confusingly referred to as the peritoneal cavity, and contains most abdominal contents.''

A small evagination extends into the thorax along the right side of the [[Oesophagus -  Anatomy & Physiology|oesophagus]]. The peritoneum evaginates to extend into the inguinal canals. Fat is often stored beneath the peritoneum. Many species have [[Lymphatic System Overview - Anatomy & Physiology|lymphoid tissue]] aggregates and fixed phagocytes in the omentum that are not covered by mesothelial cells. The peritoneum is smooth and clear in the healthy animal.

A small evagination extends into the thorax along the right side of the [[Oesophagus -  Anatomy & Physiology|oesophagus]]. The peritoneum also evaginates to extend into the inguinal canals. Fat is often stored beneath the peritoneum. Many species have [[Lymphatic System Overview - Anatomy & Physiology|lymphoid tissue]] aggregates and fixed phagocytes in the omentum that are not covered by mesothelial cells. The peritoneum is smooth and clear in the healthy animal.

''NB: Post mortem change and autolysis result in increased volumes of red-brown fluid in the abdomen, not associated with other pathology, no roughening of surfaces of organs or peritoneum.''

''NB: Post mortem change and autolysis result in increased volumes of red-brown fluid in the abdomen, not associated with other pathology, nor roughening of surfaces of organs or peritoneum.''

The peritoneal cavity is complete in the male, but a potential communication with the exterior exists in the female at the opening of the [[Oviduct - Anatomy & Physiology|oviduct]].

The peritoneal cavity is complete in the male, but a potential communication with the exterior exists in the female at the opening of the [[Oviduct - Anatomy & Physiology|oviduct]].

===Peritoneal Fluid===

===Peritoneal Fluid===

A small quantity of peritoneal fluid is produced by mesothelial cells. It fills the potential space formed by the two layers of peritoneum and allows the two layers to slide over each other freely. Peritoneal fluid is also produced as a transudate which coats the serosal surface of viscera to facilitate frictionless movement e.g. during peristalsis. It is in equilibrium with plasma but doesn't contain high molecular weight molecules like fibrinogen. The fluid is constantly being produced and resorbed through the large surface area of the peritoneum, for this reason drugs are sometimes administered by intraperitoneal injection. Bacterial toxins are also absorbed readily and can cause inflammation of the peritoneum; ''[[Peritonitis|peritonitis]]''.

A small quantity of peritoneal fluid is produced by mesothelial cells. It fills the potential space formed by the two layers of peritoneum and allows the two layers to slide over each other freely. Peritoneal fluid is also produced as a [[transudate]] which coats the serosal surface of viscera to facilitate frictionless movement e.g. during peristalsis. It is in equilibrium with plasma but doesn't contain high molecular weight molecules like fibrinogen. The fluid is constantly being produced and resorbed through the large surface area of the peritoneum, for this reason drugs are sometimes administered by intraperitoneal injection. Bacterial toxins are also absorbed readily and can cause inflammation of the peritoneum; ''[[Peritonitis|peritonitis]]''.

==Function==

==Function==

It secretes a small volume of clear fluid for lubrication. It provides a route for entry of blood and nerve and lymphatics. There is high fibrinolytic activity to protect against the formation of adhesions. Inflammed portions of the peritoneum adhere to each other and may become organised and permanent. This may help to wall of infections and bring leuckocytes to the site of infection. This trait is taken advantage of in surgery when serosal surfaces are often turned in when closing an incision.

Peritoneum secretes a small volume of clear fluid for lubrication. It provides a route for entry of blood and nerve and lymphatics. There is high fibrinolytic activity to protect against the formation of adhesions. Inflammed portions of the peritoneum adhere to each other and may become organised and permanent. This may help to wall of infections and bring leuckocytes to the site of infection. This trait is taken advantage of in surgery when serosal surfaces are often turned in when closing an incision.

==Types of Peritoneum==

==Types of Peritoneum==

===Mesenteries===

===Mesenteries===

The entire alimetary tract is attached to the dorsal body wall by mesentery, a derivative of the dorsal mesogastrium. '''Mesoduodenum''' from the [[Duodenum - Anatomy & Physiology|duodenum]] to the abdominal roof. Contains the right lobe of the [[Pancreas - Anatomy & Physiology|pancreas]]. '''Great Mesentery''' from the [[Jejunum - Anatomy & Physiology|jejunum]] and [[Ileum - Anatomy & Physiology|ileum]] to the abdominal roof. Contains the cranial abdominal artery and vein, mesenteric lymph nodes and mesenteric plexus. '''Mesocolon''' from the [[Colon - Anatomy & Physiology|colon]] to the abdominal roof. '''Mesorectum''' from the [[Rectum - Anatomy & Physiology|rectum]] to the abdominal roof. The [[:Category:Female Reproduction|female reproductive tract]] is also suspended by peritoneal derivatives. '''Broad Ligament''' consisting of mesometrium, mesosalpinx and mesovarium. From [[Ovary - Anatomy & Physiology|ovary]], [[Oviduct - Anatomy & Physiology|oviduct]], [[Uterus - Anatomy & Physiology|uterus]], [[Cervix - Anatomy & Physiology|cervix]] and cranial [[Vagina and Vestibule - Anatomy & Physiology|vagina]] to the dorsal body wall. Contains ovarian artery, uterine branch of the ovarian artery, uterine artery, ovarian vein, uterine vein and uterine [[Lymph Nodes - Anatomy & Physiology|lymph node]] (mare).

The entire alimentary tract is attached to the dorsal body wall by mesentery, a derivative of the dorsal mesogastrium. '''Mesoduodenum''' attaching the [[Duodenum - Anatomy & Physiology|duodenum]] to the abdominal roof contains the right lobe of the [[Pancreas - Anatomy & Physiology|pancreas]]. '''Great Mesentery''' extends from the [[Jejunum - Anatomy & Physiology|jejunum]] and [[Ileum - Anatomy & Physiology|ileum]] to the abdominal roof and contains the cranial abdominal artery and vein, mesenteric lymph nodes and mesenteric plexus. '''Mesocolon''' attaches the [[Colon - Anatomy & Physiology|colon]] and  '''mesorectum''' the [[Rectum - Anatomy & Physiology|rectum]] to the abdominal roof. The [[:Category:Female Reproduction|female reproductive tract]] is also suspended by peritoneal derivatives. The '''broad ligament''' consisting of mesometrium, mesosalpinx and mesovarium, from [[Ovary - Anatomy & Physiology|ovary]], [[Oviduct - Anatomy & Physiology|oviduct]], [[Uterus - Anatomy & Physiology|uterus]], [[Cervix - Anatomy & Physiology|cervix]] and cranial [[Vagina and Vestibule - Anatomy & Physiology|vagina]] to the dorsal body wall, contains ovarian artery, uterine branch of the ovarian artery, uterine artery, ovarian vein, uterine vein and uterine [[Lymph Nodes - Anatomy & Physiology|lymph node]] (mare).

===Omenta===

===Omenta===

During development in the region of the [[Monogastric Stomach - Anatomy & Physiology|stomach]], a fold of the dorsal mesogastrium becomes extended into a curtain - like structure called the '''greater omentum'''. It originates from the greater curvature of the [[Monogastric Stomach - Anatomy & Physiology|stomach]] and attaches to the proximal part of the [[Duodenum - Anatomy & Physiology|duodenum]]. The potential space between the two sheets is called the omental bursa. It covers the [[Jejunum - Anatomy & Physiology|jejunal mass]] on the ventral abdominal wall. The opening to the omental bursa is called the epiploic foramen. The '''lesser omentum''' runs from the lesser curvature of the [[Monogastric Stomach - Anatomy & Physiology|stomach]] to the [[Liver - Anatomy & Physiology|liver]].

During development in the region of the [[Monogastric Stomach - Anatomy & Physiology|stomach]], a fold of the dorsal mesogastrium becomes extended into a curtain - like structure called the '''greater omentum'''. It originates from the greater curvature of the [[Monogastric Stomach - Anatomy & Physiology|stomach]] and attaches to the proximal part of the [[Duodenum - Anatomy & Physiology|duodenum]]. The potential space between the two sheets is called the '''omental bursa'''. It covers the [[Jejunum - Anatomy & Physiology|jejunal mass]] on the ventral abdominal wall. The opening to the omental bursa is called the '''epiploic foramen'''. The '''lesser omentum''' runs from the lesser curvature of the [[Monogastric Stomach - Anatomy & Physiology|stomach]] to the [[Liver - Anatomy & Physiology|liver]].

===Ligaments===

===Ligaments===

==Retroperitoneal Organs==

==Retroperitoneal Organs==

Organs are described as retroperitoneal if they are located behind the parietal peritoneum. Retroperitoneal organs include: the [[Urinary System Overview - Anatomy & Physiology|kidneys]], [[Adrenal Glands - Anatomy & Physiology|adrenal glands]], [[Ureters - Anatomy & Physiology|ureter]], [[Urinary Bladder - Anatomy & Physiology|urinary bladder]], part of the [[Oesophagus - Anatomy & Physiology|oesophagus]], [[Rectum - Anatomy & Physiology|rectum]], [[Ovary - Anatomy & Physiology|ovaries]], [[Uterus - Anatomy & Physiology|uterus]], aorta and caudal Vena Cava.

Organs are described as retroperitoneal if they are located behind the parietal peritoneum. Retroperitoneal organs include: the [[Urinary System Overview - Anatomy & Physiology|kidneys]], [[Adrenal Glands - Anatomy & Physiology|adrenal glands]], [[Ureters - Anatomy & Physiology|ureters]], [[Urinary Bladder - Anatomy & Physiology|urinary bladder]], part of the [[Oesophagus - Anatomy & Physiology|oesophagus]], [[Rectum - Anatomy & Physiology|rectum]], [[Ovary - Anatomy & Physiology|ovaries]], [[Uterus - Anatomy & Physiology|uterus]], aorta and caudal Vena Cava.

==Links==

==Links==

[[Category:Alimentary System - Anatomy & Physiology]]

[[Category:Alimentary System - Anatomy & Physiology]]

[[Category:Peritoneal Cavity]]

[[Category:Peritoneal Cavity]]

[[Category:To Do - AimeeHicks]][[Category:To Do - AP Review]]

[[Category:A&P Done]]