Anatomy Of The GI system 1 Flashcards
Summarize the organize the peritoneal cavity
Developing gut invaginate into the peritoneal cavity. Organization of peritoneal cavity :
▪ Greater and Lesser sac
▪ Supracolic and infracolic spaces
▪ Ligaments - e.g. Greater and lesser omentum
▪ Spaces – For clinical purposes the peritoneal cavity can
be divided into several spaces because pathological processes are often contained in these spaces and their anatomy may influence diagnosis and treatment
What is a peritoneum?
Peritoneum is a continuous serous membrane which surrounds the organs of abdominal cavity and lines the abdominopelvic wall.
Provides mobility for some & stability for others via reflection points & fusion points
What are the two layers of the peritoneal cavity?
Parietal peritoneum – lines the internal surface of abdominal wall
Visceral peritoneum – clothes the abdominal organs
What is the parietal peritoneum derived from?
Parietal peritoneum –somatopleure Innervated by somatic afferents from the spinal nerves associated with the region of the abdominal wall where it is located
Pain from the parietal peritoneum is usually well localized
What is the visceral peritoneum derived from?
Visceral peritoneum-splanchnopleure Innervated by visceral afferents which accompany autonomic nerves supplying the organ in question
Pain is usually poorly localized and usually presents as sensations of discomfort
What is the peritoneal cavity?
Potential space between the parietal and visceral layers .
Secretes small amount of fluid which lubricates the surface of the peritoneum and allows free movement of viscera
Excess fluid in the peritoneal cavity is called ascites
What is the pneumoperitoneum?
Pneumoperitoneum -Abnormal presence of air/gas in the peritoneal cavity
generally due to a ruptured hollow viscus organ
What is peritonitis?
Peritonitis is inflammation of the peritoneum
What is the peritoneal cavity?
Abdominopelvic cavity –space bounded by the abdominal walls, diaphragm and pelvis
The peritoneum and viscera are in the abdomino-pelvic cavity
Where is the peritoneal cavity?
Peritoneal cavity lies between the two layers of peritoneum and is one continous space
– Extends from the diaphragm to the pelvis
– Male system closed/ Female open at uterine tube
– There are no organs in the peritoneal cavity
What are ascites?
ASCITES = abnormal fluid within peritoneal cavity ie between visceral and parietal layers
What is the mesentery?
Double fold of peritoneum that attaches the developing gut to the body wall. Contains blood vessels nerves and lymphatics
All embryonic gut tube structures including the spleen develop on a mesentery
What is the relationship of viscera to peritoneum?
Intraperitoneal organs Completely covered by visceral peritonuem
Extraperitoneal ,retroperitoneal organs: Organs that are outside the
Peritoneal cavity or posterior to the parietal peritoneum. Usually covered by peritoneum on one surface.
Eg: kidney is between the parietal peritoneum and the posterior abdominal wall and have peritoneum only on their anterior surface.
What does it mean to be an intraperitoneal organ?
Intraperitoneal
Pushes into peritoneal sac Covered by visceral peritoneum
Suspended by mesentery
(2 layers of peritoneum)
What are Retroperitoneal organs ?
Retroperitoneal: behind peritoneal sac
Primarily Retroperitoneal
Never pushed into peritoneal sac
Secondarily Retroperitoneal
Was pushed into the sac developmentally but is not in adult
What are the intraperitoneal organs?
Intraperitoneal organs (have a mesentery) • Stomach • Liver • Duodenum 1st part • Small intestine (jejunum, ileum) • Spleen • Cecum and Appendix • Transverse & Sigmoid colon
What are the primarily retroperitoneal organs?
Primarily Retroperitoneal (posterior body wall behind peritoneum) • Kidneys • Ureters • Aorta IVC • Sympathetic trunks
What are the secondary retroperitoneal organs?
Pancreas Duodenum 2nd,3rd & 4th part Ascending colon Descending colon Rectum
Where do gut structures start their development?
- All gut structures start their development on a mesentery
- Throughout the course of development i.e. rotation of the gut, the mesentery fuses with the posterior abdominal wall. Peritoneum only covers the anterior surface. Therefore the structure that once intraperitoneal now is secondarily retroperitoneal.
- Secondary retroperitoneal structures are fixed (immobile)
What is the significance of ventral and dorsal mesentery?
Ventral and dorsal mesentery
•Foregut –stomach, liver, proximal duodenum and spleen is connected to anterior and posterior abdominal walls by ventral and dorsal mesentery/ mesogastrium.
• As a result of clockwise stomach rotation ventral mesentery and liver is pushed to the right forming the lesser omentum, falciform, coronary and triangular ligaments.
•Stomach rotation also causes dorsal mesentery to be pulled to the left forming the greater omentum (gastrocolic ,gastrosplenic ,splenorenal and gastrophrenic ligaments.
•Dorsal mesentery continues as mesentery of the small intestines and mesocolon of the large intestines
What are peritoneal ligaments?
Peritoneal ligaments:-double layer of peritoneum that connects an organ with another organ or to the anterior abdominal wall. They support the organ in position and may convey their neurovascular structures.
What is the omentum?
Omentum: double layer of peritoneum
Passing from the stomach and proximal part of the duodenum to adjacent organs
What is the greater omentum?
Greater omentum: double layer of peritoneum extending from stomach to transverse colon
What is the lesser omentum?
Lesser omentum: double layer of peritoneum attaching liver to the stomach and first part of duodenum
What is the significance of the lesser omentum?
Extends from the inferior surface of the liver to the lesser curvature of the stomach and proximal duodenum and contains two ligaments :
•Hepatogastric ligament –membranous portion
Contains : gastric arteries
•Hepatoduodenal ligament - thickened portion
Contains:
1. Portal vein
2. Proper hepatic artery
3. Common bile duct
What is the significance of the greater omentum?
- Gastrophrenic ligament –to diaphragm
- Gastrosplenic ligament- to spleen
- Gastrocolic ligament – to the transverse colon and mesocolon
Greater omentum has ascending and descending portions of the greater omentum usually fuse together forming a four layered (2anterior+2 posterior) fatty
“omental apron”
Normally reffered to as the policeman of the abdomen
What is the clinical correlation of greater omentum?
Compression of the hepatoduodenal ligament (Pringle maneuver) prevents inflow of blood into the liver thereby reducing bleeding in the liver as a result of
traumatic injury
What are the greater and lesser sac?
Greater sac main and larger part of the peritoneal cavity.
Lesser sac /Omental bursae is the smaller part of the peritoneal cavity, lies posterior to the stomach lesser omentum and adjacent structure
What is the significance of peptic ulcer?
Perforation of a peptic ulcer of the stomach along its posterior wall will result in blood collecting in the lesser sac which could then communicate with the greater sac through the omental foramen
Whaat is the omental foramen?
The communication between the lesser sac and greater
What is The anterrior boundary of omental foramen?
Hepatoduodenal ligament with portal triad
What is the inderior boundary of the omental foramen?
Duodenum (superior part)
What is the posterior part of the omental foramen?
Inferior vena cava
What is the superior order of the omental formen?
Caudate lobe of the liver
What are the subdivisions of the peritoneal cavity?
The mesentery of the transverse colon divides the cavity into a supracolic compartment and an infracolic compartment
What are supracolic compartment contains?
- Stomach
- Liver
- Spleen
What does the infracolic compartment?
Infracolic compartment conatins:.
Small intestine
•Ascending colon and descending colon The infra-colic compartment lies posterior
to the greater omentum and is further divided into right and left infra colic spaces by the small intestine.
Communication between the supracolic and infracolic compartments are through the paracolic gutters
What are the clinical correlations of the paracolic gutters?
Depressions between the lateral margins of the ascending and descending colon and the posterolateral abdominal wall.
Because major vessels and lymphatics are on the medial or posteromedial sides of the ascending and descending colon, a relatively blood-free mobilization of the ascending and descending colon is possible by cutting the peritoneum along these lateral paracolic gutters.
The left paracolic gutter is narrower and partially obstructed by the phrenicolic ligament. Therefore it is easier for infection to travel to the right subphrenic space
What are the boundaries of the pouch of Morisson (hepatorenak recess)?
Boundaries
Anterior : Liver
Posterior : right kidney
Inferior :transverse colon
Whaat is the clinical correlate of the pouch of morisson?
The hepatorenal recess is the most dependent space for the collection of pathological fluid in the supine patient
What is the clinical relevance of the hepatoduodenal ligament?
Where is the lesser sac located?
What are the boundaries of lesser sac/ o mental bursae?
WHat are the boundaries of the pouch of Morrison ?
