Ingegneria delle tecnologie per la salute

Fondamenti di anatomia e istologia

aa. 2019-20

Lesson 7. Digestive system and

Peritoneum, abdominal vessel and spleen PERITONEUM: General features

= a thin that line walls of abdominal and pelvic cavities and cover organs within these cavities •Parietal peritoneum －lines walls of abdominal and pelvic cavities •Visceral peritoneum －covers organs • － potential space between parietal and visceral layer of peritoneum, in male, is a closed sac, but in female, there is a communication with exterior through uterine tubes, , and vagina Function

• Secretes a lubricating serous fluid that continuously moistens associated organs • Absorb • Support viscera Peritoneum Histology

The peritoneum is a serosal membrane that consists of a single layer of mesothelial cells and is supported by a basement membrane.

The layer is attached to the body wall and viscera by a glycosaminoglycan matrix that contains collagen fibers, vessels, nerves, macrophages, and fat cells. relationship between viscera and peritoneum

• Intraperitoneal viscera －viscera completely surrounded by peritoneum, example, , superior part of , jejunum, ileum, cecum, vermiform appendix, transverse and sigmoid colons, spleen and • Interperitoneal viscera －most part of viscera surrounded by peritoneum, example, , gallbladder, ascending and descending colon, upper part of rectum, urinary bladder and uterus • Retroperitoneal viscera －some organs lie on the posterior and are covered by peritoneum on their anterior surfaces only, example, kidney, suprarenal gland, pancreas, descending and horizontal parts of duodenum, middle and lower parts of rectum, and ureter

Intraperitoneal viscera

Interperitoneal viscera

Retroperitoneal viscera Interperitoneal viscera Structures which are formed by peritoneum

Omentum = 2- layered fold of peritoneum that extends from stomach to adjacent organs Structures which are formed by peritoneum

Lessor omentum 2-layered fold of peritoneum which extends from porta hepatis to lesser curvature of stomach and superior part of duodenum • Hepatogastric －extends from porta hepatis to lesser curvature of stomach • Extends from porta hepatis to superior part of duodenum – Contains , proper hepatic a. and hepatic portal v.

• Behind the right border of hepatoduodenal ligament • Superior－caudate lobe of liver • Inferior－superior part of duodenum • Anterior－ hepatodudenal ligament • Posterior－peritoneum covering the inferior vena cava Structures which are formed by peritoneum

Greater omentum －four-layered fold of peritoneum, the anterior two layers descend from the greater curvature of stomach and superior part of duodenum and hangs down like an apron in front of coils of small intestine, and then turns upward and attaches to the transverse colon. If an infection occurs in the intestine, plasma cells formed in the lymph nodes combat the infection and help prevent it from spreading to the peritoneum. Structures which are formed by peritoneum

Lessor omentum

Greater omentum Structures which are formed by peritoneum Omental bursa Position－situated behind the lesser omentum and stomach Walls • Superior－peritoneum which covers the caudate lobe of liver and diaphragm • Anterior－formed by lesser omentum, peritoneum of posterior wall of stomach, and anterior two layers of greater omentum • Inferior－conjunctive area of anterior and posterior two layers of greater omentum • Posterior－formed by posterior two layers of greater omentum, transverse colon and transverse mesocolon, peritoneum covering pancreas, left kidney and suprarenal gland Structures which are formed by peritoneum

• Left－formed by the spleen, and splenorenal ligament • Right－formed by omental foramen The Omental bursa (lesser sac) communicates with the through the omental foramen. Structures which are formed by peritoneum

Mesenteries or mesocolons－two- layered fold of peritoneum that attach part of the intestines to the posterior abdominal wall

Structures which are formed by peritoneum

Mesentery －suspends small intestine from posterior abdominal wall • Broad and a fan-shaped • Consists of two peritoneal layers • Intestinal border－folded, 7 m long • Radix of – 15 cm long – Directed obliquely from left side of L2 to in front of right sacroiliac joint

Structures which are formed by peritoneum Structures which are formed by peritoneum

Mesoappendix • Triangular mesentery －extends from terminal part of ileum to appendix • Appendicular artery runs in free margin of the mesoappendix Structures which are formed by peritoneum

Transverse mesocolon －a double fold of peritoneum which connects the transverse colon to the posterior abdominal wall Sigmoid mesocolon －inverted V-shaped, with apex located in front of left ureter and division of common iliac artery

Structures which are formed by peritoneum

Ligaments －two-layered folds of peritoneum that attached the lesser mobile solid viscera to the abdominal wall

Ligaments of liver • of liver – Consists of double peritoneal layer – Extends from anterior abdominal wall (umbilicus) to live – Free border of ligament site of ligamentum teres Structures which are formed by peritoneum

• －the area between upper and lower parts of the coronary ligament is the bare area of live, this area is devoid of peritoneum and lies in contract with the diaphragm • Left and right triangular ligaments －formed by right extremity of coronary ligament and left leaf of falciform ligament, respectively Structures which are formed by peritoneum

• • Hepatoduodenal ligament • Ligamentum teres hepatis Structures which are formed by peritoneum

Ligaments of spleen • Gastrosplenic ligament - a double layer of peritoneum that connects the fundus of stomach to hilum of spleen. In this double layer of peritoneum are the short gastric and left gastroepiploic vessels • Splenorenal ligament - extends between the hilum of spleen and anterior aspect of left kidney. The splenic vessels lies within this ligament, as well as the tail of pancreas • Phrenicosplenic ligament • Splenocolic ligament Structures which are formed by peritoneum

Ligaments of stomach • Hepatogastric ligament • Gastrosplenic ligament • • • Gastropancrestic ligament Structures which are formed by peritoneum

Folds and recesses of posterior abdominal wall • Superior duodenal fold and recess • Inferior duodenal fold and recess • Intersigmoid recess －formed by the inverted V attachment of sigmoid mesocolon Structures which are formed by peritoneum

• Retrocecal recess - in which the appendix frequenty lies • Hepatorenal recess - lies between the right lobe of liver, right kidney, and right colic flexure, and is the lowest parts of the peritoneal cavity when the subject is supine

Structures which are formed by peritoneum

Folds and fossas of anterior abdominal wall • Median umbilical fold － contain the remnant of urachus (median umbilical ligaments) • Medial umbilical fold － contains remnants of the umbilical arteries (medial umbilical ligaments) • － contains the inferior epigastric vessels • • •

Structures which are formed by peritoneum

Pouches • In male－ rectovesical pouch • In female – Rectouterine pouch －between rectum and uterus – Vesicouterine pouch －between bladder and uterus Structures which are formed by peritoneum

Peritoneal subdivisions The transverse colon and transverse mesocolon divides the greater sac into supracolic and infracolic compartments.

Supracolic compartments (subphrenic space)－lies between diaphragm and transverse colon and transverse mesocolon Suprahepatic recess lies between the diaphragm and live－the falciform ligament divides it into right and left suprahepatic recesses Structures which are formed by peritoneum

• Left suprahepatic recesses – left anterior suprahepatic spaces – left posterior suprahepatic spaces • Right suprahepatic recesses – right anterior suprahepatic spaces – right posterior suprahepatic spaces – bare area of live ()

Structures which are formed by peritoneum

Infrahepatic recess lies between the liver and transverse colon and transverse mesocolon－the ligamentum teres hepatic divides it into right and left infrahepatic recesses • Right infrahepatic recesses (hepatorenal recess) • Left infrahepatic recesses – left anterior infrahepatic space – left posterior infrahepatic space Structures which are formed by peritoneum

Infracolic compartments － lies below the transverse colon and transverse mesocolon • Right paracolic sulcus (gutter) • －lies lateral to the ascending colon. It communicates with the hepatorenal recess and the . It provides a route for the spread of infection between the pelvic and the upper abdominal region. • Left paracolic sulcus (gutter) • －lies lateral to the descending colon. It is separated from the area around the spleen by the , a fold of peritoneum that passes from the colic flexure to the diaphragm. Structures which are formed by peritoneum

• Right mesenteric sinus －triangular space, lies between root of mesentery, ascending colon, right 2/3 of transverse colon and transverse mesocolon • Left mesenteric sinus －lies between root of mesentery, descending colon, right 1/3 of transverse colon and transverse mesocolon, its widens below where it is continuous with the cavity of the pelvis Structures which are formed by peritoneum Supracolic region

 abdominal part of esophagus  stomach  duodenum  liver  extrahepatic biliary apparatus  spleen  pancreas ABDOMINAL VESSELS ABDOMINAL VESSELS

Abdominal aorta • Terminates at lower border of L4 • Continuation of vertebra by dividing thoracic aorta at into right and left aortic hiatus of common iliac diaphragm in front of arteries T12 ABDOMINAL VESSELS

Parietal branches • Inferior phrenic a. (one pair) • Lumbar a. (four pairs of arteries that supply the posterior abdominal wall) • Median sacral a. ABDOMINAL VESSELS

Visceral branches • Paired branches – Middle suprarenal artery – Renal artery – Testicular (ovarian) artery ABDOMINAL VESSELS

• Unpaired branches – Celiac trunk – －a short thick vessel that arises from the front of aorta, at the level of T12 – Superior mesenteric a. －arises from the front of aorta, at the level of L2 – Inferior mesenteric a. －arises from the front of aorta, at level of L3 ABDOMINAL VESSELS

Celiac trunk Left branch Left gastric a.

Right branch Short gastric a. Common hepatic a. Cystic a. Splenic a. Right gastric a.

Proper hepatic a.

Gastroduodenal a. Splemic branches

Left gastrioeploic a. Right gastroepiploic a. Superior pancreaticoduodenal a. ABDOMINAL VESSELS

Celiac trunk ABDOMINAL VESSELS

Middle colic a. Superior Mesenteric v.

Inf. pancresticodudenal a. Superior mesenteric a. Right colic a.

Ileocolic a. Jejunal and ileal a.

Appendicular a. ABDOMINAL VESSELS Inferior mesenteric v.

Inferior mesenteric a.

Left colic a.

Sigmoid a.

Superior rectal a. ABDOMINAL VESSELS

Colic marginal artery ABDOMINAL VESSELS

Relations of abdominal aorta • Anteriorly (from above downward) – Pancreas – Ascending part of duodenum – Radix of mesentery • Posteriorly – Upper four lumber vertebrae • On its right – Inferior vena cava • On its left – Left sympathetic trunk

ABDOMINAL VESSELS Veins of and pelvis Internal iliac vein • Parietal tributaries: accompany with arteries • Visceral tributaries

→superior rectal vein→inferior mesenteric v. ①Rectal venous plexus →inferior rectal vein→internal iliac v. →anal vein→internal pudendal v. ②Vesical venous plexus →vesical v. ③Uterine venous plexus →uterine v. ABDOMINAL VESSELS

• External iliac vein– accompany the artery • Common iliac vein– formed by union of internal and external iliac veins in front of sacroiliac joint, end upon L4~L5 by uniting each other to form inferior vena cava ABDOMINAL VESSELS

Inferior vena cava • Formed by union of two common iliac veins anterior to and just to the right of L4~L5 • Ascends on the right side of aorta, pierces vena cava foramen of diaphragm opposite the T8 and drains into the right atrium • Conveys blood from the whole body below the diaphragm to the right atrium ABDOMINAL VESSELS

Chief tributaries • Parietal – Paired inferior phrenic v. – paired lumbar v. (four) • Visceral – Right and left renal veins – Right suprarenal vein (left drain into left renal vein)

– Right testicular or ovarian v. (left drain into left renal vein)

– Hepatic veins : right, left and intermediate ABDOMINAL VESSELS

Relations of inferior vena cava • Anteriorly (cranially to caudally) – Liver – Head of pancreas – Horizontal part of duodenum – Right testicular (or ovarian) a. – Radix of mesentery • Posteriorly – Right crus of diaphragm – Upper four lumber vertebrae – Left sympathetic trunk – Parietal branches of abdominal aorta • On its right – Psoas major – Right kidney – Right suprarenal gland • On its left – Abdominal aorta

ABDOMINAL VESSELS

Hepatic portal vein General features • Formed behind the neck of pancreas by the union of superior mesenteric vein and splenic vein • Ascends upwards and to the right, posterior to the first part of duodenum and then enters the lesser omentum to the porta hepatis, where it divides into right and left branches • There are no functioning valves in hepatic portal system • Drains blood from gastrointestinal tract from the lower end of oesophagus to the upper end of anal canal, pancreas, gall bladder, bile ducts and spleen ABDOMINAL VESSELS

Variation and anomalies of hepatic portal vein ABDOMINAL VESSELS

Tributaries of hepatic portal vein 1. Superior mesenteric v. 2. Inferior mesenteric v. 3. Splenic v. 4. Left gastric v. 5. Right gastric v. 6. Cystic v. 7. Paraumbilical v. ABDOMINAL VESSELS

Portal-systemic anastomoses 1. At the lower end of the oesophagus Hepatic portal vein → left gastric vein → esophageal venous plexus → esophageal vein → azygos vein → superiorvena cava 2. At rectal venous plexus Hepatic portal vein → splenic vein → inferior mesenteric vein → superior rectal vein → rectal venous plexus → inferior rectal and anal veins → internal iliac vein → inferior vena cava 3. At periumbilical venous plexus Hepatic portal vein→paraumbilical vein→periumbilical venous plexus→ – thoracoepigastric and superior epigastric vein → superiorvena cava – superficial epigastric and inferior epigastric veins → inferior vena cava ABDOMINAL VESSELS

4. Portal-retroperitoneal anastomosis Between the retroperitoneal branches of the colic veins and the lumbar veins, pancreaticoduodenal veins with the renal veins and the subcapsular veins of the liver with the phrenic veins twigs of colic veins (portal) anastomosing with systemic retroperitoneal veins Lymphatic drainage of abdomen

Lymphatic drainage of abdominal wall • To axillary lymph node from region above umbilicus • To superficial inguinal lymph node from region below umbilicus • To lumbar lymph node from post wall of abdomen Lymphatic drainage of abdomen

Lymphatic drainage of abdominal viscera • Lumbar lymph nodes – Lie on posterior abdominal wall, along the abdominal aorta and inferior vena cava – Receive lymph from kidneys, suprarenal glands, testes, ovaris, fundus of uterus, ovary, and common iliac nodes – Right and left lumbar trunks formed by efferent vessel – Paired viscera－drain to the lumbar lymph nodes Lymphatic drainage of abdomen

• Celiac lymph nodes －situated around the celiac trunk • Superior mesenteric lymph node －situated around superior mesenteric a. • Inferior mesenteric lymph node －situated around inferior mesenteric a. • Intestinal trunk －formed by efferent vessel of celiac, superior and inferior lymph nodes Lymphatic drainage of abdomen

Thoracic duct • Begins in front of L1 as a dilated sac, the cisterna chyli, which formed by joining of left and right lumbar trunks and intestinal trunk • Enter thoracic cavity by passing through aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein • Travels upward, veering to left at the level of T5 • At the roof of the neck, it turns laterally and arches forwards and descends to enter the left venous angle • Just before termination, it receives the left jugular, subclavian and bronchomediastinal trunks • Drains lymph from lower limbs, pelvic cavity, , left side of thorax, and left side of the head, neck and left upper limb Spleen

Location: lies in the left hypochondriac region (between stomach and diaphragm) deep to the 9th to 11th rib, its long axis corresponds roughly to the 10th rib Shape－reddish in colour Spleen

Two surfaces • Diaphragmatic: smooth, convex • Visceral: concave, hilum of spleen Two extremities • Anterior－wider • Posterior－rounder Two border • Superior－has 2-3 splenic notch, which serve as a landmark on palpation when it is enlarge; normally it is not palpable • Inferior－rounder Functions: considered to be important in: • Formation of lymphocytes and monocyte • Phagocytosis of bacteria, inert particles and white blood cells and platelets • Destroying effete or abnormal red blood cells • Making antibodies

Spleen function

 Erythrocyte storage  Phagocytosis  Cytopoiesis  Immune responses Spleen Relationships of spleen

Diaphragmatic surface －diaphragm Visceral surface • Anteriorly－fundus of stomach • Posteriorly－left suprarenal gland and kidney • Inferiorly－tail of pancreas and left colic flexure Spleen: Histology Spleen: Histology Spleen: Histology

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