Hepatobiliary, spleen, pancreas

Question 1

What are the primary functions of the liver?

Answer 1

Bile production and excretion.
Excretion of bilirubin, cholesterol, hormones, and drugs.
Metabolism of fats, proteins, and carbohydrates.
Enzyme activation.
Storage of glycogen, vitamins, and minerals.
Synthesis of plasma proteins, such as albumin, and clotting factors.

Question 2

What is the liver?

Answer 2

Liver is the largest gland in the body weighing 1.5 kg and receives 1500ml of blood per minute.

Question 3

Where is the Liver located?

Answer 3

Right hypochondriac region under the diaphragm (superior border as high as the fifth rib and the right border of seventh and eleventh ribs

Question 4

What are the surfaces of the liver?

Answer 4

Convex diaphragmatic surface (anterior, superior, and some posterior) and flat or concave visceral surface (posteroinferior), separated anteriorly by sharp inferior border that follows the right costal margin.

Question 5

What are Subphrenic recesses associated with the Liver?

Answer 5

Subphrenic recesses: superior extensions of the peritoneal cavity (greater sac)—exist between diaphragm and the anterior and superior aspects of the diaphragmatic surface of the liver. The subphrenic recesses are separated into right and left recesses by the falciform ligament, which extends between the liver and the anterior abdominal wall.

Question 6

What is the Subhepatic space associated with the Liver?

Answer 6

The portion of the supracolic compartment of the peritoneal cavity immediately inferior to the liver is the subhepatic space.

There is also the Hepatorenal space

Question 7

What are the ligaments of the Liver?

Answer 7

Coronary ligament
Right & left triangular ligaments
Bare area of the liver. IVC traverses a deep groove within the bare area of the liver

Question 8

What is the visceral surface of the liver?

Answer 8

multiple fissures and impressions of the organs in contact. Covered with peritoneum , except at the fossa for the gallbladder and the porta hepatis—a transverse fissure where the vessels (hepatic portal vein, hepatic artery, and lymphatic vessels), the hepatic nerve plexus, and hepatic ducts that supply and drain the liver enter and leave it.

Question 9

How does the impressions on the visceral surface reflect the liver’s relationship to the organs?

Answer 9

Right side of the anterior aspect of the stomach (gastric and pyloric areas).
Superior part of the duodenum (duodenal area).
Lesser omentum (extends into the fissure for the ligamentum venosum).
Gallbladder (fossa for gallbladder).
Right colic flexure and right transverse colon (colic area).
Right kidney and suprarenal gland (renal and suprarenal areas

Question 10

What is the lesser omentum?

Answer 10

The lesser omentum, enclosing the portal triad (bile duct, hepatic artery, and hepatic portal vein) passes from the liver to the lesser curvature of the stomach and the first 2 cm of the superior part of the duodenum.
The thick, free edge of the lesser omentum extends between the porta hepatis and the duodenum (the hepatoduodenal ligament) and encloses the structures that pass through the porta hepatis. The sheet-like remainder of the lesser omentum, the hepatogastric ligament, extends between the groove for the ligamentum venosum and the lesser curvature of the stomach.

Question 11

What are the fissures of the liver?

Answer 11

Two sagitally oriented fissures, linked centrally by the transverse porta hepatis, form the letter H on the visceral surface .
The right sagittal fissure is the continuous groove formed anteriorly by the fossa for the gallbladder and posteriorly by the groove for the vena cava.
The umbilical (left sagittal) fissure is the continuous groove formed anteriorly by the fissure for the round ligament and posteriorly by the fissure for the ligamentum venosum. The round ligament of the liver (L. ligamentum teres hepatis) is the fibrous remnant of the umbilical vein, which carried well-oxygenated and nutrient-rich blood from the placenta to the fetus. The round ligament and small paraumbilical veins course in the free edge of the falciform ligament. The ligamentum venosum is the fibrous remnant of the fetal ductus venosus, which shunted blood from the umbilical vein to the IVC, short-circuiting the liver

Question 12

What are the subdivisions of the liver?

Answer 12

Two anatomical lobes and two accessory lobes by the reflections of peritoneum from its surface
The essentially midline plane defined by the attachment of the falciform ligament and the left sagittal fissure separates a large right lobe from a much smaller left lobe
Two accessory lobes (parts of the anatomic right lobe):
the quadrate lobe anteriorly and inferiorly and
the caudate lobe posteriorly and superiorly. The caudate lobe was so-named not because it is caudal in position (it is not) but because it often gives rise to a “tail” in the form of an elongated papillary process. A caudate process extends to the right, between the IVC and the porta hepatis, connecting the caudate and right lobes.

Question 13

What are functional subdivisions of the liver?

Answer 13

Liver has functionally independent right and left subdivisions or lobes. Each part receives its own primary branch of the hepatic artery and hepatic portal vein and is drained by its own hepatic duct.
The caudate lobe may be considered as a third lobe of liver; its vascularization is independent of the bifurcation of the portal triad (it receives vessels from both bundles) and is drained by one or two small hepatic veins, which enter directly into the IVC distal to the main hepatic veins.
Hepatic (Surgical) Segments of Liver: The liver can be further subdivided into four divisions and then into eight surgically resectable hepatic segments, each served independently by a secondary or tertiary branch of the portal triad.
Except for the caudate lobe (segment I), the liver is divided into right and left livers based on the primary (1°) division of the portal triad into right and left branches, the plane between the right and the left livers being the main portal fissure in which the middle hepatic vein lies.

Question 14

What are the biliary channels and ducts?

Answer 14

The biliary ducts convey bile from the liver to the duodenum. Bile is produced continuously by the liver and stored and concentrated in the gallbladder, which releases it intermittently when fat enters the duodenum. Bile emulsifies the fat so that it can be absorbed in the distal intestine.

Question 15

What is normal hepatic tissue?

Answer 15

Demonstrates a pattern of hexagonal-shaped liver lobules
Each lobule has a central vein running through its center from which sinusoids (large capillaries) and plates of hepatocytes (liver cells) radiate toward an imaginary perimeter extrapolated from surrounding interlobular portal triads (terminal branches of the hepatic portal vein and hepatic artery and initial branches of the biliary ducts)
The hepatocytes secrete bile into the bile canaliculi formed between them. The canaliculi drain into the small interlobular biliary ducts and then into large collecting bile ducts of the intrahepatic portal triad, which merges to form the hepatic ducts
The right and left hepatic ducts drain the right and left (parts of the) liver. Shortly after leaving the porta hepatis, these hepatic ducts unite to form the common hepatic duct, which is joined on the right side by the cystic duct to form the bile duct (part of the extrahepatic portal triad of the lesser omentum), which conveys the bile to the duodenum.

Question 16

What is the vasculature of the liver?

Answer 16

Dual blood supply: A dominant venous source and a lesser dominant arterial supply.
The hepatic portal vein brings 75-80% of the blood to the liver, containing about 40% more oxygen than blood returning to the heart from the systemic circuit, sustains the liver parenchyma (liver cells or hepatocytes)
The hepatic portal vein carries virtually all of the nutrients absorbed by the alimentary tract to the sinusoids of the liver. The exception is lipids, which are absorbed into and bypass the liver via the lymphatic system.
Arterial blood from the hepatic artery, accounting for only 20-25% of blood received by the liver, is distributed initially to non-parenchymal structures, particularly the intrahepatic bile ducts.

Question 17

What is the hepatic vein?

Answer 17

Between the divisions are the right, intermediate (middle), and left hepatic veins, which are intersegmental in their distribution and function, draining parts of adjacent segments. The hepatic veins, formed by the union of collecting veins that in turn drain the central veins of the hepatic parenchyma, open into the IVC just inferior to the diaphragm. The attachment of these veins to the IVC helps hold the liver in position

Question 18

What is the common bile duct?

Answer 18

The common bile duct forms in the free edge of the lesser omentum by the union of the cystic duct and common hepatic duct.
The length of the bile duct varies from 5 to 15 cm, depending on where the cystic duct joins the common hepatic duct.
The bile duct descends posterior to the superior part of the duodenum and lies in a groove on the posterior surface of the head of the pancreas. On the left side of the descending part of the duodenum, the bile duct comes into contact with the main pancreatic duct. These ducts run obliquely through the wall of this part of the duodenum, where they unite, forming a dilation, the hepatopancreatic ampulla (ampulla of Vater).
The distal end of the ampulla opens into the duodenum through the major duodenal papilla. The circular muscle around the distal end of the bile duct is thickened to form the sphincter of the bile duct (sphincter of Oddi). When this sphincter contracts, bile cannot enter the ampulla and the duodenum; hence bile backs up and passes along the cystic duct to the gallbladder for concentration and storage.

Question 19

What is the gallbladder and where is it?

Answer 19

The gallbladder (7-10 cm long) lies in the fossa for the gallbladder on the visceral surface of the liver. This shallow fossa lies at the junction of the right and left (parts of the) liver.
The relationship of the gallbladder to the duodenum is very intimate. In its natural position the body of the gallbladder lies anterior to the superior part of the duodenum, and its neck and cystic duct are immediately superior to the duodenum.

Question 20

What is the vasculature and nerves of the gallbladder?

Answer 20

The arterial supply of the gallbladder and cystic duct is from the cystic artery. The cystic artery commonly arises from the right hepatic artery
The venous drainage from the neck of the gallbladder and cystic duct flows via the cystic veins. These small and usually multiple veins enter the liver directly or drain through the hepatic portal vein to the liver

The lymphatic drainage of the gallbladder is to the hepatic lymph nodes, often through cystic lymph nodes located near the neck of the gallbladder. Efferent lymphatic vessels from these nodes pass to the celiac lymph nodes.
The nerves to the gallbladder and cystic duct pass along the cystic artery from the celiac (nerve) plexus (sympathetic and visceral afferent [pain] fibers), the vagus nerve (parasympathetic), and the right phrenic nerve (actually somatic afferent fibers).
Parasympathetic stimulation causes contractions of the gallbladder and relaxation of the sphincters at the hepatopancreatic ampulla. However, these responses are generally stimulated by the hormone cholecystokinin (CCK), produced by the duodenal walls (in response to the arrival of a fatty meal) and circulated through the bloodstream.

Question 21

What is the hepatic portal vein?

Answer 21

The hepatic portal vein (HPV) is the main channel of the portal venous system . It is formed anterior to the IVC and posterior to the neck of the pancreas (close to the level of the L1 vertebra and the transpyloric plane) by the union of the superior mesenteric and splenic veins.

Question 22

What is the spleen?

Answer 22

Largest lymphatic organ and participates in the body’s defence system as a site of lymphocyte (white blood cell) proliferation and of immune surveillance and response.
Structure – similar to a lymph node. The most vulnerable abdominal organ
Encapsulated in a delicate fibroelastic capsule that is very thin, a layer of visceral peritoneum that entirely surrounds the spleen except at the splenic hilum , soft, vascular (sinusoidal) and lymphoid tissue mass.
Adult :- 12cm long, 7cm broad, 3-4cm wide – diminished in older people
Mass 150g (80-130g) – diminished in older people.

Question 23

What is the location of the spleen?

Answer 23

Intraperitoneal and is located in the superolateral part of the left upper quadrant (LUQ) or hypochondrium of the abdomen where it enjoys protection of the inferior thoracic cage (Left 9th-11th ribs separated by the diaphragm and the costodiaphragmatic recess)
The relations of the spleen are
Anteriorly, the stomach.
Posteriorly, the left part of the diaphragm, which separates it from the pleura, lung, and ribs 9-11.
Inferiorly, the left colic flexure.
Medially, the left kidney.
The spleen varies considerably in size, weight, and shape; however, it is usually approximately 12 cm long and 7 cm wide. (A nonmetric memory device exploits odd numbers: the spleen is 1 inch thick, 3 inches wide, 5 inches long, and weighs 7 ounces. It lies between the 9th and 11th ribs, so 1, 3, 5, 7, 9, 11)

Question 24

What is the function of the spleen?

Answer 24

Defence
As blood passes through the sinusoids, reticuloendothelial cell (macrophages) lining these venous spaces remove microorganisms from the blood and destroy them by phagocytosis.
Pathogens are exposed to the T and B lymphocytes triggering an immune response
Haematopoiesis
Monocytes and T and B lymphocytes complete their development to become activated in the spleen.
Before birth, red blood cells are also formed in the spleen.
Red blood cell and platelet destruction.
Macrophages lining the spleen’s sinusoids remove worn-out red blood cells and imperfect platelets from the blood and destroy them by phagocytosis.
Also break apart the haemoglobin molecules from the destroyed red blood cells and salvage their iron content by returning them to the blood stream for storage in bone marrow and liver.
The pigment (bilirubin) derived from haem is bound to plasma carrier proteins and sent to the liver

Blood reservoir
Pulp of the spleen and its venous sinuses store considerable blood and platelets which can be released during haemorrhage. can provide a sort of “self transfusion” as a response to the stress imposed by hemorrhage. In spite of its size and the many useful and important functions it provides, it is not a vital organ (not necessary to sustain life).
others: Prenatally, the spleen is a haematopoietic (blood-forming) organ, but after birth is involved primarily in identifying, removing, and destroying expended red blood cells (RBCs) . The spleen serves as a blood reservoir, storing RBCs and platelets.

Question 25

What is the Peritoneal connections of the spleen?

Answer 25

Gastrosplenic ligament:- greater curvature of the stomach –hilum of the spleen (continuity with left side of the greater omentum)
Anterior layer – peritoneum reflected off the gastric impression (spleen), anterior surface of the stomach.
Posterior layer – continuous with the peritoneum of the splenic hilum, posterior surface of the stomach.
Splenorenal (lienorenal) ligament:- splenic hilum to the posterior abdominal wall (over the left kidney)
Tail of pancreas present in the lower part of ligament
Phrenicocolic ligament :- extends from the splenic flexure of the colon to the diaphragm (level 11th rib, anterolateral abdominal wall). Continuous with the peritoneum of the lateral end of the transverse mesocolon, lateral margin of the pancreatic tail, and the splenorenal ligament at the hilum of the spleen.

Question 26

What is the vasculature of the spleen?

Answer 26

Blood Vessels: Splenic artery is a branch from the Coeliac trunk (Coeliac trunk – left gastric, common hepatic and splenic arteries)

Splenic vein joins with SMV to form the hepatic portal vein. The IMV drains into the splenic vein.

Lymphatics
Drains to the pancreaticosplenic and celiac nodes then the thoracic duct.

Innervations
Coeliac sympathetic plexus (SANS) - vasomotor (NA – noradrenaline transmitter) - constricts

Question 27

What is the location of the pancreas?

Answer 27

The pancreas is an elongated, accessory digestive gland that lies retroperitoneally, overlying and transversely crossing the bodies of the L1 and L2 vertebra (the level of the transpyloric plane) on the posterior abdominal wall . It lies posterior to the stomach between the duodenum on the right and the spleen on the left . The transverse mesocolon attaches to its anterior margin
Epigastric and left hypochondriac regions
Posterior surface:- IVC, right crus, left kidney, spleen

Question 28

What does the pancreas produce?

Answer 28

An exocrine secretion (pancreatic juice from the acinar cells) that enters the duodenum through the main and accessory pancreatic ducts.
Endocrine secretions (glucagon and insulin from the pancreatic islets [of Langerhans] that enter the blood.

Question 29

What is the Head, neck, body, tail , one accessory lobe (uncinate process) of the pancreas?

Answer 29

The head of the pancreas is the expanded part of the gland that is lies in the C-shaped curve of the duodenum to the right of the superior mesenteric vessels just inferior to the transpyloric plane. It firmly attaches to the medial aspect of the descending and horizontal parts of the duodenum. The uncinate process, a projection from the inferior part of the pancreatic head, extends medially to the left, posterior to the SMA. The pancreatic head rests posteriorly on the IVC, right renal artery and vein, and left renal vein. On its way to opening into the descending part of the duodenum, the bile duct lies in a groove on the posterosuperior surface of the head or is embedded in its substance.
The neck of the pancreas is short (1.5-2 cm) and overlies the superior mesenteric vessels, which form a groove in its posterior aspect. The anterior surface of the neck, covered with peritoneum, is adjacent to the pylorus of the stomach. The SMV joins the splenic vein posterior to the neck to form the hepatic portal vein .
The body of the pancreas continues from the neck and lies to the left of the superior mesenteric vessels, passing over the aorta and L2 vertebra, continuing just above the transpyloric plane posterior to the omental bursa. The anterior surface of the body of the pancreas is covered with peritoneum and lies in the floor of the omental bursa and forms part of the stomach bed.

Question 30

What is the tail, main pancreatic duct and the sphincter of the pancreatic duct of the pancreas?

Answer 30

The tail of the pancreas lies anterior to the left kidney, where it is closely related to the splenic hilum and the left colic flexure. The tail is relatively mobile and passes between the layers of the splenorenal ligament with the splenic vessels .
The main pancreatic duct begins in the tail of the pancreas and runs through the parenchyma of the gland to the pancreatic head. The main pancreatic duct and bile duct usually unite to form the short, dilated hepatopancreatic ampulla (of Vater), which opens into the descending part of the duodenum at the summit of the major duodenal papilla .
The sphincter of the pancreatic duct (around the terminal part of the pancreatic duct), the sphincter of the bile duct (around the termination of the bile duct), and the hepatopancreatic sphincter (of Oddi)—around the hepatopancreatic ampulla—are smooth muscle sphincters that control the flow of bile and pancreatic juice into the ampulla and prevent reflux of duodenal content into the ampulla.

Question 31

What is the vasculature of the pancreas?

Answer 31

The arterial supply of the pancreas is derived mainly from the branches of the markedly tortuous splenic artery.
Venous drainage from the pancreas occurs via corresponding pancreatic veins, tributaries of the splenic and superior mesenteric parts of the hepatic portal vein; most empty into the splenic vein.
The pancreatic lymphatic vessels follow the blood vessels. Most vessels end in the pancreaticosplenic lymph nodes, which lie along the splenic artery. Some vessels end in the pyloric lymph nodes. Efferent vessels from these nodes drain to the superior mesenteric lymph nodes or to the celiac lymph nodes via the hepatic lymph nodes.
The nerves of the pancreas are derived from the vagus and abdominopelvic splanchnic nerves passing through the diaphragm. The parasympathetic fibers are secretomotor, but pancreatic secretion is primarily mediated by secretin and cholecystokinin, hormones formed by the epithelial cells of the duodenum and proximal intestinal mucosa under the stimulus of acid contents from the stomach.