Anatomy - GI COPY COPY Flashcards
What is this structure and what does it do?
-Hepatic portal vein
-All products of digestion, except lipids, are transported to the liver from the gut through the hepatic portal vein
Where is the liver and when is it palpable?
-Right upper guadrant
-Epigastrium
-Below right costal margin during inspiration
What surface of the liver is this?
-Diaphragmatic surface
-Anteriosuperior
-Related to inferior diaphragm surface
What surface of the liver is this?
-Visceral surface
-Posterioinferior
-Related to other organs
Regions of liver not covered by visceral peritoneum:
-Bare area of liver
-Region where gallbladder in contact with liver
-Porta hepatis
What does this show?
Liver areas not covered by visceral peritoneum
Label the diagram:
Label the structure:
What does it do?
-Falciform ligament
-Separates the left and right lobes
-Connects anterior surface of the liver to internal aspect of anterior abdominal wall
What are these and what do they all receive?
-8 functional segments of liver
-Each have their own branch of hepatic artery and portal vein
-Have their own hepatic duct
Label this diagram:
What enters the liver at the porta hepatis?
-Right and left hepatic arteries
-Right and left portal veins
-Right and left cystic ducts
how does venous blood exit the liver?
-2 or 3 large hepatic veins
-Within liver - not visible
-Unite with IVC posterior to liver
Difference between hepatic veins and hepatic portal veins:
-HPV - receive nutrient rich blood from gut from superior and inferior mesenteric veins and splenic vein
-HV - venous blood leaves liver via IFC
What is the nerve innervation to the liver?
-Hepatic plexus
-Parasympathetic fibres from vagus
-Also sympathetic fibres
-Follow paths of hepatic vessels and biliary tree ducts
What is the liver anatomically related to?
-Diaphragm connection via triangular and coronary ligaments
-Anterior abdominal wall via falciform
-Stomach and duodenum via lesser omentum
What does this show the entrance to and what is it in relation to?
-Entrance of lesser sac
-Portal triad on free edge of lesser omentum
-Form anterior boundary of epiploic foramen -> entrance to lesser sac
What 2 things are hidden?
-Hepatorenal recess - between right kidney and posterior surface of right liver side
-Left and right subphrenic recess - either side of falciform ligament - between anterosuperior surface of liver and diaphragm
What is this?
-Round ligament of the liver (ligamentum teres)
-Remnant of umbilical vein (blood from placenta to foetus)
What is this?
-Ligamentum venosum
-Remains of ductus venosus (diverted blood from umbilical vein to IVC)
Label this diagram:
-Gallbladder on posteroinferior side of liver
-Body lies in gallbladder fossa
-Fundus extends to inferior liver border
What is this the surface marking of?
-Fundus of gall bladder
-9th costal cartilage
-Midclavicular line intersects 9th costal cartilage
Explain the pathway of bile in the liver:
-Produced by hepatocytes
-Excreted into small channels called bile canaliculi
-Canaliculi drain into bile ducts
-Bile ducts converge into right and left hepatic ducts
Pathway of the bile duct:
-Runs in free edge of lesser omentum
-Posterior to superior duodenum
-Posterior to pancreas head
-Enters duodenum
Vasculature of gall bladder:
-Cystic artery (arises from right hepatic)
-Cystic vein (directly into liver or HPV)
Innervation of gall bladder and pain referrals?
-Parasympathetic and sympathetic
-Visceral afferents return to CNS with sympathetic
-Visceral pain enters spinal cord T5-T9 (epigastric pain)
-Pain referred to right shoulder
-Inflammation irritates diaphragm
-Diaphragm innervated by phrenic (C3,4,5)
-C3,4,5 also receives somatic sensory info from right shoulder skin
-Parietal peritoneum irritation
-Right hypochondrium pain
What is hepatomegaly and what can cause it? palpable?
-Enlargement of the liver
-Causes:
-Hepatitis (liver inflammation from various causes)
-Malignancy
-Heart failure
-Inferior border palpable inferior to right costal margin
What are liver metastases?
-Most cancers of liver are from cancer elsewhere in the body
-Venous blood from the gut passes to the liver so bowel cancer often metastasises in the liver
What is cirrhosis of the liver?
Causes?
-‘Scarring’ of the liver
-Causes:
-Chronic excess alcohol consumption
-Chronic hepatitis B or C infection
-Build up of fat in the liver
-Hepatocytes destroyed and replaced with fibrous tissue
-Liver shrunken, hard and nodular
-Impairs function - leads to liver failure
What level does the coeliac trunk leave the aorta?
T12
Label this diagram:
What does it show?
Coeliac axis
Label this diagram:
Describe:
-Most duodenum is retroperitoneal
-C-shape that sups pancreas
-Fourth part meets jejunum at duodenal flexure
What lies anterior and posterior to the duodenum?
-Anterior to third part:
-Superior mesenteric artery
-Posterior to first part:
-Bile duct
-Hepatic portal vein
-Gastroduodenal artery
What is this and what does it do?
-Major duodenal papilla
-Point at which bile and digestive pancreatic secretions enter duodenum
What supplies blood to the duodenum?
-First half:
-Branches of coeliac trunk
-Gastroduodenal
-Second half:
-Branches of superior mesenteric artery
-Inferior pancreaticoduodenal artery
What drains blood from the duodenum?
Tributaries of hepatic portal vein that follow arteries
Where does the pancreas lie?
-Horizontally on posterior abdominal wall (lesser sac)
-Level of L1
-Retroperitoneal (no capsule so bumpy)
-Head cupped by C-shaped duodenum
-Tail extends to hilum of spleen
What forms the pancreas?
Dorsal and ventral pancreatic buds that fuse during development
Label the parts of the pancreas:
What lies embedded in the upper border of the pancreas and posterior?
-Upper border - splenic artery
-Posterior - splenic vein
Label the two structures:
Where do they lie?
Within the substance of the pancreas
What are the functions of the pancreas?
-Endocrine and exocrine functions
-Synthesises and secreted insulin (high blood glucose) and glucagon
-Produces pancreatic juice with digestive enzymes
-Transported in main pancreatic duct and accessory pancreatic duct to duodenum
-Communication between ducts
What does the duodenum receive?
-Bile from gallbladder via bile duct
-pancreatic juice from pancreas via main and accessory pancreatic ducts
Label this diagram:
What does it show?
-Bile duct and main pancreatic duct merge at hepatopancreatic ampulla
-Ampulla opens up to second part of duodenum at major duodenal papilla (halfway down duodenum in internal wall)
What surrounds the hepatopancreatic ampulla and what is its function?
-Smooth muscle
-Sphincter of Oddi
-Contraction prevents reflux of duodenal contents into bile and main pancreatic ducts
Label this diagram:
What does it show?
Minor pancreatic duct empties pancreatic juice into duodenum at minor duodenal papilla, proximal to major duodenal papilla
What is the blood supply to the pancreas?
-Splenic artery, major branch of coeliac trunk runs along upper border of pancreas to give rise to pancreatic arteries
-Gastroduodenal artery gives rise to superior pancreaticoduodenal arteries
-Superior mesenteric gives rise to inferior pancreaticoduodenal arteries
What veins drain the pancreas?
-Veins follow arteries
-Splenic vein drains pancreas and unites with superior mesenteric vein
-Forms portal vein posterior to neck of pancreas
Describe the spleen:
-Haematopoietic and lymphoid organ
-LUQ
-Protected by ribs 9-11
What are the two surfaces of the spleen?
-Diaphragmatic surface adjacent to diaphragm
-Visceral surface in contact with stomach, left kidney and colon (vessels enter and exit at hilum on visceral surface)
Describe the 4 borders of the spleen:
-Superior - notched
-Inferior - smooth
-Anterior - notched
-Posterior - smooth
Describe the vasculature to and from the spleen:
-Splenic artery supplies blood to the spleen - embedded in the superior border of the pancreas
-Separates into 5 branches at the hilum
-Splenic vein runs posterior to the pancreas and unites with the superior mesenteric vein to form the hepatic portal vein
Label this diagram:
Describe parietal peritoneum:
Innervation?
-Lines abdominal wall
-Can be seen with naked eye
innervated by somatic nerves that supply overlying muscles and skin of abdominal wall
Describe visceral peritoneum:
+nerves
-Adhered to surface of viscera and not seen with naked eye
-Innervated by visceral sensory nerves:
-Convey painful sensations back to CNS
-Along path of sympathetic nerves that innervate the organ/structure is covers
Describe pain from parietal and visceral peritoneum:
-Parietal:
-Sharp
-Severe
-Well localised to abdominal wall
-Visceral:
-Can be severe
-Dull
-Diffuse
-Can be perceived as nausea or distension
What lies in between the two layers of peritoneum?
-Peritoneal cavity
-Healthy abdomen - thin film of peritoneal fluid lies in cavity
-Allows viscera to slide freely alongside each other
What relationship do the visceral and parietal peritoneum have?
They are continuous with each other
How can abdominal viscera be described in terms of peritoneum?
-Intraperitoneal - almost completely covered by peritoneum (e.g. stomach)
-Retroperitoneal - posterior to peritoneum, only covered on anterior surface e.g. pancreas and abdominal aorta)
Label this diagram:
What does it mean to be secondarily retroperitoneal?
Organs that were intraperitoneal in early development but came to be stuck down onto the posterior abdominal wall
What are common features of mesenteries, omenta, ligaments and folds?
-All composed of peritoneum and connect organs to each other and abdominal wall
-May carry blood vessels, nerves and lymphatics to viscera
-Contain variable amount of fat - some are very fatty
What are mesenteries?
-Folds of peritoneum containing fat
-Suspend small intestine and parts of large intestine from posterior abdominal wall
-Arteries supplying intestine
(abdominal aorta branches) and veins draining gut (portal venous system) embedded in mesenteries
Label this diagram:
What are the greater and lesser omenta?
-Folds of peritoneum that are usually fatty and connect stomach to other organs
-Greater omentum - hangs from the greater curvature of stomach and lies superficial to small intestine
-Lesser omentum - connects stomach and duodenum to the liver, portal triad embedded within its free edge
Label this diagram:
What are ligaments (abdomen)?
-Folds of peritoneum that connect organs to each other or to abdominal wall
-Falciform ligament (anterior liver surface to anterior abdominal wall)
-Coronary and triangular ligaments (superior surface of liver to diaphragm)
What are peritoneal folds?
-Raised from internal aspect of lower abdominal wall
-Created by structures they overlie, like carpet running over a cable
Describe the median umbilical fold:
-Lies in midline
-Represents remnant of urachus (embryologically connected the bladder to umbilicus
Label this diagram:
Describe the lateral umbilical folds:
-Lateral to the median umbilical fold
-Represent remnants of paired umbilical arteries (returned venous blood to placenta in foetal life)
Describe the lateral umbilical folds:
not embryologically
-Lateral to medial umbilical folds
-Inferior epigastric arteries lie deep to these peritoneal folds
-Supply anterior abdominal walls
What is the peritoneal cavity divided into?
-Smaller lesser sac (omental bursa) is a space that lies posterior to the stomach and anterior to pancreas
-Larger greater sac is the remaining part of the peritoneal cavity
How do the greater and lesser sac communicate with each other?
-Passageway that lies posterior to the free edge of the lesser omentum
-Called epiploic foramen (omental foramen)
What is this?
Where does the gastrointestinal system develop from?
-Embryonic gut tube
-Lies in midline of the abdominal cavity, suspended from the posterior abdominal wall by dorsal mesentery
What passes through the dorsal mesentery?
Major branches of the abdominal aorta that supply the developing gut tube
What is the ventral mesentery and what does it become?
-Connects stomach to anterior abdominal wall
-As liver grows within it, anterior part becomes falciform ligament
-Posterior part becomes lesser omentum
What does growth, migration and rotation of organs during development cause?
-Pull their peritoneal attachments with them
-Responsible for formation of lesser sac
-Some organs are ‘pushed’ onto the posterior abdominal wall and become retroperitoneal
Through what does the oesophagus pass through to reach the stomach and at what level?
-Oesophageal hiatus
-Level T10
What prevents reflux of stomach contents into the oesophagus?
-The muscle around the oesophageal hiatus
-Acts as a sphincter
How long is the abdominal segment of the oesophagus?
Less than 2cm
What supplies blood to the distal oesophagus?
Supplied by branches from left gastric artery
What is the venous drainage of the distal oesophagus?
-Towards both the systemic system of veins (via oesophageal veins draining into azygous vein)
-Also to portal venous system (via left gastric veins)
What is the distal oesophagus a site of and why?
-Portosystemic anastomoses
-Drains into systemic and portal venous system
What does the stomach do?
Chemically and physically breaks down food into chyme
What part of the stomach is the oesophagus continuous with?
Cardia of the stomach
Describe the most superior part of the stomach:
-Fundus of the stomach
-Superior to level of oesophagus entry
-Usually filled with gas
What is the largest part of the stomach?
Body
Describe the part of the stomach distal to the body:
-Pyloric part of the stomach
-Pyloric antrum is wide and tapers towards the pyloric canal which is narrow
-Pyloric sphincter is part of the pyloric canal
What regulates the passage of chyme from the stomach into the duodenum?
-Pyloric sphincter
-Formed of circular smooth muscle
What are the right and left borders of the stomach called?
-Right - Lesser curvature
-Left - Greater curvature
Where is the stomach positioned and what covers its surface?
-Left upper Quadrant (can be variable)
-Visceral peritoneum
What is the anterior surface of the stomach related to (3)?
-Anterior abdominal wall
-Diaphragm
-Left lobe of liver
What does the posterior surface of the stomach form?
Anterior wall of the lesser sac
What lies posterior to the stomach and what forms its posterior wall (4)?
-Lesser sac
-Posterior wall of lesser sac:
-Pancreas
-Stomach
-Left kidney
-Spleen
What connects the lesser curvature of the stomach to the liver?
Lesser omentum
What does the free edge of the lesser omentum contain?
-Hepatic artery
-Hepatic portal vein
-Bile duct
PORTAL TRIAD
What is posterior to the free edge of the lesser omentum?
-Entrance to the lesser sac
-Epiploic foramen
What hangs from the greater curvature of the stomach?
Greater omentum
What is this and at what level does it leave the abdominal aorta?
-Coeliac trunk
-one of 3 large unpaired vessels that leave the anterior aspect of the abdominal aorta to supply the abdominal viscera derived from embryological foregut
-T12
What comprises the foregut?
-Stomach
-First half of duodenum
-Liver
-Gallbladder
-Pancreas
Why is the spleen different from other organs in a similar area?
-Develops in dorsal mesentery
-Supplied by coeliac trunk
-Mesodermal in origin
What does the coeliac trunk divide into?
Which vessel is the smallest?
-Splenic artery
-Left gastric artery
-Common hepatic artery
-Left gastric artery is a much smaller calibre vessel than the other two
What vessels run along the lesser curvature of the stomach adn where do they originate?
-Left and right gastric arteries
-They anastomose with each other
-Left gastric = coeliac trunk
-Right gastric = common hepatic artery
What vessels run along the greater curvature of the stomach and where do they originate?
-Right and left gastro-omental arteries
-They anastomose with each other
-Left gastro-omental = splenic artery
-Right gastro-omental = gastroduodenal artery (branch of common hepatic)
What is the venous drainage of the foregut?
-Left and right gastric veins
-Left and right gastro-omental veins
-Splenic vein
-Accompany their correspondent arteries
-Ultimately drain into the hepatic portal vein
Describe the parasympathetic innervation to the stomach:
-Vagus nerve conveys parasympathetic fibres to stomach
-Parasympathetic stimulation promotes peristalsis and gastric secretion
Describe the parasympathetic innervation to the stomach:
-Vagus nerve conveys parasympathetic fibres to stomach
-Parasympathetic stimulation promotes peristalsis and gastric secretion
Describe sympathetic innervation to the stomach:
-Sympathetic fibres are conveyed to the stomach via the greater splanchnic nerve
-GSN is formed of preganglionic sympathetic fibres that leave spinal cord segments T5-T9
-Pass through sympathetic trunk without synapsing
-Synapse in prevertebral ganglia around coeliac trunk
-Postganglionic fibres travel to stomach and inhibit peristalsis and secretion
Label the 3 sections of the small intestine: