Gastrointestinal 3 - Viscera

Label the following diagram of the gallbladder

(Ignore the yellow lines)

What is the gallbladder?

Pear-shaped sac on visceral surface of liver, wedged in a fossa b/w the right & quadrate lobes

What is the role of the gallbladder?

Receives, concentrates & stores bile from the liver

What are the 3 major components of the gallbladder?

• Fundus: concentrates bile

• Body

• Neck: site of retrograde bile flow into gallbladder if bile is not needed

What does the gallbladder empty into?

The cystic duct, a component of the bile duct system

Describe the movement of bile from the liver to the gallbladder

1. Bile is produced in the liver

2. Bile is flows into the right hepatic & left hepatic ducts

3. Bile flows into the common hepatic duct & then into the cystic duct → gallbladder for storage

4. Bile flows into the bile duct to be delivered to the duodenum

Label the following diagram to show the positioning of the gallbladder

Label the following diagram of the pancreas & associated structures

For the pancreas, state:

• What type of organ it is

• Whether it is more superficial or deep, & retroperitoneal or intraperitoneal

• Major components

• Associated structures

• Appearance

• Exocrine & endocrine glandular tissue

  • Mostly exocrine in GIT; → signalling molecules + enzymes into ducts

• Very deep & retroperitoneal

• Major components:

  • Head (w/ uncinate process): surrounded by duodenum

  • Neck: near superior mesenteries (large blood vessels)

  • Body

  • Tail (near spleen)

• Associated structures:

  • Duodenum

  • Stomach

  • Spleen

  • Superior mesenteric vessels

  • Bile duct

• Distinct lobulated appearance w/ no capsule; looks very fatty

Label the following diagram of the pancreatic ducts

What does this diagram show about the relationship between the bile & pancreatic duct?

They join just before entering the duodenum

Where do the minor duodenal papilla & major duodenal papilla of the pancreas enter?

Enter the second part of the duodenum

Where are the minor duodenal papilla & major duodenal papilla positioned with respect to the abdominal wall?

• Fixed on the abdominal wall → more stable

• First part of the duodenum bends & twists (comes off abdominal wall)

Label the following diagram of the bile & pancreatic ducts

What is the portal triad wrapped in?

Peritoneum; part of the lesser omentum

Label the following diagram of the pancreatic & bile ducts

What is the spleen & what is its role?

Vascular organ & the largest lymphatic viscera but is NOT part of the digestive pathway

• Role: produces white blood cells (but its role changes throughout development, puberty & adulthood)

For the spleen, state:

• Where it is located & implications of this location

• Shape

• Whether it is intra- or retroperitoneal

• Close anatomical relationship to another structure

• Deep in upper left quadrant to left ribs 9-10/11

  • Risk of injury from rib fractures → life threatening due to possibility of major blood loss

• Variable in shape

• Intraperitoneal

• Splenic hilum close to pancreatic tail

Label the following diagram

For the jejunum, state:

• Where it begins

• Where it is positioned

• What is comprises

• Diameter & wall thickness

• Key feature

• Begins @ duodeno-jejunal flexure

• Largely in left upper quadrant

• Comprises proximal 40% of small intestine

• Large diameter + thick wall

• Prominent plicae circulares (luminal folds) → ^ SA for absorption

For the ileum, state:

• Where it begins

• Where it is positioned

• What is comprises

• Diameter & wall thickness

• Key feature

• Where it ends

• Poorly defined transition from jejunum to ileum

• Largely in right lower quadrant

• Comprises distal 60% of small intestine

• Narrow diameter + thin wall

• Less prominent & prevalent plicae circulares (b/c there is less stuff to absorb as food travels through the SI)

• Ends @ ileocaecal junction → empty contents into initial large intestine

Label the following diagram

Label the following diagram

How does the diameter & length of the large intestine compare to the small intestine?

• Larger diameter of LI

• Shorter length of LI

What does the large intestine begin as?

The caecum at the ileocaecal junction

What are the 5 key components of the large intestine?

1. Caecum (+ appendix)

2. Ascending colon

3. Transverse colon

4. Descending colon

5. Sigmoid colon

What are the 2 major flexures of the large intestine

• Hepatic (right colic) flexure

• Splenic (left colic) flexure

Name 3 distinctive features of the large intestine

• Taenia Coli: longitudinal bands of smooth muscle

• Haustra: sacculations (small pouches) of the colon

• Omental appendices: small pouches of peritoneum filled w/ fat

Label the following diagram

For the appendix, state:

• Shape

• Orientation

• Clinical implications

• Key feature

• Vermiform (worm-like)

• Variable orientation w/ its own mesentery (mesoappendix)

• Prone to sudden implications → appendectomy

• High proportion of lymphoid tissue

Label the following diagram

For the r3ctum, state:

• Where it begins

• What it follows & where it finishes

• Change in musculature

• What can typically be seen from an anterior view

• Begins at rectosigmoid junction

• Follows convexity of sacrum & finishes at tip of coccyx (→ @nal canal)

• Change in external musculature for sigmoid colon to r3ctum

  • Taeniae coli blending into broad, continuous, longitudinal bands

• Anterior view → 3 distinct flexures

Label the following diagram

Name the major arterial supply to the abdominal viscera & the names of the 3 branches

3 major unpaired branches from abdominal aorta:

1. Celiac trunk

2. Superior mesenteric artery

3. Inferior mesenteric artery

What does the celiac trunk supply?

Foregut:

• Liver

• Gallbladder

• Spleen

• Stomach

• Pancreas

• Duodenum

What does the superior mesenteric artery supply?

Midgut:

• Pancreas

• Duodenum

• Jejunum

• Ileum

• Caecum

• Appendix

• Ascending colon

• Transverse colon

What does the inferior mesenteric artery supply?

Hindgut:

• Transverse colon

• Descending colon

• sigmoid colon

• R3ctum

Which abdominal viscera receive blood from 2 branches of the abdominal aorta, & which branches are they?

• Pancreas + duodenum: receive blood from celiac trunk + superior mesenteric artery

• Transverse colon: receives blood from superior mesenteric artery & inferior mesenteric artery

Label the following diagram of the celiac trunk, its branches, & surrounding structures

Name the 3 major branches of the celiac trunk & what they each supply, & where they are found

• Splenic artery: pancreas, stomach, spleen

  • Tortous appearance

  • Moving towards upper left quadrant

• Common hepatic artery: stomach, duodenum, liver & gallbladder

  • Moving towards upper right quadrant

• Left gastric artery: stomach & oesophagys

  • Shorter branch

Label the following diagram

Label the following diagram

Compare the venous & arterial system of the abdominal viscera

• Both have 3 major unpaired branches:

  • Celiac trunk (arterial) & splenic vein (venous)

  • Superior mesenteric (both)

  • Inferior mesenteric (both)

• Arteries originate from abdominal aorta

• Veins drain into portal vein (NOT directly into IVC)

Label the following diagram

Label the following diagram