Five Fluids In/Out of the Liver

⭐ The liver has a DUAL blood supply: portal vein (70%, nutrient-rich venous) + hepatic artery (30%, oxygenated). All output leaves via hepatic veins, bile ducts, or lymphatics.

Direction	Vessel / Duct	Content — fill in
IN	Portal vein
IN	Hepatic artery proper
OUT	Hepatic veins (R / M / L)
OUT	Bile ducts (R + L hepatic)
OUT	Lymphatics

Hepatic Lobes & Couinaud Segments

Cantlie’s line: gallbladder fossa → ___

Caudate lobe = Couinaud segment ___ (spared in Budd-Chiari)

Quadrate + caudate are functionally ___ lobe (by Couinaud)

Porta Hepatis — BD HAP (Anterior → Posterior)

⭐ BD HAP = Bile Duct (anterior) → Hepatic Artery → Portal vein (posterior). The hepatoduodenal ligament forms the anterior wall of the foramen of Winslow.

Position at Porta Hepatis	Structure — fill in	Notes
Most anterior		Exits liver carrying bile
Middle		~30% blood flow, ~50% O₂ supply
Most posterior (largest)		~70% blood flow; nutrient-rich venous blood
Pringle maneuver — structure compressed		Temporarily halts hepatic blood flow intraoperatively

Portal-Systemic Anastomoses — Sites of Collateral Formation in Portal HTN

🎯 Step 1 Favorite — Know all 4 locations + clinical manifestation

Location	Portal Side	Systemic Side — fill in	Clinical Result — fill in
Esophagus	Left gastric (coronary) vein
Anorectal junction	Superior rectal vein (IMV)
Periumbilical	Paraumbilical veins (falciform lig.)
Retroperitoneal	Colic / retroperitoneal veins

GIT Pain Referral — Specific Patterns to Know

Condition	Referred Pain Location — fill in	Mechanism
Biliary colic / cholangitis		Diaphragm irritation → phrenic nerve (C3–C5)
Splenic rupture (Kehr’s sign)		Blood under left diaphragm → phrenic C3–C5

Biliary Tree Architecture

Step	Biliary Tree — fill in the blanks
1	Right + left hepatic ducts → (exits liver)
2	(from gallbladder) + common hepatic duct → CBD
3	CBD + main pancreatic duct → → major papilla
4	Opens at in the 2nd part (descending) of the duodenum

Gallbladder Anatomy & Calot’s Triangle

Feature	Answer — fill in
Gallbladder capacity
Murphy’s point: right ___ costal cartilage at MCL (fundus location)
Hartmann’s pouch: bulge at the ___ (where stones lodge)
Calot’s triangle: medial boundary (the named duct)
Calot’s triangle: structure found within (must ID before clipping)

Cystic Artery & Laparoscopic Cholecystectomy

Cystic artery typically arises from ___

Most common serious complication of lap cholecystectomy

Splenic Anatomy

Feature	Answer — fill in
Location (quadrant)
Deep to ribs ___
Long axis lies along rib ___
Gastrosplenic ligament contains (vessels)
Splenorenal ligament contains (vessels + structure)
Post-splenectomy blood smear finding (nuclear remnants in RBCs)

SHiN Vaccines & Splenic Clinical Correlates

⭐ Post-splenectomy patients are at risk for OPSI (overwhelming post-splenectomy infection) from encapsulated organisms — vaccinate ideally 2 weeks BEFORE elective splenectomy.

SHiN = S. pneumoniae + ___ + N. meningitidis

Spleen becomes palpable when enlarged to ___× normal size

OPSI most common causative organism (50–70% mortality)

Kehr’s sign mechanism: blood under ___ irritates phrenic nerve

Splenic Vasculature & Portal Vein Formation

Splenic artery is largest branch of ___

Splenic vein runs posterior to ___

Portal vein formed behind ___ of pancreas (SMV + splenic vein)

Parts of the Pancreas — Key Relations

Part	Location	Key Relation — fill in the blank
Head	C-loop of duodenum; L1–L2	CBD runs in groove on surface; SMA/SMV anterior
Uncinate process	Extension of head hooked behind SMA/SMV	SMA + SMV pass to uncinate — surgical danger zone
Neck	Anterior to portal vein formation	Portal vein forms immediately to neck of pancreas
Body	Crosses L1–L2; posterior to stomach	vein runs in groove on posterior surface
Tail	Extends to splenic hilum; splenorenal lig.	Only part of pancreas

Pancreatic Duct System

Main pancreatic duct = duct of ___

Accessory duct = duct of ___ (opens at minor papilla)

Hepatopancreatic ampulla is the ___ point of the biliary tract

Embryological Pancreatic Variants

Annular pancreas: failure of ___ to rotate clockwise

Annular pancreas causes ___ obstruction

Pancreas divisum: failure of ___; most common anatomic variant

Obstructive Jaundice Syndromes

🎯 Step 1 — Distinguish these three jaundice presentations

Presentation / Question	Diagnosis / Answer — fill in
Painless progressive jaundice + weight loss + palpable distended gallbladder
Acute epigastric pain + sudden-onset jaundice + pancreatitis
RUQ pain + fever/chills + jaundice (Charcot’s triad)
OJ lab pattern: ↑ direct bilirubin + ↑ ___ + ↑ GGT (mild/normal ALT/AST)
Courvoisier rationale: GB distends in cancer but NOT in gallstone disease because GB wall is ___

Visceral Pain Referral — Gut Divisions

Gut Division	Spinal Level / Nerve	Referred Pain Zone — fill in
Foregut	T5–T9 (greater splanchnic)
Midgut	T10–T11 (lesser splanchnic)
Hindgut	L1–L2 (lumbar splanchnic)

Acute Pancreatitis — GET SMASHED

⭐ GET SMASHED = Gallstones, Ethanol, Trauma, Steroids, Mumps/Malignancy, Autoimmune, Scorpion, Hyperlipidemia/Hypercalcemia, ERCP, Drugs

Two most common causes: gallstones + ___

Pain: epigastric, radiates to ___ (retroperitoneal location)

Position that relieves pancreatitis pain

Lab marker more specific than amylase

Chronic calcifying pancreatitis X-ray shows ___ in pancreatic distribution

Pancreatic Enzyme Table — Substrate & Activation

⭐ Most enzymes secreted as inactive zymogens. Trypsin is the master activator — activated first by enterokinase at the brush border. Lipase and amylase are secreted active.

Enzyme (Zymogen → Active)	Substrate — fill in	Activated By — fill in	Key Notes
Trypsinogen → Trypsin			Master activator of all other zymogens
Chymotrypsinogen → Chymotrypsin			—
Proelastase → Elastase			Causes vessel wall damage in pancreatitis
Pancreatic lipase			Requires bile salt emulsification; deficiency → steatorrhea
Pancreatic amylase			Elevated in pancreatitis; salivary amylase also contributes
Phospholipase A2			Destroys cell membranes in pancreatitis

Key Hepatic Functions — Clinical Implications

Function	Product / Action	Clinical Implication — fill in
Protein synthesis	Albumin, fibrinogen, clotting factors II, VII, IX, X
Glycogen storage	Stores glucose as glycogen; releases between meals
Cholesterol synthesis	~80% of body cholesterol; LDL precursors
Detoxification	CYP450 system metabolizes drugs, alcohol, toxins
Urea cycle	Converts ammonia → urea (excreted by kidney)

CCK vs. Secretin — Coordinate Fat Digestion

Hormone	Released By (Stimulus & Cell) — fill in	Key Actions — fill in the blank
CCK (cholecystokinin)		GB contraction; sphincter of Oddi ; pancreatic enzyme secretion (acinar)
Secretin		Pancreatic ductal cells secrete (neutralizes acid chyme)

Enterohepatic Circulation of Bile Salts

Bile salts reabsorbed in the ___ (active transport)

Approximate % of bile salts recycled per meal

Ileal resection → deficiency of fat-soluble vitamins ___

First-Pass Metabolism & Portal Nutrient Delivery

Nutrients (except fat) reach liver first via ___

Fat absorbed as ___ → enters lacteals → bypasses liver initially

In portosystemic shunting: ___ bypass liver → hepatic encephalopathy

Q1 — LO1: A 58-year-old man with alcoholic cirrhosis presents with hematemesis. Endoscopy confirms large esophageal varices. Which portal tributary is most directly responsible for the formation of esophageal varices in portal hypertension?

A) Right gastric vein

B) Left gastric (coronary) vein

C) Inferior mesenteric vein

D) Paraumbilical veins

B — Left gastric (coronary) vein. The left gastric vein drains the lesser curvature and lower esophagus into the portal system. In portal HTN, elevated pressure reverses flow through the left gastric vein, engorging submucosal esophageal veins → varices. Paraumbilical veins (D) → caput medusae; IMV (C) → anorectal/sigmoid varices.

Q2 — LO1: A surgeon planning a right hepatic lobectomy must identify Cantlie’s line to define the true functional midplane. Cantlie’s line runs between which two structures?

A) Falciform ligament and ligamentum teres

B) Left triangular ligament and porta hepatis

C) Gallbladder fossa and groove for the IVC

D) Right hepatic vein and left hepatic duct

C — Gallbladder fossa to IVC groove. Cantlie’s line is the true surgical midplane separating functional right and left lobes. The falciform ligament (A) is only a surface landmark — the quadrate and caudate lobes appear right-sided but are functionally left-sided by Couinaud classification. Never confuse the falciform with the functional midplane on Step 1.

Q3 — LO1: A surgeon performing laparoscopic cholecystectomy must achieve the “critical view of safety” within Calot’s triangle before clipping. What are the correct boundaries of Calot’s triangle?

A) Cystic duct, common bile duct, and portal vein

B) Cystic duct, hepatic artery proper, and liver surface

C) Cystic duct, common hepatic duct, and inferior liver surface

D) Common hepatic duct, right hepatic duct, and left hepatic duct

C — Cystic duct (inferior), common hepatic duct (medial), inferior liver surface (superior). The cystic artery (typically from the right hepatic artery) runs within this triangle and must be identified before clipping. Misidentifying the CBD as the cystic duct is the most feared complication of lap cholecystectomy.

Q4 — LO2: A 22-year-old man sustains blunt abdominal trauma in a motor vehicle collision. He has LUQ tenderness and left shoulder tip pain. CT shows a splenic laceration. The spleen lies deep to which ribs?

A) Ribs 5–7

B) Ribs 7–9

C) Ribs 9–11

D) Ribs 11–12

C — Ribs 9–11. The spleen lies in the LUQ deep to ribs 9–11 in the midaxillary line; its long axis follows the 10th rib. Left shoulder tip pain (Kehr’s sign) = blood under the left diaphragm irritating the phrenic nerve (C3–C5). Rib 9–11 fractures are the classic mechanism of splenic laceration. The spleen is the most commonly injured organ in blunt abdominal trauma.

Q5 — LO2: A 30-year-old woman with hereditary spherocytosis undergoes elective splenectomy. Six weeks later she develops fulminant sepsis; blood cultures grow S. pneumoniae. Which intervention should have been performed to prevent this complication?

A) Prophylactic anticoagulation to prevent splenic vein thrombosis

B) Vaccination against encapsulated organisms before splenectomy

C) Long-term antifungal prophylaxis

D) IVIG infusion to replace immunoglobulin production

B — Vaccination against encapsulated organisms (SHiN) before splenectomy. The spleen clears opsonized encapsulated bacteria (S. pneumoniae, H. influenzae type b, N. meningitidis). Without it, OPSI can be fatal (50–70% mortality). Vaccines should ideally be given 2 weeks before elective splenectomy for optimal immune response.

Q6 — LO3: A 68-year-old man with a 3-month history of painless progressive jaundice, weight loss, and new-onset diabetes presents with a palpable, non-tender gallbladder. CT shows a 3 cm mass in the head of the pancreas. Which anatomical relationship explains the jaundice?

A) The tumor compresses the portal vein → portal hypertension

B) The CBD runs in a groove on the posterior surface of the pancreatic head → tumor compresses CBD

C) The tumor invades the duodenum → malabsorption of bilirubin

D) The splenic vein thrombosis → left-sided portal hypertension

B — CBD runs in a groove on the posterior surface of the pancreatic head. This is Courvoisier’s law: painless jaundice + palpable (distended, non-tender) gallbladder = pancreatic cancer until proven otherwise. The GB distends because slow obstruction allows gradual dilation; in gallstone disease, the GB wall is fibrotic and cannot distend. 70% of pancreatic cancers arise in the head.

Q7 — LO3: A 45-year-old woman with known cholelithiasis develops sudden epigastric pain radiating to the back, vomiting, and jaundice. Labs: lipase 3,400 U/L, direct bilirubin elevated, ALP elevated. Which single anatomical site explains all three findings?

A) Cystic duct obstruction

B) Common hepatic duct obstruction

C) Ampulla of Vater (hepatopancreatic ampulla)

D) Minor duodenal papilla obstruction

C — Ampulla of Vater. A gallstone impacted at the ampulla simultaneously obstructs both the CBD (→ obstructive jaundice, ↑ ALP, ↑ direct bilirubin) and the main pancreatic duct (→ pancreatitis, ↑ lipase). The ampulla is the narrowest point of the biliary tract — gallstones passing the CBD can become trapped here. This is why gallstones and alcohol are the two most common causes of acute pancreatitis.

Q8 — LO4: A medical student is reviewing digestive physiology. Which of the following correctly pairs each hormone with its primary stimulus and action?

A) CCK released by acid → stimulates pancreatic HCO₃⁻ secretion

B) Secretin released by fat → causes gallbladder contraction

C) CCK released by fat + protein → GB contraction + sphincter of Oddi relaxation + pancreatic enzyme secretion

D) Secretin released by fat → stimulates pancreatic acinar enzyme secretion

C — CCK released by fat + protein (I-cells) → GB contraction + SOO relaxation + enzyme secretion. Remember: CCK = fat+protein stimulus, I-cells, GB contracts, SOO relaxes, acinar enzyme secretion. Secretin = acid (H⁺) stimulus, S-cells, ductal HCO₃⁻ secretion (neutralizes chyme). Both work together to optimize fat digestion in the duodenum.

Abdominal Viscera II: Liver, Pancreas & Spleen — Active Recall