Part 1 obgyn notes Sri Lanka
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    8.Pancreas

    8.Pancreas

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    ⭐ PANCREAS β€” 20% THAT GIVES 80% MARKS

    πŸ”₯ 1. Functions (Exocrine + Endocrine) – MUST KNOW

    Exocrine

    • Acini β†’ pancreatic juice β†’ drains into duodenum
    • Enzymes: lipase, amylase, proteases (trypsin, chymotrypsin)
    • Function β†’ digestion

    Endocrine

    • Islets of Langerhans
      • Ξ²-cells β†’ insulin
      • Ξ±-cells β†’ glucagon
      • Ξ΄-cells β†’ somatostatin
    • Function β†’ carbohydrate metabolism

    EXAM TIP: Always mention both systems β€” very commonly asked.

    πŸ”₯ 2. General Shape & Orientation (Visual Picture)

    • Looks like a thick β€œhook-shaped” walking stick lying horizontally.
    • Head β†’ right, Tail β†’ left (touches spleen).
    • Length ~15 cm.

    πŸ”₯ 3. Key Parts & Their Relations (VERY HIGH YIELD)

    HEAD

    • Lies in C-shaped curve of duodenum.
    • Behind it: IVC, right & left renal veins.
    • Uncinate process:
      • hooks behind SMA + SMV
      • in front of aorta

    ⭐ SUPER IMPORTANT RELATION

    β†’ Portal vein forms behind the neck (SMV + splenic vein)

    NECK

    • Anterior to SMV
    • Posterior to neck β†’ portal vein forms

    BODY

    • Crosses aorta, left renal vein, left crus.
    • Splenic artery runs along superior border (tortuous).
    • Splenic vein runs posterior to body.

    TAIL

    • Only intraperitoneal part
    • Lies in splenorenal ligament with splenic vessels
    • Reaches hilum of spleen

    Exam favourite: Tail is at risk during splenectomy β†’ damage causes insulin issues (endocrine-rich region)

    πŸ”₯ 4. Duct System (ABSOLUTE MUST KNOW)

    Main Pancreatic Duct (Wirsung)

    • Runs tail β†’ head.
    • Joins common bile duct at hepatopancreatic ampulla (ampulla of Vater).
    • Opens at major duodenal papilla.

    Accessory Duct (Santorini)

    • Drains uncinate + lower head.
    • Opens at minor papilla (2 cm above major).

    ERCP fact:

    β†’ Catheter preferentially enters pancreatic duct (common SBA).

    πŸ”₯ 5. Peritoneal Position

    • Entire pancreas is retroperitoneal

      • except the tail β†’ intraperitoneal in splenorenal ligament.

    πŸ”₯ 6. Transverse Mesocolon Attachment

    • Attached across head + neck + anterior border of body.
    • Therefore, pancreas lies in both supracolic + infracolic compartments.

    🎯 If you understand the following picture, you score 80%

    PANCREAS FLOW SUMMARY

    • Head in duodenum β†’ uncinate behind SMA/SMV
    • Neck sits over SMV β†’ portal vein forms behind
    • Body runs over aorta β†’ splenic artery above, splenic vein behind
    • Tail in splenorenal ligament β†’ touches spleen
    • Main duct + bile duct join β†’ major papilla
    • Accessory duct β†’ minor papilla

    ⭐ PANCREAS β€” BLOOD, LYMPH, NERVE, STRUCTURE

    πŸ”₯ 1. Blood Supply (SUPER HIGH YIELD)

    A. Body, Neck, Tail β†’ SPLENIC ARTERY

    • Splenic artery = MAIN vessel
    • Runs along superior border of pancreas
    • Gives a large branch β†’ Pancreatica Magna artery (important name)

    B. Head β†’ TWO ARTERIAL ARCADES

    1. Superior Pancreaticoduodenal a.
      • From gastroduodenal artery
      • Supplies upper head
    2. Inferior Pancreaticoduodenal a.
      • From SMA
      • Supplies lower head + uncinate

    High-yield concept:

    β†’ Superior + Inferior arteries form anterior & posterior arcades

    β†’ Vital collateral flow between CA (coeliac axis) & SMA.

    πŸ”₯ 2. Venous Drainage (VERY HIGH YIELD)

    • Neck, body, tail β†’ splenic vein
    • Head β†’ two veins:
      • Superior pancreaticoduodenal vein β†’ portal vein
      • Inferior pancreaticoduodenal vein β†’ SMV

    Exam trick:

    β†’ Head drains into both portal and SMV systems.

    πŸ”₯ 3. Lymph Drainage (EXAM LOVE THIS)

    Left of neck, body, tail

    • Pancreaticosplenic nodes

      • (Run along splenic artery)

    Head

    • Upper head β†’ Coeliac nodes
    • Lower head + uncinate β†’ Superior mesenteric nodes

    Rule:

    β†’ Lymph follows arteries

    β†’ Know: Coeliac (upper), SMA (lower).

    πŸ”₯ 4. Nerve Supply (Clear & Direct)

    Parasympathetic

    • From vagus (mainly posterior vagal trunk β†’ coeliac plexus)
    • Function β†’ stimulates exocrine secretion

    Sympathetic

    • From T6–T10 via greater splanchnic nerves β†’ coeliac plexus
    • Function β†’ vasoconstriction + pain fibers

    Pain referral

    β†’ Follows sympathetic T6–T10 dermatomes

    β†’ Pain radiates epigastrium β†’ mid-back (band-like)

    πŸ”₯ 5. Structure β€” MUST KNOW POINTS

    Exocrine portion

    • Serous acini form the majority.
    • Centroacinar cells β†’ make bicarbonate-rich fluid.
    • Stimulated by:
      • Secretin β†’ ↑ bicarbonate
      • CCK β†’ ↑ enzyme secretion (trypsin, lipase)

    Endocrine portion (Islets of Langerhans)

    ➑ Scattered β€œpale” cells among acini.

    • Ξ±-cells β†’ glucagon
    • Ξ²-cells β†’ insulin
    • Ξ΄-cells β†’ somatostatin

    Exam ask: Beta cells = 70% of islet cells (most common β†’ insulin).

    ⭐ PANCREAS DEVELOPMENT

    πŸ”₯ 1. Two Pancreatic Buds (The MOST important fact)

    The pancreas develops from two endodermal buds at the foregut–midgut junction:

    1. Dorsal pancreatic bud
    2. Ventral pancreatic bud

      3. (grows with bile duct into ventral mesogastrium)

    This is the single most tested concept.

    πŸ”₯ 2. Rotation & Fusion (Critical for embryology questions)

    • During gut rotation:
      • Duodenum rotates rightward/posterior
      • Ventral bud swings backwards to meet the dorsal bud
    • BOTH buds then fuse behind the peritoneum (β†’ secondary retroperitoneal position)

    πŸ”₯ 3. Final Adult Contributions (Exam GOLD)

    Dorsal bud β†’ majority of pancreas

    • Body
    • Tail
    • Neck
    • Upper head

    Ventral bud β†’ small but HIGH-YIELD parts

    • Lower head
    • Uncinate process

    If you remember this, you will answer 90% of embryology SBAs correctly.

    πŸ”₯ 4. Duct Formation (SUPER HIGH-YIELD)

    After fusion:

    • Main pancreatic duct (Wirsung) = ventral duct + distal dorsal duct
    • Accessory pancreatic duct (Santorini) = proximal dorsal duct

    KEY EXAM TRICK

    β†’ Accessory duct = dorsal bud remnant

    β†’ Main duct = ventral duct continues + dorsal duct joins

    πŸ”₯ 5. Pancreatic Development Anomaly: Annular Pancreas

    Cause:

    • Ventral bud fails to rotate properly β†’ encircles 2nd part of duodenum

    Clinical result:

    • Duodenal obstruction
    • Bilious vomiting in neonates
    • β€œDouble bubble sign” on X-ray

    This is the ONLY anomaly they test repeatedly.

    πŸ”₯ 6. Development of Acini & Islets (Short but important)

    • Acini form by branching of terminal ducts
    • Islets of Langerhans:
      • Start from the same ductal epithelium
      • Later separate and convert into endocrine hormone-secreting cells

    This explains why both endocrine and exocrine tissues share a developmental origin.

    ⭐ PANCREAS β€” SURGICAL APPROACH

    πŸ”₯ 1. Kocher’s Manoeuvre β€” The One Thing You MUST Know

    Definition:

    β†’ Mobilisation of duodenum + head of pancreas by releasing peritoneum on the right edge of D2 and reflecting duodenum medially.

    Purpose (exam gold):

    • Exposes posterior surface of duodenum
    • Exposes back of pancreatic head
    • Gives access to lower bile duct

    Structures at risk behind:

    • IVC
    • Ureter (right)
    • Gonadal vessels

    Remember:

    β†’ Kocher = access to posterior duodenum + pancreatic head + distal bile duct.

    πŸ”₯ 2. Pancreatic Head Resection (Whipple principle)

    Concept (exam-ready summary):

    • Removing pancreatic head + duodenal C-loop requires reconstruction:
      • Bile duct β†’ jejunum
      • Pancreatic remnant β†’ jejunum
      • Stomach β†’ jejunum

    KEY PROTECTION:

    β†’ Portal vein is immediately posterior to the neck β†’ must be preserved and free of tumour involvement.

    This is one of the most tested anatomical dangers.

    πŸ”₯ 3. Pseudocysts β€” High-Yield Anatomy Point

    What they test:

    • Location:

      • β†’ Pseudocysts typically expand into the lesser sac

      β†’ usually behind the stomach.

    Why this matters:

    • Because the stomach lies directly in front of the cyst.
    • Thus, cysts can be drained into the stomach lumen (conceptual, not procedural).

    πŸ”₯ 4. Critical Structures to Remember (Fast exam recall)

    Behind the duodenum & pancreatic head during mobilisation:

    • IVC
    • Right ureter
    • Right gonadal vessels
    • Portal vein behind neck of pancreas

    These appear in true/false questions frequently.