LECTURE 1: Anatomy & Physiology of Spleen

Anatomy and Physiology of the Spleen

1. ❓ Primary objective of the spleen?
   💡 Answer: To filter the peripheral blood.
2. ❓ Location of the spleen?
   💡 Answer: In the left upper quadrant (LUQ) of the abdomen.
3. ❓ Which ligament anchors the spleen to the stomach?
   💡 Answer: The gastrosplenic ligament.
4. ❓ Describe the spleen’s superior and inferior surfaces.
   💡 Answer: The superior surface is convex; the inferior surface is concave.
5. ❓ At what gestational age does splenic development begin?
   💡 Answer: Around the fifth week of gestation.
6. ❓ Spleen’s primary fetal role?
   💡 Answer: Red blood cell production (erythropoiesis).
7. ❓ Spleen’s main function in childhood?
   💡 Answer: Defending the body against infection.
8. ❓ Two types of splenic tissue?
   💡 Answer: White pulp and red pulp.
9. ❓ Function of white pulp?
   💡 Answer: Produces lymphocytes for immune defense.
10. ❓ Function of red pulp?
    💡 Answer: Phagocytosis—engulfing and destroying damaged cells and pathogens.
11. ❓ “Culling” in the spleen means what?
    💡 Answer: Removing abnormal red blood cells from the bloodstream.
12. ❓ “Pitting” in the spleen means what?
    💡 Answer: Stripping away undesirable inclusions from red blood cells without destroying them.
13. ❓ Five key functions of the spleen?
    💡 Answer:
    1. Defense against disease
    2. Hematopoiesis/erythropoiesis
    3. Destruction/removal of flawed RBCs and platelets
    4. Blood reservoir
    5. Iron storage

 Vascular Anatomy of the Spleen

1. ❓ How does blood reach the spleen?
   💡 Answer: Through the splenic artery, a branch of the celiac trunk.
2. ❓ Relationship of the splenic artery to the pancreas?
   💡 Answer: It courses superior to the pancreatic body and tail.
3. ❓ Where does the splenic artery enter the spleen?
   💡 Answer: At the splenic hilum.
4. ❓ Which vein drains blood from the spleen?
   💡 Answer: The splenic vein.
5. ❓ Where does the splenic vein join the superior mesenteric vein?
   💡 Answer: Behind the neck of the pancreas to form the portal vein.

 Sonography of the Spleen

1. ❓ Best patient position for spleen ultrasound?
   💡 Answer: Right lateral decubitus, with deep inspiration.
2. ❓ Typical sonographic appearance of the spleen vs. the liver?
   💡 Answer: Often isoechoic to the liver, though it can be slightly more echogenic.
3. ❓ Shape of the spleen on ultrasound?
   💡 Answer: Crescent-shaped, with a concave inferior margin and a convex superior border.
4. ❓ Term for an enlarged spleen?
   💡 Answer: Splenomegaly.
5. ❓ Location of splenic vessels?
   💡 Answer: At the splenic hilum, along the spleen’s medial aspect.

 Congenital Anomalies and Variants

1. ❓ Another name for an accessory spleen?
   💡 Answer: Splenule, splenunculus, or supernumerary spleen.
2. ❓ Usual location of an accessory spleen?
   💡 Answer: Near the splenic hilum or by the pancreatic tail.
3. ❓ Sonographic appearance of an accessory spleen?
   💡 Answer: Isoechoic to the main spleen.
4. ❓ What is a splenic cleft?
   💡 Answer: A congenital split in the spleen appearing as a hyperechoic line dividing it into segments.
5. ❓ What is asplenia?
   💡 Answer: Congenital absence of the spleen.
6. ❓ What is polysplenia?
   💡 Answer: Multiple small splenic masses.
7. ❓ Which syndromes feature asplenia and polysplenia?
   💡 Answer: Heterotaxia syndromes.
8. ❓ What is splenosis?
   💡 Answer: Implantation of splenic tissue in abnormal locations, typically after the spleen ruptures.
9. ❓ What leads to a wandering spleen?
   💡 Answer: Underdeveloped or absent ligaments, allowing excessive mobility.
10. ❓ Major complication of a wandering spleen?
    💡 Answer: Splenic torsion.
11. ❓ Consequence of splenic torsion?
    💡 Answer: Splenic infarction.
12. ❓ What condition can mimic a splenic mass?
    💡 Answer: Splenosis.