Anatomy and Function of the Spleen

Introduction

• The spleen is part of the lymphatic system.
• Latin Name: Lien
• Location: Left side of abdominal cavity, opposite side of the liver.

External Structures

• Size:
  • Length: 12-14 cm
  • Width: 8-10 cm
  • Thickness: 3-4 cm
• Weight: 140-200 grams
• Contains a lot of blood, influencing its function.

Functions of the Spleen

1. Destruction of Old Red Blood Cells:
   • Known as the graveyard of red blood cells.
   • Blood enters through the splenic artery; old/damaged red blood cells and platelets are destroyed.
2. Immune Response:
   • Monitors blood for pathogens and can mount an immune response.
   • Similar function to lymph nodes, but for blood instead of lymph.

Blood Supply

• Artery: Splenic artery supplies blood.
• Vein: Drained by the splenic vein.
• Monitors blood instead of lymph, distinguishing it from the lymph nodes.

Topography and Surfaces

• Location in Abdominal Cavity: Left hypochondriac region.
• Surfaces:
  • Diaphragmatic Surface: Faces the diaphragm.
  • Visceral Surface: Near the stomach, pancreas, left kidney, and transverse colon.
  • Splenic Hilum: Entrance/exit for blood vessels and nerves.

Coverings and Ligaments

1. Fibrous Capsule: Protective fibrous layer around the spleen.
2. Tunica Serosa: Slippery surface formed by peritoneal ligaments.
   • Gastrosplenic Ligament: Connects stomach to spleen.
   • Phrenicosplenic Ligament: Connects diaphragm to spleen.
   • Phrenicocolic Ligament: Connects to the left colic flexure, supporting the spleen indirectly.

Summary

• The spleen is a secondary lymphatic organ that monitors blood, not lymph.
• It is essential for the destruction of aged blood cells and mounting an immune defense against pathogens in the blood. The spleen is supported by several ligaments and has a unique position and structure within the abdominal cavity.