Hemolymphatic System: Splenic Diseases

Question 1

Spleen Anatomy:

Answer 1

• All animals have spleens and there is great morphologic variability amongst species

Question 2

Spleen location

Answer 2

• Along the greater curvature of the stomach attached by the gastrosplenic ligamnet
• In dogs, the gastrosplenic ligament tightly connects the spleen to the stomach. Also the K9 spleen is typically wider at one end than the other. A potential source of confusion is which end is the head and which is the tail.
• The tail is defined by surgeons and rediologists as the portion of spleen that is not as tightly apposed to the greater curvature of hte stomach and that is the wider or larger end
• In pigs, the gastrosplenic ligament provides a much looser connection
• In cattle and small ruminants, the spleen is firmly adherent to the rumen.
• In birds, they vary form round to oval to “sausage” shaped, typically located dorsal and left-lateral between proventriculus and ventriculus

Question 3

Spleen Histology

Answer 3

• Highly elastic with a smooth muscle capsule, and trabeculae and distinct red and white pulp.
• Red pulp:
  
  • blood-filled vascular spaces
• White Pulp:
  
  • white cell affrefates adjacent to blood vessels

Question 4

Spleen Types

Answer 4

• Two types of spleens exist with considerable overlap
• Storage spleens:
  
  • horses and carnivores:
    
    • have the larges red blood cell storage capacities
• Immunologic spleens:
  
  • most have a blood vurveillance function; site where abnormal RBC’s are removed.