B21 - Spleen, omenta, blood supply and innervation

Question 1

Spleen

Structures to mention on the spleen

Answer 1

• Lien (Abdominal lymphatic organ incorporated into the circulatory system
• Fascies parietalis [diaphragmatica] (Convex lateral surface, facing diaphragm (ru, eq) and left-cranial abdominal wall)​
• Fascies visceralis (Concave medial surface, contains hilus)
  
  • ​Fascies renalis (ø ru) (Dorsal part of fascies visceralis, facing left kidney)
  • Fascies gastrica (Cranial part of fascies visceralis, facing the stomach, ru: entire fascies visceralis)
  • Fascies intestinalis (ø ru) (Caudal part of fascies visceralis, faces jejunum and colon)
• Extremitas dorsalis
• Extremitas ventralis
• Margo cranialis
• Margo caudalis
• Hilus lienalis (Car, sus: longitudinal ridge, ru: round depression, at fascies visceralis for entrance of nerves and arteries, exit of veins and lymphatic vessels)
• Tunica serosa (Peritoneal layer covering the spleen, except for hilus lienalis and fascies visceralis (ru))
• Capsula (Consists of collage, elastic and smooth muscle fibers)
• Trabeculae lienalis (Cords of collagen, elastic and smooth muscle fibers which leaves the capsule. Contains arteries, veins, nerves and lymph vessels)
• Pulpa lienalis ruba (Red pulp. System of sinuses, filled with blood cells)
• Pulpa lienalis alba (White plup. Cell-rich lymphatic tissue which surrounds the initial segments of the intraparenchymatous rami lienalis arteriae lienalis, forming periparietal lymphatic sheaths of larger lymphonoduli)
• Rami lienalis [a. lienalis] (Branch of a. lienalis, enter capsule and trabeculae)
• Lymphonoduli [Noduli lyphatici] lienalis (Accumulation of lymphatic tisse, surrounds the intraparenchymatous rami lienalis arteriae lienalis locally)
• Lien accessorius (sus) (Small island of additional splenic tissue, in lig. gastrolienalie)

Question 2

Spleen

Location

Answer 2

• Left cranial part of the abdomen, joined to curvatura major of the stomach by inclusion within omentum major
• Lies against the left abdominal wall
• Position can not be defined exactly since it is dependent on the degree of filling of the stomach and on its own blood content

Question 3

Spleen

Interspecies differences

Answer 3

• Fascies visceralis:
  
  • Fascies renalis (ø ru)
  • Fascies intestinalis (ø ru)
• Hilus lienalis:
  
  • Car, sus, eq: longitudinal ridge, marked by splenic vessels and nerves, and attachment of lig. gastrolienalis
  • Ru: round depression
• Capsula:
  
  • Ca: capsule and trabeculae are very muscular
  • Ru: less muscular than in dog
• Shape:
  
  • Ca: dumbell shaped
  • Sus: tongue-shaped
  • Ru: broader oblong
  • Eq: falciform, comma shaped

Question 4

Spleen

Function

Answer 4

• Blood storage
• Storage of iron
• Production of erytrocytes in young animals
• Destruction of worn out erythrocytes
• Production of lymphocytes in adults

Question 5

Spleen

Hilus lienalis

Answer 5

• On fascies visceralis
• Car, sus, eq: longitudinal ridge
• Ru: round depression
• Entrance for:
  
  • Nerves
  • A. lienalis
• Exit for:
  
  • V. lienalis
  • Lymphatic vessels

Question 6

Spleen

Ligaments of the spleen

Answer 6

• Lig. gastroepiploicum
  
  • ​Spleen → stomach
  • Part of omentum minus
• Lig. phrenicosplenicum (ru, eq)​
  
  • Fascies parietalis of spleen → diaphragm
• Lig. lienorenale (eq)
  
  • Spleen → left kidney
  • Intestine can become trapped → colic

Question 7

Spleen

Draw a cross-section of the spleen

Answer 7

Question 8

Spleen

Blood supply

Answer 8

• A. coeliaca → a. lienalis
• V. lienalis → vena portae (blood from spleen to liver)
• Ru: blood vesses pass undivided through hilus
• Eq, sus: blood vesses run the length of the spleen detatching branches at intervals
• Ca: blood vesses divide as they approach the spleen into branches

Question 9

Spleen

Innervation

Answer 9

• Sympathetic and parasympathetic
• N. vagus → plexus coeliaca → plexus lienalis

Question 10

Omenta

Location

Answer 10

Serosal sheet associated with the GI-tract in the abdominal cavity, and partly in the pelvic cavity

Question 11

Omenta

Function

Answer 11

• Produce and absorb abdominal fluids
• Lymphatic and phagocytotic
• Storage of fat
• Large number of blood vesses in the omentum major may play a role in the regulation of blood pressure in the abdominal cavity

Question 12

Omenta

Give the type of mesentery and their blood supply at the different divisions of the GI-tract

Answer 12

Question 13

Omenta

Omentum major

Answer 13

• Serous fold
• Superficial and deep layer
  
  • Enclose the space called bursa omentalis
    
    • ​For. epiploicum → bursa omentalis​
    • Bursa omentalis is connection between omentum major and omentum minor
  • Left lobe of the pancreas is located between the two folds
• Attaches to curvatura major of the stomach

Question 14

Omenta

Omenta minor

Answer 14

• Serosal sheet
• Passes from curvatura minor of the stomach and cranial part of duodenum → fascies visceralis of the liver
• Ligaments from omentum minor:
  
  • ​Lig. hepatoduodenale (Liver → pars cranialis duodeni)
  • Lig. hepatogastricum (Liver → curvatura minor of the stomach)

Question 15

Omentum

Bursa omentalis

Answer 15

• Cavity in the abdomen
• Formed by omentum major and omentum minor
• Entrance:
  
  • ​For. epiploicum
    
    • Bordered by:
      
      • ​Ventral from vena cava caudalis
      • Dorsal from vena portae
      • Processus caudatus of the liver
  • Vestibulum bursa omentalis
    
    • ​Bordered ventrally by omentum minor
      
      • ​Left wall is formed by lig. gastrophrenicus whis is connected to omentum minor
      • To the right, bounded by omentum minor, pancreas, vena cava caudalis and vena porta
  • Auditus recessus caudale?​
    
    • Above curvatura minor
    • Entrance of recessus caudalis
  • Recessus caudalis
    
    • ​Space between paries superficialis and omentum major, pars profunda)

Question 16

Omenta

Blood supply

Answer 16

Omenta major:

• A. coeliaca
  
  • ​A. lienalis → a. gastroepiploica sinistra
  • A. hepatica → a. gastroepiploica dextra → rr. epiploici

Omenta minor:

• A. coeliaca → a. hepatica