Ch. 83 Spleen

Question 1

what artery supplies the spleen?

Answer 1

the splenic artery, which comes off the celiac
the celiac splits into hepatic, left gastric, and splenic arteries
the splenic artery will run the length of the left limb of the pancreas and give rise to the pancreatic artery and then angle toward the hilus of the spleen
… the splenic artery will give off some short gastrics that course through the splenogastric ligament and continue as the left gastroepiploic artery

Question 2

Do dogs have a sinusoidal or non sinusoidal spleen

Answer 2

dogs have a sinusoidal which means there is a combo of direct arteriovenous endothelial connection and some areas where RBCs must traverse a region of red pulp between vessels before entering the venous side

Question 3

Do cats have a sinusoidal or non sinusoidal spleen

Answer 3

cats have a non sinusoidal spleen
it has open ended venous channels ad perforated endothelial channels to allow direct connection between the arterial and venous vasculature

Question 4

what is splenosis

Answer 4

this is when accessory spleens have formed as a result of fracture or trauma

Question 5

What triggers the spleen to cull RBCs from circulation

Answer 5

inelastic cells like spherocytes or acanthocytes are unable to deform and pass through
RBCs may be covered in immunoglobulin and bacteria

Question 6

t/f splenic extramedullary hematopoisis is rare in cats

Answer 6

true - it is rare in cats

Question 7

how much of a dog’s RBC and platelet mass can be stored in the spleen

Answer 7

10-20% RBC mass

30% platelet mass

Question 8

What are the three splenic pools and how quickly does that blood rejoin?

Answer 8

rapid - 90% of the blood in the spleen, rejoins within 30 sec
intermediate - 9% of the blood in the spleen, rejoins within 8 minutes
slow - 1% of the blood in the spleen and rejoins in an hour

Question 9

What immunologic products is the spleen the largest producer of?

Answer 9

B cells
T cells
IgM

Question 10

what does the process of phagocytosis in the spleen involve

Answer 10

• antigen is presented to the spleen and taken up by macrophages in the marginal zone and in the sinusoids of the red pulp
• lymphocytes are trapped
• these lymphocytes are then readily available
• after they are activated, lymphocytes migrate from the primary follicle to the red pulp and marginal zone, where most antibody production occurs