TBL17 - Spleen

Question 1

Where does the retroperitoneal splenic artery course?

Answer 1

The retroperitoneal splenic artery courses within the splenorenal ligament to reach the hilum of the spleen i.e., the ligament serves as a mesentery

Question 2

Where do the short gastric arteries branch from and where? Where do the short gastric arteries course and what do they supply?

Answer 2

1) The short gastric arteries branch from the splenic artery before it enters the splenorenal ligament
2) The short gastric arteries course within the gastrosplenic ligament to supply the fundus of the intraperitoneal stomach

Question 3

What do the splenic capsule and inward projecting trabeculae encompass?

Answer 3

The dense connective tissue splenic capsule and the inward projecting trabeculae encompass a dense meshwork of reticular fibers designated the splenic pulp

Question 4

What is white pulp? What is red pulp? What is discharged into the red pulp?

Answer 4

1) Pulp contains scattered lymphoid nodules, which are collectively called white pulp
2) The vast intervening meshwork of reticular fibers is filled mainly with erythrocytes; thus, it is called red pulp
3) Open-ended capillaries discharge RBCs and the other formed elements of blood directly into the red pulp

Question 5

Where do branches of the splenic artery course to get to the red pulp? Where do these branches terminate? What interweaves throughout the red pulp for drainage?

Answer 5

1) Branches of the splenic artery course in the trabeculae where small branches arise and enter the red pulp
2) The small branches terminate in the open-ended capillaries
3) A network of venous sinusoids, which drains into tributaries of the splenic vein, interweaves throughout the red pulp

Question 6

What are endothelial cells of the sinusoids of the pulp separated by? What squeezes through the slits to re-enter the bloodstream from the red pulp?

Answer 6

1) Endothelial cells of the sinusoids are separated by slit-like spaces
2) The extravascular formed elements of the blood, except aged RBCs that lose their pliability, squeeze through the slits to re-enter the bloodstream from the red pulp

Question 7

What other cell type is found in the red pulp as a permanent resident? What do these cells therefore do to aged RBCs?

Answer 7

1) Macrophages are permanent residents of the red pulp

2) Thus, aged RBCs are removed from the red pulp via phagocytosis

Question 8

What happens to blood-borne antigens in the red pulp? What can therefore form in the white pulp?

Answer 8

1) Blood-borne antigens are either selectively bound by B cells or phagocytized by resident macrophages in the red pulp
2) Proliferation of antigen-bound B cells forms the lymphoid nodules of the white pulp

Question 9

How do clinical consequences of splenectomy in children differ from those in adults?

Answer 9

1) Splenectomy, or removal of the spleen, is used as therapy for some chronic disorders or an emergency procedure for traumatic rupture of the spleen
2) Splenectomy in adults usually has no clinical consequence, but in children it leads to increased occurrence and severity of infections