Spleen

Question 1

What is the function of the spleen?

Answer 1

• Removal of blood borne antigens,
• Removal and destruction of aged or defective blood cells,
• Haematopoiesis in the foetus,
• Storing blood platelets and RBCs

Question 2

Describe the location of the spleen

Answer 2

In adults it lies posterior to the stomach, against the diaphragm and between ribs 8-11 on the left side. Posterior to the mid-auxiliary line

Question 3

Describe the structure of the spleen

Answer 3

It has three boarders; a gastric area, a colic area and a renal area. The superior (gastric area) boarder is notched. It is made up of red and white pulp. Red = vascular and white = lymphatic. It is surrounded by

Question 4

Describe how the spleen connects to other organs

Answer 4

• Connected to the stomach via gastrosplenic ligament.

- Connected to the posterior abdominal wall by splenorenal ligament.

Question 5

What does the gastrosplenic and splenorenal ligament contain

Answer 5

Gastrosplenic - Contains left gastroepiploic and short gastric vessels. It may contain accessory spleen.
Splenorenal - Contains splenic vessels and the tail of the pancreas

Question 6

Describe the arterial supply of the spleen

Answer 6

Splenic artery runs along the upper border of the pancreas. It divides into branches that enter the spleen at the hilum.

Question 7

Describe the venous drainage of the spleen

Answer 7

Splenic vein runs along tail and body of pancreas. It receives short gastric and left gastroepiploic veins. Behind the neck of the pancreas, joins the superior mesenteric vein to form the hepatic portal vein.

Question 8

Describe the lymphatic drainage of the spleen

Answer 8

Drain to the splenic hilar LNs then to pancreatico-splenic nodes and then to coeliac nodes

Question 9

Describe the nerve supply of the spleen

Answer 9

The nerve supply accompanies the splenic artery. Sympathetic are from T5-9 (coeliac plexus), and parasympathetics from vagus.

Question 10

Describe features of injuries to the spleen

Answer 10

Because the capsule of the spleen is thin, physical injury or infection may cause the spleen to rupture. Treatment could involve a splenectomy or angiography and embolisation. Patient can live without a spleen but they will be more susceptible to infections

Question 11

Name the visceral branches of the abdominal aorta

Answer 11

• Coeliac trunk, (T12/L1).
• Middle suprarenal arteries,
• Superior mesenteric artery (L1),
• Renal arteries (L1/2 disk),
• Testicular or ovarian arteries (L2),
• Inferior mesenteric artery (L3)

Question 12

Name the parietal branches of the abdominal aorta

Answer 12

• Inferior phrenic arteries,
• 4x Lumbar arteries,
• Median sacral artery

Question 13

Name and describe the two main venous systems of the body

Answer 13

• Hepatic portal venous system (drains venous blood from the absorptive part of the GI tract and associated organs to the liver).
• Systemic venous system (Drains venous blood from all other organs and tissue into the superior or inferior vena cava)

Question 14

Describe the formation of the inferior vena cava

Answer 14

At L5 it joins from the union of the common iliac veins and the small addition of the median sacral vein posterior to the right common iliac artery

Question 15

The IVC receives drainage from what?

Answer 15

• Hepatic veins,
• Right phrenic vein,
• Right suprarenal vein (left goes to left renal),
• Both renal veins (left is longer as the IVC sites closer to the right side),
• Right gonadal vein (left goes to left renal),
• Lumbar veins

Question 16

How is the hepatic portal system formed?

Answer 16

Formes posterior to the neck of the pancrease by the union of the splenic and superior mesenteric veins. It crosses the superior part of the duodenum and enters the lesser omentum.

Question 17

Describe the drainage of blood into the liver

Answer 17

Portal vein enters the liver and its branches supply sinusoids. It then drains to hepatic veins then to the IVC. The portal venous blood is mixed with oxygenated blood from a branch of the hepatic artery proper

Question 18

Describe features of portal hypertension

Answer 18

• It is elevation of BP in portal system which leads to reversal of blood flow and a larger volume of blood flow to anastomotic areas causes them to become varicosed.

Question 19

What are some of the causes of portal hypertension?

Answer 19

Pre-hepatic causes - Portal vein/splenic vein thrombosis.
Hepatic causes - Hepatic tumours, cirrhosis and parasite infections.
Post-hepatic causes - Cardiac disease, hepatic vein or IVC thrombosis

Question 20

Name the porto-systemic anastamoses

Answer 20

• At the lower third of oesophagus (oesophageal varices)
• Halfway down the anal canal between superior rectal vein and the middle and inferior rectal veins (RECTAL varicosities),
• Around the umbilicus of the para-umbilical and epigastric veins (caput medusae).
• Posterior abdominal wall of veins of secondary retroperitoneal organs and veins of body wall