SPLEEN

Spleen

Q1. What is the spleen?

The spleen is an organ located in the upper left region of the abdomen, beneath the diaphragm.

Q2. What are the functions of the spleen?

• Filters the blood and removes old red blood cells
• Stores red blood cells, platelets, and white blood cells
• Acts as part of the immune system by filtering out pathogens and other foreign substances from the blood
• Stores and recycles iron from old red blood cells

Q3. What are the blood vessels supplying the spleen?

• Arterial supply: Splenic artery
• Venous drainage: Splenic vein

Q4. What is the lymphatic drainage of the spleen?

→ Splenic lymphatic vessels → Cisterna chyli → Thoracic duct → General circulation

Q5. What is the anatomical relationship of the spleen?

• Located in the splenic fossa of the left hypochondrium
• Related to the diaphragm, stomach, pancreas, and left kidney

Q6. What is the development of the spleen?

• Develops from the mesenchymal cells in the dorsal mesogastrium
• Forms a mass of tissue which eventually becomes the spleen
• Develops fully by the 6th month of fetal development

Q7. What is the histological structure of the spleen?

• Composed of red and white pulp
• Red pulp consists of splenic cords and splenic sinusoids
• White pulp consists of lymphoid cells and splenic nodules

Q8. What is the clinical significance of the spleen?

• Removal of the spleen (splenectomy) can lead to increased susceptibility to infections
• Enlargement of the spleen (splenomegaly) can be due to various reasons such as infection, malignancy, or blood disorders Spleen ================

Morphology

• The spleen is a vital lymphoid organ located in the upper left region of the abdominal cavity.
• It is a reddish-brown, oval-shaped organ with a smooth external surface.
• The spleen is approximately 12 cm long, 7 cm wide, and 3 cm thick.
• It weighs around 150 grams in adults.
• The spleen is divided into two main parts: the convex part ( upper part ) and the notched part ( lower part ).
• The splenic artery arises from the aorta and enters the spleen, while the splenic vein drains from the spleen and joins the portal vein.

Ligaments

• The spleen is attached to the diaphragm by the lienorenal ligament.
• The lienorenal ligament connects the spleen to the kidney.
• The splenorenal ligament connects the spleen to the kidney and contains the splenic vessels.

Functions

• The spleen filters the blood and removes old, damaged red blood cells.
• It stores platelets and helps in their circulation.
• The spleen acts as a reservoir for white blood cells, especially in times of infection.
• It produces antibodies in response to antigens.

Applied Anatomy

• The spleen is closely associated with the diaphragm and the kidney.
• The splenic vessels (artery and vein) are closely associated with the pancreas and the stomach.
• The spleen can be palpated in the left hypochondrium region.
• The spleen is a common site for metastasis in cases of lymphoma and leukemia.

Surgical Anatomy

• The spleen is removed in cases of trauma, infection, or neoplasia.
• The surgeon must be aware of the close proximity of the spleen to the diaphragm and the kidney.
• The splenic vessels must be ligated and divided carefully to avoid bleeding.

Embryology

• The spleen develops from the mesenchymal cells in the dorsal mesentery.
• The spleen is composed of red pulp and white pulp.
• The red pulp is responsible for filtering the blood, while the white pulp is involved in immune responses.

Innervation

• The spleen is innervated by the splenic nerves, which arise from the celiac plexus.
• The splenic nerves are responsible for the sympathetic innervation of the spleen.

Blood Supply

• The spleen receives its blood supply from the splenic artery.
• The splenic artery arises from the aorta and enters the spleen through the splenic hilum.
• The splenic artery gives off branches to the red pulp and white pulp.

Lymphatic Drainage

• The spleen has a rich lymphatic drainage system.
• The lymphatic vessels of the spleen drain into the splenic lymph nodes.
• The splenic lymph nodes are located along the splenic vessels and drain into the celiac lymph nodes.