spleen secondary lymphatic organ : important highlights

Spleen: It is the largest accumulation of lymphoid tissue in the body.

Function:

i)                    Removal of old red blood cells

ii)                  Immune response

iii)                Reservoir of blood

iv)                 Formation of erythrocyte in fetal life

Histological features of spleen:

i)                    Splenic pulp: white and red pulp is present

ii)                  Capsule is present (covers the spleen, )

Trabeculae arises from capsule divide spleen into incomplete compartment  

White pulp: contain

Lymphatic nodules with germinal centers,

A central arteriole

Periarterial lymphatic sheaths (surround the central arteriole,  contain T lymphocytes)

SN: Central arteriole and periarterial lymphatic sheath situated within the lymphatic nodules

Red pulp:It is formed by splenic cord and splenic sinusoid

Splenic cord contains

T & B Lymphocytes,

Reticular cells & fibers,

Macrophages, Plasma cells,

Many blood cells-Erythrocytes,Platelets, Granulocytes

Splenic sinusoids: is formed by Discontinuous endothelial cells lining with discontinous  basal lamina

Splenic circulation

Closed circulation:

Splenic artery →the trabecular artery →central artery →penicillar arteries→ terminal  arterial capillaries (TAC) →splenic sinusoids →splenic vein

Open circulation:

Splenic artery →the trabecular artery →central artery →penicillar arteries→terminal  arterial capillaries (TAC) →red pulp →splenic sinusoids →splenic vein