THE SPIDER
رئيس مجلس الادارة
عدد المساهمات : 1453
تاريخ التسجيل : 15/08/2010
العمر : 33
الموقع : Elmansoura
 |  موضوع: Spleen  الثلاثاء نوفمبر 02, 2010 6:52 pm | |
| SpleenThe spleen is a lymphatic organ interposed in the blood stream.The surface projection of the longitudinal axis of the spleen is the tenth rib. It is concealed anteriorly by the greater curvature of the stomach and the left colic (splenic) flexure. Its weight varies from 50 to 250g. The spleen consists of a diaphragmatic and visceral surface.
Diaphragmatic surface
- faces upward, backward and to the left. The diaphragm separates the spleen from the 9th, 10th and 11th ribs.
Visceral surface
- gastric - greater curvature of stomach
- renal - faces medially and caudally. Related to upper ventral surface of left kidney.
- colic - left (splenic) flexure
Superior extremity
- directed toward the vertebral column
Inferior extremity
- rests on the left colic flexure and phrenicocolic ligament
Associated ligaments of the spleen (double layers of peritoneum:
- phrenicocolic ligament
- gastrolienal ligament
- lienorenal ligament
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| Functions
There are three major functions of the spleen and these are handled by three different tissues within the spleen.
- Reticuloendothelial tissue - concerned with phagocytosis of erythrocytes and cell debris from the blood stream. This same tissue may produce foci of haemopoiesis when RBC's are needed.
- Venous sinusoids along with the power of the spleen to contract, provides a method for expelling the contained blood to meet increased circulatory demands in certain animals.
- White pulp provides lymphocytes and a source of plasma cells and hence antibodies for the cellular and humoral specific immune defenses.
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