被忽视的血液过滤器：你的脾脏如何工作？

How Does Your Spleen Work?

　

　

　

 

　

脾脏是淋巴系统的最大器官。脾脏的主要功能是位于腹腔的左上区域，用于过滤受损细胞，细胞碎片和病原体如细菌和病毒的血液。像胸腺一样，脾脏可以帮助称为淋巴细胞的免疫系统细胞成熟。淋巴细胞是白血球，可以防止外来生物感染身体细胞。淋巴细胞还通过控制癌细胞来保护身体免受损害。脾对于针对血液中的抗原和病原体的免疫应答是重要的。

 

脾脏通常被描述为小拳头的大小。它位于肋骨下方，横膈膜下方和左肾上方。脾脏富含通过脾动脉供应的血液。血液通过脾静脉离开该器官。脾脏还含有传出淋巴管，将淋巴从脾脏转移出去。淋巴是一种清澈的液体，来自血浆，从毛细血管床的血管中排出。这种液体成为围绕细胞的间质液。淋巴管收集并将淋巴引向静脉或其他淋巴结。

 

脾脏是一个柔软，细长的器官，有一个称为胶囊的外部结缔组织覆盖物。它内部分为许多较小的部分，称为小叶。脾脏由两种类型的组织组成：红髓和白髓。白髓是淋巴组织，主要由称为B淋巴细胞的淋巴细胞和围绕动脉的T淋巴细胞组成。红髓由静脉窦和脾索组成。静脉窦基本上是充满血液的腔，而脾索是含有红细胞和某些白细胞（包括淋巴细胞和巨噬细胞）的结缔组织。

 

脾功能

　

脾脏的主要作用是过滤血液。脾脏发育并产生能够识别和破坏病原体的成熟免疫细胞。脾脏的白髓中含有称为B和T淋巴细胞的免疫细胞。 T淋巴细胞负责细胞介导的免疫，这是一种免疫反应，涉及激活某些免疫细胞以对抗感染。 T细胞含有称为T细胞受体（TCR)的蛋白质，其填充T细胞膜。它们能够识别各种类型的抗原（引发免疫反应的物质）。 T淋巴细胞来自胸腺并通过血管传播到脾脏。

 

B淋巴细胞或B细胞来源于骨髓干细胞。 B细胞产生对特定抗原特异的抗体。抗体与抗原结合并将其标记为被其他免疫细胞破坏。白色和红色牙髓都含有淋巴细胞和称为巨噬细胞的免疫细胞。这些细胞通过吞噬和消化它们来处理抗原，死细胞和碎片。

 

虽然脾脏主要用于过滤血液，但它也储存红细胞和血小板。在发生极端出血的情况下，红细胞，血小板和巨噬细胞从脾脏释放。巨噬细胞有助于减少炎症并破坏受伤区域的病原体或受损细胞。血小板是帮助血液凝块阻止失血的血液成分。红细胞从脾脏释放到血液循环中以帮助补偿失血。

 

 

脾脏是一种淋巴器官，具有过滤血液的宝贵功能。虽然它是一个重要的器官，但它可以在必要时移除而不会导致死亡。这是可能的，因为其他器官，例如肝脏和骨髓，可以在体内执行过滤功能。如果脾脏受伤或扩大，可能需要移除脾脏。由于几个原因，可能出现扩大或肿胀的脾脏，称为脾肿大。细菌和病毒感染，脾静脉压增加，静脉阻塞以及癌症可能导致脾脏扩大。异常细胞也可能通过堵塞脾血管，减少血液循环和促进肿胀而引起脾脏肿大。受伤或扩大的脾脏可能会破裂。脾脏破裂会危及生命，因为它会导致严重的内出血。

 

如果脾动脉阻塞，可能是由于血凝块，可能会发生脾梗塞。这种情况涉及由于脾脏缺氧导致的组织结构的死亡。脾梗塞可能由某些类型的感染，癌症转移或血液凝固障碍引起。某些血液疾病也可能损害脾脏到它变得无功能的程度。这种情况被称为自体脾切除术，它可能由于镰状细胞病而发展。随着时间的推移，畸形细胞破坏血液流向脾脏，导致其浪费掉。

　

　

 

How Does Your Spleen Work?

 

By Regina Bailey Updated March 16, 2018

　

The spleen is the largest organ of the lymphatic system. Located in the upper left region of the abdominal cavity, the spleen's primary function is to filter blood of damaged cells, cellular debris, and pathogens such as bacteria and viruses. Like the thymus, the spleen houses and aids in the maturation of immune system cells called lymphocytes. Lymphocytes are white blood cells that protect against foreign organisms that have managed to infect body cells. Lymphocytes also protect the body from itself by controlling cancerous cells. The spleen is valuable to the immune response against antigens and pathogens in the blood.

 

The spleen is often described as being about the size of a small fist. It is positioned under the rib cage, below the diaphragm, and above the left kidney. The spleen is rich in blood supplied via the splenic artery. Blood exits this organ through the splenic vein. The spleen also contains efferent lymphatic vessels, which transport lymph away from the spleen. Lymph is a clear fluid that comes from blood plasma that exits blood vessels at capillary beds. This fluid becomes the interstitial fluid that surrounds cells. Lymph vessels collect and direct lymph toward veins or other lymph nodes.

 

The spleen is a soft, elongated organ that has an outer connective tissue covering called a capsule. It is divided internally into many smaller sections called lobules. The spleen consists of two types of tissue: red pulp and white pulp. White pulp is lymphatic tissue that mainly consists of lymphocytes called B-lymphocytes and T-lymphocytes that surround arteries. Red pulp consists of venous sinuses and splenic cords. Venous sinuses are essentially cavities filled with blood, while splenic cords are connective tissues containing red blood cells and certain white blood cells (including lymphocytes and macrophages).

 

 

Spleen Function

Pancreas, Spleen, and Gallbladder

 This is a detailed illustration of the pancreas, spleen, gallbladder, and small intestine. TefiM/iStock/Getty Images Plus

The major role of the spleen is to filter blood. The spleen develops and produces mature immune cells that are capable of identifying and destroying pathogens. Contained within the white pulp of the spleen are immune cells called B and T-lymphocytes. T-lymphocytes are responsible for cell mediated immunity, which is an immune response that involves the activation of certain immune cells to fight infection. T-cells contain proteins called T-cell receptors that populate the T-cell membrane. They are capable of recognizing various types of antigens (substances that provoke an immune response). T-lymphocytes are derived from the thymus and travel to the spleen via blood vessels.

 

B-lymphocytes or B-cells originate from bone marrow stem cells. B-cells create antibodies that are specific to a specific antigen. The antibody binds to the antigen and labels it for destruction by other immune cells. Both white and red pulp contain lymphocytes and immune cells called macrophages. These cells dispose of antigens, dead cells, and debris by engulfing and digesting them.

 

While the spleen functions chiefly to filter blood, it also stores red blood cells and platelets. In instances where extreme bleeding occurs, red blood cells, platelets, and macrophages are released from the spleen. Macrophages help to reduce inflammation and destroy pathogens or damaged cells in the injured area. Platelets are blood components that help blood clot to stop blood loss. Red blood cells are released from the spleen into blood circulation to help compensate for blood loss.

 

 

The spleen is a lymphatic organ that performs the valuable function of filtering blood. While it is an important organ, it can be removed when necessary without causing death. This is possible because other organs, such as the liver and bone marrow, can perform filtration functions in the body. A spleen may need to be removed if it becomes injured or enlarged. An enlarged or swollen spleen, referred to as splenomegaly, may occur for several reasons. Bacterial and viral infections, increased splenic vein pressure, vein blockage, as well as cancers may cause the spleen to become enlarged. Abnormal cells may also cause an enlarged spleen by clogging splenic blood vessels, decreasing circulation, and promoting swelling. A spleen that becomes injured or enlarged may rupture. Spleen rupture is life threatening because it results in serious internal bleeding.

 

Should the splenic artery become clogged, possibly due to a blood clot, splenic infarction may occur. This condition involves the death of spenic tissue due to a lack of oxygen to the spleen. Splenic infarction may result from certain types of infections, cancer metastasis, or a blood clotting disorder. Certain blood diseases may also damage the spleen to the point where it becomes non-functional. This condition is known as autosplenectomy and it may develop as a result of sickle-cell disease. Over time, the malformed cells disrupt blood flow to the spleen causing it to waste away.

 

 

Sources

Spleen Anatomy and Function  https://www.thoughtco.com/spleen-anatomy-373248