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Free Anatomy Quiz

Describe and explain the function of the lymphatic system

Test your knowledge about the skin by answering the following questions. If you get stuck on any of them, you'll find the answers in the article below.

1. The lymphatic system is part of the body's ____________ system.

2. Waste and excess body fluids are collected by the fine lymphatic __________.

3. Lymphatic nodes contain specialised cells called ____________.

4. The thoracic duct and the right lymphatic ducts carry lymph to the ____________ veins.

5. The transport of lymph through the lymphatic system relies on pressure from __________ contractions.

6. Foreign material is filtered from the lymph by the lymphatic ________.

Describe and explain the function of the lymphatic system

The lymphatic system is part of the body's immune system, and includes the following:

  • Lymph. Lymph is a whitish fluid made from white blood cells, some red blood cells, and a fluid called chyle.

  • Lymphatic capillaries. These are very fine capillaries, which collect excess fluid from the body tissues when they cannot be absorbed into blood capillaries because the particles are too large.

  • Lymphatic vessels. Lymph capillaries merge to form the slightly larger lymphatic vessels, which are still smaller than blood veins, and also more numerous. These vessels contain one-way valves, to control the direction of lymph flow.

  • Lymphatic nodes. Lymph nodes are capsules of connective tissue containing lymphocytes, and their function is to filter the lymph. They can be felt at the groin, the armpit, behind the ears, the back of the head, behind the knees, at the elbow, and at the sides of the neck and under the jaw and chin.

  • Lymphatic ducts. The thoracic duct (running from the abdomen to the neck) and right lymphatic duct (half an inch long at the left side of the neck) carry lymph to the left and right subclavian veins.

  • Organs. The organs within the lymphatic system are the tonsils, the adenoids, the spleen, and the thymus gland.

The lymph capillaries in the body tissues collect excess and waste fluid which is too large to be taken up by the blood capillaries, and transports it in the lymph into the lymph vessels. Since the lymphatic system does not have a pump in the way the circulatory system does, it relies on pressure from muscle contractions for creating a flow, and on one-way valves to ensure the lymph can only flow in one direction. The vessels transport the lymph to the lymphatic nodes, which filter it to separate out any foreign material such as bacteria, and thus protect the body from infection. The tissue in the nodes then break down this material, sometimes swelling up with increased quantities of lymphocytes if necessary (which is why they can sometimes feel swollen to the touch). The filtered lymph then passes into the lymphatic ducts, and then into the bloodstream by way of the left and right subclavian veins, from where it can be re-supplied to the body tissues. The organs of the lymphatic system are also responsible for fighting invading bacteria.

Reference: Clinically Oriented Anatomy, Moore

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