Blood and Lymphatic System

The Lymphatic System

As blood travels through capillaries in the cardiovascular system, some of the fluid leaks out. It moves through the walls of capillaries and into surrounding tissues. This fluid carries materials that the cells in the tissues need.

After bathing the cells, this fluid moves into your body's drainage system, called the lymphatic system. The lymphatic system is a network of vein-like vessels that returns the fluid to the bloodstream. The lymphatic system acts something like rain gutters after a rainstorm, carrying the excess fluid away.

Multiple Choice

What is a network of vein-like vessels that return fluid to the bloodstream?

• Lymphatic System

• Coronary Arteries

• Pulmonary Arteries

Lymph

Once the fluid is inside the lymphatic system, it is called lymph. Lymph consists of water and dissolved materials such as glucose. It also contains some white blood cells that have left the capillaries.

The lymphatic system has no pump, so lymph moves slowly. Lymphatic vessels, which are part of the cardiovascular system, connect to large veins in the chest. Lymph empties into these veins, and the fluid once again becomes part of the blood plasma.

lymph - The fluid inside the lymphatic system that consists of water and dissolved materials such as glucose.

Multiple Choice

What is the fluid inside of the Lymphatic System called?

• Bile

• Lymph

• Blood

• Hydrochloric Acid

Lymph Nodes

As lymph flows through the lymphatic system, it passes through small knobs of tissue called lymph nodes. The lymph nodes filter lymph, trapping bacteria and other disease-causing microorganisms in the fluid. When the body is fighting an infection, the lymph nodes enlarge. If you've ever had "swollen glands" when you've been sick, you've actually had swollen lymph nodes.

lymph nodes - small knobs of tissue that filter lymph and trap bacteria and disease-causing microorganisms

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The Lymphatic System

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Multiple Choice

What are the small knobs of tissue that trap bacteria and other harmful microorganisms, and filter out lymph?

• Epiglottis

• Lymph Nodes

• Valves

Lesson Complete

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