What is the lymphatic system?
Q: What is the lymphatic system?
A: The lymphatic system is a network of thin vessels that branch, like blood vessels, into tissues throughout the body. It is part of the immune system and carries cells and fluid back to the blood system.
Q: What does it carry?
A: The lymphatic system carries colorless, watery fluid called lymph and white blood cells from interstitial fluid in the tissues which is squeezed out of the blood vessels.
Q: How does it prevent infection from spreading?
A: The lymph passes through glands called lymph nodes on its way back to the blood system. When an area becomes infected, these nodes swell in order to keep the infection from spreading by preventing or reducing pathogens getting into the general bloodstream and reaching other parts of the body.
Q: Where are some common places for lymph nodes?
A: Common places for lymph nodes include areas such as at the back of neck, armpits, and groin.
Q: How does most of the lymph return to bloodstream in mammals?
A: In mammals under normal conditions most of the lymph returns to bloodstream through communications at base of neck known as "lymph-vein" communications.
Q: Are there any vertebrates with more complex systems than mammals?
A: Yes, some vertebrates have more complex systems than mammals - amphibians for example have multiple "lymph hearts" that control flow of their lymph.
