Lymphatic system (Chapter 5)

Question 1

What are the main functions of the lymphatic system?

Answer 1

• To collect the fluid that escapes from the blood capillaries and return it to the circulatory system. - The lymphatic system is also an important part of the body’s internal defence against diseases.

Question 2

What does the lymphatic system consist of?

Answer 2

• Lymph capillaries
  Lymph capillaries are slightly larger and more
  permeable than blood capillaries
• Lymph vessels
  blind-ended tubes found in the spaces between the cells of most tissues. They are ‘vein-like’ in that lymph travels at a relatively low pressure and they have valves that prevent backflow.
• 2 lymphatic ducts
  which empty the lymph into large veins in the upper chest
• Lymph nodes/glands
  found in the intervals along the lymph vessels

Question 3

Where are lymph nodes found, what is their structure and what surrounds them?

Answer 3

• Most lymphatic nodes are found in the neck, armpits, groin and alimentary canal.
• Each node is surrounded by a framework of connective tissue, containing lymphoid tissue which ‘house’ lymphocytes, phagocytes and plasma cells.

Question 4

How does the lymphatic system defend against disease?

Answer 4

• Large particles such as bacteria get trapped in meshwork of fibres in lymph nodes
• Large phagocytes destroy these particles by ingesting them and destroying them with enzymes
• Formation of lymphocytes increases when infections occur causing the lymph nodes to become swollen and sore

Question 5

Where are lymphocytes formed?

Answer 5

In the bone marrow

Question 6

Where do lymphocytes develop and mature?

Answer 6

Thymus

Question 7

Define lymph

Answer 7

Excess fluid in the tissues returned to the blood by the lymphatic system

Question 8

What is the importance of valves in the lymphatic system?

Answer 8

Valves help facilitate the movement of lymph and maintain the proper direction of flow. They also prevent the backflow of lymph and helps maintain the proper circulation of the fluid.