T3: Lymphatic System

Question 1

What are the primary lymphoid organs?

Answer 1

• thymus,
• bone marrow,
• fetal liver,
• bursa of Fabricus (birds)

Question 2

What is the lymphatic system constituted by?

Answer 2

• lymphattic vessels
• lymphoid organs (lymphatic nodules, lymphatic nodes, spleen, thymus)

Question 3

How is lymph transported?

Answer 3

by extrinsic forces:
- movements of organs
- movements of skeletal muscle

by intrinsic forces:
- rhythmic contraction of smooth muscle (in walls of lymphatic vessels)

Question 4

What are the main functions of the lymphatic system?

Answer 4

1) maintenance of fluid balance
2) absorption of dietary fats (GI tract –> blood) for metabolism and storage
3) immune system

Question 5

What are the other functions of the lymphatic system?

Answer 5

• remove excessive fluid
• transport waste materials to the blood stream
• filter lymphatic fluid, transport proteins and enzymes

Question 6

What is the main function of the lymphatic system?

Answer 6

to collect and transport tissue fluids from intercellular spaces in body tissues back to the veins.

Question 7

What happens with lymph if the lymphatic system is functioning correctly?

Answer 7

lymph is collected from tissues and released into large veins

Question 8

How do lymphatic vessels compare with veins (structurally)?

Answer 8

• have valves which prevent the lymph reflux
• movement of lymph is not pumped by the heart! it is driven by movements of body mucles

Question 9

What are lymph nodes? Where are they located?

Answer 9

• small, kidney shaped structures
• located along lymph vessels

Question 10

What is the function of lymph nodes?

Answer 10

help the organism fight infection and disease
- stimulate lymphocytes to create antibodies
- stimulate lymphocytes to destroy cells
- filter lymphatic fluid

Question 11

What elements are present in the lymph nodes of healthy organisms?

Answer 11

• B-lymphocytes
• T-lymphocytes
• Macrophages

Question 12

What 2 subgroups is the lymphatic system divided into? What is part of each system?

Answer 12

Primary Lymphoid Tissue: bone marrow, thymus
Secondary Lymphoid Tissue: lymph nodes, spleen, GALT (carry lymph back to the blood stream)

GALT= gastrointestinal associated lymphatic tissue

Question 13

What do lymph vessels merge into?

Answer 13

lymphatic ducts

Question 14

What does lymphatic fluid enter the blood stream by?

Answer 14

vena cava

Question 15

Where do B and T lymphocytes mature?

Answer 15

B-lymphocytes: bone marrow
T-lymphocytes: thymus

Question 16

What does the spleen contain? What is its function?

Answer 16

function: lymphatic system
contents: red pulp (up to 20% of body’s blood), white pulp (lymphoid tissue)

Question 17

Explain the lymphatic system of birds.

Answer 17

• no lymph nodes!
• Thymus: T-lymphocytes develop
• Bursa of Fabricius: B-lymphocytes differenciate and mature