Anatomy and Physiology
Lab
The Lymphatic System
The lymphatic system is similar to the circulatory system. Lymph, like blood flows through a system of vessels. In addition to lymphatic vessels, the lymphatic system also consists of the thymus, lymph nodes, lymph and the spleen. Unlike the circulatory system, the lymphatic vessels do not form a closed circuit. Lymph flows once through the vessels and then drains into the circulating blood.
The lymphatic system functions in the maintenance of fluid balance in tissues and plays a role in the body’s immune system. The lymphatic vessels keep the cardiovascular system functional by maintaining blood volume. The lymphoid organs help defend the body from pathogens by providing operating sites for phagocytes and cells of the immune system. The system acts as a filtering mechanism for contaminants and micro organisms and serves as a protective device against foreign invaders, such as cancer. Toxins are filtered out of the lymph and the fluid returns to the blood cleansed.
Station 1 Function and Flow
The lymphatic system is a specialized subdivision of the circulatory system. Although the cardiovascular system has pump (the heart) and arteries, veins and capillaries, the lymphatic system lacks two of these structures: the ______and ___ ____. Like the ___ __ of the cardiovascular system, the vessels of the lymphatic system are equipped with ______to prevent backflow. The lymphatic vessels act primarily to pick up__ __ __ which has leaked into the ______and return it to the _________. Approximately ________ of fluid is forced out the cardiovascular system into the interstitial space in a day. (fig 21.7) ______is returned to the cardiovascular system at the venous end. The remaining 3L of fluid enters the lymphatic system where it is _______ and returned to the bloodstream.
B. Answer the following questions.
1. What are the 3 primary functions of the lymphatic system?
a. ______
b. ______
c. ______
C. Answer the following questions regarding lymphatic return.
1. Describe 3 mechanisms that aid in the assistance of lymphatic
return.
1
2
3
2. If lymphatic return is blocked, what will occur?
Match the terms found on the cue cards with the appropriate description
_______ 1. the largest lymphatic organ
______2. filter lymph
_________ 3. produces hormones that help to program immune
system
_________4. scattered throughout body superficially and deeply
along lymph vessels
________ ___5. located in mediastinum
____________6. located below stomach and diaphragm
____________7. aggregations of lymph nodules found in mucus
membranes
____________8. participate in responses against inhaled or ingested
foreign substances
____________9. removes aged and defective red blood cells
General Questions.
Answer the following questions.
1. How do lymphatic capillaries differ from blood capillaries?
2. Why are the walls of lymphatic vessels thin, like veins?
3. What would be missing in lymph leaving a lymph node, compared with lymph entering the node?
4. Would you describe the flow of lymph through lymph nodes as being
fast or slow, compared with blood capillaries? Explain.
Application Questions
1. If you look into a child’s mouth, there are ‘golf balls’ puffing from each side of the oral cavity. What are these structures?
2. Bacteria and viruses in infected tissues easily enter lymph vessels. Explain why.
3. If a woman had a radical mastectomy (removal of a cancerous breast, surrounding tissues with axillary lymph nodes, and anterior thoracic muscles), would you expect the arm on that side to be enematous (have edema)? Explain.
4. A patient has enlarged right inguinal nodes that are very tender to the
touch. Examination of the feet reveals a small cut between the right
3rd and 4th toes that are warm and red. What would your initial
impression be and why the nodal enlargement?