4. Lymphatics

The thymus is important for ___________.

T lymphocyte maturation

A nurse palpated enlarged lymph nodes. Describe signs and symptoms that help to distinguish cancerous lymph nodes from infected lymph nodes.

Tender nodes are usually due to inflammation, whereas hard, fixed, nontender nodes are suggestive of malignancy.

_______ can enter lymphatic capillaries.

• Bacteria • Large proteins • Interstitial fluid

Which of the following would the body perceive as an antigen?

• Bacteria • Virus • Mismatched red blood cell

Lymphedema may occur as a complication after a radical mastectomy, in which lymph nodes have been removed. Explain why it might occur.

Anything that prevents the normal return of lymph to the blood, such as blockage of the lymphatics by tumors or removal of lymphatics during surgery, results in severe localized edema (lymphedema).

Which of the following represents a logical sequence of structures that contribute to the return of fluid into the blood via the lymphatic system?

Arteries, blood capillaries, lymphatic vessels, subclavian vein

Red pulp of the spleen is most concerned with _______, while white pulp is most concerned with_________.

Blood filtering; immunity

Describe why the prognosis of cancer is best when there is no detectable spread from the region of the primary tumor to the lymph nodes.

Cancer cells that break free from the primary tumor can metastasize via the lymph system. Even if a lymph node is 99% effective in trapping malignant cells, given the ability of a tumor to continuously shed cells into lymphatic capillaries, that still means that 100 out of every 10,000 cells get through. So the presence of any trapped cells in a lymph node is a warning that a few others may have escaped entrapment.

Lymphatic vessels _______.

Collect excess fluid from interstitial spaces

Lymph tends to stall inside lymph nodes. This is due to _______.

Fewer efferent lymphatic vessels than afferent lymphatic vessels

Buboes are inflamed, swollen _______.

Lymph nodes

Lymphatic capillaries owe their permeability to the presence of _______.

Minivalves in their walls

The ______ is the largest lymphoid organ.

Spleen

Which of the following lymphoid tissues removes defective red blood cells from the blood?

Spleen

A man involved in a traffic accident is rushed to the emergency room of a hospital with severe internal bleeding. Examination reveals a ruptured spleen. What is the treatment of choice and what is the likely long-term outcome (prognosis)?

Supportive care or splenic repair is the treatment of choice, depending on severity. Splenectomy is not as necessary as once believed, and is now performed less frequently. If the spleen does need to be removed, the prognosis is very good, as the functions of the spleen are largely taken over by the liver and bone marrow.

While passing through a village on safari you notice a man with one enormous leg and one normal-sized leg. What could have caused the increased size of the swollen leg?

The man has Filariasis commonly known as elephantiasis, which is caused by parasitic worms that get in the lymph system and reproduce to proportions that block the vessels. The swelling is due to edema.

As the human immunodeficiency virus (HIV) progresses, some individuals develop persistent generalized lymphadenopathy. Explain why this may occur.

This may occur because lymph nodes are overwhelmed by a large number of virus particles trapped in the nodes, which stimulate an ineffective immune reaction but cannot be quickly eliminated due to the weakened immune state. The weak immune reaction persists, causing swelling of the nodes.

Which lymphoid organ is not derived from mesodermal mesenchymal cells?

Thymus

A woman had a mastectomy that included the removal of axillary lymph nodes on her left side. What does she risk regarding her left arm and why?

Total removal of the axillary lymph nodes results in severe localized edema because the lymphatic vessels are also lost. This results in chronic edema along the arm, although some lymphatic drainage is eventually reestablished by regrowth of the vessels.

Tonsils promote memory of pathogens by ________.

Trapping pathogens so lymphocytes can encounter them and develop immune cells with memory

A mother takes her son to the doctor and describes the following symptoms that she has observed. The child is running a fever, has flu-like symptoms, and his lymph glands are very swollen and sore to the touch. Of what significance are the swollen and sore lymph glands?

When tissues are inflamed, such as due to a bacterial infection, lymphatic capillaries develop openings that permit the uptake of the pathogens. The inflammation and pain indicate lymph nodes infected by microorganisms.

An advantage to having reticular connective tissue present in lymph nodes is that ________.

• The loose organization of reticular connective tissue provides niches for macrophages and lymphocytes • Lymph filters through the nodes and is exposed to lymphocytes and macrophages • Lymphocytes cycle to various areas of the body and back to lymph nodes

Which of the following contribute(s) to the flow of lymph through lymphatic vessels?

• The milking action of skeletal muscle contraction • Pressure changes in the thorax that result from breathing